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inside "Brain" / ANATOMY / surface anatomy / frontal lobes / frontal lobes / temporal lobes /
occipital lobes / parietal lobes / limbic system / hippocampus / amydala / neuron
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association

Gray Matters
Adeistic
Eine Kleine Nattermusing
eMusings
eVolition
Galaria
Godborygmi
Godspell Follies
MetaThoughts
Mimble Wimble
Naturalism
Logodaedaly
palimpsest
Salient
Science of Evolution
Sechuam
Sintheist
Tabula Flexuosa
The Scarlet A
Weltschauung

Links to Atheism

Gray Matters
Adeistic
Avidity
Eine Kleine Nattermusing
eMusings
eVolition
Galaria
Godspell Follies
MetaThoughts
Mimble Wimble
Naturalism
Neologisms
palimpsest
Sechuam
Sintheist
Tabula Flexuosa
Weltschauung

ANATOMY

inside "Brain"

Anatomy : Function : Neuron : Imaging : Research :

surface anatomy

image site author

The medial surface of the brain shows the midline surfaces of the cerebral hemispheres and the cingulate gyrus, and cut surfaces of corpus collosum, midbrain, pons, and cerebellum. The lateral view shows the lobes of the cerebral hemispheres.

These voxel movies may be slow to open, but they are short: voxel animation - spin a brain : voxel animation - rotate a skull

frontal lobes

image site author

The cerebral hemispheres comprise paired lobes: frontal, temporal, parietal and occipital.

frontal lobes

image site author, adapted from NEJM Digitally Remastered image

Arguably the most famous neurological accident affected Phineas Gage in 1848 when a 3 ft. 7 inch tamping iron exploded up through Gage's skull. Gage recovered physically, but his personality was permanently altered by damage to his left frontal lobe. As a result of Gage's misfortune, the frontal lobes were identified as the seat of the personality.

temporal lobes

occipital lobes

parietal lobes

limbic system

image site author

Unlike the lobes of the neocortex, the limbic system has an evolutionarily primitive origin. The amygdala processes emotion, the hippocampus is central to emotional memory, and the caudate nucleus operates during execution of habitual movements.

hippocampus

amydala

neuron

The neuron is the basic operating unit of the central nervous system. Inter-neuronal information processing, involving complex neural networks, provides the nervous system with its enormous functional capacity. The human brain contains about 10^(11) neurons*, which connect, via synapses, with an average of 1000 other neurons. In total, the human brain may contain somewhere between 10^(14) and 10^(15) synaptic connections. Neurotransmitter chemicals effect the connection between neurons, when they cross the gap between neurons and interact with a specific receptor molecule. More than one hundred chemicals and a much larger number of receptors have been implicated in synaptic transmission. Some neurotransmitters are the targets of drug therapies. Receptor molecules are the targets of neurotoxic venomous substances.

* 10^(11) is equivalent to a 10 followed by 11 zeros = 1,000,000,000,000

For more information on neurons, neuroglial cells, and neurochemistry:
Main page of Neuron : action potential : axon : dendrite : dendritic spines : excitatory : inhibitory : integration : interneuron : metabotropic
neuron : synapse

Main page of Cell : cell membrane : endoplasmic reticulum : Golgi apparatus : ion channels : pinocytosis

Main page of BioChemistry : hydrophilic : hydrophobic :

Sleep: Snooze Button

HHMI News: Researchers Find the Snooze Button: "With help from some drowsy fruit flies, a team of researchers from the Howard Hughes Medical Institute (HHMI) at the University of Pennsylvania School of Medicine has identified a region of the fruit fly's brain that is crucial to controlling sleep.
The finding, reported in the June 8, 2006, issue of the journal Nature, is important because it identifies a new role for brain structures, called mushroom bodies, which have now been shown to control fruit fly slumber. Mushroom bodies were known to be involved in processing sensory information and memory. Thus, the new studies lend support to the idea that sleep helps the brain consolidate learning and memory. "

SITE MAP

Brain :

Anatomy :
frontal lobes : temporal lobes : occipital lobes : parietal lobes :
limbic system : hippocampus : amydala :

Function :
memory : consciousness : dissociation :

Neuron :

Imaging :

Research :

Dissociative Identity Disorder :

Description DID :
Dissociative Identity Disorder : prevalence : PTSD :etiology : diagnosis :dissociation :
symptoms : alter system : voices :
healing : treatment : hypnosis :
neural basis for DID and PTSD :
missed and misdiagnosed : Why is DID misdiagnosed? :common misdiagnoses : False Memory Syndrome : Why the reluctance to accept the diagnosis? :
Links to websites :
terminology :
DSM codes :
History of identification of the disorder :References :

Different DSM-IV Diagnoses:
ADHD : Bipolar Affective Disorder : Borderline Personality Disorder : : :

Articles

SITE MAP
Neurons Generated In The Adult Brain Learn To Respond To Novel Stimuli / Stress : CASL
Imaging: arterial spin labelling / Stathmin: Loss of Fear Factor Makes Timid Mouse Bold /
Solving Big Questions: HHMI Bulletin September 2005: / Misfolded Proteins /
BOLD fMRI vs electrophysiological / DTI: Diffusion Tensor Imaging / Vision / BOLD fMRI
Memory: EPIGENETIC MECHANISMS IN MEMORY FORMATION /
DID PTSD: Researchers Identify Where Emotional Fear Memory And Pain Become Permanently Etched In The Brain / FUNCTION / memory / consciousness / dissociation
NEURON / IMAGING / RESEARCH ARTICLE LINKS
Aging: Memory Loss In Older Adults Due To Distractions, Not Inability To Focus /
Neurochemistry: New Techniques Study The Brain's Chemistry, Neuron By Neuron /
Glossary / hydrophilic / hydrophobic
LINKS / Development: Imaging Study Shows Brain Maturing / Society for Neuroscience Brain Facts / Society for Neuroscience Public Resources /
mPFC: Excitotoxic lesions of the prelimbic-infralimbic areas of the rodent prefrontal cortex disrupt motor preparatory processes. /
RESEARCH /
Attention: Multiple neuronal networks mediate sustained attention. / Attention: The continuous performance test: a window on the neural substrates for attention? / Attention: Emotion: The interaction of attention and emotion. / Limbic system: The basal ganglia: anatomy, physiology, and pharmacology. / Emotion: Neural substrates of emotion as revealed by functional magnetic resonance imaging. / Fear: Emotional perseveration: an update on prefrontal-amygdala interactions in fear extinction. / Emotion: Limbic system: A review of systems and networks of the limbic forebrain/limbic midbrain. / Fear: Mesolimbic dopaminergic pathways in fear conditioning. / Positive Emotion: The neurobiology of positive emotions. / Fear: Brain activation to phobia-related words in phobic subjects. / Fear: Differential contribution of amygdala and hippocampust to cued and contextual fear conditioning / Aversion: Amygdala-prefrontal coupling depends on a genetic variation of the serotonin transporter. / Memory: Rapid prefrontal-hippocampal habituation to novel events. / Memory Suppression: Building and burying fear memories in the brain. / Memory: Subcortical loop activation during selection of currently relevant memories. / Memory: The primate working memory networks. /
Memory: Blockade of NMDA receptors in prelimbic cortex induces an enduring amnesia for odor-reward associative learning. / Memory: Glutamate: STRUCTURAL PLASTICITY AND MEMORY / Memory: Multiple memory systems: the power of interactions. / Memory: A synaptic model of memory: long-term potentiation in the hippocampus. / Stress: sfn Stress and the Brain / Stress: Medial prefrontal cortical integration of psychological stress in rats. /
Stress: Induction of deltaFosB in reward-related brain structures after chronic stress. /
Glucorticoids: Developmental regulation of the 5-HT7 serotonin receptor and transcription factor NGFI-A in the fetal guinea-pig limbic system: influen /
Somatosensory: Cytoarchitecture and cortical connections of the posterior cingulate and adjacent somatosensory fields in the rhesus monkey. /
Genes: Gene May Be Key To Evolution Of Larger Human Brain /
Fear & Cannabinoids: CB1 cannabinoid receptors modulate kinase and phosphatase activity during extinction of conditioned fear in mice. /
Placebo activates Endorphins to relieve Pain /
Pain: Attention to pain localization and unpleasantness discriminates the functions of the medial and lateral pain systems. /
Pain: Attention to pain localization and unpleasantness discriminates the functions of the medial and lateral pain systems. /
Pain: IBS: Differences in brain responses to visceral pain between patients with irritable bowel syndrome and ulcerative colitis. /
Pain: Differential projections from the mediodorsal and centrolateral thalamic nuclei to the frontal cortex in rats. /
Sleep: What can neuroimaging findings tell us about sleep disorders? /
Ion Channels /
Sleep: MEG tomography of human cortex and brainstem activity in waking and REM sleep saccades. /
Depression: 5HT: Measurement of brain regional alpha-[11C]methyl-L-tryptophan trapping as a measure of serotonin synthesis in medication-free patients /
Violence: Social Psychology: Ordinary People as Torturers /
Imaging: Emotion: The neural bases of amusement and sadness: a comparison of block contrast and subject-specific emotion intensity regression approach /
Imaging: Magnetic resonance imaging of cerebellar-prefrontal and cerebellar-parietal functional connectivity. /
Imaging: Mood Insomnia: Relationship between regional cerebral blood flow and separate symptom clusters of major depression: a single photon emission /
Imaging: Magnetic resonance imaging identifies cytoarchitectonic subtypes of the normal human cerebral cortex. /
Imaging: Disorder-specific neuroanatomical correlates of attentional bias in obsessive-compulsive disorder, panic disorder, and hypochondriasis. /
Genes: 5HT: Beyond affect: A role for genetic variation of the serotonin transporter in neural activation during a cognitive attention task. /
Genes: 5HT: Frontal and limbic metabolic differences in subjects selected according to genetic variation of the SLC6A4 gene polymorphism. /
5HT: Regulation of septo-hippocampal activity by 5-hydroxytryptamine(2C) receptors. /
Cognition: Behavior: Frontal Lobes: Cognition, behavior and the frontal lobes. /
Decision: The cognitive neuroscience of human decision making: a review and conceptual framework. /
Morality Decisions:Influence of bodily harm on neural correlates of semantic and moral decision-making. /
Empathy: Prefrontal substrates of empathy: Psychometric evidence in a community sample. /
Disgust: fMRI: The moral affiliations of disgust: a functional MRI study. /
Behaviour: Impulsivity, emotion regulation, and developmental psychopathology: specificity versus generality of linkages. /
Behaviour: The primate basal ganglia: parallel and integrative networks. /
Behaviour: Oxytocin and vasopressin immunoreactivity within the forebrain and limbic-related areas in the mustached bat, Pteronotus parnellii. /
Behaviour: Response inhibition and disruptive behaviors: toward a multiprocess conception of etiological heterogeneity for ADHD combined type and cond /
Behaviour: Dissociable aspects of performance . lesions of the dorsal anterior cingulate, infralimbic and orbit /
Decision: Corticolimbic mechanisms in emotional decisions. /
Language: Frontal and posterior sources of event-related potentials in semantic comprehension. /
FM: Planting misinformation in the human mind: A 30-year investigation of the malleability of memory -- Loftus 12 (4): 361 -- Learning & Memory /
Autism: Localized enlargement of the frontal cortex in early autism. /
Autism: Enhanced salience and emotion recognition in Autism: a PET study. /
Autism: Neuroimaging in autistic spectrum disorder (ASD). /
Imaging: Emotion: A common neural basis for receptive and expressive communication of pleasant facial affect. /
Reward: Impact of expected reward on neuronal activity in prefrontal cortex, frontal and supplementary eye fields and premotor cortex. /
Highlights from Gage to NMR /

Neurons Generated In The Adult Brain Learn To Respond To Novel Stimuli

Neurons Generated In The Adult Brain Learn To Respond To Novel Stimuli: "Recent research has shown, however, that new cells are added to certain areas of the brain -- including those involved with memory and the sense of smell -- well into adulthood. "

Stress : CASL

Penn Research Permits First-ever Visualization Of Psychological Stress In The Human Brain: "The results showed increased cerebral blood-flow during the 'stress test' in the right anterior portion of the brain (prefrontal cortex) -- an area long associated with anxiety and depression. More interestingly, the increased cerebral blood-flow persisted even when the testing was complete. These results suggest a strong link between psychological stress and negative emotions. On the other hand, the prefrontal cortex is also associated with the ability to perform executive functions -- such as working memory and goal-oriented behavior -- that permit humans to adapt to environmental challenges and threats. 'The message from this study is that while stress may be useful in increasing focus, chronic stress could also be detrimental to mental health,' concludes Jiongjiong Wang, PhD, Assistant Professor of Radiology and principal investigator of the study."

Imaging: arterial spin labelling

Penn Research Permits First-ever Visualization Of Psychological Stress In The Human Brain: "To date, most fMRI studies have indirectly measured changes in cerebral blood-flow and metabolism induced by neural activation, using a technique that is sensitive to the oxygenation levels in blood. "The fMRI technique employed in our study -- arterial spin labeling -- can measure cerebral flood-flow directly," states John A. Detre, MD, Associate Professor of Neurology and Radiology, and senior author of the study. "This technique is very similar to PET (positron emission tomography) scanning, except that it's entirely non-invasive -- without the need for injections or radioactivity. In this elegant technique, water molecules in subjects' own blood are 'tagged' by the magnet and used as the natural contrast agent to measure cerebral blood-flow." Researchers at Penn's Center for Functional Neuroimaging have been at the forefront of the development of this technique, and its applications to imaging brain-function during cognitive and emotional processes."

Stathmin: Loss of Fear Factor Makes Timid Mouse Bold

HHMI News: Loss of Fear Factor Makes Timid Mouse Bold: "Working in mice, the scientists, led by Howard Hughes Medical Institute investigator Eric R. Kandel at Columbia University, found that the protein stathmin is critical for both innate and learned fear. Mice without stathmin boldly explore environments where normal mice would be hesitant, and, unlike their normal counterparts, fail to develop a fear of cues that have been associated with electric shock. The scientists also found physiological changes in the brains of mice lacking stathmin that correlate to the behavioral changes they observed."

Solving Big Questions: HHMI Bulletin September 2005:

HHMI Bulletin September 2005: Solving Big Questions: "Janelia Farm will pursue two basic, and intertwined, goals: identifying the general principles that allow neural circuits to process information and developing imaging technologies and computational methods for image analysis. "

Misfolded Proteins

Google Image Result for http://www.bu.edu/dbin/anatneuro/assets/images/pics/lab/fmri.jpg: "Accumulation of misfolded proteins is a feature of aging and appears to be accelerated in many neurodegenerative disorders. Protein misfolding can result from defects in the chaperone system or may arise due to mutations or oxidative damage. Recent data indicates that the misfolded proteins play an active role in cellular toxicity. "

BOLD fMRI vs electrophysiological

Google Image Result for http://www.bu.edu/dbin/anatneuro/assets/images/pics/lab/fmri.jpg: "While BOLD-based neuroimaging studies have provided unprecedented amount of insights into the workings of the human brain in vivo, the explanatory power of BOLD fMRI is currently limited since there is a fundamental gap in our understanding of the linkage between the observed BOLD contrast and the underlying neuronal physiology. In particular, the extent to which the magnitude and spatial scale of the BOLD signal correlates with neuronal physiology remains elusive. To this end, a small but increasing body of results suggests a predominantly linear coupling between BOLD and neuronal activity. For example, a recent study by Ogawa et al demonstrated a linear relationship between somatosensory evoked potentials and BOLD signals for brief stimulation durations. Rees et al. and Heeger et al. demonstrated a linear correlation between BOLD contrast in humans and suprathreshold spiking rate averaged over a cortical area in monkeys during the stimulation with nearly identical stimuli. A similarly linear relationship was observed also in anesthetized monkeys by Logothetis et al. in which single unit responses were acquired simultaneously with BOLD signals for the first time inside the MRI scanner. While the these results suggest that the fundamental coupling between BOLD and the underlying neuronal activity is approximately linear, important questions remain about the spatial scale over which the presumed linear coupling between BOLD and neuronal activity remains valid. Is the hypothesized linear coupling between BOLD and neuronal activity invariant across the different spatial scales of the cortical architecture? Can we assume a universal linearity from the spatial scale of entire cortical areas (several millimeters to centimeters) to individual cortical columns (sub-millimeter)?"

DTI: Diffusion Tensor Imaging

Google Image Result for http://www.bu.edu/dbin/anatneuro/assets/images/pics/lab/fmri.jpg: "Diffusion Tensor Imaging (DTI) is a powerful MRI technique that enables us to translate the self-diffusion, or microscopic motion of water molecules in tissue into a MRI measure of tissue integrity and structure. Namely, the spatial characteristic of water diffusion highly depends on the barriers imposed on the water molecule motion, those barriers being the elements of tissue such as cell membranes, myelin sheath, intracellular microorganelles and others. Specifically, in white matter, water self diffusion is restricted, or hindered mostly by the intracellular axonal space, and by the interstitial, extracellular space among the well-packed axons in the fiber tract. By taking several diffusion weighted images in several dimensions, one can reconstruct the so-called diffusion tensor for each image unit, or pixel. The diffusion tensor gives a three dimensional representation of the preferred direction of diffusion, in the shape of the 3D ellipsoid. This ellipsoid can be characterized by six parameters; diffusion constants along the longest, middle, and shortest axes ( λ1, λ2, and λ3, called principal axes) and the direction of the three principal axes. Once the diffusion ellipsoid is fully characterized at each pixel of the brain images, local fiber structure can be derived. For example, if λ1 >> λ2 ≥ λ3 (diffusion is anisotropic), it suggests the existence of dense and aligned fibers within the each pixel, whereas isotropic diffusion (λ1 ≈ λ2 ≈ λ3) suggests sparse or unaligned fibers. When diffusion is anisotropic, the direction of λ1 indicates the direction of the fibers. Recently, such DTI techniques in combination with 3-D fiber reconstruction algorithm was used to generate spectacular images of the axonal connectivity pattern in vivo both in humans, rodents, and recently also in cats."

Vision

Google Image Result for http://www.bu.edu/dbin/anatneuro/assets/images/pics/lab/fmri.jpg: "Like in other primates, human visual areas are clustered along two "streams" diverging from the occipital pole: the ventro-temporal "what or perception" stream and the dorsal "where or action" stream. While the areas in the dorsal stream are tuned for visual stimuli and tasks related to stimulus location and/or action, the ventral stream consists of a web of exquisitely category selective areas. For example, a region in the lateral occipital cortex (LOC) extending anteriorly into the temporal cortex responds strongly to a variety of complex shaped objects such as polygonal figures, chairs, and gloves, etc. Furthermore, in the so called fusiform face area (FFA; located within the fusiform gyrus, cells are tuned to faces and facial stimuli (e.g., front-view photographs of faces and line drawings of faces, etc.) in a way comparable to the receptive field properties of face-selective neurons in primate inferotemporal cortex (IT). Further down the temporal cortex, in the so called parahippocampal place area (PPA), maximum functional response can be obtained using scenic or place type of stimuli. The description of highly specialized areas such as FFA and PPA raises the question how many category-selective regions of cortex exist in the human visual system, and, more generally, how the ventral temporal cortex is organized. Hypotheses range from the assumption that there are a few specialized processing modules, i.e., for faces, places, letters and human body parts up to the proposal of widely distributed and overlapping cortical object representations. Effects of category-related expertise and, more recently, different category-related resolution needs have also been proposed to explain the topology of the human what-pathway. Further insights into the question how objects are represented in ventral visual cortex might come from functional imaging studies investigating within-category responses, for example, by comparing responses to single object images, such as two different faces or two different houses (Kriegeskorte et al., personal communication). It has also been proposed that the eccentricity gradient observed in early visual areas continues into ventral visual cortex (Malach et al., 2002). For example, regions selective to faces (FFA) overlap with the representation of the fovea, while regions that are selective to houses (PPA) overlap with a peripheral visual representation located in the collateral sulcus."

BOLD fMRI

Google Image Result for http://www.bu.edu/dbin/anatneuro/assets/images/pics/lab/fmri.jpg

" Laboratory of Brain Imaging







This laboratory uses high field MRI to investigate cortical plasticity, face representation in the cortex, and axonal connectivity. Members of the lab are also involved in the development of new MRI applications, and the verification of existing techniques using single unit recording and optical imaging. We are particularly interested in developing novel multimodal imaging techniques to simultaneously map the structure, function, and connectivity of various cortical functions in the mammalian brains. Few examples of our research enterprise are listed below:

Use of BOLD fMRI for mapping the detailed layout of the cortical functional architecture in vivo:

The BOLD technique is based on the use of deoxyhemoglobin as nature's own intravascular paramagnetic contrast agent. When placed in a magnetic field, deoxyhemoglobin alters the magnetic field in its vicinity, particularly when it is compartmentalized as it is within red blood cells and vasculature. The effect increases as the concentration of deoxyhemoglobin increases. At concentrations found in venous blood vessels, a detectable local distortion of the magnetic field surrounding the red blood cells and surrounding blood vessel is produced. This affects the magnetic resonance behavior of the water proton nuclei within and surrounding the vessels, which in turn result in decreases in the transverse relaxation times (T2 and T2*. During the activation of the brain, this process is reduced: increase in neuronal and metabolic activity results in a reduction of the relative deoxyhemoglobin concentration due to an increase of blood flow (and hence increased supply of fresh oxyhemoglobin) that follows. Consequently, in conventional BOLD fMRI, brain "activity" can be measured as an increase in T2 or T2* weighted MR signals. Since its introduction about 10 years ago, BOLD fMRI was successfully applied Ð among numerous other examples - to precisely localize the cognitive, motor, and perceptual function of the human cortex cerebri."

Memory: EPIGENETIC MECHANISMS IN MEMORY FORMATION

Nature Reviews Neuroscience - Reviews: "Discoveries concerning the molecular mechanisms of cell differentiation and development have dictated the definition of a new sub-discipline of genetics known as epigenetics. Epigenetics refers to a set of self-perpetuating, post-translational modifications of DNA and nuclear proteins that produce lasting alterations in chromatin structure as a direct consequence, and lasting alterations in patterns of gene expression as an indirect consequence. The area of epigenetics is a burgeoning subfield of genetics in which there is considerable enthusiasm driving new discoveries. Neurobiologists have only recently begun to investigate the possible roles of epigenetic mechanisms in behaviour, physiology and neuropathology. Strikingly, the relevant data from the few extant neurobiology-related studies have already indicated a theme -- epigenetic mechanisms probably have an important role in synaptic plasticity and memory formation.


Recently, cellular, molecular and behavioural approaches have led to several exciting developments in the area of epigenetics that specifically concern neurobiological systems. In this review, the topic of epigenetics is introduced. The idea that the conservation of epigenetic mechanisms for information storage represents a unifying model in biology is then discussed, with epigenetic mechanisms being used for cellular memory at different levels that range from cellular differentiation to development to behavioural memory.
Epigenetics is defined as a mechanism for the stable maintenance of gene expression that involves physically 'marking' DNA or its associated proteins, which allows genotypically identical cells to be phenotypically distinct. Epigenetic marking of the genome can take several forms. Methylation of DNA and acetylation, phosphorylation, ubiquitylation and methylation of histones are discussed as potential mechanisms for the epigenetic tagging of the genome.
Neural development and differentiation involve the actions of the RE1-silencing transcription factor (REST), which recruits transcriptional co-factors and ultimately modulates the acetylation of histones.
The master circadian oscillator in the suprachiasmatic nucleus uses epigenetic mechanisms, including histone acetylation and phosphorylation, to generate circadian patterns of gene expression and to modulate gene expression in response to phase-resetting stimuli.
Seizures are known to lead to several lasting changes in gene expression. These changes seem to be due, at least in part, to changes in histone acetylation.
The formation of long-term memories requires a highly coordinated pattern of gene expression. Several recent studies indicate that epigenetic mechanisms are involved in long-term memory formation. Exposure to learning paradigms that result in the formation of long-term memories lead to changes in histone acetylation. Interference with the function of the CREB-binding protein (CBP), which is a histone acetyltransferase, impairs long-term memory formation. Treatment of animals with histone deacetylase inhibitors, which increase levels of histone acetylation, enhances the formation of long-term memories.
Synaptic plasticity is a candidate cellular mechanism that is implicated in long-term memory formation. Induction of synaptic plasticity leads to changes in histone acetylation that are similar to those seen in long-term memory formation. Disruption of normal CBP function leads to deficits in long-term potentiation. Moreover, treatment with histone deacetylase inhibitors ameliorates deficits in long-term potentiation that are seen in animal models of CBP dysfunction, and enhances long-term potentiation in normal animals.
Several diseases of human cognition are reviewed, in which one of the candidate molecular mechanisms involves dysfunction in epigenetic tagging of the genome. Diseases highlighted are Rubinstein–Taybi syndrome, Rett syndrome, Fragile X mental retardation, Alzheimer's disease and schizophrenia."

Jonathan M. Levenson & J. David Sweatt
EPIGENETIC MECHANISMS IN MEMORY FORMATION
Nature Reviews Neuroscience 6, 108-118 (2005); doi:10.1038/nrn1604

DID PTSD: Researchers Identify Where Emotional Fear Memory And Pain Become Permanently Etched In The Brain

Researchers Identify Where Emotional Fear Memory And Pain Become Permanently Etched In The Brain: "Zhuo says that fear memory does not occur immediately after a painful event; rather, it takes time for the memory to become part of our consciousness. The initial event activates NMDA receptors -- molecules on cells that receive messages and then produce specific physiological effect in the cell -- which are normally quiet but triggered when the brain receives a shock. Over time, the receptors leave their imprint on brain cells."

FUNCTION

memory

consciousness

dissociation

Most people experience mild forms of dissociation occasionally, particularly when under stress. However, more pronounced and frequent dissociation is a prominent feature of Dissociative Identity Disorder.

Dissociation is a mental process in which the main, host identity is no longer fully aware of the contents of consciousness. This is different than sleep and unconsciousness in that a different segment of the consciousness, an alter identity or personality, is awake and conscious during dissociation.

Dissociation can be partial and result in not feeling fully conscious and in control of thoughts, feelings, and actions. Depersonalization, a sense of not being oneself, is a mild form of dissociation.

At other times, dissociation is complete and results in amnesia for events that happened during the dissociative event. This is experienced as a disruption in the continuity of time, resembling the cut from one scene to another that we observe in motion pictures and TV dramas. Episodes where the person is unaware of actions, particularly of movement from one locale to another, are often called Dissociative Fugues, or fugue states.

NEURON

IMAGING

RESEARCH ARTICLE LINKS

Science Week
Brain Activity Correlates of Visual and Verbal Memory
New Neurons and Memory
discussion of perception, memory, intelligence, language, and attention
INTRODUCTION ON MEMORY AND BRAIN FUNCTION
ON THE NEUROBIOLOGICAL MECHANISMS OF MEMORY
ON THE BIOLOGICAL SUBSTRATES OF MEMORY FORMATION
NEUROBIOLOGY: NEURONAL OSCILLATIONS IN CORTICAL NETWORKS
Specific impairments of attention, memory, and executive function
A Proposal for Memory Suppressor Genes
NEUROSCIENCE: ON SPATIAL MEMORY
SPATIAL WORKING MEMORY LOCALIZED IN HUMAN FRONTAL CORTEX
NEUROSCIENCE: ON WORKING MEMORY
cerebral trauma induces loss of recent memory
NEUROSCIENCE: ON COGNITIVE MEMORY
NEUROSCIENCE: FRONTAL CORTEX AND COGNITIVE CONTROL
NEUROBIOLOGY: ON BRAIN SIZE
memory of these "pictures" may be stored in the brain
PHYSIOLOGY: EFFECTS OF SOCIAL TRAUMA IN ANIMALS AND HUMANS
Traumatic Pasts: History, Psychiatry, and Trauma in the Modern Age
Public Health: On Mental Disorders in the US 1990-2003
PUBLIC HEALTH: CULTURE AND DEPRESSION
dopamine hypothesis of depression
neurons play a role in the pathophysiology of anxiety disorders
MEDICAL BIOLOGY: ON GENERALIZED ANXIETY DISORDER
MEDICAL BIOLOGY: ON OBSESSIVE-COMPULSIVE DISORDER
TRAUMATIC BRAIN INJURIES IN HIGH SCHOOL ATHLETES
MEDICAL BIOLOGY: ON BLAST INJURIES
ON PREHOSPITAL TREATMENT OF SEVERE TRAUMATIC BRAIN INJURY
HISTORY OF MEDICINE: ON LOBOTOMY
ON THE ETIOLOGY AND TREATMENT OF SCHIZOPHRENIA
dopamine theory of schizophrenia
Neuropsychiatry: The Development of Chlorpromazine

MEDICAL BIOLOGY: ON GENERALIZED ANXIETY DISORDER
dopamine and norepinephrine implicated in ADHD
MEDICAL BIOLOGY: ON ATTENTION DEFICIT-HYPERACTIVITY DISORDER
MEDICAL BIOLOGY: ON ATTENTION-DEFICIT/HYPERACTIVITY IN ADULTS
PUBLIC HEALTH: PRENATAL FAMINE AND ADULT SCHIZOPHRENIA
ON AUTISM
MEDICAL BIOLOGY: ON RETT SYNDROME AND AUTISM
MEDICAL BIOLOGY: ON THE EARLY ORIGINS OF AUTISM
Brain Sex Differences and Adult Brain Plasticity In Focus
NEUROSCIENCE: GENDER AND BRAIN DYSFUNCTION
Effect of Estrogen on Human Brain Activation Patterns
MEDICAL BIOLOGY: SEX DIFFERENCES IN READING DISABILITY
ON DYSLEXIA AND FUNCTIONAL DISRUPTION IN BRAIN ORGANIZATION
MEDICAL BIOLOGY: ALCOHOL AND COGNITIVE FUNCTION IN WOMEN
ON THE ADDICTED BRAIN
NEUROBIOLOGY: ON ADDICTION IN RATS
NEUROBIOLOGY: ON THE BRAIN AND VIOLENCE
PUBLIC HEALTH: ON SCHOOL-ASSOCIATED STUDENT SUICIDES
PUBLIC HEALTH: METHODS OF SUICIDE AMONG ADOLESCENTS

Characterization of an In Vitro Blood-Brain Barrier

Spotlight: On the Development of the Brain 2
EVOLUTION/DEVELOPMENT: ON THE NEURAL CREST
DEVELOPMENTAL BIOLOGY: ON THE NOTOCHORD
Neurobiology: Induction of Neurogenesis in the Mammalian Brain
ON NEW NERVE CELLS IN THE ADULT HUMAN BRAIN
NEUROBIOLOGY: ON NEURONAL CELL TYPES
A NERVE CELL TYPE UNIQUE TO HUMANS AND GREAT APES
SLOW SYNAPTIC TRANSMISSION AND NEUROTRANSMITTERS
NEUROBIOLOGY: ON NEUROTRANSMITTERS
Estrogen and Brain Synapses
NEUROSCIENCE: ON SYNAPSE PHYSIOLOGY
NEUROBIOLOGY: SYNAPTOGENESIS, EXCITATION, AND INHIBITION
CELL BIOLOGY: ACTIVE ION TRANSPORT VS. PASSIVE ION CHANNELS
NEUROBIOLOGY: ASTROCYTES AND SYNAPSE FORMATION
NEUROBIOLOGY: ON RECEPTOR CLUSTERING
DRUG ADDICTION AND THE GLUTAMATE NEUROTRANSMITTER
riluzole, an inhibitor of glutamate release
Neuroscience: The NMDA Receptor
SECRETION OF GLUTAMATE BY BRAIN ASTROCYTES
CALCIUM SENSING OF METABOTROPIC GLUTAMATE RECEPTORS
Kainic acid -- algal neurotoxin, structural analogue of glutamate
excitotoxins (eg, glutamate, cytotoxic cytokines, and calcium)
Glutamate and Neurological Disease
glutamate antagonists
glutamate transmitter receptors
Glutamate receptors -- AMPA receptors
NMDA receptor: (N-methyl-D-aspartate receptor)
N-methyl-D-aspartate type glutamate receptors (NMDARs)
potential intracellular messenger
Glutamate
dendrites of principal mitral cells
Stress and glutamate in the striatum
terminal apical dendrites
D-serine, a potent activator of N-methyl-D-aspartate type glutamate receptor
endogenous cannabinoids attenuate pain
receptor superfamily
chemical transmitters, including acetylcholine, glutamate, GABA, glycine, serotonin, dopamine, and norepinephrine

Dopamine
D4 dopamine-receptor gene
drug binds with high affinity to dopamine
dopamine beta-hydroxylase
Glutamate and dopamine co-transporters
GABA, serotonin and norepinephrine co-transporters
various neurotransmitters (eg, glutamate, norepinephrine, dopamine) all raise calcium in astrocytes
classical biogenic amines (serotonin, dopamine, and histamine) as neuromodulators
release of acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, growth hormone


Zinc and the Nervous System
Integrins of the Cell Surface
Biological Cells: Surface Molecular Recognition

NEUROBIOLOGY: ON THE FORMATION OF AXONS
DEVELOPMENTAL NEUROBIOLOGY: ON AXON GUIDANCE
NEUROSCIENCE: ON AXON GROWTH TARGETING
MEDICAL BIOLOGY: ON THE NETRIN-1 PROTEIN
NEUROBIOLOGY: ON THE FUNCTIONS OF BRAIN GLIAL CELLS
NEUROSCIENCE: ON MICROCIRCUIT INHIBITION FLOW
BRAIN WAVES AND BRAIN WIRING: THE ROLE OF ENDOGENOUS AND SENSORY-DRIVEN NEURAL ACTIVITY IN DEVELOPMENT
NEUROBIOLOGY: NEURON ACTIVITY AND BRAIN NEURONAL CONNECTIONS
NEUROBIOLOGY: NEURONAL OSCILLATIONS IN CORTICAL NETWORKS
Regeneration of a Germinal Layer in the Adult Mammalian Brain
NEUROBIOLOGY: ON HYBRID NEURAL NETWORKS
NEUROSCIENCE: NEURON INCLUSION BODIES AND DISEASE
MOLECULAR BIOLOGY: ON DNA POLYMERASES
Neuroscience: A Tour of the Brain
On Localization of Function in the Human Brain
Imaging the Functioning Human Brain
On the History and Applications of Functional Brain Imaging
Mapping in the Brain
Human Neurobiology: Split-Brain Research
HUMAN NEUROBIOLOGY: SPLIT-BRAIN RESEARCH
Neurobiology: London Taxi Drivers: Navigation and Brain Structural Changes
NEUROBIOLOGY: PLASTICITY AND HORMONE RESPONSE OF THE ADULT BRAIN
XYY chromosomal disorder

NEUROSCIENCE: ON THE HUMAN OLFACTORY SYSTEM
PLANT BIOLOGY: ON PLANT VOLATILES
HEARING LOSS
MEDICAL BIOLOGY: THE COCHLEA, HEARING, AND HEARING LOSS
NEUROBIOLOGY: SPEECH-LIKE BRAIN ACTIVITY IN PROFOUNDLY DEAF PEOPLE
SENSORY PHYSIOLOGY: ON ION CHANNELS IN AUDITORY HAIR CELLS
SENSORY PHYSIOLOGY: ON HAIR CELLS AND HEARING
NEUROSCIENCE: ON AUDITORY LOCALIZATION
NEUROSCIENCE: ON TUNING IN VISUAL CORTEX
NEUROSCIENCE: ON COLOR PROCESSING IN THE BRAIN
NEUROBIOLOGY: VISION AND THE BRAIN
EVOLUTIONARY BIOLOGY: ON ANCIENT PHOTORECEPTORS
NEUROBIOLOGY: ON SENSORIMOTOR GATING
NEUROSCIENCE: ON HUMAN BRAIN NONVISUAL RESPONSES TO LIGHT
COGNITIVE SCIENCE: ON THE VISUAL PERCEPTION OF MOTION
COGNITIVE SCIENCE: ON VIEWING MOVING OBJECTS
NEUROBIOLOGY: FORM VS. MOTION IN VISUAL SYSTEM ANALYSIS
NEUROBIOLOGY: CORTICAL CORRELATES OF VISUAL ILLUSIONS
NEUROSCIENCE: VISUAL CORTEX AND EARLY BLINDNESS IN HUMANS
Neurobiology: Human Cerebellar Activity During Motor Learning
NEUROBIOLOGY: ON THE OUTPUT OF THE MOTOR CORTEX
COGNITIVE SCIENCE: ON PROPRIOCEPTION
NEUROSCIENCE: ON LIMB MOVEMENTS

MEDICAL BIOLOGY: BLOOD MERCURY AND NEUROBEHAVIORAL FUNCTION
MEDICAL BIOLOGY: EXTRA-NEURAL PRION PROTEIN IN BRAIN DISEASE
EPIDEMIOLOGY: NEW VARIANTS OF SCRAPIE
MEDICAL BIOLOGY: ON BELL'S PALSY
MEDICAL BIOLOGY: ON INTENSIVE STATIN THERAPY

ON CIRCADIAN RHYTHMS AND THE NERVOUS SYSTEM
NEUROBIOLOGY: ON LEPTIN AND THE BRAIN
NEUROSCIENCE: ON GLUCOSE AND THE BRAIN
ON INSULIN SIGNALING IN THE BRAIN
NEUROSCIENCE: ON BLOOD FLOW IN THE BRAIN
NEUROSCIENCE: ON GRANDMOTHER CELLS

NEUROSCIENCE: ON SYNESTHESIA
MEDICAL BIOLOGY: EPILEPSY AND THE TEMPORAL LOBES

NEUROBIOLOGY: ON BRAIN PLASTICITY AND STROKE
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IMAGING THE PROGRESSION OF ALZHEIMER PATHOLOGY THROUGH THE BRAIN
MEDICAL BIOLOGY: ON GENETIC FACTORS IN ALZHEIMER'S DISEASE
MEDICAL BIOLOGY: ALZHEIMER'S DISEASE UPDATE
MEDICAL BIOLOGY: ALZHEIMER'S DISEASE, DIET, AND LIFESTYLE
MEDICAL BIOLOGY: ON PARKINSON'S DISEASE DEMENTIA
MEDICAL BIOLOGY: ANTIBIOTICS AND NEURODEGENERATIVE DISEASES
MEDICAL BIOLOGY: MULTIPLE SCLEROSIS AND THE HYGIENE HYPOTHESIS
MEDICAL BIOLOGY: ON FIBROMYALGIA SYNDROME
MEDICAL BIOLOGY: ON IRRITABLE BOWEL SYNDROME

ON MODULAR COGNITIVE SYSTEMS IN THE HUMAN BRAIN PSYCHOLOGY: ON LAUGHTER
COGNITIVE SCIENCE: ON HUMAN ATTACHMENTS
COGNITIVE SCIENCE: BRAIN ACTIVITY AND DELAYED REWARDS
Origin of Human Vocal Behavior: An Anatomical Consideration
ANTHROPOLOGY: ON THE ORIGINS OF HUMAN LANGUAGE
COGNITIVE SCIENCE: ON THE ACQUISITION OF LANGUAGE IN CHILDREN
COGNITIVE SCIENCE: WORD MEANING AND WORLD KNOWLEDGE
COGNITION: LANGUAGE AND THE ORIGIN OF NUMERICAL CONCEPTS
COGNITIVE SCIENCE: LANGUAGE AND NUMBER

Neurobiology: On Brain and Mind
NEUROBIOLOGY: SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, BRAIN
Classical Conditioning and Brain Systems: Role of Awareness
COGNITIVE SCIENCE: FREE WILL AND THE BRAIN
HISTORY OF BIOLOGY: ON BRAIN AND SOUL
MEDICAL ETHICS: ON HEREDITARY DISEASE RISKS

Random Graph Models of Social Networks
ON LARGE-SCALE SPATIAL PATTERNS IN BIOLOGY
THEORETICAL BIOLOGY: ON SCALE AND COMPLEXITY
CELL BIOLOGY: ON MITOCHONDRIAL CELL DEATH
CELL BIOLOGY: ON OXYGEN SENSORS
SUBUNIT OF ACID SENSING ION CHANNELS IN BRAIN AND DORSAL ROOT GANGLION CELLS
EVIDENCE OF LIPID INVOLVEMENT IN BRAIN CELL DEATH
PROTEIN CHEMISTRY: PROTEIN FOLDING AND DISEASE
DEVELOPMENTAL BIOLOGY: AUTOPHAGY AND NEONATAL DEVELOPMENT

EVOLUTION: ON SOCIAL SELECTION FOR ECCENTRICITY

Evolution of the Mammalian Brain
ANTHROPOLOGY: ENDURANCE RUNNING AND HUMAN EVOLUTION
ANTHROPOLOGY: ON HUMANS AND RACE
ANIMAL BIOLOGY: ON HUMANS AND CHIMPANZEES
EVOLUTIONARY BIOLOGY: NATURAL SELECTION AND HUMAN POPULATIONS
HUMAN EVOLUTION: THE FATE OF THE NEANDERTHALS
On the Earliest Humans in Northeast Asia
PALEOANTHROPOLOGY: ON THE FLORES FOSSILS
ANTHROPOLOGY: ON HOMINID FOSSILS
EVOLUTION: ON THE MENTALITY OF CROWS
NEUROBIOLOGY: ON INVERTEBRATE LEARNING
EVOLUTION: ON THE OPTICAL STRUCTURE OF ANIMAL EYES
SENSORY PHYSIOLOGY: ON ECHOLOCATION
PALEONTOLOGY: ON THE OLDEST BIRD BRAIN
ANIMAL BEHAVIOR: SONGBIRDS AND RELATIVE PITCH
EVOLUTION: ON THE POLICING OF INSECT SOCIETIES
ANIMAL PHYSIOLOGY: ON OXYGEN EXCHANGE IN INSECTS
ANIMAL BEHAVIOR: ON SOCIAL SIGNALS IN RODENTS

PUBLIC HEALTH: HEAVY METALS IN AYURVEDIC HERBAL MEDICINES
as of September 12, 2005

Aging: Memory Loss In Older Adults Due To Distractions, Not Inability To Focus

Memory Loss In Older Adults Due To Distractions, Not Inability To Focus: "Although older patients often report difficulty tuning out distractions, this is the first hard evidence from functional magnetic resonance imaging (fMRI) studies of the brain that memory failure owes more to interference from irrelevant information than to an inability to focus on relevant information. "

Neurochemistry: New Techniques Study The Brain's Chemistry, Neuron By Neuron

New Techniques Study The Brain's Chemistry, Neuron By Neuron: "Researchers at the University of Illinois at Urbana-Champaign have developed tools for studying the chemistry of the brain, neuron by neuron. The analytical techniques can probe the spatial and temporal distribution of biologically important molecules, such as vitamin E, and explore the chemical messengers behind thought, memory and emotion."

Glossary

Glossary of terms related to the neuroanatomy, neurophysiology, and neurochemistry.

Back to: Main page of Brain: Main page of Dissociative Identity Disorder

hydrophilic

Hydrophilic, meaning 'water loving', is the chemical property of dissolving in, or orienting toward ionic, charged, solutions (such as extra- and intracellular fluids). This condition is the opposite of hydrophobic.

Back to: Main : ion channels :

hydrophobic

Hydrophobic, meaning 'water avoiding', molecules exhibit orientation toward, or solution in, uncharged media (such as oils). This condition is opposite to hydrophilic.

Back to: Main : ion channels

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Development: Imaging Study Shows Brain Maturing

Imaging Study Shows Brain Maturing: "Time-Lapse Imaging Tracks Brain Maturation from ages 5 to 20 -- Constructed from MRI scans of healthy children and teens, the time-lapse "movie", from which the above images were extracted, compresses 15 years of brain development (ages 5 - 20) into just a few seconds. Red indicates more gray matter, blue less gray matter. Gray matter wanes in a back-to-front wave as the brain matures and neural connections are pruned. Areas performing more basic functions mature earlier; areas for higher order functions mature later. The prefrontal cortex, which handles reasoning and other "executive" functions, emerged late in evolution and is among the last to mature. Studies in twins are showing that development of such late-maturing areas is less influenced by heredity than areas that mature earlier. (Source: Paul Thompson, Ph.D., UCLA Laboratory of Neuroimaging)"

Society for Neuroscience | Public Resources

Society for Neuroscience Public Resources: "Neuroscience research encompasses thousands of diseases and disorders from addiction to stroke. The following neuroscience-related resources are intended to help you stay apprised of neuroscience research in its path from laboratory to bedside and to better understand the functions of the healthy brain. Links are provided to hundreds of sites related to neuroscience, including patient advocacy groups. New links are added regularly. If you would like to suggest a link, please use the add a link form."

Society for Neuroscience | Brain Facts

Society for Neuroscience Brain Facts: "Brain Facts is a 52-page primer on the brain and nervous system, published by the Society for Neuroscience. In addition to serving as a starting point for a lay audience interested in neuroscience, the book is used at the annual Brain Bee, which is held in conjunction with Brain Awareness Week. The 2002 revised edition of Brain Facts is available now in PDF format only."

mPFC: Excitotoxic lesions of the prelimbic-infralimbic areas of the rodent prefrontal cortex disrupt motor preparatory processes.

Entrez PubMed: "The medial prefrontal cortex (mPFC) is involved in a variety of cognitive and emotional processes; in rodents its implication in motor planning is less known, however. We therefore investigated how the mPFC contributes to the information processes involved in the execution of a reaction time task in rats. Subjects were trained to rapidly release a lever at the onset of a cue light, which was presented after an unpredictable period of variable duration (500, 750, 1000 and 1250 ms). Excitotoxic lesions of the whole mPFC or two mPFC subregions [e.g. the dorsal anterior cingulate and the prelimbic-infralimbic (PL-IL) areas] were achieved by intracerebral infusions of ibotenic acid (9.4 micro g/ micro L) at different volumes. Extensive mPFC lesions produced increased premature responding and disrupted motor readiness, e.g. the distribution of preparatory patterns during the variable preparatory periods. The deficits lasted for 3 weeks and could be reinstated 2 months after the lesion by varying the duration of the preparatory periods to increase time uncertainty. Furthermore, lesions restricted to the PL-IL cortex areas reproduced all the deficits of mPFC lesions, whereas pregenual anterior cingulate cortex lesions had no effect. The results emphasize a critical role of the rat PL-IL region in motor preparatory processes. Hence, discrete lesions of this area reproduce some deficits such as impairment of time estimation and disinhibitory behaviours observed in humans with frontal hypoactivity."

Excitotoxic lesions of the prelimbic-infralimbic areas of the rodent prefrontal cortex disrupt motor preparatory processes.
Risterucci C, Terramorsi D, Nieoullon A, Amalric M.
Eur J Neurosci. 2003 Apr;17(7):1498-508.

RESEARCH

Attention: Multiple neuronal networks mediate sustained attention.

Entrez PubMed: "Sustained attention deficits occur in several neuropsychiatric disorders. However, the underlying neurobiological mechanisms are still incompletely understood. To that end, functional MRI was used to investigate the neural substrates of sustained attention (vigilance) using the rapid visual information processing (RVIP) task in 25 healthy volunteers. In order to better understand the neural networks underlying attentional abilities, brain regions where task-induced activation correlated with task performance were identified. Performance of the RVIP task activated a network of frontal, parietal, occipital, thalamic, and cerebellar regions. Deactivation during task performance was seen in the anterior and posterior cingulate, insula, and the left temporal and parahippocampal gyrus. Good task performance, as defined by better detection of target stimuli, was correlated with enhanced activation in predominantly right fronto-parietal regions and with decreased activation in predominantly left temporo-limbic and cingulate areas. Factor analysis revealed that these performance-correlated regions were grouped into two separate networks comprised of positively activated and negatively activated intercorrelated regions. Poor performers failed to significantly activate or deactivate these networks, whereas good performers either activated the positive or deactivated the negative network, or did both. The fact that both increased activation of task-specific areas and increased deactivation of task-irrelevant areas mediate cognitive functions underlying good RVIP task performance suggests two independent circuits, presumably reflecting different cognitive strategies, can be recruited to perform this vigilance task."

Multiple neuronal networks mediate sustained attention.
Lawrence NS, Ross TJ, Hoffmann R, Garavan H, Stein EA.
Cogn Neurosci. 2003 Oct 1;15(7):1028-38.

Attention: The continuous performance test: a window on the neural substrates for attention?

Entrez PubMed: "The continuous performance test: a window on the neural substrates for attention? Attention is a complex process whose disturbance is considered a core deficit in a number of disorders [e.g., Attention Deficit Hyperactivity Disorder (ADHD), schizophrenia]. In 1956, Rosvold and colleagues [J. Consult. Psychol. 20 (1956) 343.] demonstrated that the continuous performance test (CPT) as a measure of sustained attention was highly sensitive to brain damage or dysfunction. These findings have been replicated with various populations and with various versions of the CPT. The CPT is now cited as the most frequently used measure of attention in both practice and research. Across studies, results are consistent with models of sustained attention that involve the interaction of cortical (frontal, temporal, parietal), subcortical (limbic, basal ganglia), and functional systems including the pathways between the basal ganglia, thalamus, and frontal lobes. Right hemisphere involvement (asymmetric response) is also evident across multiple studies. As such, the CPT demonstrates sensitivity to dysfunction of the attentional system whether this is due to diffuse or more focal damage/dysfunction or in conjunction with any specific disorder. CPT performance can be viewed as symptom specific (attentional disturbance), but it is not disorder specific (e.g., ADHD). Implications for neuropsychological interpretation of CPT results are presented."

The continuous performance test: a window on the neural substrates for attention?
Riccio CA, Reynolds CR, Lowe P, Moore JJ.Arch Clin Neuropsychol. 2002 Apr;17(3):235-72.

Attention: Emotion: The interaction of attention and emotion.

Entrez PubMed: "We analyse emotions from the viewpoint of how emotion and attention interact in the brain. Much has been learnt about the brain structures involved in attention, especially in vision. In particular the manner in which attention functions as a high-level control system, able to make cognitive processing so effective, has been studied both at a global level by brain imaging (fMRI, PET, MEG and EEG), at a local single cell level in monkeys and lower animals, and computationally by a variety of models. The manner in which emotions impinge on this attention control system is not so well analysed, although numerous new results are now emerging from using the same tools. Here we use an engineering control approach to attention to model it in a global manner but with relatively sure local foundations at singe neuron level. The manner in which emotional value (as coded in amygdale and orbito-frontal cortex) can interact with the attention control circuitry is analysed using results of various experimental paradigms. A general model of this interaction is first developed and tested against a list of paradigms, and then more detailed computations are performed using more specific features of the attention control system and the limbic value coding. These computations are completed by a simulation of the emotional attentional blink, a demanding paradigm for any model of attention alone, but made more so by the presence of emotional value codes for stimuli. We conclude the paper with a general discussion of further avenues of research."

The interaction of attention and emotion.
Taylor JG, Fragopanagos NF.
Neural Netw. 2005 May;18(4):353-69.

Limbic system: The basal ganglia: anatomy, physiology, and pharmacology.

Entrez PubMed: "The basal ganglia are perceived as important nodes in cortico-subcortical networks involved in the transfer, convergence, and processing of information in motor, cognitive, and limbic domains. How this integration might occur remains a matter of some debate, particularly given the consistent finding in anatomic and physiologic studies of functional segregation in cortico-subcortical loops. More recent theories, however, have raised the notion that modality-specific information might be integrated not spatially, but rather temporally, by coincident processing in discrete neuronal populations. Basal ganglia neurotransmitters, given their diverse roles in motor performance, learning, working memory, and reward-related activity are also likely to play an important role in the integration of cerebral activity. Further work will elucidate this to a greater extent, but for now, it is clear that the basal ganglia form an important nexus in the binding of cognitive, limbic, and motor information into thought and action."

The basal ganglia: anatomy, physiology, and pharmacology.
Tisch S, Silberstein P, Limousin-Dowsey P, Jahanshahi M.
Psychiatr Clin North Am. 2004 Dec;27(4):757-99.

Emotion: Neural substrates of emotion as revealed by functional magnetic resonance imaging.

Entrez PubMed: "OBJECTIVES: To examine the brain circuitry involved in emotional experience and determine whether the cerebral hemispheres are specialized for positive and negative emotional experience. BACKGROUND: Recent research has provided a preliminary sketch of the neurologic underpinnings of emotional processing involving specialized contributions of limbic and cortical brain regions. Electrophysiologic, functional imaging, and Wada test data have suggested positive, approach-related emotions are associated with left cerebral hemisphere regions, whereas negative, withdrawal-related emotions appear to be more aligned with right hemisphere mechanisms. . . RESULTS: Emotional pictures resulted in significantly increased blood flow bilaterally in the mesial frontal lobe/anterior cingulate gyrus, dorsolateral frontal lobe, amygdala/anterior temporal regions, and cerebellum. Negative emotional pictures resulted in greater activation of the right hemisphere, and positive pictures caused greater activation of the left hemisphere. CONCLUSIONS: Results are consistent with theories emphasizing the importance of circuitry linking subcortical structures with mesial temporal, anterior cingulate, and frontal lobe regions in emotion and with the valence model of emotion that posits lateralized cerebral specialization for positive and negative emotional experience."

Neural substrates of emotion as revealed by functional magnetic resonance imaging.
Lee GP, Meador KJ, Loring DW, Allison JD, Brown WS, Paul LK, Pillai JJ, Lavin TB.
Cogn Behav Neurol. 2004 Mar;17(1):9-17.

Emotion: Limbic system: A review of systems and networks of the limbic forebrain/limbic midbrain.

Entrez PubMed: "Evolutionarily older brain systems, such as the limbic system, appear to serve fundamental aspects of emotional processing and provide relevant and motivational information for phylogenetically more recent brain systems to regulate complex behaviors. Overall, overt behavior is, in part, determined by the interactions of multiple learning and memory systems, some seemingly complementary and some actually competitive. An understanding of limbic system function in emotion and motivation requires that these subsystems be recognized and characterized as extended components of a distributed limbic network. Behavioral neuroscientists face the challenge of teasing apart the contributions of multiple overlapping neuronal systems in order to begin to elucidate the neural mechanisms of the limbic system and their contributions to behavior. One major consideration is to bring together conceptually the functions of individual components of the limbic forebrain and the related limbic midbrain systems. For example, in the rat the heterogeneous regions of the prefrontal cortex (e.g., prelimbic, anterior cingulate, subgenual cortices and orbito-frontal areas) make distinct contributions to emotional and motivational influences on behavior and each needs consideration in its own right. Major interacting structures of the limbic system include the prefrontal cortex, cingulate cortex, amygdaloid nuclear complex, limbic thalamus, hippocampal formation, nucleus accumbens (limbic striatum), anterior hypothalamus, ventral tegmental area and midbrain raphe nuclei; the latter comprising largely serotonergic components of the limbic midbrain system projecting to the forebrain. The posterior limbic midbrain complex comprising the stria medullaris, central gray and dorsal and ventral nuclei of Gudden are also key elements in the limbic midbrain. Some of these formations will be discussed in terms of the neurochemical connectivity between them. We put forward a systems approach in order to build a network model of the limbic forebrain/limbic midbrain system, and the interactions of its major components. In this regard, it is important to keep in mind that the limbic system is both an anatomical entity as well as a physiological concept. We have considered this issue in detail in the introduction to this review. The components of these systems have usually been considered as functional units or 'centers' rather than being components of a larger, interacting, and distributed functional system. In that context, we are oriented toward considerations of distributed neural systems themselves as functional entities in the brain."

A review of systems and networks of the limbic forebrain/limbic midbrain.
Morgane PJ, Galler JR, Mokler DJ.
Prog Neurobiol. 2005 Feb;75(2):143-60.

Fear: Emotional perseveration: an update on prefrontal-amygdala interactions in fear extinction.

Entrez PubMed: "Fear extinction refers to the ability to adapt as situations change by learning to suppress a previously learned fear. This process involves a gradual reduction in the capacity of a fear-conditioned stimulus to elicit fear by presenting the conditioned stimulus repeatedly on its own. Fear extinction is context-dependent and is generally considered to involve the establishment of inhibitory control of the prefrontal cortex over amygdala-based fear processes. In this paper, we review research progress on the neural basis of fear extinction with a focus on the role of the amygdala and the prefrontal cortex. We evaluate two competing hypotheses for how the medial prefrontal cortex inhibits amygdala output. In addition, we present new findings showing that lesions of the basal amygdala do not affect fear extinction. Based on this result, we propose an updated model for integrating hippocampal-based contextual information with prefrontal-amygdala circuitry."

Emotional perseveration: an update on prefrontal-amygdala interactions in fear extinction.
Sotres-Bayon F, Bush DE, LeDoux JE.
Learn Mem. 2004 Sep-Oct;11(5):525-35.

Full text article is available online:
http://www.learnmem.org/cgi/content/full/11/5/525

Fear: Mesolimbic dopaminergic pathways in fear conditioning.

Entrez PubMed: "One of the most common paradigms used to study the biological basis of emotion, as well as of learning and memory, is Pavlovian fear conditioning. In the acquisition phase of a fear conditioning experiment, an emotionally neutral conditioned stimulus (CS)--which can either be a discrete stimulus, such as a tone, or a contextual stimulus, such as a specific environment--is paired with an aversive unconditioned stimulus (US), for example a foot shock. As a result, the CS elicits conditioned fear responses when subsequently presented alone during the expression phase of the experiment. While considerable work has been done in relating specific circuits of the brain to fear conditioning, less is known about its regulation by neuromodulators; the understanding of which would be of therapeutic relevance for fear related diseases such as phobia, panic attacks, post traumatic stress disorder, obsessive compulsive disorder, or generalized anxiety disorder. Dopamine is one of the neuromodulators most potently acting on the mechanisms underlying states of fear and anxiety. Recently, a growing body of evidence has suggested that dopaminergic mechanisms are significant for different aspects of affective memory, namely its formation, expression, retrieval, and extinction. The aim of this review is to clarify the complex actions of dopamine in fear conditioning with respect to the wide-spread distribution of dopaminergic innervation over structures constituting the fear related circuitry. A particular effort is made to understand how dopamine in the amygdala, medial prefrontal cortex and nucleus accumbens--target structures of the mesolimbic dopamine system originating from the ventral tegmental area--could relate to different aspects of fear conditioning."

Mesolimbic dopaminergic pathways in fear conditioning.
Pezze MA, Feldon J.
Prog Neurobiol. 2004 Dec;74(5):301-20.

Positive Emotion: The neurobiology of positive emotions.

Entrez PubMed: "Compared to the study of negative emotions such as fear, the neurobiology of positive emotional processes and the associated positive affect (PA) states has only recently received scientific attention. Biological theories conceptualize PA as being related to (i) signals indicating that bodies are returning to equilibrium among those studying homeostasis, (ii) utility estimation among those favoring neuroeconomic views, and (iii) approach and other instinctual behaviors among those cultivating neuroethological perspectives. Indeed, there are probably several distinct forms of positive affect, but all are closely related to ancient sub-neocortical limbic brain regions we share with other mammals. There is now a convergence of evidence to suggest that various regions of the limbic system, including especially ventral striatal dopamine systems are implemented in an anticipatory (appetitive) positive affective state. Dopamine independent mechanisms utilizing opiate and GABA receptors in the ventral striatum, amygdala and orbital frontal cortex are important in elaborating consummatory PA (i.e. sensory pleasure) states, and various neuropeptides mediate homeostatic satisfactions."

Keywords: Affect; Emotions; Pleasure; Play; Seeking; Foraging;Vocalizations; Dopamine

The neurobiology of positive emotions.
Burgdorf J, Panksepp J.
Neurosci Biobehav Rev. 2005 Aug 11; [Epub ahead of print]