Memory: Rapid prefrontal-hippocampal habituation to novel events.

Entrez PubMed: "Unexpected novel events generate an orienting response that plays an important role in some forms of learning and memory. The orienting response involuntarily captures attention and rapidly habituates as events become familiarized. Although evidence from patients with focal lesions and scalp and intracranial event-related brain potential recordings supports the involvement of a distributed neural network involving association cortex and the limbic system in novelty detection, the key neural substrates and temporal dynamics have not been defined. . . Novel stimuli activated the bilateral superior/middle frontal gyrus, temporal-parietal junction, superior parietal lobe, cingulate gyrus, hippocampus, and fusiform gyrus. The superior/middle frontal gyrus and hippocampus showed significant reduction of BOLD signal during the first few novel stimuli, whereas the signals in the fusiform and cingulate gyrus were constant. Prefrontal and hippocampal responses to attended and unattended novel stimuli were comparably habituated. These results, and previous data from lesion studies, support the view that prefrontal and hippocampal regions are involved in rapid automatic detection and habituation to unexpected environmental events and are key elements of the orienting response in humans."

Rapid prefrontal-hippocampal habituation to novel events.
Yamaguchi S, Hale LA, D'Esposito M, Knight RT.
J Neurosci. 2004 Jun 9;24(23):5356-63.

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