Si. Wiener, SPATIAL, BEHAVIORAL AND SENSORY CORRELATES OF HIPPOCAMPAL CA1 COMPLEXSPIKE CELL-ACTIVITY - IMPLICATIONS FOR INFORMATION-PROCESSING FUNCTIONS, Progress in neurobiology, 49(4), 1996, pp. 335
The aim of this review is to better understand hippocampal function dr
awing almost entirely from single unit recording studies of pyramidal
cells in areas CA1 and CA3 of behaving animals. Hippocampal location-s
electivity (''place cell activity'') as well as place-independent beha
vioral correlates and sensory-triggered discharges are demonstrated to
have common features: (1) abstraction, that is, development within th
e hippocampal circuit of novel, cue-invariant supramodal representatio
ns; (2) varying degrees of generalization or specificity; (3) capacity
for abrupt changes in discharge correlates of individual neurons as t
he animal changes its behavior pattern or its environment changes dram
atically; (4) though individual neurons discharge when the subject occ
upies a certain place, or performs a certain behavior, the ensemble of
hippocampal neurons comprehensively represent the whole environment a
nd all behaviors required for the task at hand. A concordance is propo
sed: hippocampal neuronal discharge correlates represent elements part
itioned from information abstracted along one or more systems of categ
orization or ''information domains'': the physical structure of the en
vironment, regularities in the behavioral exigencies of the current si
tuation. (Sensory stimuli can be considered as temporally varying feat
ures of the environment.) Location-selectivity and behavioral correlat
es are extreme cases, and mixed correlates occur. The hippocampus is p
roposed to carry out several fundamental processes that transform info
rmation: abstraction, partitioning and recombination, that is, formati
on of conjunctive associations between events. Simultaneously activate
d neurons could then promote extrahippocampal associations linking tog
ether the diverse brain regions at the origin of these signals. Copyri
ght (C) 1996 Elsevier Science Ltd.