Editors' ChoiceNeuroscience

The Wheres and Hows of Memory

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Science's STKE  31 Aug 2004:
Vol. 2004, Issue 248, pp. tw312
DOI: 10.1126/stke.2482004tw312

The hippocampus plays a fundamental role in encoding, consolidating, and retrieving episodic and semantic memory (see the Perspective by Bilkey). Fyhn et al. show that precise spatial information exists and arises in neural activity upstream of the hippocampus in a hitherto unexplored dorsocaudal area in the medial entorhinal cortex, and that this information is being computed within this area. The entorhinal cortex may thus have the computational power to compute and represent position. To understand the functional differentiation underlying structural differences in the patterns of neuronal connectivity within the hippocampus, Leutgeb et al. performed ensemble recordings in hippocampal areas CA1 and CA3 when rats were placed in varying enclosures in different recording rooms. The ensemble codes in CA3 were independently organized, whereas codes in CA1 overlapped one another, especially when the animals were placed in familiar-looking surroundings. The CA1 appears to register more general features, whereas CA3 appears to store overlapping but different memories with minimal interference.

M. Fyhn, S. Molden, M. P. Witter, E. I. Moser, M.-B. Moser, Spatial representation in the entorhinal cortex. Science 305, 1258-1264 (2004). [Abstract] [Full Text]

S. Leutgeb, J. K. Leutgeb, A. Treves, M.-B. Moser, E. I. Moser, Distinct ensemble codes in hippocampal areas CA3 and CA1. Science 305, 1295-1298 (2004). [Abstract] [Full Text]

D. K. Bilkey, In the place space. Science 305, 1245-1246 (2004). [Summary] [Full Text]

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