Thu, 21 Aug 2008 15:33:48 BST CiteULike: nelmor Leutgeb http://www.citeulike.org/user/nelmor/author/Leutgeb CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/nelmor/article/2961490 <i>Science, Vol. 321, No. 5885. (4 July 2008), pp. 140-143.</i><br /><br />To determine how spatial scale is represented in the pyramidal cell population of the hippocampus, we recorded neural activity at multiple longitudinal levels of this brain area while rats ran back and forth on an 18-meter-long linear track. CA3 cells had well-defined place fields at all levels. The scale of representation increased almost linearly from <1 meter at the dorsal pole to [~]10 meters at the ventral pole. The results suggest that the place-cell map includes the entire hippocampus and that environments are represented in the hippocampus at a topographically graded but finite continuum of scales. 10.1126/science.1157086 Finite Scale of Spatial Representation in the Hippocampus Kirsten Kjelstrup Trygve Solstad Vegard Brun Torkel Hafting Stefan Leutgeb Menno Witter Edvard Moser May-Britt Moser doi:10.1126/science.1157086 Science, Vol. 321, No. 5885. (4 July 2008), pp. 140-143. 2008-07-03T23:30:05-00:00 2008 Science 321 5885 140 143 hippocampus place-cell http://www.citeulike.org/user/nelmor/article/2282625 <i>Neuron, Vol. 57, No. 2. (24 January 2008), pp. 290-302.</i><br /><br />Summary Place-specific firing in the hippocampus is determined by path integration-based spatial representations in the grid-cell network of the medial entorhinal cortex. Output from this network is conveyed directly to CA1 of the hippocampus by projections from principal neurons in layer III, but also indirectly by axons from layer II to the dentate gyrus and CA3. The direct pathway is sufficient for spatial firing in CA1, but it is not known whether similar firing can also be supported by the input from CA3. To test this possibility, we made selective lesions in layer III of medial entorhinal cortex by local infusion of the neurotoxin [gamma]-acetylenic GABA. Firing fields in CA1 became larger and more dispersed after cell loss in layer III, whereas CA3 cells, which receive layer II input, still had sharp firing fields. Thus, the direct projection is necessary for precise spatial firing in the CA1 place cell population. Impaired Spatial Representation in CA1 after Lesion of Direct Input from Entorhinal Cortex Vegard Brun Stefan Leutgeb Hui-Qiu Wu Robert Schwarcz Menno Witter Edvard Moser May-Britt Moser doi:10.1016/j.neuron.2007.11.034 Neuron, Vol. 57, No. 2. (24 January 2008), pp. 290-302. 2008-01-24T01:04:55-00:00 2008 Neuron 57 2 290 302 ca1 ca3 erc learning lesion place-cell http://www.citeulike.org/user/nelmor/article/1109603 <i>Science, Vol. 315, No. 5814. (16 February 2007), pp. 961-966.</i><br /><br />Theoretical models have long pointed to the dentate gyrus as a possible source of neuronal pattern separation. In agreement with predictions from these models, we show that minimal changes in the shape of the environment in which rats are exploring can substantially alter correlated activity patterns among place-modulated granule cells in the dentate gyrus. When the environments are made more different, new cell populations are recruited in CA3 but not in the dentate gyrus. These results imply a dual mechanism for pattern separation in which signals from the entorhinal cortex can be decorrelated both by changes in coincidence patterns in the dentate gyrus and by recruitment of nonoverlapping cell assemblies in CA3. 10.1126/science.1135801 Pattern Separation in the Dentate Gyrus and CA3 of the Hippocampus Jill Leutgeb Stefan Leutgeb May-Britt Moser Edvard Moser doi:10.1126/science.1135801 Science, Vol. 315, No. 5814. (16 February 2007), pp. 961-966. 2007-02-16T10:00:31-00:00 2007 Science 315 5814 961 966 ca3 dentate hippocampus