Place cells and place recognition maintained by direct entorhinal-hippocampal circuitry.
Place cells in hippocampal area CA1 may receive positional information from the intrahippocampal associative network in area CA3 or directly from the entorhinal cortex. To determine whether direct entorhinal connections support spatial firing and spatial memory, we removed all input from areas CA3 to CA1, thus isolating the CA1 area. Pyramidal cells in the isolated CA1 area developed sharp and stable place fields. Rats with an isolated CA1 area showed normal acquisition of an associative hippocampal-dependent spatial recognition task. Spatial recall was impaired. These results suggest that the hippocampus contains two functionally separable memory circuits: The direct entorhinal-CA1 system is sufficient for recollection-based recognition memory, but recall depends on intact CA3-CA1 connectivity.
Brun
Vegard H
VH
Neuroscience Unit, Medical-Technical Research Centre, Norwegian University of Science and Technology, 7489 Trondheim, Norway.
Otnass
Mona K
MK
Molden
Sturla
S
Steffenach
Hill-Aina
HA
Witter
Menno P
MP
Moser
May-Britt
MB
Moser
Edvard I
EI
D000200:Action Potentials; D000818:Animals; D001931:Brain Mapping; D003714:Denervation; D004567:Electrodes, Implanted; D018728:Entorhinal Cortex / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology*; D007395:Interneurons / Q000502:physiology; D018782:Maze Learning; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D013028:Space Perception / Q000502:physiology*