Spatial learning with a minislab in the dorsal hippocampus.
We have determined the volume and location of hippocampal tissue required for normal acquisition of a spatial memory task. Ibotenic acid was used to make bilateral symmetric lesions of 20-100% of hippocampal volume. Even a small transverse block (minislab) of the hippocampus (down to 26% of the total) could support spatial learning in a water maze, provided it was at the septal (dorsal) pole of the hippocampus. Lesions of the septal pole, leaving 60% of the hippocampi intact, caused a learning deficit, although normal electrophysiological responses, synaptic plasticity, and preserved acetylcholinesterase staining argue for adequate function of the remaining tissue. Thus, with an otherwise normal brain, hippocampal-dependent spatial learning only requires a minislab of dorsal hippocampal tissue.
Moser
M B
MB
Centre for Neuroscience, University of Edinburgh, United Kingdom.
Moser
E I
EI
Forrest
E
E
Andersen
P
P
Morris
R G
RG
D000110:Acetylcholinesterase / Q000302:isolation & purification; D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D006651:Histocytochemistry; D007051:Ibotenic Acid / Q000494:pharmacology; D007858:Learning; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology*; D013550:Swimming
D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid; D000110:Acetylcholinesterase