Involvement of the hippocampal CA3-region in acquisition and in memory consolidation of spatial but not in object information in mice.
This study investigates the implication of the hippocampal CA3-region in the different phases of learning and memory in spatial and non-spatial tasks. For that purpose, we performed focal injections of diethyldithiocarbamate (DDC) into the CA3-region of the dorsal hippocampus. The DDC chelates most of the heavy metals in the brain which blocks selectively and reversibly the synapses containing heavy metals, i.e., the mossy fibres synaptic buttons and synapses of the dendrites of pyramidal cells. The effects of temporal inactivation of the CA3-region was examined in a non-associative task, the spatial open-field, designed to estimate the ability of mice to react to spatial changes, and in the object recognition task, designed to estimate the ability of mice to identify a familiar object. The results show that DDC induced a specific impairment on learning and memory consolidation in the spatial open-field but had no effect on recall in this task. In the object recognition task, DDC did not induce any impairment in the different phases of learning and memory. These data demonstrate that the hippocampal CA3-region is specifically implicated in spatial information processing and seems to be involved not only in acquisition but also in consolidation of spatial information.
Centre de Recherches Sur la Cognition Animale, CNRS FRE 2382, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 4, France.
Grégory
G
Stupien
Cédrick
C
Florian
Pascal
P
Roullet
D000818:Animals; D002614:Chelating Agents / Q000494:pharmacology; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology; D004050:Ditiocarb / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009949:Orientation / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D002614:Chelating Agents; D004050:Ditiocarb