Research reportNeural circuitry for rat recognition memory

- We present a summary of findings from object recognition memory tasks revealing the roles played by cortical, hippocampal and thalamic regions.
- We report a neural circuit for object-location association recognition memory and temporal order recognition memory.
- The neural circuit involves the perirhinal cortex, medial prefrontal cortex and hippocampus.
- Experimental evidence shows that all structures in the circuit play critical roles in memory formation which can potentially be differentiated.

Information concerning the roles of different brain regions in recognition memory processes is reviewed. The review concentrates on findings from spontaneous recognition memory tasks performed by rats, including memory for single objects, locations, object-location associations and temporal order. Particular emphasis is given to the potential roles of different regions in the circuit of interacting structures involving the perirhinal cortex, hippocampus, medial prefrontal cortex and medial dorsal thalamus in recognition memory for the association of objects and places. It is concluded that while all structures in this circuit play roles critical to such memory, these roles can potentially be differentiated and differences in the underlying synaptic and biochemical processes involved in each region are beginning to be uncovered.