¹Dept of Psychology, Johns Hopkins University, Baltimore, MD  21218
²Cog Sci Dept, UCSD, La Jolla, CA  92093

Interconnections between orbitofrontal cortex (OFC) and basolateral amygdala (ABL) may be critical for encoding and utilizing associative information about the motivational significance of stimuli. In previous research, we found that neurons in OFC and ABL fired selectively to cues based on their associative significance during a go, no-go odor discrimination task. Neurons in ABL developed selective activity during odor evaluation very early in training.  In contrast, such neurons in OFC rarely exhibited selective activity during odor evaluation before the rats reached the go no-go criterion for learning.  Here we present an analysis of the correlated firing at baseline in the cell pairs recorded in the prior study.  Correlated firing was examined on a 10 ms time scale within the intertrial interval of the discrimination task.  The effectiveness of these short latency interactions changed significantly as the rats learned the discrimination and again when the response contingencies of the odor cues were reversed; these patterns mirrored findings in the selective neurons described above.  Effectiveness increased significantly in OFC during learning, and this increase was most pronounced during the phase of training when the rats were performing accurately.  In ABL, the increase was most pronounced during the early stages of learning, well before accurate performance had been established.  This pattern supports data from the single units indicating that changes in information processing during sampling in ABL precede those in OFC in this task, putting ABL in a position to support encoding in OFC.  Supported by K08-AG00882-01 to GS and RO1 MH53667 to MG.