Background and Aim :
Basolateral amygdala (BLA),
nucleus accumbens (NAC),
prefrontal cortex (PFC) and
ventral hippocampus (vHC) are known as the key structures in cortico-limbic network, which plays a central role in processing emotions and higher cognitive functions. Functional alterations in specific connections of this network has been reported in several psychiatric disorders. However, it is not clear whether these alterations occurring in the direct pathways or alternatively through indirect interactions.Methods : Using multi-site probes and under light anesthesia, we performed extracellular recording in three brain regions simultaneously in BLA-NAC-PFC-vHC network. To investigate the functional connectivity of these five pairs we used spike count cross-correlation and time-resolved partial directed
coherence analysis.Results : Our results show that BLA, NAC, PFC and vHC are highly interconnected and synchronized during spontaneous activity. We show that in most of tested connections a considerable amount of synchrony is mediated by the third recorded region. Furthermore, for each paired brain region we determine the directionality of interaction by measuring the strength of feedback and feedforward connections. We find that although all tested connections are reciprocal, the strength of the information flow, depending on target area, is weighted toward either directions. These findings indicate that in a given region in BLA-NAC-PFC-vHC network, the dominant direction of information flow interaction changes according to the target region, which is an evidence of region-specific interaction in this network.Conclusion : Our results in characterization of functional connectivity in four key brain regions in cortico-limbic network, not only can extend the previous findings on functional interaction, but also provide the basis to study alterations in this network in animal models of psychiatric disorders.