Brain pathways activated by formation of sensory association – a 2DG study

Abstract

Event Abstract Back to Event Brain pathways activated by formation of sensory association – a 2DG study Malgorzata Kossut1*, Anita Cybulska-Klosowicz1 and Renata Zakrzewska1 1 Nencki Institute, Poland The neural bases of sensory conditioning at various stages of learning may engage distinct cortical and subcortical networks. Using [14C]2-deoxyglucose (2-DG) autoradiography we examined brain activation in mice during classical conditioning involving stimulation of whiskers (CS) on one side of the muzzle paired with an aversive UCS (tail shock). During conditioning, the mice were in a restraining apparatus and head movements during application of CS were recorded. Pairing of CS and UCS resulted in significant reduction in the number of head movements during the conditioning sessions and in a test 24 hrs after last session. The results were compared in the conditioned (CS+UCS) and pseudoconditioned group. Analysis of autoradiograms revealed that during the first training session in the CS+UCS group a significantly higher 2DG uptake was found in posterior parietal cortex (PPC), the shell of nucleus accumbens (NA), cingulate gyrus (CG), retrosplenial cortex (RET), caudate nucleus, ventral posterior nucleus of the thalamus and posterior nucleus of the thalamus. Interestingly, formation of sensory association, compared to pseudoconditioning, induces more activity in the subcortical sensory processing pathway (ventral postero-medial and posterior nuclei of the thalamus) but not in the barrel cortex, although it induces a plastic modification of cortical representation of the stimulated vibrissae [1]. Also, conditioning, contrasted with pseudoconditioning, increases activity in structures important for cognitive and attentional functions (PPC, NA, CG, RET), which might provide the enhancing input necessary for memory trace formation.