EN
The neural bases of appetitive and aversive conditioning are different, and 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 on one side of the muzzle paired with an aversive or appetitive UCS. Both variants result in modifi cation of cortical representations of vibrissae activated during the conditioning. Analysis of autoradiograms revealed that the nucleus basalis of Meynert (NBM) and ventral pallidum showed stronger labeling during appetitive training while the lateral hypothalamus (LH) and basolateral amygdala (BLA) were activated only by aversive learning. Apart from that, classicalconditioning with appetitive or aversive UCS increased 2-DG uptake in a similar set of brain structures – the posterior parietal cortex (PPC), cingulate (CG) and retrosplenial gyrus (RET), caudate nucleus (CPU) and nucleus accumbens (NA). 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. Also, conditioning contrasted with pseudoconditioning increases activity in structures important for cognitive and attentional functions (PPC, NA, CG, RET, CPU), which might provide the enhancing input necessary for memory trace formation.