Contribution of the parafascicular nucleus in the spontaneous object recognition task

Abstract

The parafascicular (PF) nucleus, a posterior component of the intralaminar nuclei of the thalamus, is con-sidered to be an essential structure in the feedback systems of basal ganglia–thalamo-cortical circuitscritically involved in cognitive processes. The specific role played by multimodal information encodedin PF neurons in learning and memory processes is still unclear. We conducted two experiments to inves-tigate the role of the PF in the spontaneous object recognition (SOR) task. The behavioral effects of pre-training rats with bilateral lesions of PF with N-methyl-D-aspartate (NMDA) were compared to vehiclecontrols. In the first experiment, rats were tested on their ability to remember the association immedi-ately after training trials and in the second experiment after a 24 h delay. Our findings provide evidencethat PF lesions critically affect both SOR tests and support its role in that non-spatial form of relationalmemory