Nucleus cuneiformis lesion increases high-voltage spindle incidence in unrestrained rat neocortex

The effects of bilateral electrolytical lesions of the mesencephalic nucleus cuneiformis (CU) on both the high-voltage splindle (HVS) activity and the spontaneous behaviour of unrestrained rats have been investigated. In control experiments, EEG spectral power mapping indicated different HVS rhythms in frontal and occipital cortices. The main lesion effect was a strong significant increase of the HVS incidence in the frontal cortex. However, the CU lesion did not affect the incidence of relaxed waking immobility which is specifically related to HVS generation. Furthermore, CU lesion did not alter the power spectra of the frontal cortical EEG during different behavioural states. The results indicate that CU exerts inhibitory influences on the generation of HVSs, which probable correlates with facilitation of the sensory information transfer through the thalamus.