The ventromedial nucleus as thalamic relay for fastigial projections to the cat insular cortex

Electrical stimulation of the thalamic ventromedial nucleus (VM) produced surface-negative field potentials in the insular cortex of the cat. Laminar field potential analysis revealed that the VM-evoked potentials showed the same depth profile as the potentials evoked by stimulation of the cerebellar fastigial nucleus (FN). The active synaptic site for both evoked potentials is indicated to be located in layer I of the insular cortex. These results suggest that the VM mediates the FN projections onto layer I of the insular cortex.