Projection of thalamic neurons to cat primary vestibular cortical fields studied by means of retrograde axonal transport of horseradish peroxidase.

The two vestibular cortical projection areas in the anterior suprasylvian sulcus and post-cruciate dimple regions were defined by evoked potential technique in anaesthetized cats. The thalamic location of neurons with axon terminals in these fields was determined using the method of retrograde axonal transport of horseradish peroxidase. The ascending vestibular pathway appeared to be separated also at the thalamic level, where cells in the ventroposterolateral nucleus were found to project to the post cruciate dimple and cells in the posterior nuclear group to the anterior suprasylvian vestibular cortical fields.