Lesions of the mediodorsal thalamic nucleus do not change thresholds for hypothalamic defensive attack in cats

Electrolytic lesions of the mediodorsal thalamic nucleus (nMD) were made in 10 cats to evaluate their effects on thresholds for hypothalamic defensive attack and emotional reactivity to noxious stimuli. Only 2 cats showed minimal threshold changes after the lesions, one of which was accompanied by an increased emotional reactivity to noxious stimuli; however, this was attributed to damage to the fornical column. The nMD appeared not to be involved directly in the central mechanism of defensive attack.