Spontaneous neuronal activity of the posterior hypothalamus in trigeminal autonomic cephalalgias

Microrecordings of three neurons were obtained at the target site in three patients with trigeminal autonomic cephalalgias who were implanted with deep brain stimulators in the posterior hypothalamus. Two patients had chronic cluster headache, one short unilateral neuralgiform headache with conjunctival injection and tearing. Average firing rate was around 24 spikes/s. All neurons were firing randomly, and for most of the recordings in tonic fashion. In one patient, tactile stimulation of the ophthalmic branch, contralateral to the recording site, decreased the firing rate. Neuronal activity in these patients was similar to that reported in animal studies of the posterior hypothalamus. Positioning deep brain stimulators in the posterior hypothalamus may offer a tool to better characterise the activity of this part of the brain in humans.