" ... High frequency (~130 Hz) deep brain stimulation (DBS) of
the subthalamic region is an established clinical therapy for the
treatment of late stage Parkinson's disease (PD). Direct modulation of
the hyperdirect pathway, defined as cortical layer V pyramidal neurons
that send an axon collateral to the subthalamic nucleus (STN), has
emerged as a possible component of the therapeutic mechanisms.
...We found robust AP propagation throughout the complex axonal
arbor of the hyperdirect neuron. Even at therapeutic DBS frequencies,
stimulation induced APs could reach all of the intracortical axon
terminals with ~100% fidelity. The functional result of this high
frequency axonal driving of the thousands of synaptic connections made
by each directly stimulated hyperdirect neuron is a profound synaptic
suppression that would effectively disconnect the neuron from the
cortical circuitry. ..."
Anderson RW, Farokhniaee A, Gunalan K, Howell B, McIntyre CC (2018) Action potential initiation, propagation, and cortical invasion in the hyperdirect pathway during subthalamic deep brain stimulation Brain Stimulation