抄録
The STN provides glutamatergic projections to both pallidal segments and the substantia nigra pars reticulata (SNr). In these experiments we explored the effect of STN stimulation on the neuronal activity in SNc. Two monkeys received chronic recording chambers directed at STN and SNc. One chamber was used to carry out electrical stimulation of the STN with a microelectrode (monophasic stimulation at 1/s, pulse width 50 μs, amplitude < 300 μA), and the other to simultaneously record the neuronal activity in SNc, using standard extracellular single-unit recording techniques. Peristimulus histograms were used to calculate the latency and duration of responses.
The experiments showed two response patterns in the SNc. The first was an inhibition of activity, which typically started immediately after the stimulation and lasted 41.4 ± 23.7 ms (n = 122). The second pattern consisted of brief excitatory responses after the stimulation, occurring at a latency of 4.5 ± 2.5 ms (n = 72). Neurons with the two types of responses were not found in a specific topographic organization.
The results suggest that electrical stimulation of the STN has prominent effects on SNc activity. The inhibitory responses are likely due to activation of SNr neurons which then would inhibit SNc neurons. Short-latency excitatory responses are likely mediated via the monosynaptic projection from STN to SNc, or via the pedunculopontine nucleus. [Jpn J Physiol 54 Suppl:S185 (2004)]
