Article
Effects of deep brain stimulation in the nucleus entopeduncularis on neuronal network activity after apomorphine-induced deficient sensorimotor gating in a rat model
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Authors
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Kerstin Schwabe
- Department of Neurosurgery, Medical School Hannover, Germany
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Götz Lütjens
- Department of Neurosurgery, Medical School Hannover, Germany
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Joachim K. Krauss
- Department of Neurosurgery, Medical School Hannover, Germany
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Mesbah Alam
- Department of Neurosurgery, Medical School Hannover, Germany
| Published: | June 8, 2016 |
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Outline
Text
Objective: Deficient sensorimotor gating induced by dopamine receptor agonists is used as an endophenotype for certain neuropsychiatric disorders, such as Tourette's syndrome (TS), schizophrenia, and attention deficit disorders. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is experimentally used to alleviate tics in TS. One operational measure of sensorimotor gating is prepulse inhibition (PPI) of the acoustic startle response (ASR). We recently showed that DBS of the rat nucleus entopeduncularis (EPN, the equivalent to the human GPi) alleviates an apomorphine-induced PPI deficit. The aim of our study was to investigate the effects of stimulation in the EPN on single neuronal activity of the nucleus accumbens (NAC) and coherence of oscillatory activity with sensorimotor cortex.
Method: Neuronal recordings were carried out in urethane anesthetized (1.4 g/kg, i.p.) male Sprague-Dawley rats. A concentric bipolar electrode for stimulation was stereotaxically implanted in the EPN. Single neuronal recordings were acquired from the NAC before and after apomorphine-injection (1mg/kg BW). Thereafter, 60 sec EPN stimulation (130 Hz, 100 µA current, with 120 µs biphasic square wave pulses) was applied and the neuronal activity recorded.
Results: Neuronal firing rate and burst activity in the NAC was not affected by apomorphine-injection, whereas firing rate was significantly increased and burst activity significantly decreased by EPN stimulation. The coefficient of variation (CV, a measure of regularity) was enhanced after apomorphine-injection, but normalized by stimulation. The coherence of oscillatory theta (4-8 Hz) and alpha (8-12 Hz) band activity between the NAC local field potentials and sensory motor cortical field potentials was enhanced after apomorphine-injection, but significantly reduced after EPN stimulation.
Conclusions: These investigations shed new light on the effect of DBS on disturbed neuronal network activity in an animal model of TS, which may be used to understand and improve this experimental therapy in neuropsychiatric disorders.
