Objective: The aim of our study was to investigate the effects of stimulation in the rat entopeduncular nucleus (EPN) on single neuronal activity of the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAC) and coherence of oscillatory activity with sensorimotor cortex.

Background: Deficient sensorimotor gating induced by dopamine receptor agonists is used as an endophenotype for certain neuropsychiatric disorders, such as Tourette´s syndrome. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is experimentally used to alleviate tics in Tourette`s syndrome. One operational measure of sensorimotor gating is prepulse inhibition (PPI) of the acoustic startle response (ASR). We recently showed that DBS of the rat EPN (the equivalent to the human GPi) alleviates an apomorphine induced PPI deficit.

Methods: 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 mPFC and 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 was not affected by apomorphine injection in both regions, but enhanced after stimulation in the NAC. Measures of irregularity were enhanced after apomorphine injection in both regions. Stimulation normalized this measure in the NAC, but had no effect in the mPFC. Coherence of oscillatory theta (4-8 Hz) and alpha (8-12 Hz) band activity between the mPFC and NAC local field potentials and sensory motor cortical field potentials was enhanced after apomorphine injection. EPN stimulation reduced theta and alpha coherence in the NAC, while in the PFC only alpha activity was reduced.

Conclusions: These investigations shed new light on the effect of DBS on disturbed neuronal network activity in an animal model with sensorimotor gating deficit, which may be used to understand and improve this experimental therapy in neuropsychiatric disorders.

(Data have been presented at the ESSFN 2016 in Madrid)

« Back to 2017 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/stimulation-in-the-nucleus-entopeduncularis-affects-neuronal-activity-in-the-nucleus-accumbens-and-medial-prefrontal-cortex-after-apomorphine-induced-deficient-prepulse-inhibition-in-rats/