Deep Brain Stimulation of the Ventral Pallidum Attenuates Epileptiform Activity and Seizing Behavior in Pilocarpine-Treated Rats

Brain Stimul. 2016 Mar-Apr;9(2):285-95. doi: 10.1016/j.brs.2015.11.006. Epub 2015 Nov 26.

Abstract

Background: Brain stimulation is effective for people with intractable epilepsy. However, modulating neural targets that provide greater efficacy to more individuals is still needed.

Objective/hypothesis: We investigate whether bilateral deep brain stimulation of the ventral pallidum (VP-DBS) has potent seizure control in pilocarpine-treated rats.

Methods: VP-DBS (50 Hz) was applied prior to generalized forebrain seizures or after generalized brainstem seizures manifested. Behavioral seizures were assessed using a modified Racine scale. In vitro and in vivo electrophysiological techniques were employed to identify how VP-DBS affects proximal and distal neuronal activity. The open field test was used to see if acute and chronic VP-DBS affected gross motor function or arousal state. Parametric and non-parametric statistics with post-hoc analysis were performed.

Results: VP-DBS prior to pilocarpine prevented behavioral forebrain and brainstem seizures in most animals (n = 15). VP-DBS after brainstem seizures emerged prevented or reduced the appearance of subsequent behavioral brainstem seizures (n = 11). VP-DBS attenuated epileptiform activity in the hippocampus (n = 5), but not in the primary somatosensory cortex (S1) (n = 4) in vivo. Electrical stimulation in the VP increased VP GABAergic neuronal firing activity from 3.1 ± 1.4 Hz to 7.6 ± 1.7 Hz (n = 8) in vitro and reduced substantia nigra reticulata and superior colliculus neuronal spiking activity from 25.4 ± 3.3 Hz to 18.2 ± 1.4 Hz (n = 6) and 18.2 ± 1.4 Hz to 11.0 ± 1.1 Hz (n = 18), respectively, in vivo.

Conclusion: VP-DBS can be a novel and potent therapeutic approach for individuals with intractable epilepsy.

Keywords: Basal ganglia; Brainstem seizures; Electrical stimulation; Epilepsy; Seizures.

MeSH terms

  • Animals
  • Arousal / physiology
  • Basal Forebrain / cytology
  • Basal Forebrain / physiopathology*
  • Deep Brain Stimulation / methods*
  • Epilepsy / physiopathology
  • Epilepsy / therapy*
  • GABAergic Neurons / metabolism
  • Hippocampus / physiopathology
  • Male
  • Motor Activity / physiology
  • Pilocarpine / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Seizures / chemically induced
  • Seizures / physiopathology
  • Seizures / prevention & control*
  • Seizures / therapy*
  • Somatosensory Cortex / physiopathology
  • Substantia Nigra / physiopathology
  • Superior Colliculi / physiopathology

Substances

  • Pilocarpine