Modulation of medial geniculate nucleus neuronal activity by electrical stimulation of the nucleus accumbens.
Dysfunctional sensory gating has been proposed to result in the generation of phantom perceptions. In agreement, it has been recently suggested that tinnitus, a phantom perception of sound commonly associated with hearing loss, is the result of a breakdown of circuitry involving the limbic system and the medial geniculate nucleus (MGN) of the thalamus. In humans with tinnitus, structural changes and abnormal activity have been found to occur in the auditory pathway as well as parts of the limbic system such as the nucleus accumbens (NAc). However, at present, no studies have been conducted on the influence of the NAc on the MGN. We investigated the functional connectivity between the NAc and MGN single neurons. Bipolar electrical stimulation was delivered to the NAc while recording single neuron activity in MGN in anesthetized Wistar rats. Histological analysis was used to confirm placement of electrodes. NAc electrical stimulation generally decreased spontaneous firing rates in MGN neurons and, in a limited number of neurons, caused an increase in firing rate. This suggests that NAc can modulate the activity of auditory neurons in the MGN and may play a role in the development of tinnitus.
The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
K M
KM
Barry
School of Health Sciences, RMIT University, Bundoora, Victoria, Australia; School of Psychology and Public Health, La Trobe University, Bundoora, Victoria, Australia.
A G
AG
Paolini
The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
D
D
Robertson
The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia. Electronic address: helmy.mulders@uwa.edu.au.
W H A M
WH
Mulders
D000161:Acoustic Stimulation; D000200:Action Potentials; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D001307:Auditory Perception / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D005829:Geniculate Bodies / Q000502:physiology*; D008297:Male; D008839:Microelectrodes; D023421:Models, Animal; D009434:Neural Pathways / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology; D009474:Neurons / Q000502:physiology*; D009714:Nucleus Accumbens / Q000502:physiology*; D010197:Pancuronium / Q000494:pharmacology; D010243:Paralysis / Q000503:physiopathology; D017208:Rats, Wistar; D014520:Urethane / Q000494:pharmacology
D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D014520:Urethane; D010197:Pancuronium
electrophysiology; limbic system; medial geniculate nucleus; nucleus accumbens; tinnitus