title: Electrophysiological evidence of alterations to the nucleus accumbens and dorsolateral striatum during chronic cocaine self-administration.
abstract: As drug use becomes chronic, aberrant striatal processing contributes to the development of perseverative drug-taking behaviors. Two particular portions of the striatum, the nucleus accumbens (NAc) and the dorsolateral striatum (DLS), are known to undergo neurobiological changes from acute to chronic drug use. However, little is known about the exact progression of changes in functional striatal processing as drug intake persists. We sampled single-unit activity in the NAc and DLS throughout 24 daily sessions of chronic long-access cocaine self-administration, and longitudinally tracked firing rates (FR) specifically during the operant response, an upward vertical head movement. A total of 103 neurons were held longitudinally and immunohistochemically localised to either NAc Medial Shell (n = 29), NAc Core (n = 30), or DLS (n = 54). We modeled changes representative of each category as a whole. Results demonstrated that FRs of DLS Head Movement neurons were significantly increased relative to baseline during all sessions, while FRs of DLS Uncategorised neurons were significantly reduced relative to baseline during all sessions. NAc Shell neurons' FRs were also significantly decreased relative to baseline during all sessions while FRs of NAc Core neurons were reduced relative to baseline only during training days 1-18 but were not significantly reduced on the remaining sessions (19-24). The data suggest that all striatal subregions show changes in FR during the operant response relative to baseline, but longitudinal changes in response firing patterns were observed only in the NAc Core, suggesting that this region is particularly susceptible to plastic changes induced by abused drugs.
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Coffey
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Barker
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Nick
authors.initials: N
authors.lastname: Gayliard
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Julianna M
authors.initials: JM
authors.lastname: Kulik
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Pawlak
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Stamos
authors.affiliation: Department of Psychology, Rutgers University, Piscataway, NJ, 08854, USA.
authors.forename: Mark O
authors.initials: MO
authors.lastname: West
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D058256:Brain Waves / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects; D003342:Corpus Striatum / Q000166:cytology / Q000187:drug effects*; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D020318:Rats, Long-Evans; D012646:Self Administration
chemical_list: D000779:Anesthetics, Local; D003042:Cocaine
keywords: addiction; basal ganglia; single-unit; stimulant