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Electrophysiological evidence of alterations to the nucleus accumbens and dorsolateral striatum during chronic cocaine self‐administration
Author(s) -
Coffey Kevin R.,
Barker David J.,
Gayliard Nick,
Kulik Julianna M.,
Pawlak Anthony P.,
Stamos Joshua P.,
West Mark O.
Publication year - 2015
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12904
Subject(s) - nucleus accumbens , striatum , ventral striatum , neuroscience , self administration , medium spiny neuron , psychology , electrophysiology , medicine , basal ganglia , central nervous system , dopamine
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 ( NA c) 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 NA c 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 NA c Medial Shell ( n = 29), NA c Core ( n = 30), or DLS ( n = 54). We modeled changes representative of each category as a whole. Results demonstrated that FR s of DLS Head Movement neurons were significantly increased relative to baseline during all sessions, while FR s of DLS Uncategorised neurons were significantly reduced relative to baseline during all sessions. NA c Shell neurons' FR s were also significantly decreased relative to baseline during all sessions while FR s of NA c 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 NA c Core, suggesting that this region is particularly susceptible to plastic changes induced by abused drugs.