Attentional and motivational deficits in rats withdrawn from intravenous self-administration of cocaine or heroin.
BACKGROUND
Identifying the long-term neurocognitive sequelae of drug addiction may have important implications for understanding the compulsive, chronically relapsing nature of this brain disorder.


OBJECTIVE
Our aim was to investigate the consequences of chronic intravenous self-administration of cocaine or heroin on visual attentional processes in rats.


METHODS
Adult male rats were pretrained on a five-choice serial reaction time task (5-CSRTT) of sustained visual attention and impulsivity and later trained to self-administer cocaine or heroin intravenously during multiple 'long-access' self-administration cycles. Control rats had identical training and surgical experience, but received passive infusions of saline during self-administration sessions. Executive cognitive processes of selection and inhibitory response control were evaluated 24 h after drug discontinuation and for a further 6 days prior to the next cycle of self-administration.


RESULTS
Findings indicate similar behavioural disturbances on the five-choice task in cocaine- and heroin-withdrawn rats with significantly impaired attentional accuracy, increased omissions and slower latencies to respond correctly during the early, but not late, withdrawal period. The self-administration of either drug was not associated with significant alterations in impulsive actions, and there was no evidence of persistent alterations in visual attentional performance. However, unlike rats self-administering cocaine, the motivation to collect food reward on the 5-CSRTT was significantly reduced in heroin-withdrawn animals for a period of at least 6 weeks.


CONCLUSIONS
These data, together with recent findings of attentional dysfunction during the withdrawal of intravenous self-administration of amphetamine, suggest that generically different drugs of abuse produce similar disturbances in visual attentional performance during the early withdrawal period.
Dalley
Jeffrey W
JW
MRC Centre for Behavioural and Clinical Neuroscience, Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK. jwd20@cam.ac.uk
Lääne
Kristjan
K
Pena
Yolanda
Y
Theobald
David E H
DE
Everitt
Barry J
BJ
Robbins
Trevor W
TW
D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects*; D000704:Analysis of Variance; D000818:Animals; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D001522:Behavior, Animal / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage / Q000009:adverse effects*; D003216:Conditioning, Operant / Q000187:drug effects; D004333:Drug Administration Routes; D005108:Extinction, Psychological / Q000187:drug effects; D003932:Heroin / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D009042:Motivation; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D012054:Reinforcement, Psychology; D012646:Self Administration; D019966:Substance-Related Disorders / Q000150:complications* / Q000523:psychology; D013997:Time Factors
D000700:Analgesics; D003932:Heroin; D003042:Cocaine