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Alcohol‐Preferring P Rats Exhibit Elevated Motor Impulsivity Concomitant with Operant Responding and Self‐Administration of Alcohol
Author(s) -
Beckwith Steven Wesley,
Czachowski Cristine Lynn
Publication year - 2016
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/acer.13044
Subject(s) - impulsivity , self administration , delay discounting , psychology , alcohol , extinction (optical mineralogy) , operant conditioning , conditioning , reinforcement , medicine , endocrinology , developmental psychology , chemistry , social psychology , biochemistry , mineralogy , statistics , mathematics
Background Increased levels of impulsivity are associated with increased illicit drug use and alcoholism. Previous research in our laboratory has shown that increased levels of delay discounting (a decision‐making form of impulsivity) are related to appetitive processes governing alcohol self‐administration as opposed to purely consummatory processes. Specifically, the high‐seeking/high‐drinking alcohol‐preferring P rats showed increased delay discounting compared to nonselected Long Evans rats ( LE ) whereas the high‐drinking/moderate‐seeking HAD 2 rats did not. The P rats also displayed a perseverative pattern of behavior such that during operant alcohol self‐administration they exhibited greater resistance to extinction. Methods One explanation for the previous findings is that P rats have a deficit in response inhibition. This study followed up on this possibility by utilizing a countermanding paradigm (stop signal reaction time [ SSRT ] task) followed by operant self‐administration of alcohol across increasing fixed ratio requirements ( FR ; 1, 2, 5, 10, and 15 responses). In separate animals, 24‐hour access 2‐bottle choice (10% Et OH vs. water) drinking was assessed. Results In the SSRT task, P rats exhibited an increased SSRT compared to both LE and HAD 2 rats indicating a decrease in behavioral inhibition in the P rats. Also, P rats showed increased operant self‐administration across all FR s and the greatest increase in responding with increasing FR requirements. Conversely, the HAD 2 and LE had shorter SSRT s and lower levels of operant alcohol self‐administration. However, for 2‐bottle choice drinking HAD 2s and P rats consumed more Et OH and had a greater preference for Et OH compared to LE . Conclusions These data extend previous findings showing the P rats to have increased delay discounting (decision‐making impulsivity) and suggest that P rats also have a lack of behavioral inhibition (motor impulsivity). This supports the notion that P rats are a highly impulsive as well as “high‐seeking” model of alcoholism, and that the HAD2s' elevated levels of alcohol consumption are not mediated via appetitive processes or impulsivity.