Differential effects of cocaine and ketamine on time estimation: Implications for neurobiological models of interval timing
Cheng RK, Macdonald CJ, Meck WH.
Department of Psychology and Neuroscience,
Genome Sciences Research Building II - 3rd Floor,
572 Research Drive - Box 91050,
Duke University, Durham, North Carolina 27708, USA.
Pharmacol Biochem Behav. 2006 Sep;85(1):114-22.


The present experiment examined the effects of cocaine (0.0 and 15 mg/kg, i.p.) and ketamine (0.0, 10.0 and 15 mg/kg, i.p.) on timing behavior using a 12-s differential reinforcement of low rates (DRL) procedure and a 2- vs. 8-s bisection procedure in rats. DRL (time production) and bisection (time perception) procedures are sensitive to effects of dopaminergic drugs and provide an assessment of the accuracy and precision of interval timing as well as the subject's level of impulsivity. When administered to rats trained on either the DRL or the bisection procedure, cocaine shifted the psychophysical functions leftward relative to control conditions. In contrast, ketamine produced no change in the temporal control of behavior on either procedure. These differential effects of cocaine and ketamine are consistent with previous reports suggesting that dopamine levels in the dorsal striatum, but not in prefrontal cortex, ventral striatum or hippocampal regions, are crucial for the regulation of the speed of an internal clock.

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Ketamine and cognition
Anaesthesia and anaesthetics
Ketamine: long-term outcomes
Ketamine as an antidepressant
Ketamine: medical and non-medical use
The role of ketamine in pain management
Low-dose ketamine as a fast-onset, long-acting antidepressant

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The Abolitionist Project
The Hedonistic Imperative
MDMA: Utopian Pharmacology
Dissociative Anaesthetics: Ketamine

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