Clock Speed as a Window into Dopaminergic Control of Emotion and Time Perception

© 2016 by Koninklijke Brill NV, Leiden, The Netherlands.Although fear-producing treatments (e.g., electric shock) and pleasure-inducing treatments (e.g., methamphetamine) have different emotional valences, they both produce physiological arousal and lead to effects on timing and time perception that have been interpreted as reflecting an increase in speed of an internal clock. In this commentary, we review the results reported by Fayolle et al. (2015): Behav. Process., 120, 135-140) and Meck (1983: J. Exp. Psychol. Anim. Behav. Process., 9, 171-201) using electric shock and by Maricq et al. (1981: J. Exp. Psychol. Anim. Behav. Process., 7, 18-30) using methamphetamine in a duration-bisection procedure across multiple duration ranges. The psychometric functions obtained from this procedure relate the proportion 'long' responses to signal durations spaced between a pair of 'short' and 'long' anchor durations. Horizontal shifts in these functions can be described in terms of attention or arousal processes depending upon whether they are a fixed number of seconds independent of the timed durations (additive) or proportional to the durations being timed (multiplicative). Multiplicative effects are thought to result from a change in clock speed that is regulated by dopamine activity in the medial prefrontal cortex. These dopaminergic effects are discussed within the context of the striatal beat frequency model of interval timing (Matell & Meck, 2004: Cogn. Brain Res., 21, 139-170) and clinical implications for the effects of emotional reactivity on temporal cognition (Parker et al., 2013: Front. Integr. Neurosci., 7, 75)