Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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BCCN/BFNT AG-Seminar

Tuesday, 23.11.2010 17 c.t.

Dopaminergic modulation of time perception

by Dr. Joachim Haß
from ZI für seelische Gesundheit, Mannheim

Contact person: Annette Witt

Location

Seminarraum Haus 2, 4. Stock (Bunsenstr.)

Abstract

Pharmacological experiments in both animal and man show that the estimation of time is affected by dopamine [1]. Specifically, the duration of time intervals is underestimated if D2 dopamine receptors are inactivated, while other dopamine receptors such as D1 have no such effect [2]. The mechanism for this phenomenon and its receptor specificity is unknown. To provide a possible explanation, we use a biophysical cortical model of time perception, and incorporate the currently known effects of D2 modulation on cellular and synaptic properties. The model relates time estimating to the slow increasing of firing rates [3] which is observed in cortical areas such as the prefrontal cortex [4]: If firing rates increase monotonically over the range of several seconds, the rate at any instant in time provides a code for the time elapsed since the start of the increase. We incorporate the effects of D2 in the prefrontal cortex, namely a decrease in both NMDA and GABA peak conductances [5]. This modulation turns out to affect the slope of the rate in such a way that increasing D2 activation yields a steeper increase, and vice versa. Thus, blocking D2 receptors indeed yields a bias towards slowing the internal clock (Fig. 1). Furthermore, we discuss the effects of the D1 dopamine receptor and its missing influence on clock speed. References [1] C. V. Buhusi and W. H. Meck (2005) Nature Neuroscience, 6:755–765. [2] W. H. Meck (1986) Pharmacology Biochemistry and Behavior, 25:1185–1189. [3] D. Durstewitz (2003) The Journal of Neuroscience 23(12):5342-5353. [4] D. Durstewitz (2004) Neuroreport, 15:745–749 [5] C. Lapish et al. (2007) Psychopharmacology, 191(3):609–625

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