A proxy measure of striatal dopamine predicts individual differences in temporal precision

Abstract

The perception of time is characterized by pronounced variability across individuals, with implications for a diverse array of psychological functions. The neurocognitive sources of this variability are poorly understood, but accumulating evidence suggests a role for inter-individual differences in striatal dopamine levels. Here we present a pre-registered study that tested the predictions that spontaneous eyeblink rates, which provide a proxy measure of striatal dopamine availability, would be associated with aberrant interval timing (lower temporal precision or overestimation bias). Neurotypical adults (N = 69) underwent resting state eye tracking and completed visual psychophysical interval timing and control tasks. Elevated spontaneous eyeblink rates were associated with poorer temporal precision but not with inter-individual differences in perceived duration or performance on the control task. These results signify a role for striatal dopamine in variability in human time perception and can help explain deficient temporal precision in psychiatric populations characterized by elevated dopamine levels.

Keywords: Dopamine; Eye-tracking; Schizophrenia; Temporal cognition; Time perception.

Fig. 1

PF models of task performance. The lines in saturated colors show spline-interpolated sample means of actual p(response) for each stimulus. Top row: The pale grey lines represent individual PFs for all participants and the vertical lines denote veridical and perceived bisection points (BPs). Circular markers and error bars denote sample means and 95% bootstrapped confidence intervals for the proportions of long [p(long)] or red [p(red)] responses. Bottom row: Group PFs for low, medium, and high eyeblink rate (EBR) terciles. To improve legibility of the overlapping error bars, only the lower limits are plotted

Fig. 2

Individual Weber fractions (WFs; blue) and bisection points (BPs; green) as a function of spontaneous eyeblink rate (EBR). Square brackets denote bootstrapped 95% confidence intervals. Plots show original non-ranked data with winsorized outliers, and the least-squares line fit for visualization purposes. r_s = Spearman correlation. * p<.05