Article

Individual Differences in the Morphometry and Activation of Time Perception Networks are Influenced by Dopamine Genotype.

Center for Cognitive Neuroscience, University of Pennsylvania. Electronic address: .
NeuroImage (Impact Factor: 6.36). 11/2013; 89. DOI: 10.1016/j.neuroimage.2013.11.019
Source: PubMed

ABSTRACT Individual participants vary greatly in their ability to estimate and discriminate intervals of time. This heterogeneity of performance may be caused by reliance on different time perception networks as well as individual differences in the activation of brain structures utilized for timing within those networks. To address these possibilities we utilized event-related functional magnetic resonance imaging (fMRI) while human participants (n=25) performed a temporal or color discrimination task. Additionally, based on our previous research, we genotyped participants for DRD2/ANKK1-Taq1a, a single-nucleotide polymorphism associated with a 30-40% reduction in striatal D2 density and associated with poorer timing performance. Similar to previous reports, a wide range of performance was found across our sample; crucially, better performance on the timing versus color task was associated with greater activation in prefrontal and sub-cortical regions previously associated with timing. Furthermore, better timing performance also correlated with increased volume of the right lateral cerebellum, as demonstrated by voxel-based morphometry. Our analysis also revealed that A1 carriers of the Taq1a polymorphism exhibited relatively worse performance on temporal, but not color discrimination, but greater activation in the striatum and right dorsolateral prefrontal cortex, as well as reduced volume in the cerebellar cluster. These results point to the neural bases for heterogeneous timing performance in humans, and suggest that differences in performance on a temporal discrimination task are, in part, attributable to the DRD2/ANKK1 genotype.

Download full-text

Full-text

Available from: Yune Sang Lee, Dec 31, 2013
1 Follower
 · 
82 Views
  • Source
    • "Remarkably too, the % CR was higher for long than for short exposition in the color task, hinting that attention was caught during the full stimulus exposition and that the performance was improved as more time was available to treat the visual stimulus content . Finally, a Pearson correlation analysis revealed no significant correlation between the % CR obtained in the duration task and that obtained in the color task, which is in line with previous studies [Gilaie-Dotan et al., 2011; Wiener et al., 2014] and suggests that separate mechanisms are involved in temporal and color processing. The imaging results of the localizer task uncovered the existence of two distinct neural networks that were specifically activated, one, during the color task contrasted to the duration task and, the other, during the duration task contrasted to the color task. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The reason why human beings are inclined to overestimate the duration of highly arousing negative events remains enigmatic. The issue about what neurocognitive mechanisms and neural structures support the connection between time perception and emotion was addressed here by an event-related neuroimaging study involving a localizer task, followed by the main experiment. The localizer task, in which participants had to categorize either the duration or the average color of visual stimuli aimed at identifying the neural structures constitutive of a duration-specific network. The aim of the main experiment, in which participants had to categorize the presentation time of either neutral or emotionally negative visual stimuli, was to unmask which parts of the previously identified duration-specific network are sensitive to emotionally negative arousal. The duration-specific network that we uncovered from the localizer task comprised the cerebellum bilaterally as well as the orbitofrontal, the anterior cingulate, the anterior insular, and the inferior frontal cortices in the right hemisphere. Strikingly, the imaging data from the main experiment underscored that the right inferior frontal cortex (IFC) was the only region within the duration-specific network whose activity was increased in the face of emotionally negative pictures compared to neutral ones. Remarkably too, the extent of neural activation induced by emotionally negative pictures (compared to neutral ones) in this region correlated with a behavioral index reflecting the extent to which emotionally negative pictures were overestimated compared to neutral ones. The results are discussed in relation to recent models and studies suggesting that the right anterior insular cortex/IFC is of central importance in time perception. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc.
    Human Brain Mapping 10/2014; 36(3). DOI:10.1002/hbm.22680 · 6.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The capacity to synchronize movements to the beat in music is a complex, and apparently uniquely human characteristic. Synchronizing movements to the beat requires beat perception, which entails prediction of future beats in rhythmic sequences of temporal intervals. Absolute timing mechanisms, where patterns of temporal intervals are encoded as a series of absolute durations, cannot fully explain beat perception. Beat perception seems better accounted for by relative timing mechanisms, where temporal intervals of a pattern are coded relative to a periodic beat interval. Evidence from behavioral, neuroimaging, brain stimulation and neuronal cell recording studies suggests a functional dissociation between the neural substrates of absolute and relative timing. This chapter reviews current findings on relative timing in the context of rhythm and beat perception.
    Advances in Experimental Medicine and Biology 01/2014; 829:325-38. DOI:10.1007/978-1-4939-1782-2_17 · 2.01 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Our perception of time constrains our experience of the world and exerts a pivotal influence over a myriad array of cognitive and motor functions. There is emerging evidence that the perceived duration of subsecond intervals is driven by sensory-specific neural activity in human and nonhuman animals, but the mechanisms underlying individual differences in time perception remain elusive. We tested the hypothesis that elevated visual cortex GABA impairs the coding of particular visual stimuli, resulting in a dampening of visual processing and concomitant positive time-order error (relative underestimation) in the perceived duration of subsecond visual intervals. Participants completed psychophysical tasks measuring visual interval discrimination and temporal reproduction and we measured in vivo resting state GABA in visual cortex using magnetic resonance spectroscopy. Time-order error selectively correlated with GABA concentrations in visual cortex, with elevated GABA associated with a rightward horizontal shift in psychometric functions, reflecting a positive time-order error (relative underestimation). These results demonstrate anatomical, neurochemical, and task specificity and suggest that visual cortex GABA contributes to individual differences in time perception.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 03/2014; 34(12):4364-70. DOI:10.1523/JNEUROSCI.3972-13.2014 · 6.75 Impact Factor
Show more