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Time Adaptation Shows Duration Selectivity in the Human Parietal Cortex.

Hayashi MJ, Ditye T, Harada T, Hashiguchi M, Sadato N, Carlson S, Walsh V, Kanai R - PLoS Biol. (2015)

Bottom Line: Adaptation was strongest when stimuli of identical durations were repeated, and it gradually decreased as the difference between the reference and test durations increased.Repetition of a nontemporal aspect of the stimulus (i.e., shape) did not produce neural adaptation in the IPL.These results provide neural evidence for duration-tuned representations in the human brain.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Frontier Biosciences, Osaka University, Suita, Japan; School of Psychology, University of Sussex, Brighton, United Kingdom; Institute of Cognitive Neuroscience, University College London, London, United Kingdom; Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.

ABSTRACT
Although psychological and computational models of time estimation have postulated the existence of neural representations tuned for specific durations, empirical evidence of this notion has been lacking. Here, using a functional magnetic resonance imaging (fMRI) adaptation paradigm, we show that the inferior parietal lobule (IPL) (corresponding to the supramarginal gyrus) exhibited reduction in neural activity due to adaptation when a visual stimulus of the same duration was repeatedly presented. Adaptation was strongest when stimuli of identical durations were repeated, and it gradually decreased as the difference between the reference and test durations increased. This tuning property generalized across a broad range of durations, indicating the presence of general time-representation mechanisms in the IPL. Furthermore, adaptation was observed irrespective of the subject's attention to time. Repetition of a nontemporal aspect of the stimulus (i.e., shape) did not produce neural adaptation in the IPL. These results provide neural evidence for duration-tuned representations in the human brain.

No MeSH data available.


Effects of duration adaptation during the graded-shape task in experiment 3.(A) Results of experiment 3. The right SMG cluster showing duration adaptation effects during the graded-shape task is shown on a standard brain. Plots of the beta values at the peak coordinates of the cluster in the right SMG (x, y, z = 60, −44, 30) for each set of stimulus durations (B) and for each set of stimulus widths (C). The color scale indicates the T-values. Error bars indicate standard errors of the mean. Please refer to S1 Data for the numerical values underlying (B) and (C).
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pbio.1002262.g006: Effects of duration adaptation during the graded-shape task in experiment 3.(A) Results of experiment 3. The right SMG cluster showing duration adaptation effects during the graded-shape task is shown on a standard brain. Plots of the beta values at the peak coordinates of the cluster in the right SMG (x, y, z = 60, −44, 30) for each set of stimulus durations (B) and for each set of stimulus widths (C). The color scale indicates the T-values. Error bars indicate standard errors of the mean. Please refer to S1 Data for the numerical values underlying (B) and (C).

Mentions: Finally, we also examined whether the repetition of the same duration during the graded-shape task showed adaptation in the right IPL. Plots of the relationship between BOLD responses and the test duration conditions at the same coordinates as in Fig 5A and 5B are shown in Fig 5C and 5D. Although the duration adaptation was not very clear at these coordinates, we instead found that the slightly more posterior part of the right IPL (SMG) showed a significant graded adaptation to stimulus durations (Fig 6). These results further support our findings in experiments 1 and 2 that neural adaptation to the repetition of identical duration in the right IPL (SMG) occurred regardless of whether the durations were explicitly estimated.


Time Adaptation Shows Duration Selectivity in the Human Parietal Cortex.

Hayashi MJ, Ditye T, Harada T, Hashiguchi M, Sadato N, Carlson S, Walsh V, Kanai R - PLoS Biol. (2015)

Effects of duration adaptation during the graded-shape task in experiment 3.(A) Results of experiment 3. The right SMG cluster showing duration adaptation effects during the graded-shape task is shown on a standard brain. Plots of the beta values at the peak coordinates of the cluster in the right SMG (x, y, z = 60, −44, 30) for each set of stimulus durations (B) and for each set of stimulus widths (C). The color scale indicates the T-values. Error bars indicate standard errors of the mean. Please refer to S1 Data for the numerical values underlying (B) and (C).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4574920&req=5

pbio.1002262.g006: Effects of duration adaptation during the graded-shape task in experiment 3.(A) Results of experiment 3. The right SMG cluster showing duration adaptation effects during the graded-shape task is shown on a standard brain. Plots of the beta values at the peak coordinates of the cluster in the right SMG (x, y, z = 60, −44, 30) for each set of stimulus durations (B) and for each set of stimulus widths (C). The color scale indicates the T-values. Error bars indicate standard errors of the mean. Please refer to S1 Data for the numerical values underlying (B) and (C).
Mentions: Finally, we also examined whether the repetition of the same duration during the graded-shape task showed adaptation in the right IPL. Plots of the relationship between BOLD responses and the test duration conditions at the same coordinates as in Fig 5A and 5B are shown in Fig 5C and 5D. Although the duration adaptation was not very clear at these coordinates, we instead found that the slightly more posterior part of the right IPL (SMG) showed a significant graded adaptation to stimulus durations (Fig 6). These results further support our findings in experiments 1 and 2 that neural adaptation to the repetition of identical duration in the right IPL (SMG) occurred regardless of whether the durations were explicitly estimated.

Bottom Line: Adaptation was strongest when stimuli of identical durations were repeated, and it gradually decreased as the difference between the reference and test durations increased.Repetition of a nontemporal aspect of the stimulus (i.e., shape) did not produce neural adaptation in the IPL.These results provide neural evidence for duration-tuned representations in the human brain.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Frontier Biosciences, Osaka University, Suita, Japan; School of Psychology, University of Sussex, Brighton, United Kingdom; Institute of Cognitive Neuroscience, University College London, London, United Kingdom; Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.

ABSTRACT
Although psychological and computational models of time estimation have postulated the existence of neural representations tuned for specific durations, empirical evidence of this notion has been lacking. Here, using a functional magnetic resonance imaging (fMRI) adaptation paradigm, we show that the inferior parietal lobule (IPL) (corresponding to the supramarginal gyrus) exhibited reduction in neural activity due to adaptation when a visual stimulus of the same duration was repeatedly presented. Adaptation was strongest when stimuli of identical durations were repeated, and it gradually decreased as the difference between the reference and test durations increased. This tuning property generalized across a broad range of durations, indicating the presence of general time-representation mechanisms in the IPL. Furthermore, adaptation was observed irrespective of the subject's attention to time. Repetition of a nontemporal aspect of the stimulus (i.e., shape) did not produce neural adaptation in the IPL. These results provide neural evidence for duration-tuned representations in the human brain.

No MeSH data available.