Duration Selectivity in Right Parietal Cortex Reflects the Subjective Experience of Time

Abstract

The perception of duration in the subsecond range has been hypothesized to be mediated by the population response of duration-sensitive units, each tuned to a preferred duration. One line of support for this hypothesis comes from neuroimaging studies showing that cortical regions, such as in parietal cortex exhibit duration tuning. It remains unclear if this representation is based on the physical duration of the sensory input or the subjective duration, a question that is important given that our perception of the passage of time is often not veridical, but rather, biased by various contextual factors. Here we used fMRI to examine the neural correlates of subjective time perception in human participants. To manipulate perceived duration while holding physical duration constant, we employed an adaptation method, in which, prior to judging the duration of a test stimulus, the participants were exposed to a train of adapting stimuli of a fixed duration. Behaviorally, this procedure produced a pronounced negative aftereffect: A short adaptor biased participants to judge stimuli as longer and a long adaptor biased participants to judge stimuli as shorter. Duration tuning modulation, manifest as an attenuated BOLD response to stimuli similar in duration to the adaptor, was only observed in the right supramarginal gyrus (SMG) of the parietal lobe and middle occipital gyrus, bilaterally. Across individuals, the magnitude of the behavioral aftereffect was positively correlated with the magnitude of duration tuning modulation in SMG. These results indicate that duration-tuned neural populations in right SMG reflect the subjective experience of time. 3 Significance statement The subjective sense of time is a fundamental dimension of sensory experience. To investigate the neural basis of subjective time, we conducted an fMRI study, using an adaptation procedure that allowed us to manipulate perceived duration while holding physical duration constant. Regions within the occipital cortex and right parietal lobe showed duration tuning that was modulated when the test stimuli were similar in duration to the adaptor. Moreover, the magnitude of the distortion in perceived duration was correlated with the degree of duration tuning modulation in the parietal region. These results provide strong physiological evidence that the population coding of time in the right parietal cortex reflects our subjective experience of time.

Temporal enhancement of cross-adaptation between density and size perception based on the theory of magnitude

“…A possible mechanism would be that a common system to code magnitude adapts to the temporal number of a particular presentation because it also estimates the temporal presentation number, and temporal duration could be coded there (12–14). The temporal frequency and velocity of stimuli affect the perceived duration (e.g.…”

Change biases identify the features that drive time perception

“…This idea is additionally supported by findings regarding duration after-effects, the phenomenon that after repeated presentation of the same duration, subsequent temporal judgements are skewed away from the adapter duration, suggesting the existence of 'duration channels' (Becker & Rasmussen, 2007;Heron et al, 2012;Maarseveen et al, 2017;Walker et al, 1981). Recent research on such duration adaptation related this phenomenon to changing neural responses in the parietal cortex, suggesting that this is a key site for representing durations in a manner that is sensitive to the magnitude of neural responses (Hayashi et al, 2015;Hayashi & Ivry, 2020). Future neuroimaging studies might therefore similarly be able to relate the change biases of the present study to response attenuation in the parietal cortex.…”

“…In recent years, more advanced analysis techniques and the usage of 7T fMRI have made it possible to further partial out such networks into topographic maps, where different adjacent neural populations selectively respond to different intervals. Such chronotopic maps were first identified in the supplementary motor area and in the intraparietal sulcus (Protopapa et al, 2019), and later in the right parietal cortex in a study explicitly relating them to subjective temporal perception (Hayashi & Ivry, 2020). Harvey et al (2020) presented evidence indicative of a hierarchically organized network of maps that range from from dorsal to anterior cortical areas.…”

Change biases identify the features that drive time perception.

“…This idea is additionally supported by findings regarding duration aftereffects, the phenomenon that after repeated presentation of the same duration, subsequent temporal judgments are skewed away from the adapter duration, suggesting the existence of “duration channels” (Becker & Rasmussen, 2007; Heron et al, 2012; Maarseveen et al, 2017; Walker et al, 1981). Recent research on such duration adaptation related this phenomenon to changing neural responses in the parietal cortex, suggesting that this is a key site for representing durations in a manner that is sensitive to the magnitude of neural responses (Hayashi et al, 2015; Hayashi & Ivry, 2020). Future neuroimaging studies might therefore similarly be able to relate the change biases of the present study to response attenuation in the parietal cortex.…”