A systematic examination of the neural correlates of subjective time perception with fMRI and tDCS = 運用功能性腦磁力共振與直接電流刺激（tDCS）有系統地研究腦部與時間流動感知之關聯
Project title
A systematic examination of the neural correlates of subjective time perception with fMRI and tDCS = 運用功能性腦磁力共振與直接電流刺激（tDCS）有系統地研究腦部與時間流動感知之關聯
Principal Investigator
Department
Grant Awarding Body
Research Grants Council
Grant Type
Faculty Development Scheme
Project Code
UGC/FDS15/M01/17
Amount awarded
$709,742
Funding Year
2017
Duration of the Project
24 months
Status
Completed
Abstract
The ability to measure the passage of time is a crucial survival skill. However, it is well known that the subjective experience of time is not the same as its true duration. Factors influencing the subjective experience of time include physical stimuli and an individual’s cognitive and emotional state. Most people either overestimate or underestimate time. Thus, an individual’s normal timing system is easily affected by surrounding factors, yet it is highly important for daily life. Consequently, researchers are very interested in the mechanisms of human perceptions of time.
The attentional gate model is the most common conceptual framework in studies of subjective time perception. It has three major components: a pacemaker that periodically generates mental ticks, a gate switch monitor that counts these ticks and an accumulator that accrues the counts. The accumulator works closely with memory to affect decisions about the passage of time and relevant behaviour. This conceptual framework provides the basis for hypotheses regarding how various factors affect subjective time perception. Although its utility has been well established, the attentional gate model has been criticised for its lack of neurophysiological support; few studies have attempted to systematically identify its components and their neural correlates. Recent studies of animals provide support for the alternative striatal beat frequency theory (SBF), which explains the neural correlates of subjective time perception in terms of dopaminergic connections between brain regions.
This proposed study will examine two potential neurophysiological cortical correlates of subjective time perception to test hypotheses formulated based on the attentional gate model. Previous studies have established that the dorsolateral prefrontal cortex (DLPFC) is associated with working memory tasks and that there is a correlation between activity in the cerebellum and the timing of tasks. An fMRI study will first be administered to confirm that these two cortical regions are activated during the execution of a time bisection task. It is hypothesised that if these areas are the neural correlates of the attentional gate model, perturbing the neural activities within these areas may change subjective time perception. To perturb neural activities in a noninvasive way, this proposed study will use transcranial direct current stimulation (tDCS). If the two areas (DLPFC and cerebellum) are indeed the anatomical loci of subjective time perception, then perturbing their activities will influence subjective time experience. Otherwise, the stimulation will not influence the participant’s subjective time experience or will only result in a non-specific influence related to the tingling sensation caused by the tDCS.
The participants will complete two tasks, a time bisection task to measure subjective time experience and an attention network task (ANT) to provide an alternative behavioural measurement. The attentional gate model is a conceptual framework for understanding attention and working memory. If tDCS perturbation influences time perception in the manner predicted by the attentional gate model, then a corresponding influence will be detectable in attention-related tasks, as these are both components of the model. ANT will provide performance measurements of alerting, orienting and executive control. We expect that tDCS perturbation will lead to ANT results that align with changes in the perceived duration.
In summary, the proposed study will explore the possibility of causally manipulating subjective time experience using tDCS perturbation. We will first use an fMRI study to confirm that our selected cortical areas are activated during a time bisection task. Specific hypotheses will be drawn based on the attentional gate model. In addition to a time bisection task, ANT will be administered to provide an alternative measurement of performance related to the attentional gate model. The findings will offer novel evidence for the physiological basis of time perception, will test the attentional gate model and will provide a framework for future studies in the field.
The attentional gate model is the most common conceptual framework in studies of subjective time perception. It has three major components: a pacemaker that periodically generates mental ticks, a gate switch monitor that counts these ticks and an accumulator that accrues the counts. The accumulator works closely with memory to affect decisions about the passage of time and relevant behaviour. This conceptual framework provides the basis for hypotheses regarding how various factors affect subjective time perception. Although its utility has been well established, the attentional gate model has been criticised for its lack of neurophysiological support; few studies have attempted to systematically identify its components and their neural correlates. Recent studies of animals provide support for the alternative striatal beat frequency theory (SBF), which explains the neural correlates of subjective time perception in terms of dopaminergic connections between brain regions.
This proposed study will examine two potential neurophysiological cortical correlates of subjective time perception to test hypotheses formulated based on the attentional gate model. Previous studies have established that the dorsolateral prefrontal cortex (DLPFC) is associated with working memory tasks and that there is a correlation between activity in the cerebellum and the timing of tasks. An fMRI study will first be administered to confirm that these two cortical regions are activated during the execution of a time bisection task. It is hypothesised that if these areas are the neural correlates of the attentional gate model, perturbing the neural activities within these areas may change subjective time perception. To perturb neural activities in a noninvasive way, this proposed study will use transcranial direct current stimulation (tDCS). If the two areas (DLPFC and cerebellum) are indeed the anatomical loci of subjective time perception, then perturbing their activities will influence subjective time experience. Otherwise, the stimulation will not influence the participant’s subjective time experience or will only result in a non-specific influence related to the tingling sensation caused by the tDCS.
The participants will complete two tasks, a time bisection task to measure subjective time experience and an attention network task (ANT) to provide an alternative behavioural measurement. The attentional gate model is a conceptual framework for understanding attention and working memory. If tDCS perturbation influences time perception in the manner predicted by the attentional gate model, then a corresponding influence will be detectable in attention-related tasks, as these are both components of the model. ANT will provide performance measurements of alerting, orienting and executive control. We expect that tDCS perturbation will lead to ANT results that align with changes in the perceived duration.
In summary, the proposed study will explore the possibility of causally manipulating subjective time experience using tDCS perturbation. We will first use an fMRI study to confirm that our selected cortical areas are activated during a time bisection task. Specific hypotheses will be drawn based on the attentional gate model. In addition to a time bisection task, ANT will be administered to provide an alternative measurement of performance related to the attentional gate model. The findings will offer novel evidence for the physiological basis of time perception, will test the attentional gate model and will provide a framework for future studies in the field.