Kurzfassung

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 states. 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....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 states. 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 neural 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 conducted 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.» weiterlesen» einklappen