Biology subjects
Publications and source records attributed to Baykan, C..
Humans and non-human animals adaptively boost their encoding speed when they expect limited sensory exposure time, so that they can capture essential information before it is gone. However, it is unclear how the brain implements this crucial adaptation. Using multivariate pattern analysis of human EEG data, we found that an accelerated neural code underlies adaptations in visual working memory encoding speed.
Duration judgments are calibrated by the statistics of recent temporal experience, but how this contextual influence is expressed across human timing-related brain regions remains unclear. We used functional MRI while 24 participants performed a visual temporal bisection task under two distributional contexts: one biased toward longer durations and one biased toward shorter durations. Behaviorally, distributional context shifted subjective duration judgments without changing in temporal precision, consistent with a prior-related bias. Neurally, duration-related BOLD responses varied across a priori timing regions as a function of context. The clearest region-specific evidence was stronger left-insula duration modulation in the short-biased context. SMA/pre-SMA contributed to the broader timing-network pattern, and its context-specific asymmetry was sensitive to the alignment of the duration regressor. Exploratory SMA-seeded connectivity analyses provided converging evidence that context also modulated duration-related coupling with timing- and attention-related regions. Together, these findings indicate that distributional context impacts the relative weighting of established timing-related regions during duration judgments, rather than recruiting anatomically separate timing systems.
Despite relatively accurate time judgment, subjective time is susceptible to various contexts, such as sample spacing and frequency. Several electroencephalographic (EEG) components have been linked to timing, including the contingent negative variation (CNV), offset P2, and late positive component of timing (LPCt). However, the specific role of these components in the contextual modulation of perceived time remains unclear. In this study, we conducted two temporal bisection experiments, where participants had to judge if a test duration was close to a short or long standard. Unbeknownst to participants, the sample spacing (Experiment 1) and frequency (Experiment 2) were altered to create short and long contexts while keeping the test range and standards the same in different sessions. The results showed that the bisection threshold shifted toward the ensemble mean and that CNV and LPCt were sensitive to context modulation. Compared to the long context, the CNV climbing rate increased in the short context, and the amplitude and latency of the LPCt were reduced. These findings suggest the CNV represents an expectancy wave for upcoming decision-making, while LPCt reflects the decision-making process, both influenced by the temporal context.