At Braintime Lab at Taipei Medical University,
we study time in the brain at multiple scales: from milli-seconds to π⋅10^7 seconds.

We study how time is represented in the brain, using experimental animal models and computational methods. Our primary focus has been the neural circuits of circadian clocks that make up the seasonal (yearly) clock. These physiologically relevant circadian processes connect to cognitively relevant seconds-to-minutes scale events in the brain.

Sociology Emergence Psychology of clocks!

Sociology of body clocks

Interaction between the master circadian clock and peripheral clocks 
It turns out that the suprachiasmatic nucleus (SCN) is not the only circadian clock in the body. We recently found that the choroid plexus clock exceeds even the SCN clock in terms of robustness (2018) and the kidney clock can influence the behavioral circadian rhythms, potentially through feedback to the master clock (2019). These investigations recast the role of the SCN as the master coordinator of the distributed local circadian clocks, rather than the master pacemaker, and let us think that the circadian organization of the body is likely more democratic and less strictly hierarchical than previously thought.

Myung et al (2019)

References
· The kidney clock contributes to timekeeping by the master circadian clock (2019)
· The choroid plexus is an important circadian clock component (2018)

The circuit of circadian clocks

While a single cell is fully capable of maintaining a circadian clock, evolution chose a multi-cellular clock system in mammals. We have previously found that the main circadian clock, the suprachiasmatic nucleus (SCN), can be reduced to a simple neural circuit of two oscillators. The two-oscillator model predicts novel stability pockets that enable previously unforeseen circadian behaviors. These new insights provide us with specific model-based strategies that we can test in vivo and ex vivo. We seek clinical applications of these findings to quickly stabilize circadian rhythms under unusual seasonal conditions or after abrupt transitions to a new day-night cycle.

References



Emergence of circadian clocks

The society of circadian clocks emerges slowly and sequentially over the developmental time course. We track and consider this emergence time course in light of preterm development in the neonatal intensive care unit (NICU). This project is conducted under Taiwan's collaborative project grant (MOST PPG) with Prof. Chao-Ching Huang at National Cheng Kung University (NCKU).

Reference



Circadian Regulation of Time Perception and Mood

The seasonality is an important cue for mood fluctuation, as evidenced by a seasonal peak of suicide rate among the major depression and affective disorder patients (let us recite T.S. Eliot's "April is the cruelest month"). Psychological studies show that the second-to-minute scale time perception can be a good indicator of the mood state. There is strong evidence that the perceived time length is a function of dopamine and serotonin release, which are likely to be regulated by circadian and seasonal rhythms. We are putting these clues together to understand how circadian rhythms modulate degrees of time perception and distinct mood states. These studies have substantial potential to open up new avenues of treatment for abnormal mood conditions.

References