Morningstar, M. | bioRxiv Science

bioRxiv2025

Learning to blink strategically is crucial to performance in a predictable saccade task and varies across the lifespan

Humans blink their eyes 16-20 times each minute to spread tear film on the cornea, representing a substantial amount of waking time when ones eyes are closed. These spontaneous blinks are strategically timed to prioritize the processing of important visual input, balancing both stimulus characteristics and personal goals. Until now, the learning process underlying optimal blink timing has not been investigated in detail. Here, we present video-based eye-tracking data from 703 healthy participants (aged 5-91 years, 470 female) performing a structured interleaved pro-/anti-saccade task, in which we previously found that blink suppression occurs in anticipation of visual stimulus appearance (Pitigoi et al., 2024). Our goals are to understand (1) how participants modify their blink timing according to the temporal contingencies of the task; (2) whether the capacity to optimize blink timing impacts performance; and (3) whether this pattern varies with age. We found that participants quickly and strategically modified their blink distribution to optimize task performance. Blink probability decreased in periods that would compromise anti-saccade execution and increased when visual input was less critical. We also found significant differences in blink patterns and adaptive ability based on cognitive control capacity (indicated by participants anti-saccade error rates). Furthermore, we demonstrated that blink optimization improves gradually from childhood to early adulthood, before declining with advanced age. This supports a possible link between regulation of blink behavior and age-related changes in learning capacity and inhibitory control across the lifespan.

neuroscience↗

bioRxiv2024

Neural basis of cognitive control signals in anterior cingulate cortex during delay discounting

Cognitive control involves allocating cognitive effort according to internal needs and task demands. The anterior cingulate cortex (ACC) is hypothesized to play a central role in this process. We investigated the neural basis of cognitive control in the ACC of rats performing an adjusting-amount delay discounting task, with a 4s or 8s delay between lever choice and reward. A reinforcement learning model indicated that decision making on this task can be guided by either a value tracking strategy, requiring a resource-based form of cognitive control or a delay-lever biased strategy requiring a resistance-based form of cognitive control. This was then tested in vivo by multiple single unit recordings and local field potentials acquired from male rats performing the task. On this task, the behavioral manifestation of resistance-based control is an excessive focus on delayed lever choices which was observed during a substantial portion of 4s but not 8s delay sessions. On a neural level, this was associated with an increase in Theta (6-12Hz) oscillations prior to delay choices which was present exclusively on 4s delay sessions. By contrast, evidence of a resource-based control signal was found in spike trains that closely tracked lever value prior to choice, and was far more prevalent on 8s delay sessions. These data provide candidate neural signatures of resource-based versus resistance-based forms of cognitive control. While mediated by distinct neural mechanisms, either form could be engaged by individual subjects under different task conditions.

neuroscience↗