Biology subjects

Claron, J.

Publications and source records attributed to Claron, J..

3 recordsLinked to original sources

bioRxiv2025

Revisiting Free Will: Distributed Activity in the Medial Frontal Cortex Predicts Self-Initiated Action

Research indicates that significant damage to primates medial frontal cortex (MFC) can impede action initiation when anticipating rewards. However, the specific roles within the MFC related to self-generated action preparation remain debated. Here, while two macaques were engaged in an oculomotor task, they occasionally paused and self-resumed the task after varying amounts of time. We utilized the high signal-to-noise ratio from spatial changes in cerebrovascular blood volume (CBV) recorded with ultrafast ultrasound imaging (fUSi) to determine whether the intervals of breaks or the resumption of task-related CBV signals could predict the execution of an ongoing single action. We show that self-initiated eye movements activate the Supplementary eye field (SEF) and the midcingulate cortex (MCC) up to 5.5 seconds before movement execution. Importantly, our results show that a concurrent activity in the SEF and MCC predicts how these two regions might simultaneously exert opposing influences on the voluntary pause and resume of tasks on a single trial basis. The quantification of this dynamic interaction is a novel step for understanding voluntary action in primates and its ability to initiate ones movement based on internal motivations rather than driven, instructed behavior.

neuroscience↗

bioRxiv2022

Covariations of cerebral blood volume and single neurons discharge during resting state and behavioral visual cognitive tasks in non-human primates

To better understand how the brain allows primates to perform various set of tasks, the ability to simultaneously record the activity of the brain at multiple temporal and spatial scales is challenging but necessary. In non-human primates, combined fMRI and electrophysiological recordings have not disentangle the contributions of spiking activity to the neurovascular response. Here, we combined functional ultrasound imaging (fUS) of cerebral blood volume (CBV) and recording of single-unit activities (SUA) in visual and fronto-medial cortices of behaving macaques. We computed task-induced and SUA-induced CBV activation maps. We demonstrate that SUA provides a significant estimate of the neurovascular response below the typical fMRI voxel spatial resolution of 2mm3. Furthermore, our results also show that single unit and CBV activities are statistically uncorrelated during the resting states but correlate during behaving tasks. Conversely, during the resting states, CBV activities across known connected brain areas are correlated but decorrelate at the onset of the tasks as expected if participating in the default mode network (DMN). These results have important implications for interpreting functional imaging findings collected with fMRI or fUS while one constructs inferences of spiking activities during resting-state or while primates perform tasks.

neuroscience↗

bioRxiv2021

The Supplementary Eye Field Tracks Cognitive Efforts

Pupil dilation is known to be an index of cognitive effort. Nevertheless, our lack of knowledge of the precise dynamics through which pupil size and activity of the medial prefrontal cortex are conjugated during cognitive tasks highlights the need for its further investigation before, during, and after changes in pupil size. Here, we tested whether pupil dynamics are related to the activity of the supplementary eye field (SEF) during a mixed pro/anti-saccade oculomotor task in two macaque monkeys. We used functional ultrasound imaging (fUS) to examine temporal changes in brain activity at the 0.1-s time scale and 0.1-mm spatial resolution in relation to behavioral performance and pupil dynamics. By combining the pupil signals and real-time imaging of NHP during cognitive tasks, we were able to infer localized CBV responses within a restricted part of the dorsomedial prefrontal cortex, referred to as the SEF, an area in which anti-saccade preparation activity is also recorded. Inversely, SEF neurovascular activity measured by fUS imaging was found to be a robust predictor of specific variations in pupil diameter over short and long time scales. Furthermore, we directly manipulated pupil diameter and CBV in the SEF using reward and cognitive effort. These results demonstrate that the SEF is an underestimated but pivotal cortical area for the monitoring and implementation of cognitive effort signals.

neuroscience↗