Biology subjects

Amengual, J. L.

Publications and source records attributed to Amengual, J. L..

3 recordsLinked to original sources

bioRxiv2021

Early changes in corticomotor excitability underlie proactive inhibitory control of error correction

Converging evidence indicates that response inhibition may arise from the interaction of effortful proactive and reflexive reactive mechanisms. However, the distinction between the neural basis sustaining proactive and reactive inhibitory processes is still unclear. To identify reliable neural markers of proactive inhibition, we examined the behavioral and electrophysiological correlates elicited by manipulating the degree of inhibitory control in a task that involved the detection and amendment of errors. Restraining or encouraging the correction of errors did not affect the time course of the behavioral and neural correlates associated to reactive inhibition. We rather found that a bilateral and sustained decrease of corticomotor excitability was required for an effective proactive inhibitory control, whereas selective strategies were associated with defective response suppression. Our results provide behavioral and electrophysiological conclusive evidence of a comprehensive proactive inhibitory mechanism, with a distinctive underlying neural basis, governing the commission and amendment of errors. Together, these findings hint at a decisive role for changes in corticomotor excitability in determining whether an action will be successfully suppressed. SIGNIFICANCE STATEMENTResponse inhibition is a fundamental brain function that must be flexible enough to incorporate volitional goal-directed demands, along with rapid, automatic and well consolidated behaviors. Previous studies reflect a lack of consensus regarding the neural correlates subserving these two -proactive and reactive- distinct modes of inhibitory control. We combined electrophysiological recordings with behavioral measures within a paradigm of detection and correction of errors under two degrees of inhibitory control to identify genuine neural markers of proactive inhibitory control. We found evidence supporting a sustained and global -not selective- reduction of corticomotor excitability subserving successful proactive inhibition of motor responses. Our findings favor a distinctive mechanism of comprehensive inhibitory control to amend errors under a high degree of response competition.

neuroscience↗

bioRxiv2019

Causal modulation of right fronto-parietal phase synchrony with Transcranial Magnetic Stimulation during a conscious visual detection task

Correlational evidence in non-human primates has reported evidence of increased frontoparietal high-beta band (22-30 Hz) synchrony during the endogenous allocation of visuospatial attention. But may the engagement of inter-regional synchrony at this specific frequency band provide the causal mechanism by which top-down processes are engaged and they facilitate visual perception in humans? Here we further analyzed electroencephalographic (EEG) signals from a group of healthy human participants who performed a conscious visual detection task, under the influence of brief rhythmic (30 Hz) or random bursts of Transcranial Magnetic Stimulation (TMS), with an identical number of pulses and duration, delivered to the right Frontal Eye Field (FEF) prior to the onset of a lateralized near-threshold target. We report increases of inter-regional synchronization in the high-beta band (25-35 Hz) between the electrode closest to the stimulated region (right FEF) and parietal leads, and increases of local inter-trial coherence in the same frequency band over parietal contacts, both driven by rhythmic but not random TMS patterns. Importantly, such increases were accompained by increases of visual sensitivity for left visual targets (contralateral to the stimulation) in the rhythmic but not the random TMS condition at the group level. These outcomes suggest that human high-beta synchrony between right frontal and parietal regions can be modulated non-invasively and that high-beta oscillatory activity across the right dorsal fronto-parietal network may contribute to the facilitation of conscious visual detection. Our study also supports future applications of non-invasive brain stimulation technologies for the manipulation of inter-regional synchrony, which could be administered to improve visual behaviors in healthy humans or neurological patients.

neuroscience↗

bioRxiv2019

Entrainment of local synchrony reveals a causal role for high-beta right frontal oscillations in human visual consciousness

Prior evidence supports the critical role of oscillatory activity in cognitive function, but are cerebral oscillations simply correlated or causally linked to specific aspects of visual cognition? Here, EEG signals were recorded on humans performing a conscious visual detection task, while they received brief rhythmic or random noninvasive stimulation patterns delivered to the right Frontal Eye Field prior to the onset of a lateralized target. Compared to random patterns, rhythmic high-beta patterns led to greater entrainment of local oscillations (i.e., increased power and phase alignment at the stimulation frequency), and to higher conscious detection of contralateral targets. When stimulation succeeded in enhancing visual detection, the magnitude of oscillation entrainment correlated with visual performance increases. Our study demonstrates a causal link between high-beta oscillatory activity in the Frontal Eye Field and conscious visual perception. Furthermore, it supports future applications of brain stimulation to manipulate local synchrony and improve or restore impaired visual behaviors.

neuroscience↗