Perceptual uncertainty alternates top-down and bottom-up fronto-temporal network signaling during response inhibition

Response inhibition is a primary executive control function that allows the withholding of inappropriate responses, and requires appropriate perception of the external environment to achieve a behavioral goal. It remains unclear, however, how response inhibition is achieved when goal-relevant information involves perceptual uncertainty. Twenty-six human participants of both sexes performed a go/no-go task where visually presented random-dot motion stimuli involved perceptual uncertainties. The right inferior frontal cortex (rIFC) was involved in response inhibition, and the middle temporal (MT) region showed greater activity when dot motions involved less uncertainty. A neocortical temporal region in the superior temporal sulcus (STS) specifically showed greater activity during response inhibition in more perceptually certain trials. In this STS region, activity was greater when response inhibition was successful than when it failed. Directional effective connectivity analysis revealed that in more coherent trials, the MT and STS regions showed enhanced connectivity to the rIFC, whereas in less coherent trials, the signal direction was reversed. These results suggest that a reversible fronto-temporal functional network guides response inhibition under perceptual uncertainty, and in this network, perceptual information in the MT is converted to control information in the rIFC via STS, enabling achievement of response inhibition.

An Evaluation of Executive Control Function and Its Relationship with Driving Performance

The driver’s attentional state is a significant human factor in traffic safety. The executive control process is a crucial sub−function of attention. To explore the relationship between the driver’s driving performance and executive control function, a total of 35 healthy subjects were invited to take part in a simulated driving experiment and a task−cuing experiment. The subjects were divided into three groups according to their driving performance (aberrant driving behaviors, including lapses and errors) by the clustering method. Then the performance efficiency and electroencephalogram (EEG) data acquired in the task−cuing experiment were compared among the three groups. The effect of group, task transition types and cue−stimulus intervals (CSIs) were statistically analyzed by using the repeated measures analysis of variance (ANOVA) and the post hoc simple effect analysis. The subjects with lower driving error rates had better executive control efficiency as indicated by the reaction time (RT) and error rate in the task−cuing experiment, which was related with their better capability to allocate the available attentional resources, to express the external stimuli and to process the information in the nervous system, especially the fronto−parietal network. The activation degree of the frontal area fluctuated, and of the parietal area gradually increased along with the increase of CSI, which implied the role of the frontal area in task setting reconstruction and working memory maintaining, and of the parietal area in stimulus−response (S−R) mapping expression. This research presented evidence of the close relationship between executive control functions and driving performance.

Changes in cortical activity measured with EEG during a high-intensity cycling exercise

This study investigated the effects of a high-intensity cycling exercise on changes in spectral and temporal aspects of electroencephalography (EEG) measured from 10 experienced cyclists. Cyclists performed a maximum aerobic power test on the first testing day followed by a time-to-exhaustion trial at 85% of their maximum power output on 2 subsequent days that were separated by ∼48 h. EEG was recorded using a 64-channel system at 500 Hz. Independent component (IC) analysis parsed the EEG scalp data into maximal ICs. An equivalent current dipole model was calculated for each IC, and results were clustered across subjects. A time-frequency analysis of the identified electrocortical clusters was performed to investigate the magnitude and timing of event-related spectral perturbations. Significant changes ( P < 0.05) in electrocortical activity were found in frontal, supplementary motor and parietal areas of the cortex. Overall, there was a significant increase in EEG power as fatigue developed throughout the exercise. The strongest increase was found in the frontal area of the cortex. The timing of event-related desynchronization within the supplementary motor area corresponds with the onset of force production and the transition from flexion to extension in the pedaling cycle. The results indicate an involvement of the cerebral cortex during the pedaling task that most likely involves executive control function, as well as motor planning and execution.

Compensatory Neural Responses After 36 Hours of Total Sleep Deprivation and its Relationship with Executive Control Function

The neurobiological mechanisms of Total Sleep Deprivation (TSD) - induced changes in executive control function were investigated. Fourteen participants were measured by functional magnetic resonance imaging (fMRI) with the visual Go/No-go task after normal sleep and following 36 hours of TSD. The TSD-induced positive and negative blood oxygenation level-dependent (BOLD) signals compared with that after a normal night's sleep (NORM). The areas activated with positive BOLD signals include the superior prefrontal cortex and inferior prefrontal cortex, with negative BOLD signals in the anterior cingulated cortex (ACC) and right lingual gyrus. Increased activation may be related to the compensatory response since more attention resources are needed to perform the Go/No-go task after 36 hours of TSD and the decreased activation in the ACC may reflect the impact of executive control function by the TSD.