White matter disconnection of left multiple demand network is associated with post-lesion deficits in cognitive control.

Cognitive control modulates other cognitive functions to achieve internal goals and is important for adaptive behavior. Cognitive control is enabled by the neural computations distributed over cortical and subcortical areas. However, due to technical challenges in recording neural activity from the white matter, little is known about the anatomy of white matter tracts that coordinate the distributed neural computations that support cognitive control. Here, we leverage a large sample of human patients with focal brain lesions (n = 643) and investigate how lesion location and connectivity profiles account for variance in cognitive control performance. We find that lesions in white matter connecting left frontoparietal regions of the multiple demand network reliably predict deficits in cognitive control performance. These findings advance our understanding of the white matter correlates of cognitive control and provide an approach for incorporating network disconnection to predict deficits following lesions.

Interference and integration in hierarchical task learning.

A key feature of human task learning is shared task representation: Simple, subordinate tasks can be learned and then shared by multiple complex superordinate tasks as building blocks to facilitate task learning. An important yet unanswered question is how superordinate tasks sharing the same subordinate task affects the learning and memory of each other. Leveraging theories of associative memory, we hypothesize that shared subordinate tasks can cause both interference and facilitation between superordinate tasks. These hypotheses are tested using a novel experimental task which trains participants to perform superordinate tasks consisting of shared, trained subordinate tasks. Across 3 experiments, we demonstrate that sharing a subordinate task can (a) impair the memory of previously learned superordinate tasks and (b) integrate learned superordinate tasks to facilitate new superordinate task learning without direct experience. These findings shed light on the organizational principles of task knowledge and their consequences on task learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Electrophysiological Evidence for Distinct Proactive Control Mechanisms in a Stop-Signal Task: An Individual Differences Approach.

Proactive control reflects a sustained, top-down maintenance of a goal representation prior to task-related events, whereas reactive control reflects a transient, bottom-up goal reactivation in response to them. We designed a manual stop-signal task to isolate electrophysiological signals specifically involved in proactive control. Participants performed a simple choice reaction time task but had to withhold their response to an infrequent stop signal, resulting in go- and stop-signal trials. We manipulated the stop-signal probability (30% vs. 10%) over different blocks of trials so that different proactive control levels were sustained within each block. The behavioral results indicated that most participants proactively changed their behaviors. The reaction times in the go trials increased and the number of response errors in the stop-signal trials decreased. However, those two behavioral measures did not correlate: individuals with an increased delayed reaction did not necessarily manifest a higher decrease in response errors in the stop-signal trials. To isolate the proactive control signal, we obtained event-related potentials (ERPs) locked to an uninformative fixation onset and compared the signals between the two stop-signal probability conditions. We found that the ERPs at the left hemisphere were more negatively shifted with the increasing stop-signal probability. Moreover, ERP differences obtained from a set of electrodes in the left hemisphere accounted for the changes in response errors in the stop-signal trials but did not explain the changes in reaction times of the go trials. Together, the behavioral and electrophysiological results suggest that proactive control mechanisms reducing erroneous responses of the stop-signal trials are different from mechanisms slowing reaction times of the go trials.