The Functional Role of the Anterior Insular Cortex in Cognitive Control

Cognitive control, a higher level psychological construct, refers to efficient coordination of thoughts and actions for the accomplishment of goal-directed behaviors. Cognitive control is supported by a commonly activated cognitive control network, and the anterior insular cortex (AIC) serves as one of its key structures. However, the functional role of the AIC in cognitive control has not been fully understood. A human lesion study was conducted to examine the necessary function of the AIC in cognitive control. A mouse optogenetic study with fiber photometry recording further examinedwhether the bilateral AIC was important for cognitive control and how the AIC played a role in different stages of cognitive control (e.g., state uncertainty processing, execution of control, or motor generation). Compatible versions of the post-target interference task consisting of congruent and incongruent conditions were used to measure cognitive control in humans and mice, respectively. In the human lesion study, the patients with lesions in the AIC showed longer overall response time (RT), lower overall processing efficiency, and greater conflict effects of RT and processing efficiency. These findings provided lesion-based evidence to support a causally necessary function of the AIC in cognitive control. In the mouse study, the accuracy of the congruent condition decreased when the AIC was silenced unilaterally or bilaterally by optogenetics after the cue sound and when the AIC was silenced bilaterally during the presentation of target and distractor stimuli, indicating that the disruption of the AIC resulted in a reduction in global processing efficiency. The fiber photometry results showed a significant decrease of the calcium-dependent signal after the cue sound compared to baseline, suggesting that the AIC was involved in state uncertainty processing. The results of the human lesion study identified the necessary role of the AIC in cognitive control. The findings of the mouse study further demonstrated the role of the AIC in cognitive control in both hemispheres and suggested a critical role of the AIC in state uncertainty processing

Investigating Cognitive Control And Task Switching Using The Macaque Oculomotor System

Cognitive control is crucial to voluntary behaviour. It is required to select appropriate goals and guide behaviour to achieve the desired outcomes. Cognitive control is particularly important for the ability to adapt behaviour to changes in the external environment and internal goals, and to quickly switch between different tasks. Successful task switching involves a network of brain areas to select, maintain, implement, and execute the appropriate task. Uncovering the neural mechanisms of this goal-directed behaviour using lesions, functional neuroimaging, and neurophysiology studies is central to cognitive neuroscience. The oculomotor system provides a valuable framework for understanding the neural mechanisms of cognitive control, as it is anatomically and functionally well characterized. In this project, pro-saccade and anti-saccade tasks were used to investigate the contributions of oculomotor and cognitive brain areas to different stages of task processing. In Chapter 2, non-human primates performed cued and randomly interleaved pro-saccade and anti-saccade tasks while neural activity was recorded in the superior colliculus (SC). In Chapter 3, non-human primates performed cued and randomly interleaved pro-saccade and anti-saccade tasks while local field potential activity was recorded in the SC and reversible cryogenic deactivation was applied to the dorsolateral prefrontal cortex (DLPFC). In Chapter 4, non-human primates performed uncued and cued pro-saccade and anti-saccade switch tasks while reversible cryogenic deactivation was applied to the dorsal anterior cingulate cortex (dACC). The first study clarifies that macaque monkeys demonstrate similar error rate and reaction time switch costs to humans performing cued and randomly interleaved pro-saccade and anti-saccade tasks. These switch costs were associated with switch-related differences in stimulus-related activity in the SC that were resolved by the time of saccade onset. The second study shows that bilateral DLPFC deactivation decreases preparatory beta and gamma power in the superior colliculus. In addition, the correlation of gamma power with spike rate in the SC was attenuated by DLPFC deactivation. Lastly, bilateral dACC deactivation in the third study impairs anti-saccade performance and increases saccadic reaction times for pro-saccades and anti-saccades. Deactivation of the dACC also impairs the ability to integrate feedback from the previous trial. Overall, these findings suggest unique roles for the dACC, DLPFC, and SC in cognitive control and task switching. The dACC may monitor feedback to select the appropriate task and implement cognitive control, the DLPFC may maintain the current task-set and modulate the activity of other brain areas, and the SC may be modulated by task switching processes and contribute to the production of switch costs

Development of brain structures following perinatal cerebral lesions suggests the involvement of the cerebellum in the working memory network

openCrossed cerebro-cerebellar diaschisis in very preterm born individuals, following perinatal cerebral lesions, reveals functional connectivity between some cerebral areas involved in working memory (WM) and yet undefined cerebellar regions: this may support the role of the latter in the WM network. The cerebellum has long been associated with motor control and coordination. In the last two decades, researchers have studied its involvement in a broad range of cognitive functions, such as visuospatial attention and WM. In this overview, I define the brain regions activated by the WM network and their development in term- and very preterm- infants compared, according to the most recent studies. These findings could contribute to support the involvement of the cerebellum in non-motor functions, specifically in WM.Crossed cerebro-cerebellar diaschisis in very preterm born individuals, following perinatal cerebral lesions, reveals functional connectivity between some cerebral areas involved in working memory (WM) and yet undefined cerebellar regions: this may support the role of the latter in the WM network. The cerebellum has long been associated with motor control and coordination. In the last two decades, researchers have studied its involvement in a broad range of cognitive functions, such as visuospatial attention and WM. In this overview, I define the brain regions activated by the WM network and their development in term- and very preterm- infants compared, according to the most recent studies. These findings could contribute to support the involvement of the cerebellum in non-motor functions, specifically in WM

The cognitive neuroscience of visual working memory

Visual working memory allows us to temporarily maintain and manipulate visual information in order to solve a task. The study of the brain mechanisms underlying this function began more than half a century ago, with Scoville and Milner’s (1957) seminal discoveries with amnesic patients. This timely collection of papers brings together diverse perspectives on the cognitive neuroscience of visual working memory from multiple fields that have traditionally been fairly disjointed: human neuroimaging, electrophysiological, behavioural and animal lesion studies, investigating both the developing and the adult brain

Information-Based Approaches of Noninvasive Transcranial Brain Stimulation

Progress in cognitive neuroscience relies on methodological developments to increase the specificity of knowledge obtained regarding brain function. For example, in functional neuroimaging the current trend is to study the type of information carried by brain regions rather than simply compare activation levels induced by task manipulations. In this context noninvasive transcranial brain stimulation (NTBS) in the study of cognitive functions may appear coarse and old fashioned in its conventional uses. However, in their multitude of parameters, and by coupling them with behavioral manipulations, NTBS protocols can reach the specificity of imaging techniques. Here we review the different paradigms that have aimed to accomplish this in both basic science and clinical settings and follow the general philosophy of information-based approach

Hierarchical control over effortful behavior by rodent medial frontal cortex : a computational model

The anterior cingulate cortex (ACC) has been the focus of intense research interest in recent years. Although separate theories relate ACC function variously to conflict monitoring, reward processing, action selection, decision making, and more, damage to the ACC mostly spares performance on tasks that exercise these functions, indicating that they are not in fact unique to the ACC. Further, most theories do not address the most salient consequence of ACC damage: impoverished action generation in the presence of normal motor ability. In this study we develop a computational model of the rodent medial prefrontal cortex that accounts for the behavioral sequelae of ACC damage, unifies many of the cognitive functions attributed to it, and provides a solution to an outstanding question in cognitive control research-how the control system determines and motivates what tasks to perform. The theory derives from recent developments in the formal study of hierarchical control and learning that highlight computational efficiencies afforded when collections of actions are represented based on their conjoint goals. According to this position, the ACC utilizes reward information to select tasks that are then accomplished through top-down control over action selection by the striatum. Computational simulations capture animal lesion data that implicate the medial prefrontal cortex in regulating physical and cognitive effort. Overall, this theory provides a unifying theoretical framework for understanding the ACC in terms of the pivotal role it plays in the hierarchical organization of effortful behavior