1,721,041 research outputs found
Neural correlates of cognitive control of reaching movements in the dorsal premotor cortex of rhesus monkeys
Full text linkMirabella G, Pani P, Ferraina S. Neural correlates of cognitive control of reaching movements in the dorsal premotor cortex of rhesus monkeys. J Neurophysiol 106: 1454-1466, 2011. First published June 22, 2011; doi: 10.1152/jn.00995.2010.-Canceling a pending movement is a hallmark of voluntary behavioral control because it allows us to quickly adapt to unattended changes either in the external environment or in our thoughts. The countermanding paradigm allows the study of inhibitory processes of motor acts by requiring the subject to withhold planned movements in response to an infrequent stop-signal. At present the neural processes underlying the inhibitory control of arm movements are mostly unknown. We recorded the activity of single units in the rostral and caudal portion of the dorsal premotor cortex (PMd) of monkeys trained in a countermanding reaching task. We found that among neurons with a movement-preparatory activity, about one-third exhibit a modulation before the behavioral estimate of the time it takes to cancel a planned movement. Hence these neurons exhibit a pattern of activity suggesting that PMd plays a critical role in the brain networks involved in the control of arm movement initiation and suppression.Mirabella G, Pani P, Ferraina S. Neural correlates of cognitive control of reaching movements in the dorsal premotor cortex of rhesus monkeys. J Neurophysiol 106: 1454-1466, 2011. First published June 22, 2011; doi: 10.1152/jn.00995.2010.-Canceling a pending movement is a hallmark of voluntary behavioral control because it allows us to quickly adapt to unattended changes either in the external environment or in our thoughts. The countermanding paradigm allows the study of inhibitory processes of motor acts by requiring the subject to withhold planned movements in response to an infrequent stop-signal. At present the neural processes underlying the inhibitory control of arm movements are mostly unknown. We recorded the activity of single units in the rostral and caudal portion of the dorsal premotor cortex (PMd) of monkeys trained in a countermanding reaching task. We found that among neurons with a movement-preparatory activity, about one-third exhibit a modulation before the behavioral estimate of the time it takes to cancel a planned movement. Hence these neurons exhibit a pattern of activity suggesting that PMd plays a critical role in the brain networks involved in the control of arm movement initiation and suppression
Inhibitory control and impulsive responses in neurodevelopmental disorders
No full textThe impairment of inhibitory control is often assumed to be the core deficit of several neurodevelopmental disorders characterized by poor impulse control. However, could the same deficit explain different clinical phenotypes? Evidence from behavioural studies is very mixed. This is partly because inhibition is a highly complex executive function. Thus, the different types of tasks that generically tap into inhibitory control are likely to provide different outcomes. Additionally, sample inhomogeneity in terms of age, comorbidity, and medical treatment are confounding factors. Therefore, to make a reliable assessment of the deficit of inhibitory control in a given disorder, the same task and samples with similar characteristics must be employed. This article reviews and discusses studies on five neurodevelopmental disorders with impaired impulse control where these criteria have been used: Tourette syndrome; obsessive–compulsive disorder; attention-deficit/hyperactivity disorder; primary motor stereotypies; and autism spectrum disorder. Overall, they suggest that the mechanisms underlying the inability to control urges are extremely heterogeneous and cannot be ascribed to a general impairment of inhibition. These findings do not support the hypothesis that inhibitory deficits represent a transdiagnostic feature of neurodevelopmental disorders with poor impulse control. What this paper adds: The mechanisms underlying the inability to control urges in neurodevelopmental disorders are heterogeneous. Inhibition impairments cannot generally explain all neurodevelopmental disorders characterized by poor urge control
Does the Power to Suppress an Action Make Us ‘Free’?
No full textWe, humans, live under the impression that agents’ conscious intentions to act are at the origin of our actions. However, experimental evidence challenged this common intuition of free will, suggesting that such subjective experience is something of a perceptual illusion. The awareness of the intention to act would be generated as a side effect of unconscious processes that determine our decisions. If proven true, such a conclusion would shake the cornerstones of western ethics and law as it would require a profound revision of the concept of moral responsibility. A possible way outcomes from our ability to inhibit “pending” actions, i.e., to exert a veto power. In fact, although awareness of intention appears after the start of an action-related brain process, it still precedes the physical execution of a movement, allowing a person enough time to withhold the upcoming action if the expected outcome might be inappropriate. Thus, we would be in control of our actions by exerting free will not. Although it is appropriate to be very cautious when interpreting the results of the empirical approach of neuroscience to such complex mental phenomena, as it bears some intrinsic limitations, empirical evidence gathered so far suggests that, except specific medical conditions, we are free of choosing what and how to do, and thus, we are responsible for our actions
Decisioni e Rimpianti
No full textConferenza divulgativa. 30° NEUROSCIENCE CAFÈ, presso l'Antico Caffè San Marco. Trieste, 8 Novembre 2005. Evento organizzato dal Prof. PP Battaglin
- …
