Altered awareness of voluntary action after damage to the parietal cortex

Abstract

A central question in the study of human behavior is the origin of willed action. EEG recordings of surface brain activity from human subjects performing a self-initiated movement show that the subjective experience of wanting to move follows, rather than precedes, the 'readiness potential'--an electrophysiological mark of motor preparation. This raises the issue of how conscious experience of willed action is generated. Here we show that patients with parietal lesions can report when they started moving, but not when they first became aware of their intention to move. This stands in contrast with the performance of cerebellar patients who behaved as normal subjects. We thus propose that when a movement is planned, activity in the parietal cortex, as part of a cortico-cortical sensorimotor processing loop, generates a predictive internal model of the upcoming movement. This model might form the neural correlate of motor awareness.

Anarchic hand with abnormal agency following right inferior parietal lobe damage: a case report

“…This theoretical explanation of AHS is consistent with the established role of the parietal lobe in a multitude of sensorimotor functions relating to the body, movement and self-awareness (Sirigu et al, 2004). In particular, Desmurget and Sirigu (2009) propose a functional neuroanatomical model identify the posterior parietal cortex as important in motor awareness (i.e.…”

“…However, this prediction fails to take into account the fact that the posterior parietal lobe is involved in monitoring one's own movements, while parallel, low-level comparison of actual and predicted sensory information depends on premotor areas (Desmurget & Sirigu, 2009;Sirigu et al, 2004). Thus, damage to the inferior parietal lobe might result in poor motor awareness and abnormal agency ratings even when low-level signals of sensorimotor incongruence are present, because such signals are not able to engage parietal areas responsible for conscious (veridical) motor 14 awareness.…”

The role of parietal cortex in overimitation: a study with fNIRS

“…A similar pattern was seen in right angular gyrus, with stronger engagement for observation of action than for performance. Neuropsychological evidence has linked the angular gyrus with generating internal representations of motor actions before they are performed (Sirigu et al, 2003) and for being more active when observing objects (Moore & Price, 1999). Increased angular gyrus activity during the observation phase of the experiment could signal the participants forming representations of their future actions and how they interact with objects.…”

Wherever is my arm? Impaired upper limb position accuracy in Complex Regional Pain Syndrome

“…Responsible for integrating visual, tactile and proprioceptive inputs and sensory-motor information, the post-parietal cortex may play a key role [16,19,41]. Importantly, post-parietal lesions typically result in spatial deficits and clinical disturbances in body representation [39].…”