Moving with or without will: functional neural correlates of alien hand syndrome

Abstract

Alien hand syndrome is a rare neurological disorder in which movements are performed without conscious will. By using functional magnetic resonance imaging in a patient with alien hand syndrome after right parietal lesion, we could identify brain regions activated during involuntary or voluntary actions with the affected left hand. Alien hand movements involved a selective activation of contralateral primary motor cortex (M1), presumably released from conscious control by intentional planning systems. By contrast, voluntary movements activated a distributed network implicating not only the contralateral right M1 and premotor cortex but also the left inferior frontal gyrus, suggesting an important role of the dominant hemisphere in organizing willed actions.

Alien Hand Syndrome

“…The posterior variant more commonly affects the non-dominant (left) hand [23]. It is associated with strong feelings of estrangement from the affected limb, less complex motor activity (e.g., limb levitation, ataxia, non-purposeful or nonconflicting movements), and parietal sensory deficits (visual o r s e n s o r y n e g l e c t , b o d y s c h e m a d y s f u n c t i o n , hemiasomatognosia, spatial neglect, or astereognosis).…”

“…It is associated with strong feelings of estrangement from the affected limb, less complex motor activity (e.g., limb levitation, ataxia, non-purposeful or nonconflicting movements), and parietal sensory deficits (visual o r s e n s o r y n e g l e c t , b o d y s c h e m a d y s f u n c t i o n , hemiasomatognosia, spatial neglect, or astereognosis). The lesion is typically in the non-dominant (right) parietal lobe (posterior postcentral gyrus, posterior primary sensory cortex, and tertiary somatosensory cortex in the superior parietal lobule) [23]. Uncommonly, the occipital lobe and thalamus are involved [24].…”

“…One study used fMRI to assess volitional movement in a patient with left AHS and involuntary hand grasping, following a right parietal stroke [23]. The left hand was assessed by fMRI at rest, during alien hand movements and voluntary movements.…”

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

“…One notable exception is an functional magnetic resonance imaging (fMRI) study of a patient with extensive right parietal lobe damage, who performed spontaneous (flexion-extension) movements of the left hand (fingers) without conscious will (Assal, Schwartz & Vuilleumier, 2007).…”

Response to Comment on “Movement Intention After Parietal Cortex Stimulation in Humans”

“…Neuropsychological findings have demonstrated that patients with selective lesions in PPC lose the early subjective experience of wanting to move, being aware of their movement only when it is about to be executed (7). A recent study also indicated that circumscribed lesions of the PPC can cause the occurrence of alien movements generated without conscious intention through the recruitment of the precentral executive motor regions (8).…”