The medial frontal-prefrontal network for altered awareness and control of action in corticobasal syndrome.
Brain. 2013-11-29; 137(1): 208-220
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1. Brain. 2014 Jan;137(Pt 1):208-20. doi: 10.1093/brain/awt302. Epub 2013 Nov 29.
The medial frontal-prefrontal network for altered awareness and control of action
in corticobasal syndrome.
Wolpe N(1), Moore JW, Rae CL, Rittman T, Altena E, Haggard P, Rowe JB.
(1)1 Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2
The volitional impairments of alien limb and apraxia are a defining feature of
the corticobasal syndrome, but a limited understanding of their neurocognitive
aetiology has hampered progress towards effective treatments. Here we combined
several key methods to investigate the mechanism of impairments in voluntary
action in corticobasal syndrome. We used a quantitative measure of awareness of
action that is based on well-defined processes of motor control; structural and
functional anatomical information; and evaluation against the clinical volitional
disorders of corticobasal syndrome. In patients and healthy adults we measured
‘intentional binding’, the perceived temporal attraction between voluntary
actions and their sensory effects. Patients showed increased binding of the
perceived time of actions towards their effects. This increase correlated with
the severity of alien limb and apraxia, which we suggest share a core deficit in
motor control processes, through reduced precision in voluntary action signals.
Structural neuroimaging analyses showed the behavioural variability in patients
was related to changes in grey matter volume in pre-supplementary motor area, and
changes in its underlying white matter tracts to prefrontal cortex. Moreover,
changes in functional connectivity at rest between the pre-supplementary motor
area and prefrontal cortex were proportional to changes in binding. These
behavioural, structural and functional results converge to reveal the frontal
network for altered awareness and control of voluntary action in corticobasal
syndrome, and provide candidate markers to evaluate new therapies.
PMID: 24293266 [Indexed for MEDLINE]