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Cortical Reorganisation In Amyotrophic Lateral Sclerosis Patients
A DGReview of :"Pattern of cortical reorganization in amyotrophic lateral sclerosis: a functional magnetic resonance imaging study"
Experimental Brain Research
04/08/2002
By Anne MacLennan
Partial compensation between functionally-related motor areas may be a strategy for optimising performance for patients with amyotrophic lateral sclerosis if the most efficient pathway is unavailable.
There is a high interindividual variability in the reorganization of the human motor system, depending on individual lesion location and extent. Further complicating the interpretation of functional imaging studies is the variability of forces exerted, of motor effort, and of movement strategies.
This finding is one suggestion of a study of the pattern of cortical reorganisation in amyotrophic lateral sclerosis (ALS) patients using functional magnetic resonance imaging.
C Konrad and colleagues from the Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin, United States, hypothesized that a general pattern of reorganisation might be identified in a homogeneous patient population under controlled experimental conditions.
These researchers trained a group of ALS patients and a matched group of healthy volunteers to perform a simple finger flexion task with 10 percent of each individual's maximum grip force with constant movement amplitude and frequency.
The activation pattern of the ALS patients was distinctly different from the controls, with motor cortex activation located more anteriorly and encompassing the premotor gyrus. The cluster volume within the supplementary motor area (SMA) was higher and shifted toward the pre-SMA. Contralateral inferior area six and bilateral parietal area 40 revealed higher cluster volumes.
These findings demonstrate a general pattern of functional changes after motor neuron degeneration. They also support the concept of a structurally parallel and functionally-specialized organisation of voluntary motor control.
Degeneration of the first and second motor neurons leads to enhanced recruitment of motor areas usually involved in initiation and planning of movement.
Exp Brain Res 2002 Mar;143(1):51-6.
"Pattern of cortical reorganization in amyotrophic lateral sclerosis: a functional magnetic resonance imaging study"
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