Comparing axonal excitability in past polio to amyotrophic lateral sclerosis
1Department of Neurology and Clinical Neurophysiology, Royal North Shore Hospital, Sydney, St Leonards, New South Wales, 2065, Australia.
Introduction:
Poliomyelitis causes selective destruction of anterior horn cells and usually has a stable disease course post-infection. We assessed the excitability characteristics in patients with a stable course after past poliomyelitis and compared them with changes described in amyotrophic lateral sclerosis (ALS).
Methods:
The excitability characteristics of motor and sensory nerves were studied in 10 subjects with stable past poliomyelitis.
Results:
Motor rheobase was increased, but there were no significant changes in strength-duration properties or depolarizing threshold electrotonus, as have been seen in previous studies of ALS.
Conclusions:
There is minimal change in axonal excitability properties in patients with stable past poliomyelitis. The results may signify sufficient compensation in the stable state of the disease. Increased subexcitability in 1 subject with demonstrable hyperexcitability may represent compensation for increased ectopic activity rather than a different process in surviving motor neurons. Muscle Nerve 50: 602-604, 2014.
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