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In this second edition, the authors present a thorough, advanced
review of the interactions between motoneurones and muscles in
vertebrates. The book discusses the significance of nerve-muscle
interactions for the normal development and maintenance of the
vertebrate neuromuscular system and reviews the consequences of
their disruption. The plasticity of nerve-muscle interactions and
the potential for repair is analyzed, as is the importance of
neuromuscular activity in development. The subject is approached
from a broad viewpoint and the authors integrate results from many
disciplines to illustrate the significance of neuromuscular
interaction for normal locomotor activity. This approach makes the
book useful for clinical researchers of neuromuscular disease.
The first evidence that electrical changes can cause muscles to
contract was p- vided by Galvani (1791). Galvani's ideas about
'animal electricity' were explored during the 19th and 20th century
when it was firmly established that 'electricity' is one of the
most important mechanisms used for communication by the nervous
system and muscle. These researches lead to the development of ever
more soph- ticated equipment that could either record the
electrical changes in nerves and muscles, or elicit functional
changes by electrically stimulating these structures. It was indeed
the combination of these two methods that elucidated many of the
basic principles about the function of the nervous system.
Following these exciting findings, it was discovered that
electrical stimulation and the functions elicited by it also lead
to long-term changes in the properties of nerves and particularly
muscles. Recent findings help us to understand the mec- nisms by
which activity induced by electrical stimulation can influence
mature, fully differentiated cells, in particular muscles, blood
vessels and nerves. Electrically elicited activity determines the
properties of muscle fibres by activating a sequence of signalling
pathways that change the gene expression of the muscle. Thus,
elect- cal activity graduated from a simple mechanism that is used
to elicit muscle c- traction, to a system that could induce
permanent changes in muscles and modify most of its characteristic
properties.
Now almost eighty years old, Gerta Vrbova recalls the dramatic
events in Slovakia and Hungary between 1939 and 1945 which saw many
of his relations, friends and neighbours perish in the Nazi gas
chambers."
In the second century, Galen recognized that nerve and muscle were
functionally inseparable since contraction of muscle occurred only
if the nerves supplying that muscle were intact. He therefore
concluded that the shortening of a muscle was controlled by the
central nervous sytem while the extension of a muscle could occur
in the absence of innervation. Nerves, he thought, were the means
of transport for animal spirits to the muscles; the way in which
animal spirits may bring about contraction dominated the study of
muscle physiology from that time until the historical discovery of
Galvani that muscle could be stimulated electrically and that nerve
and muscle were themselves a source of electrical energy. It is now
well known that nerves conduct electrically and that transmission
from nerve to striated muscle is mediated by the chemical which is
liberated from nerve terminals onto the muscle membrane. In
vertebrates this chemical is acetylcholine (ACh). Thus the concept
of spirits that are released from nerves and control muscle
contraction directly, is no longer tenable. Nevertheless the
concept of 'substances' transported down nerv~s which directly
control many aspects of muscle has not been abandoned, and has in
fact been frequently reinvoked to account for the long-term regula
tion of many characteristics of muscle (see review by Gutmann,
1976) and for the maintenance of its structural integrity.
In many cases of neuromuscular disorders the physician is faced
with a complete lack of therapeutic approaches. This helplessness
places the doctor in a position of conflict between his desire to
help and his awareness that there is no treatment. In this
situation it is tempting to indiscriminately use any procedure that
avoids an admission of medical helplessness while satisfying the
patient's demand for treatment. Electrical interventions are often
used to avoid this situation. Due to the random use of therapeutic
approaches it is not known what really happens. Presumptions and
biased empirical observations have led to the exten sive use of
different forms of electrical stimulation regimes in neuromuscular
diseases. Due to this unsatisfactory situation it is necessary to
know more about appropriate methods that are being used in
particular disorders. The search for a better understanding of
nerve-muscle interaction has shown that certain activity patterns
can influence muscle. These experi mental results provide a
rational basis for a possible therapeutic use of electrical
stimulation of nerve and muscle. Previously most research has been
conducted in normal tissue, and little is known regarding the re
sponses of diseased muscle. In an interdisciplinary approach to
this, it is our intention to present the current knowledge about
basic principles of electrical stimulation in normal muscle. Before
electrical stimulation can be accepted as a therapeutic tool, we
felt it necessary to summarize the effects of activity in normal
and diseased muscle and nerve."
The first evidence that electrical changes can cause muscles to
contract was p- vided by Galvani (1791). Galvani's ideas about
'animal electricity' were explored during the 19th and 20th century
when it was firmly established that 'electricity' is one of the
most important mechanisms used for communication by the nervous
system and muscle. These researches lead to the development of ever
more soph- ticated equipment that could either record the
electrical changes in nerves and muscles, or elicit functional
changes by electrically stimulating these structures. It was indeed
the combination of these two methods that elucidated many of the
basic principles about the function of the nervous system.
Following these exciting findings, it was discovered that
electrical stimulation and the functions elicited by it also lead
to long-term changes in the properties of nerves and particularly
muscles. Recent findings help us to understand the mec- nisms by
which activity induced by electrical stimulation can influence
mature, fully differentiated cells, in particular muscles, blood
vessels and nerves. Electrically elicited activity determines the
properties of muscle fibres by activating a sequence of signalling
pathways that change the gene expression of the muscle. Thus,
elect- cal activity graduated from a simple mechanism that is used
to elicit muscle c- traction, to a system that could induce
permanent changes in muscles and modify most of its characteristic
properties.
Following injury or disease, neural circuitry can be altered to
varying degrees leading to highly individualized characteristics
that may or may not resemble original function. In addition, lost
or partially damaged circuits and the effects of biological
recovery processes coupled with learned compensatory strategies
create a new neuroanatomy with capabilities that are often not
functional or may interfere with daily life. To date, the majority
of approaches used to treat neurological dysfunction have focused
on the replacement of lost or damaged function, usually through the
suppression of surviving neural activity and the application of
mechanical assistive devices. Restorative Neurology of Spinal Cord
Injury offers a different and novel approach.
Focusing on the spinal cord and its role in motor control, the book
details the clinical and neurophysiological assessment process and
methods developed throughout the past half century by basic and
clinical scientists. Then, through the use of specialized clinical
and neurophysiological testing methods, conduction and processing
performed within the surviving neural circuitry is examined and
characterized in detail. Based on the results of such assessment,
treatment strategies, also described in this book, are applied to
augment, rather than replace, the performance of surviving neural
circuitry and improve the functional capacity of people who have
experienced injury to their spinal cords.
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