Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0004
- Subject:
- Neuroscience, Molecular and Cellular Systems
The connection between motoneuronal axons and skeletal muscle fibres (neuromuscular junction, NMJ) shares basic characteristics with many excitatory chemical synapses inside the central nervous ...
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The connection between motoneuronal axons and skeletal muscle fibres (neuromuscular junction, NMJ) shares basic characteristics with many excitatory chemical synapses inside the central nervous system (CNS). The presynaptic action potential gives rise to a presynaptic influx of calcium ions (presynaptic voltage-gated calcium channels), which causes a presynaptic release of transmitter (here acetylcholine, ACh). At the postsynaptic membrane, the binding of ACh to receptor molecules causes an increased ionic permeability, which gives rise to a depolarizing shift of postsynaptic membrane potential (endplate potential, EPP), normally large enough for eliciting a postsynaptic action potential which will activate the contractile mechanisms of the muscle fibre. Compared with most CNS synapses, the NMJ is of enormous size, and its main function is to amplify the weak currents associated with presynaptic axonal spikes such that action potentials will be safely transmitted in a 1:1 fashion from the nerve terminal to the muscle fibre.Less
The connection between motoneuronal axons and skeletal muscle fibres (neuromuscular junction, NMJ) shares basic characteristics with many excitatory chemical synapses inside the central nervous system (CNS). The presynaptic action potential gives rise to a presynaptic influx of calcium ions (presynaptic voltage-gated calcium channels), which causes a presynaptic release of transmitter (here acetylcholine, ACh). At the postsynaptic membrane, the binding of ACh to receptor molecules causes an increased ionic permeability, which gives rise to a depolarizing shift of postsynaptic membrane potential (endplate potential, EPP), normally large enough for eliciting a postsynaptic action potential which will activate the contractile mechanisms of the muscle fibre. Compared with most CNS synapses, the NMJ is of enormous size, and its main function is to amplify the weak currents associated with presynaptic axonal spikes such that action potentials will be safely transmitted in a 1:1 fashion from the nerve terminal to the muscle fibre.
Paul Katz (ed.)
- Published in print:
- 1999
- Published Online:
- March 2012
- ISBN:
- 9780198524243
- eISBN:
- 9780191724435
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198524243.001.0001
- Subject:
- Neuroscience, Behavioral Neuroscience
There are many modes of communication that neurons use to transmit information besides what has come to be called neurotransmission. Many of these other types of communication can be classified as ...
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There are many modes of communication that neurons use to transmit information besides what has come to be called neurotransmission. Many of these other types of communication can be classified as neuromodulatory, where instead of conveying excitation or inhibition, the signal from one neuron changes the properties of other neurons or synapses. This form of neuronal communication is often overlooked by systems physiologists, but it is extremely prevalent in the nervous system and needs to be included in any description of how the nervous system processes information. This book provides the foundations for understanding the cellular and molecular basis for neuromodulatory effects. It illustrates some key examples of the roles played by neuromodulation in sensory processing, neuromuscular transmission, generation of motor behaviours, and learning. Finally, the book seeks to point out areas that are likely to be of importance in the future study of information processing by the nervous system. It also summarizes a vast amount of research, and puts it into the context of how these cellular mechanisms are used in systems of neurons. By spanning the levels of analysis from sub-cellular mechanisms through cellular properties and neuronal systems to behaviour, the book provides a framework for understanding this currently exploding field of research.Less
There are many modes of communication that neurons use to transmit information besides what has come to be called neurotransmission. Many of these other types of communication can be classified as neuromodulatory, where instead of conveying excitation or inhibition, the signal from one neuron changes the properties of other neurons or synapses. This form of neuronal communication is often overlooked by systems physiologists, but it is extremely prevalent in the nervous system and needs to be included in any description of how the nervous system processes information. This book provides the foundations for understanding the cellular and molecular basis for neuromodulatory effects. It illustrates some key examples of the roles played by neuromodulation in sensory processing, neuromuscular transmission, generation of motor behaviours, and learning. Finally, the book seeks to point out areas that are likely to be of importance in the future study of information processing by the nervous system. It also summarizes a vast amount of research, and puts it into the context of how these cellular mechanisms are used in systems of neurons. By spanning the levels of analysis from sub-cellular mechanisms through cellular properties and neuronal systems to behaviour, the book provides a framework for understanding this currently exploding field of research.
Daniel Kernell
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198526551
- eISBN:
- 9780191723896
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198526551.003.0009
- Subject:
- Neuroscience, Molecular and Cellular Systems
The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and ...
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The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and may be expressed as either a net increase (potentiation) or a net depression (fatigue) of input-output relations. For voluntary motor activity, such changes may take place within (e.g., central fatigue) as well as outside (e.g., peripheral fatigue) the central nervous system. In such activity, an increasing degree of muscle and/or central fatigue will be experienced as an increasing sense of effort needed for continued action. In muscle physiology a distinction is made between high- and low-frequency fatigue, and extensive studies have been performed as to the role of energy metabolism, cross-bridge interactions, excitation-contraction coupling and neuromuscular transmission. The various manners in which motoneurone properties are matched to muscle characteristics might help to counteract fatigue-related declines of motor output.Less
The functional properties of neurones, synapses, and muscles often change as a result of preceding use. In the short term (minutes to hours), such changes are typically rather rapidly reversible and may be expressed as either a net increase (potentiation) or a net depression (fatigue) of input-output relations. For voluntary motor activity, such changes may take place within (e.g., central fatigue) as well as outside (e.g., peripheral fatigue) the central nervous system. In such activity, an increasing degree of muscle and/or central fatigue will be experienced as an increasing sense of effort needed for continued action. In muscle physiology a distinction is made between high- and low-frequency fatigue, and extensive studies have been performed as to the role of energy metabolism, cross-bridge interactions, excitation-contraction coupling and neuromuscular transmission. The various manners in which motoneurone properties are matched to muscle characteristics might help to counteract fatigue-related declines of motor output.
Alan J. McComas
- Published in print:
- 2011
- Published Online:
- September 2011
- ISBN:
- 9780199751754
- eISBN:
- 9780199897094
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199751754.003.0011
- Subject:
- Neuroscience, History of Neuroscience, Sensory and Motor Systems
Eccles, having returned to Australia from Oxford, is appointed Director of a pathology institute in Sydney, and sets up neurophysiology laboratories there. To assist him, he first recruits Stephen ...
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Eccles, having returned to Australia from Oxford, is appointed Director of a pathology institute in Sydney, and sets up neurophysiology laboratories there. To assist him, he first recruits Stephen Kuffler and then Bernard Katz, both of them refugees from Nazi-dominated Europe. The three collaborate in examining transmission between nerve and muscle, concluding that the nerve effects are entirely due to acetylcholine, as Dale had proposed.Less
Eccles, having returned to Australia from Oxford, is appointed Director of a pathology institute in Sydney, and sets up neurophysiology laboratories there. To assist him, he first recruits Stephen Kuffler and then Bernard Katz, both of them refugees from Nazi-dominated Europe. The three collaborate in examining transmission between nerve and muscle, concluding that the nerve effects are entirely due to acetylcholine, as Dale had proposed.
