Abstract：
:Static and dynamic components of the stretch reflex were studied in elbow flexors of 13 hemiparetic brain-injured individuals. Constant-velocity joint rotations were applied to the elbow, and the resulting stretch reflex torque and electromyographic responses were recorded in the biceps brachii and brachioradialis muscles. Ten elbow extension velocities between 6 and 150 deg s(-1) were applied in random order. The resulting reflex torque response was plotted as a function of elbow angle and fitted with a mathematical model designed to depict elbow flexor activation. We found that four of the six model parameters were essentially independent of test velocity. Conversely, 73% (19/26) of cases involving the other two model parameters were dependent on velocity of joint extension (p<0.05). We conclude from these results that four of the model parameters reflect the static reflex response while the two remaining velocity-dependent parameters reflect the dynamic reflex response. To describe overall velocity dependence of stretch reflexes in spastic elbow muscles, the two dynamic reflex parameters were fitted to a fractional exponential function of velocity, similar to a model previously used to describe spindle firing rate in the cat hindlimb. We found that the mean velocity exponent of the dynamic reflex parameters was 0.24 + 0.17 (s.d.) (N = 13), a value similar to that for muscle spindle velocity sensitivity in reduced animal preparations. We conclude that both static and dynamic reflex sensitivities can be measured by examining different aspects of the torque/angle relation associated with the reflex response to a large-amplitude ramp stretch of the elbow.
journal_name
Ann Biomed Engjournal_title
Annals of biomedical engineeringauthors
Schmit BD,Rymer WZdoi
10.1114/1.1359496subject
Has Abstractpub_date
2001-04-01 00:00:00pages
330-9issue
4eissn
0090-6964issn
1573-9686journal_volume
29pub_type
杂志文章abstract：:To study pulsatile pressure-flow rate relationships in the intact pulmonary vascular network of mice, we developed a protocol for measuring pulmonary vascular resistance and impedance in isolated, ventilated, and perfused mouse lungs. We used pulmonary emboli to validate the effect of vascular obstruction on resistanc...
journal_title：Annals of biomedical engineering
pub_type： 杂志文章
doi：10.1007/s10439-005-9050-z
更新日期：2006-04-01 00:00:00
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pub_type： 杂志文章
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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journal_title：Annals of biomedical engineering
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更新日期：2015-09-01 00:00:00
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journal_title：Annals of biomedical engineering
pub_type： 临床试验,杂志文章
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journal_title：Annals of biomedical engineering
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更新日期：2018-01-01 00:00:00
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journal_title：Annals of biomedical engineering
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