کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9415999 1614328 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Nerve specific modulation of somatosensory inflow to cerebral cortex during submaximal sustained contraction in first dorsal interosseous muscle
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب (عمومی)
پیش نمایش صفحه اول مقاله
Nerve specific modulation of somatosensory inflow to cerebral cortex during submaximal sustained contraction in first dorsal interosseous muscle
چکیده انگلیسی
Modulation of the early component (latency ∼20-30 ms) of somatosensory evoked potentials (SEPs) and that of the middle and long latency cutaneous reflexes was examined in 13 healthy volunteers during fatiguing submaximal voluntary contraction (20% maximum) of the first dorsal interosseous muscle (FDI). The SEP was evoked by stimulating the ulnar nerve (U-SEP), a mixed nerve innervating the FDI muscle, the purely cutaneous nerves of the 2nd digit (D2-SEP) and the 5th digit (D5-SEP). The cutaneous reflex was recorded concurrently with D2-SEP. The size of D2- and D5-SEP significantly decreased during fatiguing contraction as compared to rest, and the decrease in both SEPs persisted throughout fatiguing contraction. In contrast, the significant decrease in the gating of U-SEP disappeared during the latter phase of fatiguing contraction. The ratio (reflex response/background EMG) of excitatory E2 (latency ∼60-90 ms) and E3 (∼120-180 ms) responses following D2 stimulation significantly increased during the middle or latter phase of fatiguing contraction. In contrast, no significant changes in inhibitory I1 and I2 were seen. The release of the attenuation of U-SEP and a constant gating of the D2- and D5-SEP suggests that the brain selectively permits the muscular afferent inflow into the cortex during fatiguing contraction. An increase in the E2 and E3 reflex ratio of cutaneous reflexes during the later phase of fatiguing contraction most likely results from an increase in the excitability of the motor cortex.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Brain Research - Volume 1053, Issues 1–2, 16 August 2005, Pages 146-153
نویسندگان
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