Conduction time in central somatosensory pathways in man

Hume, Ann L.; Cant, B.R

doi:10.1016/0013-4694(78)90188-8

Cited by 262 publications

(41 citation statements)

References 20 publications

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“…Other methods of intra-operative neuromonitoring, including electrophysiological [23][24][25][26][27][28][29][30], microvascular Doppler sonography [21][22][23][24][25], and neuroendoscopy [31][32][33][34][35], have historically been used alone or in combination with intra-operative DSA during aneurysm surgery [36]. Gruber, et al compared the value of ICG with data simultaneously generated from other intra-operative monitoring and vascular imaging techniques.…”

Section: Discussionmentioning

confidence: 99%

Indocyanine Green Videoangiography and Intraoperative Catheter Digital Subtraction Angiography in the Treatment of Intracranial Aneurysms: A Consecutive Series of 235 Cases

Defillo¹,

Qureshi²,

Nussbaum³

2014

Cureus

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Section: Discussionmentioning

confidence: 99%

Indocyanine Green Videoangiography and Intraoperative Catheter Digital Subtraction Angiography in the Treatment of Intracranial Aneurysms: A Consecutive Series of 235 Cases

Defillo¹,

Qureshi²,

Nussbaum³

2014

Cureus

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“…During each block the nerve was stimulated 400 times at a duration of 0.2 ms, a frequency of 1 Hz and at an intensity just below motor threshold (Hume and Cant, 1978). No participant reported pain or discomfort with this level of stimulation.…”

Section: Methodsmentioning

confidence: 99%

Early and late activity in somatosensory cortex reflects changes in bodily self-consciousness: An evoked potential study

2012

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Abstract-How can we investigate the brain mechanisms underlying self-consciousness? Recent behavioural studies on multisensory bodily perception have shown that multisensory conflicts can alter bodily self-consciousness such as in the ''full body illusion'' (FBI) in which changes in self-identification with a virtual body and tactile perception are induced. Here we investigated whether experimental changes in self-identification during the FBI are accompanied by activity changes in somatosensory cortex by recording somatosensory-evoked potentials (SEPs). To modulate self-identification, participants were filmed by a video camera from behind while their backs were stroked, either synchronously (illusion condition) or asynchronously (control condition) with respect to the stroking seen on their virtual body. Tibial nerve SEPs were recorded during the FBI and analysed using evoked potential (EP) mapping. Tactile mislocalisation was measured using the crossmodal congruency task. SEP mapping revealed five sequential periods of brain activation during the FBI, of which two differed between the illusion condition and the control condition. Activation at 30-50 ms (corresponding to the P40 component) in primary somatosensory cortex was stronger in the illusion condition. A later activation at $110-200 ms, likely originating in higher-tier somatosensory regions in parietal cortex, was stronger and lasted longer in the control condition. These data show that changes in bodily self-consciousness modulate activity in primary and higher-tier somatosensory cortex at two distinct processing steps. We argue that early modulations of primary somatosensory cortex may be a consequence of (1) multisensory integration of synchronous vs. asynchronous visuo-tactile stimuli and/or (2) differences in spatial attention (to near or far space) between the conditions. The later activation in higher-tier parietal cortex (and potentially other regions in temporo-parietal and frontal cortex) likely reflects the detection of visuo-tactile conflicts in the asynchronous condition.

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“…4 Although still controversial, it is generally agreed that the major negative peak recorded over C2 represents arrival of the afferent stimulus at a (N14) fixed generator site, probably the dorsal column nuclei (DCN). 3 ' 6 The first major negative peak recorded from the somatosensory cortex (N20) represents the arrival of the afferent volley at the cortex. * Hume and Cant, in 1978, introduced the concept of central conduction time (CCT) N20-N14, to measure the electrical conduction in the central nervous system independent of peripheral involvement.…”

mentioning

confidence: 99%

Central conduction time in primate brain ischemia -- a study in baboons.

Hargadine¹,

Branston²,

Symon³

1980

Stroke

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SUMMARYThe relationship between central conduction time (CCT) and levels of regional blood flow were studied in 9 primates. Flows were recorded in both hemispheres using the method of hydrogen (2 min) clearance. The somatosensory evoked potentials were recorded over the contralateral cortex and the dorsal columns, following median nerre stimulation. The CCT, a measure of the brain's electrical conduction, was determined by the difference in latencies between N10, (the arrival of the afferent volley at the sensory cortex) and N7 (its arrival at the dorsal column). Ischemia was produced by transorbital occlusion of the right middle cerebral artery.In the acute iscbemic phase within 5 minutes of occlusion, there was a significant correlation between the change in CCT and the decrease in flow. In the later occlusive phase, the CCT was unaltered with flows above 15 ml/lOOg/min. Below that level smaller decreases in flow resulted in progressively larger changes in CCT until a flow was reached where the N10 disappeared or the entire cortex was electrically silent.Focal ischemia had no effect on the first positive deflection recorded from the cortex (P8) or the first negative peak response from the cervical region (N7). However, the latency of P8 was increased or it was absent with the introduction of hypotension, while N8 was unaltered.From our measurements, it appears that prolongation of CCT can be related to developing ischemia, and that the thresholds for change are not dissimilar to those already recorded for somatosensory evoked responses on the basis of amplitude alterations in the cortex. Below these levels, prolongation of CCT appears to bear a parametric relationship to alteration in blood flow. While the measurement displays only one of the many alterations which are Induced by ischemia in the brain, its attraction lies in its simplicity and in the fact that it may be applied with relative ease in the clinical situation. Under these circumstances, it appears to be an adequately sensitive monitor of developing brain ischemia, and deserves further study.Stroke, Vol II, No 6, 1980

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Conduction time in central somatosensory pathways in man

Cited by 262 publications

References 20 publications

Indocyanine Green Videoangiography and Intraoperative Catheter Digital Subtraction Angiography in the Treatment of Intracranial Aneurysms: A Consecutive Series of 235 Cases

Indocyanine Green Videoangiography and Intraoperative Catheter Digital Subtraction Angiography in the Treatment of Intracranial Aneurysms: A Consecutive Series of 235 Cases

Early and late activity in somatosensory cortex reflects changes in bodily self-consciousness: An evoked potential study

Central conduction time in primate brain ischemia -- a study in baboons.

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