Mechanically and electrically evoked somatosensory potentials in humans: Effects of stimulus presentation rate

Pratt, Hillel; Politoske, D.; Starr, Arnold

doi:10.1016/0013-4694(80)90218-7

Cited by 71 publications

(17 citation statements)

References 16 publications

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“…At first sight, the functional MRI data presented here contrast with electrophysiological data, which show a reduction of the somatosensory evoked potentials (SEP) at stimulation rates above 5-8 Hz [Pratt et al, 1980;Delberghe et al, 1990]. Of the primary cortical response to electrical median nerve stimulation, the N20 component is supposed to be generated in the primary somatosensory cortex by EPSPs (excitatory postsynaptic potentials) in pyramids of area 3b [Allison et al, 1991].…”

Section: Discussionmentioning

confidence: 59%

“…Data from anaesthetized animals [Gyngell et al, 1996] showed a decrease of the fMRI response measured at 4.7T for stimulation frequencies above 3 Hz, with negligible responses at 9 Hz. Based on the observation that the amplitude of the SEP declines above 5-8 Hz [Pratt et al, 1980;Delberghe et al, 1990], most previous fMRI studies using electrical nerve stimulation have not exceeded a stimulation rate of 10 Hz.…”

Section: Introductionmentioning

confidence: 99%

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Frequency dependence of the functional MRI response after electrical median nerve stimulation

2000

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Localizing sensorimotor areas with high resolution functional MRI is of considerable interest for a wide range of medical applications from the preoperative planning of neurosurgical interventions to determining the course of neuroplastic reorganisation after brain lesions. We examined the effect of the stimulation frequency on the blood oxygen level dependent (BOLD) fMRI response and on perfusion weighted fMRI using electrical median nerve stimulation at 5, 15, 40, and 100 Hz. BOLD fMRI was performed using a single shot gradient echo EPI sequence to acquire 15 contiguous slices. For the qualitative flow sensitive studies, a single slice inversion recovery prepared spin echo echoplanar sequence (IR-SE EPI) was used. In the primary sensorimotor cortex, a linear increase of the fMRI-BOLD response, affecting both the number of activated pixels and the amplitude of the signal changes, was seen with increasing stimulation frequencies. The qualitative in-flow sensitive studies, using the IR-SE EPI sequence, indicate that the tissue perfusion also increases over the same range of frequencies. This implicates that larger fMRI responses can be obtained if electrical median nerve stimulation is performed at higher frequencies. The results are compared with electrophysiological data, which show a decrease of the early somatosensory evoked potentials at higher frequencies.

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Section: Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Frequency dependence of the functional MRI response after electrical median nerve stimulation

2000

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“…Using the dipole description, the generator would be a dipole with its positive pole placed rostral close to Oz. Previous results on the effects of varying interstimulus intervals on an analogous component in cats (Wiederholt 1978) and humans (Pratt et al 1980) suggest this component to be generated postsynaptically, possibly at the dorsal column nuclei. The final nuchal positivity at 16.8 msec to electrical stimulation (24.0 msec to mechanical stimulation), which at Oz and rostral was recorded as negativity and reversed polarity caudal to Oz arises from a different generator than the negative wave recorded over the neck.…”

Section: Discussionmentioning

confidence: 87%

Mechanically and electrically evoked somatosensory potentials in humans: Scalp and neck distributions of short latency components

Pratt

Starr

1981

Electroencephalography and Clinical Neurophysiology

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“…Somatosensory evoked responses are known to increase in amplitude as a function of ISI [2,29]. In the auditory modality, such a behavior has been interpreted to reflect varying lifetimes of sensory memory traces at different brain areas [25].…”

Section: Discussionmentioning

confidence: 99%

Interaction between afferent input from fingers in human somatosensory cortex

Forss¹,

Jousmäki²,

Hari³

1995

Brain Research

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We recorded somatosensory evoked magnetic fields from eight healthy subjects with a 122-channel whole-scalp SQUID magnetometer. The stimulus sequence consisted of 'standard' stimuli (85%) delivered to palmar side of the left thumb with an interstimulus interval of 0.6 s and of 'deviants' (15%), randomly interspersed among the standards, to little finger, and vice versa. Both stimuli activated four source areas: the contralateral primary somatosensory cortex (SI), the contra-and ipsilateral secondary somatosensory cortices (SII), and the contralateral posterior parietal cortex (PPC). The short-latency (20-40 ms) responses originated in the SI cortex, whereas long-latency responses arose from all 4 areas. At SII and PPC, the deviant stimuli elicited larger responses when presented alone, without intervening standards, than among standards. This implies interaction between afferent impulses from the two fingers and/or partly intermingled cortical representations. Our findings show, in agreement with animal data, different excitatory/inhibitory balance in the various somatosensory areas.

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Mechanically and electrically evoked somatosensory potentials in humans: Effects of stimulus presentation rate

Cited by 71 publications

References 16 publications

Frequency dependence of the functional MRI response after electrical median nerve stimulation

Frequency dependence of the functional MRI response after electrical median nerve stimulation

Mechanically and electrically evoked somatosensory potentials in humans: Scalp and neck distributions of short latency components

Interaction between afferent input from fingers in human somatosensory cortex

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