Somatosensory evoked magnetic fields following passive finger movement.

Brain research. Cognitive brain research · 1997 · Unclear · Insufficient evidence

← Research stream

UnclearInsufficient evidencePaper 4146

Study snapshot

PublicationBrain research. Cognitive brain research · 1997

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

The somatosensory evoked magnetic field (SEF) following passive finger movement and electrical stimulation of finger was studied in 10 normal subjects. Four main components were identified in SEFs recorded at the hemisphere contralateral to the moved finger: 1M(P), 2M(P), 3M(P) and 4M(P). The 1M(P) was clearly identified only in three subjects and was smaller than other components. The equivalent current dipoles (ECDs) of 1M(P) were located around the finger area of the primary sensorimotor cortex and oriented either posteriorly or anteriorly. We speculate that it was generated in areas 3a or 2 of the primary sensory cortex. The 2M(P) and 3M(P) were usually combined as one large deflection with two peaks. Because the ECDs of 2M(P) and 3M(P) were located around the finger area of the sensorimotor cortex and both oriented posteriorly, they were considered to be generated in area 4 and/or 3b, and their activities have temporal overlapping. The 4M(P) has large inter-individual difference in terms of amplitude and latency. The ECD of 4M(P) was also located around the finger area of the primary sensorimotor cortex, and oriented anteriorly. The 4M(PI), the main component recorded from the hemisphere ipsilateral to the moved finger, was located in the upper bank of the sylvian fissure, probably the second sensory cortex (SII). Five components, 1M(E), 2M(E), 3M(E), 4M(E) and 4M(EI), corresponding to 1M(P), 2M(P), 3M(P), 4M(P) and 4M(PI), were identified following electrical stimulation of the same finger. However, SEFs following passive movement were clearly different from SEFs following electrical stimulation, in terms of waveforms and source locations, probably due to differences of ascending fibers and receptive fields.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

Population10 normal subjects

Sample size10

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

In 10 normal subjects, four main SEF components (1M(P)–4M(P)) were identified contralateral to passive finger movement, with ECDs localized around the finger area of primary sensorimotor cortex; an ipsilateral component (4M(PI)) was localized to the upper bank of the sylvian fissure (probably SII). Following electrical stimulation, five corresponding components (1M(E)–4M(E) and 4M(EI)) were identified. SEFs after passive movement differed from those after electrical stimulation in waveform and source location, attributed to differences in ascending fibers and receptive fields.

Outcomes measured

Somatosensory evoked magnetic fields (SEFs) components following passive finger movement
SEFs components following electrical stimulation of finger
Equivalent current dipole (ECD) source locations and orientations in sensorimotor cortex/SII
Differences in SEF waveforms and source locations between passive movement vs electrical stimulation

Limitations

Small sample size (10 subjects)
1M(P) component clearly identified only in three subjects
Speculative attribution of generators to specific cortical areas is stated as speculation

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "10 normal subjects",
  "sample_size": 10,
  "outcomes": [
    "Somatosensory evoked magnetic fields (SEFs) components following passive finger movement",
    "SEFs components following electrical stimulation of finger",
    "Equivalent current dipole (ECD) source locations and orientations in sensorimotor cortex/SII",
    "Differences in SEF waveforms and source locations between passive movement vs electrical stimulation"
  ],
  "main_findings": "In 10 normal subjects, four main SEF components (1M(P)–4M(P)) were identified contralateral to passive finger movement, with ECDs localized around the finger area of primary sensorimotor cortex; an ipsilateral component (4M(PI)) was localized to the upper bank of the sylvian fissure (probably SII). Following electrical stimulation, five corresponding components (1M(E)–4M(E) and 4M(EI)) were identified. SEFs after passive movement differed from those after electrical stimulation in waveform and source location, attributed to differences in ascending fibers and receptive fields.",
  "effect_direction": "unclear",
  "limitations": [
    "Small sample size (10 subjects)",
    "1M(P) component clearly identified only in three subjects",
    "Speculative attribution of generators to specific cortical areas is stated as speculation"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "somatosensory evoked magnetic fields",
    "SEF",
    "passive finger movement",
    "electrical stimulation",
    "magnetoencephalography",
    "equivalent current dipole",
    "primary sensorimotor cortex",
    "SII"
  ],
  "suggested_hubs": []
}

AI can be wrong. Always verify against the paper.

AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/s0926-6410(97)00017-7
PubMed: 9450601

Read the original paper →

Related papers

← Back to the Research Library