Dermatome versus homunculus; detailed topography of the primary somatosensory cortex following trunk stimulation

Itomi, Kazuya; Kakigi, Ryusuke; Maeda, Kengo; Hoshiyama, Minoru

doi:10.1016/s1388-2457(99)00290-4

Cited by 30 publications

(21 citation statements)

References 44 publications

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“…The stimulus used in the present study involved a large area likely encompassing dermatomes Th4 to Th10 that, at variance with the study of Itomi et al [2000], therefore received simultaneous stimulation. In addition, moving stimuli could be more effective in eliciting a cortical response.…”

Section: Comparison With Other Studiesmentioning

confidence: 99%

Bilateral cortical representation of the trunk midline in human first somatic sensory area

Fabri

Polonara

Salvolini

et al. 2005

Human Brain Mapping

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The cortical representation of the trunk zone in the human first somatosensory area was studied with functional magnetic resonance imaging (fMRI) to establish whether the cutaneous regions close to the midline are represented in this area of both hemispheres. Cortical activation foci evoked by unilateral tactile stimulation of ventral trunk regions were detected in the postcentral gyrus of the contralateral hemisphere slightly medial to or just behind the omega-shaped region of the central sulcus and in the anterior bank of the postcentral sulcus. These regions probably correspond to the trunk ventral midline representation zones of areas 3a-3b and 1-2, respectively. Stimulation of cutaneous regions adjacent to the midline evoked activation foci also in the ipsilateral postcentral gyrus in regions symmetrical to those activated in the contralateral hemisphere. These data demonstrate that in humans, as in nonhuman primates, the cutaneous regions adjacent to the trunk midline are represented bilaterally in the first somatic sensory cortex. Whether the ipsilateral activation depends on callosal or extracallosal inputs remains to be elucidated.

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Section: Comparison With Other Studiesmentioning

confidence: 99%

Bilateral cortical representation of the trunk midline in human first somatic sensory area

Fabri

Polonara

Salvolini

et al. 2005

Human Brain Mapping

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“…In comparison, tactile stimulation of trunk dermatomes revealed a rather small cortical representation and overlapping somatotopy [Itomi et al, 2000] while the nociceptive processing of thoracic areas has rarely been studied [Strigo et al, 2003].…”

Section: Introductionmentioning

confidence: 99%

Differences in cortical coding of heat evoked pain beyond the perceived intensity: An fMRI and EEG study

Haefeli

Freund

Kramer

et al. 2013

Human Brain Mapping

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Imaging studies have identified a wide network of brain areas activated by nociceptive stimuli and revealed differences in somatotopic representation of highly distinct stimulation sites (foot vs. hand) in the primary (S1) and secondary (S2) somatosensory cortices. Somatotopic organization between adjacent dermatomes and differences in cortical coding of similarly perceived nociceptive stimulation are less well studied. Here, cortical processing following contact heat nociceptive stimulation of cervical (C4, C6, and C8) and trunk (T10) dermatomes were recorded in 20 healthy subjects using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Stimulation of T10 compared with the C6 and C8 revealed significant higher response intensity in the left S1 (contralateral) and the right S2 (ipsilateral) even when the perceived pain was equal between stimulation sites. Accordingly, contact heat evoked potentials following stimulation of T10 showed significantly higher N2P2 amplitudes compared to C6 and C8. Adjacent dermatomes did not reveal a distinct somatotopical representation. Within the assessed cervical and trunk dermatomes, nociceptive cortical processing to heat differs significantly in magnitude even when controlling for pain perception. This study provides evidence that controlling for pain perception is not sufficient to compare directly the magnitude of cortical processing [blood oxygen level dependence (BOLD) response and amplitude of evoked potentials] between body sites. Hum Brain Mapp 35:1379-1389,

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“…In order to stimulate sensory cortex a variety of methods have been used, such as electric current, air pressure, heat and cold. We chose to use electrical median nerve stimulation, as this has been associated with the most robust sensory response of the brain, and was preferred over touch in most studies of the cortical representation of dermatomes to localize the sensory cortex [21,22]. This approach maximizes the signal to noise ratio and we believe enhances our ability to successfully localize the somatosensory cortex in individual patients.…”

Section: Discussionmentioning

confidence: 99%

Preoperative Magnetoencephalographic Sensory Cortex Mapping

Niranjan

Laing

Laghari

et al. 2013

Stereotact Funct Neurosurg

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The use of functional neuroimaging holds the promise of improving neurosurgical outcomes by providing preoperative localization of critical brain functions. The brain representation of somatosensory function can be effectively localized using magnetoencephalography (MEG) in both normal subjects and in patients with tumors, vascular malformation, and epilepsy. This study investigates the pattern of somatosensory localization in 45 patients. Thirty-two of these patients underwent subsequent resective surgery for brain pathologies. Electrical stimulation of the median nerve was conducted, and the most prominent somatosensory peak in the resultant averaged data was localized using the single equivalent current dipole technique. Results showed that this peak localized either to the central or postcentral sulcus of the somatosensory cortex. We found that neither age nor the presence of brain pathologies had significant effect on the recognition of the somatosensory cortex. Patients who underwent surgery after presurgical planning using MEG suffered no new somatosensory deficits, indicating the valuable role of pre-surgical mapping using MEG in the surgical planning.

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Dermatome versus homunculus; detailed topography of the primary somatosensory cortex following trunk stimulation

Cited by 30 publications

References 44 publications

Bilateral cortical representation of the trunk midline in human first somatic sensory area

Bilateral cortical representation of the trunk midline in human first somatic sensory area

Differences in cortical coding of heat evoked pain beyond the perceived intensity: An fMRI and EEG study

Preoperative Magnetoencephalographic Sensory Cortex Mapping

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