Representational overlap of adjacent fingers in multiple areas of human primary somatosensory cortex depends on electrical stimulus intensity: an fMRI study
| Autor: | Jan Ruben, Stephan A. Brandt, Gabriel Curio, Matthias Moosmann, Arno Villringer, Ralf Kurth, Kersten Villringer, Michael Deuchert, Thomas Krause, Karl-Juergen Wolf, Jessica Schwiemann |
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| Rok vydání: | 2001 |
| Předmět: |
Adult
Male Sensory system Stimulus (physiology) Middle finger Somatosensory system Statistics Nonparametric Fingers Nuclear magnetic resonance medicine Humans Molecular Biology Brain Mapping medicine.diagnostic_test Postcentral gyrus General Neuroscience Somatosensory Cortex Magnetic Resonance Imaging Central sulcus Electric Stimulation medicine.anatomical_structure Female Neurology (clinical) Psychology Functional magnetic resonance imaging Neuroscience Developmental Biology Brodmann area |
| Zdroj: | Brain Research. 899:36-46 |
| ISSN: | 0006-8993 |
| Popis: | Functional magnetic resonance imaging (fMRI) was used to examine the influence of non-painful electrical stimulus intensity on the BOLD response in human primary somatosensory cortex (SI). In ten healthy subjects, index and middle finger of the right hand were stimulated separately at two different stimulus intensities. The activated volume of single finger representations as well as the volume of representational overlap of the two activations increased following an increase in stimulus intensity. This effect was seen in two different subdivisions of SI, one in the depth of the central sulcus, presumably corresponding to Brodmann area (BA) 3b, and one on the crown of the postcentral gyrus, presumably corresponding to BA 1/2. Relative overlap (ratio of overlap volume to volume of individual finger representation) was larger in BA 1/2 than in BA 3b. Additionally, in both areas relative overlap increased significantly from low to high stimulus intensity. Relative overlap did not change when different correlation thresholds were employed arguing against an unspecific 'spillover effect'. Analysis of signal intensity time courses indicated that the response difference to high versus low stimulus strength was not present during the initial seconds of stimulation, during which both led to a similar signal intensity increase. Only during the following maintenance level of the response did the response to high stimulus intensity reach a significantly higher plateau level than the one due to low intensity stimulation, an effect which was present in both areas, BA 3b and BA 1/2, respectively. |
| Databáze: | OpenAIRE |
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