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Somatosensory imagery activates primary sensory cortex in human: A functional MRI study
ABSTRACTS
Somatosensory Imagery Activates Primary Sensory Cortex in Human: A Functional MRI Study C. Hodge, J. Dubroff, S. Huckins, N. Szeverenyi Health Science Center at Syracuse Departments of Neurosurgery and Radiology Syracuse, NY,, USA
Introduction: This study asked whether somatosensory imagery in humans results in activation of the primary sensory cortex (SI) and other cortical areas, such as second somatosensory area (SII) and parietal cortex, known to be activated by real sensory stimulation. Methods: An echoplanar(EP) modification of a GE 1.5 T clinical MR machine was used to acqmre multislice images of human brain during somatosensory imagery. This task consists of imagining the sensation of air puff or tactile stimulation of the face or digits. Locations of SI and $1I were determined by air puff or tactile stimulation of the face or hand during the same imaging session. At times the real sensory task was done after the imagery task. Six subjects underwent 20 imaging sessions. Pixel by pixel analysis with t-test (p<.05), time course concordance and cluster analysis were used to determine the areas activated. Results: Somatosensory imagery results in activation of SI. The site of activation was the same as the sites activated by real stimulation, though the area activated during imagination was more localized than that activated by real stimulation. At times activation of SII was also demonstrated. There was variable parietal association cortex activation. Discussion: The fact that somatotopically precise primary sensory cortex is activated during somatosensory imagery provides an important clue to how fl~e brmn fimctions during some cvgni~ive tasks, i.e. by using primary cortex to create ideational representaaons. The pathways by w1~sch tk~is activation occurs is unknown but is approachable by studying patients with anatomic lesions. The difference between real and imagined sensory events deserves further investigation.
$2O9
Somatosensory Imagery Activates Primary Sensory Cortex in Human: A Functional MRI Study C. Hodge, J. Dubroff, S. Huckins, N. Szeverenyi Health Science Center at Syracuse Departments of Neurosurgery and Radiology Syracuse, NY,, USA
Introduction: This study asked whether somatosensory imagery in humans results in activation of the primary sensory cortex (SI) and other cortical areas, such as second somatosensory area (SII) and parietal cortex, known to be activated by real sensory stimulation. Methods: An echoplanar(EP) modification of a GE 1.5 T clinical MR machine was used to acqmre multislice images of human brain during somatosensory imagery. This task consists of imagining the sensation of air puff or tactile stimulation of the face or digits. Locations of SI and $1I were determined by air puff or tactile stimulation of the face or hand during the same imaging session. At times the real sensory task was done after the imagery task. Six subjects underwent 20 imaging sessions. Pixel by pixel analysis with t-test (p<.05), time course concordance and cluster analysis were used to determine the areas activated. Results: Somatosensory imagery results in activation of SI. The site of activation was the same as the sites activated by real stimulation, though the area activated during imagination was more localized than that activated by real stimulation. At times activation of SII was also demonstrated. There was variable parietal association cortex activation. Discussion: The fact that somatotopically precise primary sensory cortex is activated during somatosensory imagery provides an important clue to how fl~e brmn fimctions during some cvgni~ive tasks, i.e. by using primary cortex to create ideational representaaons. The pathways by w1~sch tk~is activation occurs is unknown but is approachable by studying patients with anatomic lesions. The difference between real and imagined sensory events deserves further investigation.
$2O9