• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.114-118
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• 1997

Purpose: Functional MR imaging is the method of demonstrating changes in regional cerebral blood flow produced by sensory, motor, and any other tasks. Functional MR of visual cortex is performed as a patient stares a photic stimulation, so adaptable photic stimulation is necessary. The purpose of this study is to evaluate whether the size of photic stimulator can affect the degree of visual cortex activation. Materials and Methods: Functional MR imaging was performed in 5 volunteers with normal visual acuity. Photic stimulator was made by 39 light-emitting diodes on a plate, operating at 8Hz. The sizes of photic stimulator were full field, half field and focal central field. The MR imager was Siemens 1.5-T Magnetom Vision system, using standard head coil. Functional MRI utilized EPI sequence (TR/TE= 1.0/51. Omsec, matrix $No.=98{\times}128$, slice thickness=8mm) with 3sets of 6 imaging during stimulation and 6 imaging during rest, all 36 scannings were obtained. Activation images were obtained using postprocessing software(statistical analysis by Z-score), and these images were combined with T-1 weighted anatomical images. The activated signals were quantified by numbering the activated pixels, and activation a index was obtained by dividing the pixel number of each stimulator size with the sum of the pixel number of 3 study using 3 kinds of stimulators. The correlation between the activation index and the stimulator size was analysed. Results: Mean increase of signal intensities on the activation area using full field photic stimulator was about 9.6%. The activation index was greatest on full field, second on half field and smallest on focal central field in 4. The index of half field was greater than that of full field in 1. The ranges of activation index were full field 43-73%(mean 55%), half field 22-40 %(mean 32%), and focal central field 5-24%(mean 13%). Conclusion: The degree of visual cortex activation increases with the size of photic stimulator.

• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.16-23
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• 2005

Purpose : In order to investigate the functional brain anatomy associated with mental calculation, functional magnetic resonance imaging was performed. Materials and Methods : In six normal right handed subjects, functional MR images were obtained using a 1.57 MR scanner and the EPI BOLD technique. The study included experiment I and experiment II. Each experiment consisted of five resting and four activation periods with each period of 30 seconds. During the activation period of both experiment I and II, calculation equations[an example: $(4+5)\times8=72$] were presented and the subjects were instructed to decide true or false of them. During the resting period of experiment I, the subjects were instructed to visually fixate on a crosshair. During the resting period of experiment II, two diagrams (an example: $(\bullet,\;\blacksquare)$)were presented and the subjects were instructed to decide they are same or not. For the post-processing of images, the SPM program was used, with the threshold of significance set at p<0.00001. The activated areas during the tasks were assessed. Results : In experiment 1, the inferior frontal gyrus, prefrontal cortex, promoter area, supplementary motor area, and intraparietal sulcus including superior parietal cortex were activated bilaterally. Although these areas were also activated in experiment II, the activated signals in the right frontal and parietal lobes were lessened. Conclusion : The left inferior frontal gyrus and prefrontal cortex and bilateral intraparietal sulci were activated during mental calculation. The right frontal and parietal lobes might be related to attention and decision making.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• The Journal of Korean Academy of Sensory Integration
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• v.11 no.1
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• pp.11-27
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• 2013

Objective : This is a descriptive study using a program review collaborative group program by special educator and occupational therapist for supporting children's school tasks, and it is designed to explore how changed school performance skills and to analyze how applied intervention methods including sensory integrative approach. Methods : Participants were 6 male elementary students(5 = 1st grade, 1 = 2nd grade). Pilot program had reviewed and its results used as base for planning main program. Main program was implemented by collaborative process with teacher and occupational therapist for 1 year. School AMPS was used to assess school task participants, and informal motor and process skill observation was used to assess self-help activities. Description of records by professions about intervention strategies through assessments was described as qualitative way. Japanese sensory inventory was used by parents. Results : Through the collaborative process, assessing children, planning and modifying program, establishing intervention strategies were implemented. Self-help abilities in group program were increased much more independently. School task abilities were increased slightly but skills changed irregularly and unexpectedly and their reasons became considered more complex from sensory processing reasons to social and emotional reasons. Conclusion : Sensory integration had benefits for primary group program and more complex intervention strategies became to emerge demands for person- environment-task challenges. Collaborative practice with teacher and occupational therapist was supplement and synergic effect for children and group dynamics. More objective and comprehensive methods for measure collaboration and group effect would be needed in further study.