The aim of this study is to investigate the mechanism of motor recovery using both functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS) in a patient with hemorrhagic contusion on the right basal ganglia area. Functional MRI showed that the left primary sensorimotor cortex and the supplementary motor area were activated when the right fingers performed the flexion-extension exercise. On the other hand, the bilateral primary sensorimotor cortex and the left premotor area were activated with the excerise of left hand. Brain mapping for both abductor pollicis brevis muscles (APB) using TMS revealed that ipsilateral motor evoked potentials (MEPs) were obtained at left APB. Ipsilateral MEPs of left APB showed delayed latency and lower amplitude compared to that of right APB when stimulated at the left motor cortex. We concluded that ipsilateral motor pathway from undamaged motor cortex seems to contribute to the motor recovery in this patient and combining TMS with fMRI may provide a powerful tool for investigating the mechanism of motor recovery.

Objective: This study involves an experiment using functional magnetic resonance imaging (fMRI) to delineate neural network and laterality of language related brain activation for spoken and written Korean words in normal adults.

Method: Eight normal right-handed Korean males, aged 20∼33 years, were investigated. Language tasks consisted of auditory and visual verb generation tasks. In fMRI, twenty slices were obtained for each functional volume using single shot echoplanar image sequences. Data were motion corrected, coregistered, normalized, and statistically analyzed using SPM-96 software. The number of activated voxels were counted in each hemisphere to calculate the laterality index according to each language task.

Results: In auditory verb generation task, inferior frontal gyrus and superior temporal region were activated in the left side. Right temporal lobe was also activated in the superior and middle temporal areas. Other activated area included medial frontal lobe. Lateralization index of auditory verb generation task was ⁢78.6⁑30.7. In visual verb generation task, inferior frontal gyrus was activated in the left side. Medial frontal lobe, both lateral occipital lobe, and left parietal lobe were also activated. The laterality index was ⁢87.6⁑10.1.

Conclusion: We could delineate cortical regions subserved for spoken and written Korean language and laterality of language related brain activation using fMRI. These results can contribute to understand underlying mechanism of language disorders in brain injury patients and to investigate the pattern of reorganization of language network after rehabilitation.

The higher cognitive functions of human brain are hypothesized to be selectively distributed across large-scale neural networks interconnected cortical and subcortical areas. Recently, advances in functional imaging made it possible to visualize the brain areas activated by certain cognitive function in vivo. Out of several technologies currently available for brain activation study, functional magnetic resonance imaging (fMRI) is increasingly being used because of its superior time resolution and finer spatial resolution. The technique is non-invasive without radiation hazard, which allow to take repeated multiple scans within the same individual. The most common approach to fMRI of brain is the one using 'blood-oxygen level dependent (BOLD)' contrast, which based on the localized hemodynamic changes following neural activities in the certain areas of brain.

With functional imaging techniques including fMRI, neural networks subserving for higher cognitive functions such as language, memory, attention, and visuospatial functions could be visualized. Neural substrates of human emotion and motivation behaviors also begin to be unveiled. Brain mapping with functional imaging is a very useful method for detecting eloquent areas in a neurosurgical setting to prevent the residual disabilities. One of the issues recently having attention in the field of functional imaging is the reorganization of neural network following brain injuries. Much research results using fMRI identified intra- and/or interhemispheric reorganization of neural networks accompanied with functional recovery after brain injury. Effects of learning and rehabilitation on the extent and pattern of neural reorganization was also delineated. fMRI will be a very useful tool for developing of various rehabilitation treatments, which promote successful functional recovery by maximizing the plasticity of brain.

Objective: To investigate cortical reorganization of the brain during voluntary activities of the hand in patients with subcortical cerebral infarction.

Method: Twelve patients with first-ever subcortical brain lesion causing hemiparesis had been evaluated with functional MRI. Bilateral hand clenching was done to test voluntary hand activities. Recovery period ranged from 2 to 36 months.

Results: During the unaffected hand movement, activation of contralateral primary sensorimotor cortex (SMC) were recorded in all cases and supplmentary motor area (SMA) in 1 case. The affected hand movement showed activation of the cotralateral SMC in all cases, ipsilateral SMC in 4 cases, SMA in 4 cases and contralateral prefrontal area in 2 cases. As for the contralateral SMC, affected hand movement showed more increased activation than the unaffected. For the bilateral SMC activation during movement of the affected hand, contralateral SMC activation was greater than the ipsilateral.

Conclusion: Ipsilateral activation of the SMC, SMA, prefrontal area and increased activation of the contralateral SMC during affected hand movement suggest that these may play an important role in the reorganization of sensory and motor system in stroke patients with subcortical lesion. Functional MRI studies of patients who recovered from subcortical stroke provide evidence for several process that may be related to restoration of neurologic function.

Objectives: To report the results of functional magnetic resonance imaging (fMRI) experiment to delineate brain network for auditory language tasks in normal Korean adults.

Method: Five normal right-handed Korean males, aged 20∼33 years, were investigated using fMRI technique. Language tasks consisted of auditory listening and verb generation tasks. In fMRI, twenty slices were obtained for each functional volume using single shot echoplanar image sequences. Eighty-four volumes were obtained for each functional run. Data were motion corrected, coregistered, normalized, and statistically analyzed using SPM-96 software (Wellcom Department of Cognitive Neurology, Oxford, UK).

Results: Functional activation were detected in superior temporal region (coordinates: x=⁣64, y=⁣42, z=2) in the left side and superior to middle temporal lobe (coordinates: x=50, y=⁣20, z=2) in the right side for auditory listening task. Auditory verb generation task activated inferior frontal gyrus (coordinates: x=⁣56, y=16, z=14), superior temporal region, and medial frontal region in the left side. Right temporal lobe was also activated in the superior to middle temporal areas. Activation was more extensive in the left side for both language tasks.

Conclusion: Our results can remarkably delineate cortical and subcortical regions subserved for auditory language processing. These results can be contributing to understand the underlying mechanism of language disorders in brain-injured patients and to investigate the pattern of reorganization of language network after rehabilitation.