• Journal of the Korean Magnetic Resonance Society
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• v.10 no.2
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• pp.126-140
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• 2006

Purpose: Contrary to the human study, it has rarely investigated metabolic alterations in the dorsolateral prefrontal cortex (DLPFC) of depressed rats versus age and sex-matched controls using proton magnetic resonance spectroscopy (MRS). Thus, the purpose of this research was to verify the feasibility of metabolic differences between the normal rat and the depression model rat. Materials and Methods: A homogeneous group of 20 SD male rats was used for MRI and in vivo 1H MRS. To induce a depressed status in SD rats, we performed the forced swimming test (FST). Using image-guide, water suppressed in vivo 1H MRS with 4.7 T MRI/MRS system, NAA/Cr and Cho/Cr ratios were mainly measured between depressed rats and normal subjects. Results: In depressed rats, increased Cho/Cr ratio was measured versus control subjects. However, no significant group effect for NAA/Cr was observed between case-control pairs. Discussion and Conclusions: The present 1H MRS study shows significant brain metabolic alterations of dorsolateral prefrontal cortex with experimental depressed status of SD rat induced by FST compared to normal subjects. This result provides new evidence that in vivo 1 H MRS may be a useful modality for detecting localized functional neurochemical markers alterations in left DLPFC in SD rats.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1745-1748
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• 2005

Near-infrared spectroscopy (NIRS) can be used to monitor brain activation by measuring changes in the concentration of oxy- and deoxy-hemoglobin (Hb) by their different spectra in the near-infrared range. Because NIRS is a noninvasive, highly flexible and portable device, it is very suitable to study brain activation when a human repeatedly performs a manipulative task, and possibly provides useful information to construct human adaptive mechatronics (HAM). There is some evidence that the dorsolateral prefrontal cortex (DLPFC) plays a major role in working memory and it is proposed that the use of working memory decreases as a human develops manipulative skills. In the present study, we investigated the activation of the dorsolateral prefrontal cortex (DLPFC) of the brain in Brodmann's areas 9 and 46 in drawing tasks to examine whether NIRS can measure the changes of DLPFC activation as a human develops manipulative skills. Subjects performed a mirror image drawing task and a square drawing task by ones' left hands. In the mirror image task the subject drew following a star shape based on a mirror image of it, but square drawing did not involve mirror image and was estimated to be simpler. The changes of the concentration of oxy-Hb was higher in the mirror image drawing than the square drawing in most subjects. The changes of oxy-Hb decreased as the subject repeated the drawing task in most subjects. In conclusion, The activation of DLPFC measured by NIRS can reflect the brain activity in the development of manipulative skills.

• The Journal of Korean Physical Therapy
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• v.35 no.6
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• pp.190-194
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• 2023

Purpose: Traumatic brain injury (TBI) refers to brain damage caused by external forces or trauma. TBIs can vary in severity and result from accidents, falls, sports injuries, assaults, or other forms of physical trauma. The prefrontal cortex (PFC) is known have roles in various cognitive functions. We report on a patient with traumatic brain injury who showed prefrontal symptoms after injury of thalamocortical connections between mediodorsal nuclei (MD) of thalamus and PFC. Methods: A 54-year-old, male patient suffered a TBI as a result of a heavy object falling on his head. After onset of TBI, he showed typical symptoms of prefrontal lobe injury, including personality changes, memory impairment, and general cognition problem. The thalamocortical connections between MD and PFC (ventrolateral prefrontal cortex (VLPFC), dorsolateral prefrontal cortex (DLPFC), and obrbitofrontal cortex (OFC)) were reconstructed using diffusion tensor tractography. In terms of fractional anisotropy value, the right thalamocortical connections to the OFC were significantly lower than those of control subjects. Results: The value of mean diffusivity in the right thalamocortical connections to the DLPFC was significantly higher than that of control subjects. By contrast, both VLPFC and left OFC showed significant decrement in the tract volume of thalamocortical connections compared with that of control subjects. Conclusion: We reported on a patient who showed cognitive and neuropsychiatric impairment due to global injury of the thalamocoritcal connections between MD and PFC following TBI.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.445-452
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• 2015

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers a low-intensity direct current to the cortical areas, thereby facilitating or inhibiting spontaneous neuronal activity. This study was designed to examine the changes in various sensory functions after tDCS. A single-center, single-blinded, randomized trial was conducted to determine the effect of a single session (August 4 to August 29) of tDCS with the current perception threshold (CPT) in 50 healthy volunteers. Nerve conduction studies (NCS) were performed in relation to the median sensory and motor nerves on the dominant hand to discriminate peripheral nerve lesions. The subjects received anodal tDCS with 1mA for 15 minutes under two different conditions, with 25 subjects in each group. The conditions were as follows: tDCS on the dorsolateral prefrontal cortex (DLPFC) and sham tDCS on DLPFC. The parameters of the CPT was recorded with a Neurometer$^{(R)}$ at frequencies of 2000, 250 and 5 Hz in the dominant index finger to assess the tactile sense, fast pain and slow pain, respectively. In the test to measure the CPT values of the DLPFC in the anodal tDCS group, the values increased significantly in all of 250 and 5 Hz. All CPT values decreased for the sham tDCS. These results showed that DLPFC anodal tDCS can modulate the sensory perception and pain thresholds in healthy adult volunteers. This study suggests that tDCS may be a useful strategy for treating central neurogenic pain in rehabilitation medicine.

• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.30-35
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• 2005

Purpose : The purpose of this study is to observe the blood oxygen level dependent (BOLD) contrast changes due to the reaction of human brain at a gustatory sense in response to a salty-taste stimulation. Materials and Methods : Twelve healthy, non-smoking, right-handed male subjects (mean age: 25.6, range: 23-28 years) participated in this salty-taste stimulus functional magnetic resonance (fMRI) study. MRI scans were performed with 1.57 GE Signa, using a multi-slice GE-EPI sequence according to a blood-oxy-gen-level dependent (BOLD) experiment paradigm. Scan parameters included matrix size $128\times128$, FOV 250 mm, TR 5000 msec, TE 60 msec, TH/GAP 5/2 mm. Sequential data acquisitions were carried out for 42 measurements with a repetition time of 5 sec for each taste-stimulus experiments. Analysis of fMRI data was carried out using SPM99 implemented in Matlab. NaCl solution $(3\%)$ was used as a salty stimulus. The task paradigm consisted of alternating rest-stimulus cycles (30-second rest, 15-second stimulus) for 210 seconds. During the stimulus period, NaCl-solution was presented to the subject's mouth through plastic tubes as a bolus of delivered every 5 sec using -processor controlled auto-syringe pump. Results : Insula, frontal opercular taste cortex, amygdala and orbitofrontal cortex (OFC) were activated by a salty-taste stimulation $(NaCl,\;3\%)$ in the fMRI experiments. And dosolateral prefrontal cortex (DLPFC) was also significantly responded to salty-taste stimuli. Activation areas of the right side hemisphere were more superior to the left side hemisphere. Conclusion : The results of this study well correspond to the fact that both insula, amygdala, OFC, DLPFC areas are established as taste cortical areas by neuronal recordings in primates. Authors found that laboratory-developed auto-syringe pump is suitable for gustatory fMRI study. Further research in this field will accelerate to inquire into the mechanism of higher order gustatory process.

• Korean Journal of Biological Psychiatry
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• v.24 no.3
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• pp.95-109
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• 2017

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique which can change cortical excitability in targeted area by producing magnetic field pulses with an electromagnetic coil. rTMS treatment has been used to treat various neuropsychiatric disorders including depression. In this review, we evaluate the literature on rTMS for depression by assessing its efficacy on different subtypes of depression and different technical parameters. In particular, we focus on the results of randomized clinical trials and meta-analyses for depression after the US Food and Drug Administration approval in 2008, which acknowledged its efficacy and acceptability. We also review the new forms of rTMS therapy including deep TMS, theta-burst stimulation, and magnetic seizure therapy (MST) that have been under recent investigation. High frequency rTMS over left dorsolateral prefrontal cortex (DLPFC), low frequency rTMS over right DLPFC, or bilateral rTMS is shown to be effective and acceptable in treatment for patients with non-psychotic, unipolar depression either as monotherapy or adjuvant. Deep TMS, theta-burst stimulation and MST are promising new TMS techniques which warrant further research.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.113-126
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• 2017

The purpose of the study was to find grey matter (GM) and white matter (WM) volume reduction in the brain reward system among patients with alcohol dependency. This study investigated regional GM and WM in chronic alcoholic patients, focusing primarily on the reward system, including principal components of the mesocorticolimbic reward circuit as well as cortical areas with modulating and oversight functions. Sixteen abstinent long-term chronic alcoholic men and demographically matched 16 healthy control men participated in the study. Morphometric analysis was performed on magnetic resonance brain scans using voxel-based morphometry (VBM)-diffeomorphic Anatomical Registration through Exponentiated Liealgebra (DARTEL). We derived GM and WM volumes from total brain and cortical and subcortical reward-related structures. Morphometric analyses that revealed the total volume of GM and WM was reduced and cerebrospinal fluid (CSF) was increased in the alcohol group compared to control group. The pronounced volume reduction in the reward system was observed in the GM and WM of the nucleus accumbens (NAc), GM of the amygdala, GM and WM of the hippocampus, WM of the thalamus, GM and WM of the insula, GM of the dorsolateral prefrontal cortex (DLPFC), GM of the orbitofrontal cortex (OFC), GM of the cingulate cortex (CC), GM and WM of the parahippocampal gyrus in the alcohol group. We identified volume reductions in WM as well as GM of reward system in the patients with alcohol dependency. These structural deficits in the reward system elucidate underlying impairment in the emotional and cognitive processing in alcoholism.

• Korean Journal of Acupuncture
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• v.31 no.1
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• pp.20-32
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• 2014

Objectives : There has been some controversy about the modulatory effects on brain function during acupuncture on each side of the same acupoint. This study was designed to investigate and compare the blood oxygen level-dependent(BOLD) responses of acupuncture on each side of ST36. Methods : Fourteen healthy subjects were recruited for imaging and received acupuncture or placebo stimulations either on the left or on the right acupoint of ST36 in each scan. For the voxel-wise statistical analysis, one sample T-test and the within-subject analysis of variance(ANOVA) test were performed using SPM8 software. Results : This study showed that acupuncture on each side of ST36 showed different BOLD signal patterns. Higher BOLD responses after acupuncture stimulations at the left ST36 compared to the right were observed mainly in the parahippocampal gyrus(BA 28), dorsolateral prefrontal cortex(DLPFC, BA 44), thalamus, culmen and claustrum. We investigated the different neural responses between rest and activation periods of placebo and acupuncture stimulations on each side of ST36. Acupuncture at the right ST36 elicited activation mainly in the insula, supplementary motor area(SMA) and anterior cingulate cortex(ACC), while acupuncture at the left ST36 elicited activation mainly in the insula, primary somatosensory cortex(SI, BA 2) and DLPFC(BA 44). Conclusions : To our knowledge, this is the first reported functional MRI study directly comparing when needling at the right and at the left side of ST36. This study's preliminary results proved to be evidence of acupuncture's different effects when performed on opposite sides of an acupoint.