• Animal cells and systems
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• v.6 no.2
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• pp.159-165
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• 2002

Projections from the prefrontal cortex to subdivisions of the dorsal raphe nucleus were investigated in the rat using retrograde and anterograde tracing methods. A retrograde tracer, gold-conjugated horseradish peroxidase (WGA-apo-HRP-gold), was injected into each subdivision of the dorsal raphe including lateral wing, dorsomedial, and ventromedial areas. The majority of retrogradely labeled cells were located in the prelimbic, infralim-bic, and dorsal peduncular areas of the medial prefrontal cortex. A few cells were also identified in the cingulate, various regions of the orbital, and agranular insular cortices. Secondly, an anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), was injected into the medial prefrontal cortex involving the prelimbic or infralimbic areas. Axonal fibers with varicosities were identified in all subdivisions of the DR including the lateral wing, dorsomedial, and ventromedial areas. Projections were bilateral, with ipsilateral predominance. Axonal fibers were observed at the lateral border of medial longitudinal fasciculus or in the interfascicular region at the midline. The present findings demonstrate that both the midline and lateral wing regions of the dorsal raphe nucleus receive excitatory input from cognitive and emotional centers of the cerebral cortex.

• Animal cells and systems
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• v.7 no.1
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• pp.49-55
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• 2003

The fiber projection from the prefrontal cortex to the locus coeruleus (LC) in the periventricular region was analyzed in rat using anterograde and retrograde tracing methods. Following injection of an anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), into prelimbic and infralimbic regions of the medial prefrontal cortex, labeled axonal fibers with varicosities were observed bilaterally within the LC, with ipsilateral predominance. Terminal labeling was also observed in the region medial to the nucleus at rostral to middle levels of the LC, whereas axonal labeling in the caudal LC was minimal. Anterogradely-labeled axonal fibers were not found in the subcoerulear region. A retrograde tracer, gold-conjugated and inactivated wheatgerm-agglutinin horseradish-peroxidase (WGA-apo-HRP-gold), was injected into several rostro-caudal levels of the LC. Majority of retrogradely-labeled cells were observed in the prelimbic or infralimbic regions of the medial prefrontal cortex when the injections were made into rostral to middle levels of the LC. Only a few cells were observed in cingulate, dorsal peduncular, orbital, or insular cortices. The present findings suggest that the nucleus LC receives restricted, excitatory inputs from cognitive, emotional, and autonomic centers of the cerebral cortex and might secondarily have influences on widespread brain regions via its diversified monoaminergic innervation.

• Journal of Ginseng Research
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• v.42 no.3
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• pp.298-303
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• 2018

Background: Panax ginseng is one of the most commonly used medicinal herbs worldwide for a variety of therapeutic properties including neurocognitive effects. Ginsenoside Rg1 is one of the most abundant active chemical constituents of this herb with known neuroprotective, anxiolytic, and cognition improving effects. Methods: We investigated the effects of Rg1 on the medial prefrontal cortex (mPFC), a key brain region involved in cognition, information processing, working memory, and decision making. In this study, the effects of systemic administration of Rg1 (1 mg/kg, 3 mg/kg, or 10 mg/kg) on (1) spontaneous firing of the medial prefrontal cortical neurons and (2) long-term potentiation (LTP) in the hippocampal-medial prefrontal cortical (HP-mPFC) pathway were investigated in male Sprague-Dawley rats. Results: The spontaneous neuronal activity of approximately 50% the recorded pyramidal cells in the mPFC was suppressed by Rg1. In addition, Rg1 attenuated LTP in the HP-mPFC pathway. These effects were not dose-dependent. Conclusion: This report suggests that acute treatment of Rg1 impairs LTP in the HP-mPFC pathway, perhaps by suppressing the firing of a subset of mPFC neurons that may contribute to the neurocognitive effects of Rg1.

• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.109-114
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• 2017

Purpose: The ascending reticular activating system (ARAS) is responsible for regulation of consciousness. In this study, using diffusion tensor imaging (DTI), we attempted to reconstruct the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. Methods: DTI data were acquired in 24 healthy subjects and eight kinds of thalamocortical projections were reconstructed: the seed region of interest (ROI) - the intralaminar thalamic nuclei and the eight target ROIs - the medial prefrontal cortex, dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, orbitofrontal cortex, premotor cortex, primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. Results: The eight thalamocortical projections were reconstructed in each hemisphere and the pathways were visualized: projections to the prefrontal cortex ascended through the anterior limb and genu of the internal capsule and anterior corona radiata. Projections to the premotor cortex passed through the genu and posterior limb of the internal capsule and middle corona radiata; in contrast, projections to the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex ascended through the posterior limb of the internal capsule. No significant difference in fractional anisotropy, mean diffusivity, and fiber volume of all reconstructed thalamocortical projections was observed between the right and left hemispheres (p>0.05). Conclusion: We reconstructed the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. We believe that our findings would be useful to clinicians involved in the care of patients with impaired consciousness and for researchers in studies of the ARAS.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.230-239
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• 2020

Previous studies have shown disrupted synaptic plasticity and neural activity in depression. Such alteration is strongly associated with disrupted synaptic structures. Chronic stress has been known to induce changes in dendritic structure in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), but antidepressant effect on structure of these brain areas has been unclear. Here, the effects of imipramine on dendritic spine density and morphology in BLA and mPFC subregions of stressed mice were examined. Chronic restraint stress caused depressive-like behaviors such as enhanced social avoidance and despair level coincident with differential changes in dendritic spine structure. Chronic stress enhanced dendritic spine density in the lateral nucleus of BLA with no significant change in the basal nucleus of BLA, and altered the proportion of stubby or mushroom spines in both subregions. Conversely, in the apical and basal mPFC, chronic stress caused a significant reduction in spine density. The proportion of stubby or mushroom spines in these subregions overall reduced while the proportion of thin spines increased after repeated stress. Interestingly, most of these structural alterations by chronic stress were reversed by imipramine. In addition, structural changes caused by stress and blocking the changes by imipramine were corelated well with altered activation and expression of synaptic plasticity-promoting molecules such as phospho-CREB, phospho-CAMKII, and PSD-95. Collectively, our data suggest that imipramine modulates stress-induced changes in synaptic structure and synaptic plasticity-promoting molecules in a coordinated manner although structural and molecular alterations induced by stress are distinct in the BLA and mPFC.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.413-422
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• 2022

Background: The neocortex, including the medial prefrontal cortex (mPFC), contains many neurons expressing nitric oxide synthase (NOS). In addition, increasing evidence shows that the nitric oxide (NO) and opioid systems interact in the brain. However, there have been no studies on the interaction of the opioid and NO systems in the mPFC. The objective of this study was to investigate the effects of administrating L-arginine (L-Arg, a precursor of NO) and N(gamma)-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NOS) into the mPFC for neuropathic pain in rats. Also, we used selective opioid receptor antagonists to clarify the possible participation of the opioid mechanism. Methods: Complete transection of the peroneal and tibial branches of the sciatic nerve was applied to induce neuropathic pain, and seven days later, the mPFC was cannulated bilaterally. The paw withdrawal threshold fifty percent (50% PWT) was recorded on the 14th day. Results: Microinjection of L-Arg (2.87, 11.5 and 45.92 nmol per 0.25 µL) increased 50% PWT. L-NAME (17.15 nmol per 0.25 µL) and naloxonazine (an antagonist of mu opioid receptors, 1.54 nmol per 0.25 µL) inhibited anti-allodynia induced by L-Arg (45.92 nmol per 0.25 µL). Naltrindole (a delta opioid receptor antagonist, 2.45 nmol per 0.25 µL) and nor-binaltorphimine (a kappa opioid receptor antagonist, 1.36 nmol per 0.25 µL) were unable to prevent L-Arg (45.92 nmol per 0.25 µL)-induced antiallodynia. Conclusions: Our results indicate that the NO system in the mPFC regulates neuropathic pain. Mu opioid receptors of this area might participate in pain relief caused by L-Arg.

• Clinical Psychopharmacology and Neuroscience
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• v.16 no.4
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• pp.449-460
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• 2018

Objective: Prior functional magnetic resonance imaging (fMRI) work has revealed that children/adolescents with disruptive behavior disorders (DBDs) show dysfunctional reward/non-reward processing of non-social reinforcements in the context of instrumental learning tasks. Neural responsiveness to social reinforcements during instrumental learning, despite the importance of this for socialization, has not yet been previously investigated. Methods: Twenty-nine healthy children/adolescents and 19 children/adolescents with DBDs performed the fMRI social/non-social reinforcement learning task. Participants responded to random fractal image stimuli and received social and non-social rewards/non-rewards according to their accuracy. Results: Children/adolescents with DBDs showed significantly reduced responses within the caudate and posterior cingulate cortex (PCC) to non-social (financial) rewards and social non-rewards (the distress of others). Connectivity analyses revealed that children/adolescents with DBDs have decreased positive functional connectivity between the ventral striatum (VST) and the ventromedial prefrontal cortex (vmPFC) seeds and the lateral frontal cortex in response to reward relative to non-reward, irrespective of its sociality. In addition, they showed decreased positive connectivity between the vmPFC seed and the amygdala in response to non-reward relative to reward. Conclusion: These data indicate compromised reinforcement processing of both non-social rewards and social non-rewards in children/adolescents with DBDs within core regions for instrumental learning and reinforcement-based decision-making (caudate and PCC). In addition, children/adolescents with DBDs show dysfunctional interactions between the VST, vmPFC, and lateral frontal cortex in response to rewarded instrumental actions potentially reflecting disruptions in attention to rewarded stimuli.

• The Journal of Korean Academy of Sensory Integration
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• v.14 no.1
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• pp.50-59
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• 2016

Objective : The goal of this study was to investigate neurological mechanism of emotional regulation and to examine the relationship between the regulation and sensory processing. Subjective : Emotional regulations are mainly processed in limbic system, particularly the basal-lateral group of amygdala takes on a major role in the regulations. The basal-lateral group of amygdala links to thalamus directly and/or indirectly which processes sensory information together. This sensory information connects to orbital and medial prefrontal cortex. Inadequate sensory processing may cause difficulties in emotional regulations and behaviors because of a circuit linking the amygdala, the thalamus, and the orbital and medial prefrontal cortex. These difficulties and impairments has been reported in neurological studies for children with ASD and ADHD. Conclusion : Neurological states are different between the normal children and children with ASD and ADHD and these represent various aspects in sensory processing, emotional regulations and behaviors. Thus, therapists working with children with ASD and ADHD need to understand mechanisms of sensory processing and emotional regulations in order to provide adequate treatments.

• Herbal Formula Science
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• v.28 no.1
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• pp.53-62
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• 2020

Objective : This study is accomplished in order to investigate the effect of banggibongnyeongtang on the immunohistological change in LPS-induced depression rats to confirm the histological result of the previous behavioral and biochemical effect. Methods : LPS 5 ㎍ was injected to lateral ventricle and experimental groups were administered BBT intraperitoneally. The concentration of 5-HT in the Medial Prefrontal Cortex, Striatum, Hippocampus, Amygdala was measured by ELISA. IL-1β, TNF-α mRNA and BDNF mRNA expression in the hippocampus was examined by RT-PCR. Result : BBT enhanced 5-HT concentration at all part of brain but no significantly difference at medial prefrontal cortex and striatum. LPS+BBT400 group increased 5-HT concentration significantly than LPS group at hippocampus and amygdala (p<0.05). BBT decreased IL-1β mRNA expression dose dependently but only with significantly decrease in LPS+BBT400 group than LPS group's in Hippocampus (p<0.05). But BBT did not decrease TNF-α mRNA expression significantly in Hippocampus. BBT increased the expression of BDNF mRNA at hippocampus and LPS+BBT400 group significantly increased comparing with LPS group does (p<0.05). Conclusion : It is postulated that the anti-depressant effect of BBT can be validated through the anti-inflammatory effect, 5-HT concentration increase, and the neuro-protective effect mediated by BDNF by combining the results of the previous report about the behavioral and biochemical effect.

• Journal of Korean Neurosurgical Society
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• v.47 no.1
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• pp.17-25
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• 2010

Objective: The focus of this study is brain plasticity associated with semantic aspects of language function in patients with medial temporal lobe epilepsy (mTLE) Methods: Using longitudinal functional magnetic resonance imaging (fMRI), patterns of brain activation were observed in twelve left and seven right unilateral mTLE patients during a word-generation task relative to a pseudo-word reading task before and after anterior temporal section surgery. Results: No differences were observed in precentral activations in patients relative to normal controls (n = 12), and surgery did not alter the phonological-associated activations. The two mTLE patient groups showed left inferior prefrontal activations associated with semantic processing (word-generation>pseudo-word reading), as did control subjects. The amount of semantic-associated activation in the left inferior prefrontal region was negatively correlated with epilepsy duration in both patient groups. Following temporal resection, semantic-specific activations in inferior prefrontal region became more bilateral in left mTLE patients, but more left-lateralized in right mTLE patients. The longer the duration of epilepsy in the patients, the larger the increase in the left inferior prefrontal semantic-associated activation after surgery in both patient groups. Semantic activation of the intact hippocampus, which had been negatively correlated with seizure frequency, normalized after the epileptic side was removed. Conclusion: These results indicate alternation of semantic language network related to recruitment of left inferior prefrontal cortex and functional recovery of the hippocampus contralateral to the epileptogenic side, suggesting an intra- and inter-hemispheric reorganization following surgery.