Language：English   Publishing type：Research paper (scientific journal)  

High gamma activity (HGA) is a crucial biomarker for functional brain mapping, particularly in sensorimotor areas, to preserve functionality after brain surgeries. HGA mapping paradigms typically involve multiple task blocks alternating with resting (R) conditions, where each block comprises consecutive tasks under nonresting (NR) conditions. However, the repetitive nature of these tasks may lead to attenuation due to repetition suppression, potentially compromising the accuracy of HGA mapping. This study tests the hypothesis that repetitive grasping paradigms result in attenuated HGA over time in sensorimotor areas. It explores the temporal and spatial characteristics of this attenuation to optimize electrocorticography (ECoG) HGA protocols and enhance result interpretation. Eleven consecutive patients who underwent surgical treatment of intractable epilepsy or malignant glioma were included in this study. Intracranial electrode locations on the pre- and postcentral gyrus were considered regions of interest (ROI). Each patient performed ten blocks of ten consecutive grasping trials. The mean z-scored HGA (60-170 Hz) across these trials was calculated, and attenuation was analyzed using the Kruskal-Wallis test. Obtained signals were also divided into three grouped periods for R and NR groups to assess short-term attenuation within movement blocks and long-term attenuation over multiple blocks. Electrode locations were mapped to the MNI152 (Montreal Neurological Institute) brain template to investigate the spatial distribution of attenuation. Distances from each electrode to the hand-knob region were compared between attenuated and nonattenuated electrodes. A total of 568 electrodes from 11 patients were analyzed, including 139 electrodes within the ROI. Thus, 60 electrodes demonstrated significant HGAs during the grasping task (p < 0.05). Sensorimotor HGA z-scores significantly attenuated over time during both consecutive grasping trials and repeated blocks. Short-term attenuation (25%, 15/60 electrodes in ROI) was more pronounced than long-term attenuation (15%, 9/60 electrodes in ROI). Notably, three patients undergoing intraoperative mapping demonstrated less short-term attenuation compared to long-term attenuation. Spatially, attenuated electrodes clustered around the hand-knob region of the precentral gyrus and adjacent areas of the postcentral gyrus. However, no significant differences were observed in the distances from electrodes to the hand-knob region between attenuated and nonattenuated electrodes. The present study showed that repetitive grasping tasks attenuated the HGA of significant electrodes in the sensorimotor area over time. Considering the findings with the characteristics can further improve the usability of ECoG mapping in terms of more precise results in the most reasonable mapping time.

DOI： 10.1002/hbm.70153

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: The study aims to explore MRI phenotypes that predict glioblastoma's (GBM) methylation status of the promoter region of MGMT gene (pMGMT) by qualitatively assessing contrast-enhanced T1-weighted intensity images. METHODS: A total of 193 histologically and molecularly confirmed GBMs at the Kansai Network for Molecular Diagnosis of Central Nervous Tumors (KANSAI) were used as an exploratory cohort. From the Cancer Imaging Archive/Cancer Genome Atlas (TCGA) 93 patients were used as validation cohorts. "Thickened structure" was defined as the solid tumor component presenting circumferential extension or occupying >50% of the tumor volume. "Methylated contrast phenotype" was defined as indistinct enhancing circumferential border, heterogenous enhancement, or nodular enhancement. Inter-rater agreement was assessed, followed by an investigation of the relationship between radiological findings and pMGMT methylation status. RESULTS: Fleiss's Kappa coefficient for "Thickened structure" was 0.68 for the exploratory and 0.55 for the validation cohort, and for "Methylated contrast phenotype," 0.30 and 0.39, respectively. The imaging feature, the presence of "Thickened structure" and absence of "Methylated contrast phenotype," was significantly predictive of pMGMT unmethylation both for the exploratory (p = .015, odds ratio = 2.44) and for the validation cohort (p = .006, odds ratio = 7.83). The sensitivities and specificities of the imaging feature, the presence of "Thickened structure," and the absence of "Methylated contrast phenotype" for predicting pMGMT unmethylation were 0.29 and 0.86 for the exploratory and 0.25 and 0.96 for the validation cohort. CONCLUSIONS: The present study showed that qualitative assessment of contrast-enhanced T1-weighted intensity images helps predict GBM's pMGMT methylation status.

DOI： 10.1093/noajnl/vdae016

PubMed

researchmap

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese  

Regulation of posture-gait control by the basal ganglia (BG) plays a critical role in the acquisition of automatically executed context-dependent learned motor acts, technically referred to as habit formation. Patients with Parkinson's disease (PD) show posture-gait disturbances and progressively lose habitual behaviors. Injury to dopamine (DA) neurons in the midbrain is implicated as the primary pathophysiological mechanism underlying PD; therefore, DA actions in the BG play a pivotal role in optimal BG function. In this commentary, we discuss the mechanism underlying BG-modulated regulation of cognitive posture-gait control by the cerebral cortex through the cortico-BG loop and the basic posture-gait mechanisms underlying the actions of the brainstem and spinal cord via the BG-brainstem projection. The BG primarily regulates excitability of the cerebral cortex and brainstem through its DA-mediated inhibitory action. Based on these considerations, we describe the pathophysiological mechanisms that contribute to posture-gait disturbances in PD. Recent clinical studies suggest that posture-gait disturbances may be attributable to functional disconnection between the BG and the cerebral cortex and brainstem. Injury to various neurotransmitter systems in addition to the DA system and significant alpha-synuclein (Lewy body)-induced degeneration of the brainstem neurons may worsen posture-gait control impairment in PD.

DOI： 10.11477/mf.1416202185

PubMed

CiNii Books

CiNii Research

researchmap

Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I032392096

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: The occipital artery (OA) is an important donor artery for posterior fossa revascularization. Harvesting the OA is difficult in comparison to the superficial temporal artery because the OA runs between suboccipital muscles. Anatomical knowledge of the suboccipital muscles and OA is essential for harvesting the OA during elevation of the splenius capitis muscle (SPL) for reconstruction of the posterior inferior cerebellar artery. We analyzed the running pattern of the OA and its anatomic variations using preoperative and intraoperative findings. METHODS: From April 2012 to March 2018, we surgically treated 162 patients with suboccipital muscle dissection by OA dissection using the lateral suboccipital approach. The running pattern and relationship between the suboccipital muscles and OA were retrospectively analyzed using the operation video and preoperative enhanced computed tomography (CT) images. The anatomic variation in the running pattern of the OA was classified into two types: lateral type, running lateral to the muscle and medial type, running medial to the longissimus capitis muscle (LNG). RESULTS: The medial pattern was observed in 107 (66%) patients and the lateral pattern in 54 (33.3%); 1 (0.6%) patient had the OA running between the LNGs. CONCLUSION: Preoperative CT is effective in determining the running course of the OA, which is important for safely harvesting the OA during SPL elevation. There is a risk of causing OA injury in patients with the lateral pattern. This is the first report showing that the OA rarely runs in between the LNGs.

DOI： 10.25259/SNI-16-2019

PubMed

researchmap

Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

researchmap

J-GLOBAL

researchmap

Language：English   Publisher：(一社)日本臨床神経生理学会  

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：札幌  

Event date： 2023.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：金沢  

Event date： 2023.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：WEB  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：札幌市  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：札幌