Resting-state functional connectivity predicts recovery from visually induced motion sickness

映像酔いからの回復時に脳結合の増加を発見 --酔いの回復を促す技術開発の足がかりに--. 京都大学プレスリリース. 2021-01-14.Movies depicting certain types of motion often provoke uncomfortable symptoms similar to motion sickness, termed visually induced motion sickness (VIMS). VIMS generally evolves slowly during the viewing of a motion stimulus and, when the stimulus is removed, the recovery proceeds over time. Recent human neuroimaging studies have provided new insights into the neural bases of the evolution of VIMS. In contrast, no study has investigated the neural correlates of the recovery from VIMS. Study of the recovery process is critical for the development of a way to promote recovery and could provide further clues for understanding the mechanisms of VIMS. We thus investigated brain activity during the recovery from VIMS with functional connectivity magnetic resonance imaging. We found enhanced recovery-related functional connectivity patterns involving brain areas such as the insular, cingulate and visual cortical regions, which have been suggested to play important roles in the emergence of VIMS. These regions also constituted large interactive networks. Furthermore, the increase in functional connectivity was correlated with the subjective awareness of recovery for the following five pairs of brain regions: insula–superior temporal gyrus, claustrum–left and right inferior parietal lobules, claustrum–superior temporal gyrus and superior frontal gyrus–lentiform nucleus. Considering the previous findings on the functions of these regions and the present results, it is suggested that the increase in FC may reflect brain processes such as enhanced interoceptive awareness to one’s own bodily state, a neuroplastic change in visual-processing circuits and/or the maintenance of visual spatial memory

Inter-hemispheric desynchronization of the human MT+ during visually induced motion sickness

映像に酔うと右脳と左脳の活動が乖離する現象を発見 -安全で快適な高臨場感映像技術開発の足がかりに-.　京都大学プレスリリース. 2015-05-26.Visually induced motion sickness (VIMS) is triggered in susceptible individuals by stationary viewing of moving visual scenes. VIMS is often preceded by an illusion of self-motion (vection) and/or by inappropriate optokinetic nystagmus (OKN) responses associated with increased activity in the human motion-sensitive middle temporal area (MT+). Neuroimaging studies have reported predominant right hemispheric activation in MT+ during both vection and OKN, suggesting that VIMS may result from desynchronization of activity between left and right MT+ cortices. However, this possibility has not been directly tested. To this end, we presented VIMS-free and VIMS-inducing movies in that order while measuring the temporal correlations between corresponding left and right visual cortices (including MT+) using functional magnetic resonance imaging. The inter-hemispheric correlation was reduced significantly during the viewing of the VIMS-inducing movie compared to the control VIMS-free movie in the MT+ of subjects reporting VIMS, but not in insusceptible subjects. In contrast, there were no significant inter-hemispheric differences within VIMS-free or VIMS-inducing movie exposure for visual area V1, V2, V3, V3A or V7. Our findings provide the first evidence for an association between asynchronous bilateral MT+ activation and VIMS. Desynchronization of left and right MT+ regions may reflect hemispheric asymmetry in the activities of functional networks involved in eye movement control, vection perception and/or postural control

Physiological and Genomic Features of a Novel Sulfur-Oxidizing Gammaproteobacterium Belonging to a Previously Uncultivated Symbiotic Lineage Isolated from a Hydrothermal Vent

<div><p>Strain Hiromi 1, a sulfur-oxidizing gammaproteobacterium was isolated from a hydrothermal vent chimney in the Okinawa Trough and represents a novel genus that may include a phylogenetic group found as endosymbionts of deep-sea gastropods. The SSU rRNA gene sequence similarity between strain Hiromi 1 and the gastropod endosymbionts was approximately 97%. The strain was shown to grow both chemolithoautotrophically and chemolithoheterotrophically with an energy metabolism of sulfur oxidation and O₂ or nitrate reduction. Under chemolithoheterotrophic growth conditions, the strain utilized organic acids and proteinaceous compounds as the carbon and/or nitrogen sources but not the energy source. Various sugars did not support growth as a sole carbon source. The observation of chemolithoheterotrophy in this strain is in line with metagenomic analyses of endosymbionts suggesting the occurrence of chemolithoheterotrophy in gammaproteobacterial symbionts. Chemolithoheterotrophy and the presence of homologous genes for virulence- and quorum sensing-related functions suggest that the sulfur-oxidizing chomolithotrophic microbes seek animal bodies and microbial biofilm formation to obtain supplemental organic carbons in hydrothermal ecosystems.</p></div

Predicted sulfur oxidation pathways of strain Hiromi 1 inferred from the previously published literatures [63], [66]–[68], [74], [75].

<p>TCEP; tris(2-carboxyethyl)phosphine.</p

Predicted central metabolism of strain Hiromi 1.

<p>Red lines indicate conserved pathways in most of the publically accessible genomes of the chemolithoautotrophic <i>Gammaproteobacteria</i>. EC numbers are given on each enzymatic reaction. Light blue font indicates concentrations (per pmol 10¹⁰ cells) of metabolites. Metabolites that were not targets of the metabolomic analysis were given neither concentrations nor N.D. N.D.; not detected. Pi, phosphate; PPi, pyrophosphate; Glc, α-D-glucose; αG6P, α-D-glucose-6-phosphate; G1P, α-D-glucose-1-phosphate; βG6P, β-D-glucose-1-phosphate; F6P, β-D-fructose-6-phophate; FBP, β-D-fructose-1,6-bisphosphate; GAP, glyceraldehyde-3-phosphate; GBP, glycerate-1,3-bisphosphate; G3P, glycerate-3-phosphate; G2P, glycerate-2-phosphate; PEP, phosphoenolpyruvate; E4P, erythrose-4-phosphate; acetyl-P, acetyl phosphate; DHAP, dihydroxyacetone phosphate; X5P, D-xylulose-5-phosphate; SBP, D-sedoheptulose-1,7-bisphosphate; S7P, D-sedoheptulose-7-phosphate; RuBP, ribulose-1,5-bisphosphate; Ru5P, ribulose-5-phophate; R5P, D-ribose-5-phosphate.</p

Electron micrographs of the new isolate strain Hiromi 1.

<p>A transmission electron micrograph of a negatively stained cell (A) and a thin section cell (B) grown under the chemolithoautotrophic condition. White and black arrows indicate intracellular particle and outer membrane, respectively. Scanning micrographs of cells adhering on elemental sulfur by pilus to biofilm (C, D). Cells attached on biofilm formation and pili structures were shown by large and small black arrows. Other cells grew under the polysaccharide-like substances. Bars, 0.2 µm (A), 0.5 µm (B) and 1 µm (C, D).</p

A SSU rRNA gene phylogenetic tree of chemolithoautotrophic and methanotrophic <i>Gammaproteobacteria</i> including strain Hiromi 1 constructed by the neighbor-joining method using 1253 identical positions.

<p>Bootstrap values higher than 50% are presented. GenBank/EMBL/DDBJ accession numbers are given in parentheses. Bar indicates 1 substitutions per 100 nucleotides.</p

The Association between Electroencephalography with Auditory Steady-State Response and Postoperative Delirium

Delirium is a disorder of consciousness and a risk factor for cognitive dysfunction and poor prognosis. We hypothesized that preoperative gamma activities would be linked to postoperative delirium. We enrolled 71 subjects for elective surgery and recorded auditory steady-state response (ASSR) by electroencephalography (EEG) before the surgery and examined postoperative delirium with DSM-5. The EEG data were analyzed for baseline power, and ASSR evoked power (EP) and phase-locking factor (PLF) within the gamma range. Postoperative delirium was found in 18 patients (delirium group) but not in 53 patients (non-delirium group). There were no significant differences in the 40-Hz EP or PLF between the two groups. The baseline gamma activity negatively correlated with the 40-Hz PLF in the non-delirium group (ρ = −0.444, p < 0.01). The correlation between baseline gamma activity and 40-Hz EP was not significant in either the delirium or non-delirium group. In all patients, both preoperative PLF and EP had no significant correlations with the Delirium Rating Scale Revised-98 and the Memorial Delirium Assessment Measure at the post-operation, respectively. The disruption of the neurophysiological relationship between baseline gamma activity before sound stimuli and the PLF of the 40-Hz ASSR may be one of the potential neurophysiological indicators associated with postoperative delirium