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1.
J Acoust Soc Am ; 151(6): 4039, 2022 06.
Article in English | MEDLINE | ID: mdl-35778224

ABSTRACT

The practicality of the finite-difference time-domain (FDTD) method was confirmed by comparing head-related transfer functions obtained from a three-dimensional (3D) digital model of a bat (Rhinolophus ferrumequinum nippon) head with acoustic experiments using a 3D printed physical model. Furthermore, we simulated the auditory directionality using a 3D digital model that was modified based on the pinna movement of a bat during echolocation and found that the alternating movements of the left and right pinna result in a binaural sound pressure difference for vertical sources. Using the FDTD method, suitable for simulating acoustics in large spaces, we could analyze in detail the binaural echoes that bats receive and the acoustic cues they use for echolocation.


Subject(s)
Chiroptera , Ear Auricle , Echolocation , Acoustics , Animals , Ear, External
2.
Curr Opin Neurobiol ; 70: 34-42, 2021 10.
Article in English | MEDLINE | ID: mdl-34303124

ABSTRACT

Conventional theories assume that long-term information storage in the brain is implemented by modifying synaptic efficacy. Recent experimental findings challenge this view by demonstrating that dendritic spine sizes, or their corresponding synaptic weights, are highly volatile even in the absence of neural activity. Here, we review previous computational works on the roles of these intrinsic synaptic dynamics. We first present the possibility for neuronal networks to sustain stable performance in their presence, and we then hypothesize that intrinsic dynamics could be more than mere noise to withstand, but they may improve information processing in the brain.


Subject(s)
Models, Neurological , Synapses , Brain/physiology , Neuronal Plasticity/physiology , Neurons/physiology , Synapses/physiology
3.
J Chem Phys ; 152(17): 174310, 2020 May 07.
Article in English | MEDLINE | ID: mdl-32384850

ABSTRACT

We have established an apparatus for terahertz and mid-infrared spectroscopy in an ultrahigh vacuum and have measured absorption spectra of D2O clusters trapped in solid Ar. To assign terahertz absorption peaks due to the D2O dimer, trimer, and tetramer, the dependence of the spectrum on the annealing temperature and D2O dilution was analyzed. The assignment was also examined by ab initio calculations with the use of the "our own N-layered integrated molecular orbital and molecular mechanics" method, where the flexibility of surrounding Ar atoms was systematically incorporated. We identified all the intermolecular fundamentals of the dimer and those with significant intensities of the trimer and tetramer, whose structural symmetries were revealed to be broken down. After isolating the D2O clusters in solid Ar, we sublimated only Ar atoms to leave behind matrix-sublimation ice, which was found to be amorphous- or crystal-like depending on the formation conditions: the dilution and sublimation temperature. The crystallinity of matrix-sublimation ice was determined by decomposing its terahertz spectrum into the spectra of amorphous and crystalline ices. Since the crystallinity got higher by raising the dilution and sublimation temperature, the diffusion of the D2O monomer on the surface of sublimating solid Ar was found to be crucial to the crystallization of the sublimation ice.

4.
Intern Med ; 59(11): 1445-1449, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32132331

ABSTRACT

Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been associated with steroid-responsive cortical encephalitis and comorbid generalized epilepsy. A 44-year-old woman developed repeated epilepsia partialis continua (EPC) without generalized seizures and was anti-MOG antibody-positive. Radiological abnormalities were detected in the bilateral medial frontoparietal cortices, but there were no cerebrospinal fluid abnormalities. She achieved remission with anti-epileptic drugs alone. However, encephalitis recurred four months later when pleocytosis appeared, and steroid therapy was effective. Altogether, EPC without typical cerebrospinal fluid features can be an early sign of anti-MOG antibody-positive encephalitis. Thus, patients with EPC of unknown etiology need to be screened for anti-MOG antibodies.


Subject(s)
Encephalitis/complications , Encephalitis/immunology , Epilepsia Partialis Continua/diagnosis , Epilepsia Partialis Continua/drug therapy , Epilepsia Partialis Continua/immunology , Immunosuppressive Agents/therapeutic use , Myelin-Oligodendrocyte Glycoprotein/immunology , Adult , Autoantibodies/immunology , Epilepsia Partialis Continua/etiology , Female , Humans , Treatment Outcome
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