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Mitsuo Tonoike

Publications and source records attributed to Mitsuo Tonoike.

7 recordsLinked to original sources
PubMed2003

Effect of a forward masker on the N1m amplitude: varying the signal delay.

Auditory sensation is affected by a forward masker, and this phenomenon has been demonstrated in a neural adaptation model and a temporal window (integration) model. To study forward masking in the central auditory system, the growth of the N1m amplitude was measured by varying the signal delay. In the adaptation model, the masking increases as the signal delay decreases. However, in our results, the minimum N1m amplitude was observed at a signal delay of 40 ms. As the signal delay decreased from 40 ms, the N1m amplitude increased although the masking increased. Our results suggest that the growth of the N1m amplitude largely depends on temporal integration at signal delays below 40 ms.

Acoustic Stimulation↗
PubMed2003

Magnetoencephalographic study of cortical activity evoked by electrogustatory stimuli.

Electrogustometry is a convenient method to examine taste acuity in clinical situations. Some basic properties of neural activity in the cerebral cortex in response to electrogustatory stimulation were revealed by measuring magnetoencephalography (MEG) signals with a whole-cortex-type system in response to varying intensities of anodal DC currents focally applied to the tongue surface in human subjects. Independent component analysis was used to eliminate stimulus artifacts in MEG signals. Electrogustatory stimulation with intensities of induced electric taste evoked responses bilaterally, mainly in the opercular-insular cortex with a mean onset latency of approximately 350 ms, while subthreshold electrogustatory stimulation induced modest responses in the cortex. Stronger stimulation induced a tingling sensation and elicited large transient responses in both the opercular-insular and somatic sensory cortices. This is the first description of the basic properties of human MEG responses to electrogustatory stimulation.

Adult↗
PubMed2002

Magnetic cortical responses evoked by visual linear forward acceleration.

Cortical site processing the information of whole body linear acceleration has not yet been identified. In this study, neuromagnetic responses to visually induced linear forward acceleration were recorded in six healthy-right-handed adult subjects using a 122-channel whole cortex neuromagnetometer. Significant activation was estimated in the cortex around the posterior insula, which belongs to the vestibular cortex. Hence, it is suggested that the vestibular cortex not only receives vestibular input from the peripheral vestibular apparatus, but also processes the vestibular sensation from multi-modal information.

Acceleration↗
PubMed2002

Effect of stimulus duration for bone-conducted ultrasound on N1m in man.

Ultrasound can be heard by bone conduction in man. However, there has been no consensus about the perception mechanism of bone-conducted ultrasound (BCU). In the current study, to clarify the central auditory system of BCU, the effects of stimulus duration for 30 kHz BCU on N1m were compared with those for air-conducted 1 kHz tone bursts by magnetoencephalography. As a result, the growth of N1m amplitude for both stimuli saturated at the duration of 40 ms, which suggest that the temporal integration system of BCU is similar to that of audible sound. However, significant differences in the growth were observed below the saturation points. The results indicate a possibility that there are some differences in the central auditory system between BCU and audible sound.

Acoustic Stimulation↗
PubMed2002

Autocorrelation analyses of magnetoencephalographic alpha waves in relation to subjective preference for a flickering light.

Human cortical responses corresponding to the subjective preference for a flickering light of varying period were investigated. Paired-comparison tests were performed to examine the subjective preference for a flickering light, and MEG was recorded during presentations of the most preferred and less preferred flickering lights alternately. Results showed that the effective duration of the autocorrelation function, tau(e), which represents a repetitive feature of the MEG alpha waves, becomes longer during the preferred condition. This reveals that the brain repeats a similar rhythm under preferred conditions.

Adult↗
PubMed2002

MEG responses during rhythmic finger tapping in humans to phasic stimulation and their interpretation based on neural mechanisms.

The phase-resetting experiment was applied to human periodic finger tapping to understand how its rhythm is controlled by the internal neural clock that is assumed to exist. In the experiment, the right periodic tapping movement was disturbed transiently by a series of left finger taps in response to impulsive auditory cues presented randomly at various phases within the tapping cycle. After each left finger tap, the original periodic tapping was reestablished within several tapping cycles. Influences of the disturbance on the periodic right finger tapping varied depending on the phase of the periodic right finger tapping at which each left finger tap was made. It was confirmed that the periodic tapping was disturbed not by the auditory cues but by the left finger taps. Based on this fact, in this paper each single left tap was considered as the stimulus, and the phase of the periodic tapping of the right index finger when the left tap was executed as the phase of the stimulus. Responses of the neural activities (magnetoencephalography, MEG), the tapping movement, and the corresponding muscle activities (electromyography) were simultaneously measured. Phase-resetting curves (PRCs) representing the degree of phase reset as a function of the phase of the stimulus were obtained both for the left sensorimotor cortex MEG response and for the right index finger tapping response. The shapes of both PRCs were similar, suggesting that the phase reset of the left sensorimotor cortex activities and that of the finger tapping rhythm were the same. Four out of eight subjects showed type-0 reset in Winfree's definition, and the others showed type-1 reset. For general limit-cycle oscillators, type-0 reset is obtained for relatively strong perturbations and type 1 for weak perturbations. It was shown that the transient response of MEG to the single left tap stimuli in type-0 subjects, where the phase was progressively reset, were different from those in type-1 subjects. Based on detailed analysis of the differences, a neural network model for the phase reset of the tapping rhythm is proposed.

Acoustic Stimulation↗