Biomedical subjects

Yutaka Hosokawa

Publications and source records attributed to Yutaka Hosokawa.

3 recordsLinked to original sources

PubMed2006

Layer-specific short-term dynamics in network activity in the cerebral cortex.

Optical imaging with a voltage-sensitive dye was conducted in frontal slices of rat auditory cortex to study spatiotemporal patterns of response to repetitive electrical stimulation. When the rate of repetitive stimulation increased to 40 Hz, the amplitude ratio of the response after the fifth stimulus to the response after the first stimulus was significantly smaller in layers II/III than in layer IV or in layers V/VI. Similar results were obtained regardless of where electrical stimulation was applied. When the rate of stimulation was at 10 Hz, no difference was observed in response ratios among layers. These results show that the manner of responding to repetitive stimulation is different among layers and that it is stimulation rate-dependent.

Animals↗

PubMed2004

Optical imaging of binaural interaction in multiple fields of the guinea pig auditory cortex.

Locating the source of a sound is an important function of the auditory system and interaural intensity differences are one of the most important cues. To study the functional pathways of sound localisation processing in the auditory cortex, activity in multiple fields of the guinea pig auditory cortex during stimulation with interaural intensity differences was studied using optical imaging with a voltage-sensitive dye. Of the auditory core (primary and dorsocaudal) and the belt fields which surround them, the posterior and ventroposterior belt fields were the most sensitive to interaural intensity differences. This suggests that the caudal pathway of the auditory cortex is involved in sound localisation.

Acoustic Stimulation↗

PubMed2002

Spatial focusing of neuronal responses induced by asynchronous two-tone stimuli in the guinea pig auditory cortex.

Spatiotemporal patterns of neuronal responses to asynchronous two-tone stimuli in the anterior field of the auditory cortex of anesthetized guinea pigs were studied using an optical recording method (12 x 12 photodiode array, voltage sensitive dye RH795). Interactions between the onset response to the first tone (masker; 5, 8, 10, 12 and 15 kHz, 200 ms) and to the second tone (probe; 10 kHz, 30 ms) with onset delays relative to the masker onset (0, 5, 10, 15 and 20 ms) were investigated. In general, two-tone interaction was suppressive rather than facilitative. At 0-10 ms probe delays, two-tone responses induced in the probe isofrequency area on the cortex tended to fuse with the masker response. At 15-20 ms probe delays, the probe response was apparently reduced, but was spatially focused and separated from the masker response. This spatial focusing of the probe response may have been due to neuronal inhibition originating after the masker onset response. These results are in agreement with psychoacoustical observations in human subjects, such as auditory segregation, and indicate that the spatial focusing of the cortical response provides a neuronal basis for detecting slightly asynchronous auditory inputs.

Acoustic Stimulation↗