Biomedical subjects

Tadashi Sugihara

Publications and source records attributed to Tadashi Sugihara.

3 recordsLinked to original sources

PubMed2007

Border-ownership-dependent tilt aftereffect in incomplete figures.

A recent physiological finding of neural coding for border ownership (BO) that defines the direction of a figure with respect to the border has provided a possible basis for figure-ground segregation. To explore the underlying neural mechanisms of BO, we investigated stimulus configurations that activate BO circuitry through psychophysical investigation of the BO-dependent tilt aftereffect (BO-TAE). Specifically, we examined robustness of the border ownership signal by determining whether the BO-TAE is observed when gestalt factors are broken. The results showed significant BO-TAEs even when a global shape was not explicitly given due to the ambiguity of the contour, suggesting a contour-independent mechanism for BO coding.

Algorithms↗

PubMed2006

Integration of auditory and visual communication information in the primate ventrolateral prefrontal cortex.

The integration of auditory and visual stimuli is crucial for recognizing objects, communicating effectively, and navigating through our complex world. Although the frontal lobes are involved in memory, communication, and language, there has been no evidence that the integration of communication information occurs at the single-cell level in the frontal lobes. Here, we show that neurons in the macaque ventrolateral prefrontal cortex (VLPFC) integrate audiovisual communication stimuli. The multisensory interactions included both enhancement and suppression of a predominantly auditory or a predominantly visual response, although multisensory suppression was the more common mode of response. The multisensory neurons were distributed across the VLPFC and within previously identified unimodal auditory and visual regions (O'Scalaidhe et al., 1997; Romanski and Goldman-Rakic, 2002). Thus, our study demonstrates, for the first time, that single prefrontal neurons integrate communication information from the auditory and visual domains, suggesting that these neurons are an important node in the cortical network responsible for communication.

Acoustic Stimulation↗

PubMed2005

Prior experience of rotation is not required for recognizing objects seen from different angles.

An object viewed from different angles can be recognized and distinguished from similar distractors after the viewer has had experience watching it rotate. It has been assumed that as an observer watches the rotation, separate representations of individual views become associated with one another. However, we show here that once monkeys learned to discriminate individual views of objects, they were able to recognize objects across rotations up to 60 degrees , even though there had been no opportunity to learn the association between different views. Our results suggest that object recognition across small or medium changes in viewing angle depends on features common to similar views of objects.

Animals↗