Spatial contexts can inhibit a mislocalization of visual stimuli during smooth pursuit

The position of a flash presented during pursuit is mislocalized in the direction of the pursuit. Although this has been explained by a temporal mismatch between the slow visual processing of flash and fast efferent signals on eye positions, here we show that spatial contexts also play an important role in determining the flash position. We put various continuously lit objects (walls) between veridical and to-be-mislocalized positions of flash. Consequently, these walls significantly reduced the mislocalization of flash, preventing the flash from being mislocalized beyond the wall (Experiment 1). When the wall was shortened or had a hole in its center, the shape of the mislocalized flash was vertically shortened as if cutoff or funneled by the wall (Experiment 2). The wall also induced color interactions; a red wall made a green flash appear yellowish if it was in the path of mislocalization (Experiment 3). Finally, those flash–wall interactions could be induced even when the walls were presented after the disappearance of flash (Experiment 4). These results indicate that various features (position, shape, and color) of flash during pursuit are determined with an integration window that is spatially and temporally broad, providing a new insight for generating mechanisms of eye-movement mislocalizations

The temporal stability and variability across frequency bands in neural synchrony between primary and secondary somatosensory areas following somatosensory stimulation

Objectives: To examine the temporal stability and variability of neuronal synchronization among the contralateral primary somatosensory cortex (cSI) and contralateral (cSII) and ipsilateral secondary somatosensory cortex (iSII) in response to median nerve stimulation. Methods: Both the spontaneous magnetoencephalography (MEG) signals as the pre-stimulus condition and somatosensory evoked magnetic-fields (SEF) were recorded in eleven healthy subjects. We calculated a phase-locking value (PLV) between two areas among cSI, cSII, and iSII in five frequency bands (theta: 5–7 Hz, alpha: 8–12 Hz, beta: 15–29 Hz, gamma-1: 30–59 Hz, and gamma-2: 60–90 Hz), and compared the PLV among in pre-stimulus and stimulus conditions. Results: The PLV between cSI and cSII for the theta band activity varied within 2 s from the stimulus onset. On the other hand, the PLV between cSI and iSII for the alpha band did not vary within 2 s. Conclusion: The fluctuation of neuronal synchrony among sensory-related cortices in response to median nerve stimulation depends on the induced frequency band and inter-region. Significance: This study is the first to report the temporal characteristic of stimulus-driven neural synchrony following somatosensory stimulation. Keywords: Somatosensory, Neural synchrony, Phase-locking value, Magnetoencephalograph

Use of parametric speaker for older people with dementia in a residential care setting: A preliminary study of two cases

Objective/Background Older people with dementia often show behavioural and psychological symptoms of dementia such as agitation, aggression, and depression that affect their activities of daily living, and hence reduce the quality of life of their caregivers. The aim of this study was to investigate the effects of a new technological intervention—a parametric speaker, creating a narrow personal acoustic environment, which may reduce the manifestation of behavioural and psychological symptoms of dementia symptoms. Methods A parametric speaker was placed on the ceiling of a large day room, and personally selected pieces of music were provided in a narrow space just under the speaker during the intervention. Two older residents with behavioural and psychological symptoms of dementia participated in the experiment. Results Playing pieces of favorite music via the parametric speaker decreased their behavioural and psychological symptoms of dementia during the intervention. In addition, this intervention reduced the burden on caregivers. One of the advantages of using parametric speaker was being able to create a personal space in a common room. Conclusion We considered that the parametric speaker might be useful to reduce behavioural and psychological symptoms of dementia and the burden on caregivers, providing individualized rehabilitation for the improved quality of life of residents