Disappearance of afterimages at 'impossible' locations in space

An eccentrically positioned afterimage, viewed in the dark, will disappear if the eye is positioned so that the afterimage now projects to a more extreme location relative to straight ahead. It was found that the afterimage disappeared when it projected to a location which corresponded to the edge of the visual field defined by the brow, cheek, and nose. This suggests that visibility of stimuli from those retinal regions shadowed by the head is influenced by eye-position information.     

Theodicy in a Deterministic Universe: God and the Problem of Suffering in Vyāsatīrtha’s Tātparyacandrikā

International Journal of Hindu Studies - The classical traditions of Vedānta in India explored the problem of why an omnipotent being like God would permit sentient beings to suffer in His...     

Motivation and anxiety for dental treatment and dental attendance: The roles of the locus of causality personality and treatment styles

The purpose of the present study was to test a self-determination theory model with the following hypotheses: (1) Patients’ autonomous causality personality orientation and oral health care professionals’ autonomy-supportive treatment styles, as perceived by patients, would both be positively indirectly associated with dental attendance through patients’ autonomous motivation for dental treatment. (2) Patients’ controlled causality personality orientation and oral health care professionals’ controlling treatment styles, as perceived by patients, would both be positively indirectly associated with avoidance of making a dental clinic appointment through patients’ anxiety for dental treatment. A sample size of about 200 patients was estimated to be acceptable in detecting moderate effect sizes (independent variables: 5–6; power: .80; p < .05). Student patients (N = 226) responded to a survey with validated questionnaires. Using LISREL, both hypotheses were supported. In addition, patients’ perception of a controlling treatment style moderated the controlled personality—dental anxiety relation, so that a lower controlling treatment style mitigated dental anxiety substantially among patients with a high control orientation. Effect sizes were moderate to large. Analyses (Z-scores) also revealed that the autonomous personality is more strongly linked to situational autonomous motivation than situational autonomy support, whereas a controlled personality and a perceived controlling treatment style are equally and significantly associated to dental anxiety. Both patient personalities and oral health care professionals’ treatment styles are substantially linked to autonomous motivation and anxiety for dental treatment, which are relatively strongly associated with dental attendance and avoiding dental clinic appointments, respectively.     

Aging Affects the Ability to Process the Optic Flow Stimulations: A Functional Near-Infrared Spectrometry Study

Abstract

Optic flow (OF) has been utilized to investigate the sensory integration of visual stimuli during postural control. It is little known how the OF speed affects the aging brain during the sensory integration process of postural control. This study was to examine the effect of OF speeds on the brain activation using functional near-infrared spectroscopy (fNIRS) and postural sway between younger and older adults. Eleven healthy younger adults (5M/6F, age 22?±?1-year-old) and ten healthy older adults (4M/6F, age 71?±?5-year-old) participated in this study. A virtual reality headset was used to provide the OF stimulus at different speeds. A forceplate was used to record the center-of-pressure to compute the amplitude of postural sway (peak-to-peak). Compared with younger adults, older adults showed significantly increased activation in the OF speed of 10?m/s and decreased activation in the OF speed of 20?m/s in the left dorsolateral prefrontal cortex. Older adults also showed decreased activation in the left temporoparietal region (VEST) in the OF speed of 20?m/s. A significant difference in peak-to-peak was found between groups. Our results indicated that age might be associated with the ability to process fast OF stimulation.