Age and functions of the transient component of ON and OFF responses in visual processes

Detections of appearances and disappearances in briefly interrupted complex patterns were examined in young and old subjects. According to neurophysiological evidence developed by Singer and Phillips (1974), the detection rates for the two types of events, which differ substantially as pattern durations and interstimulus intervals vary, are attributable to inhibitory interactions of ON- and OFF-centre relay cells of the lateral geniculate nucleus. The interactions affect the latency and amplitude of the transient component of the cells' responses. Phillips and Singer (1974) found that the neural model predicted the ability to detect the events. Using the same paradigm, we replicated their findings and found that differences in patterns of detection rates for appearances and disappearances in young and old subjects were consistent with the hypothesis that inhibitory interactions are stronger in older subjects, producing longer latency of OFF-centre relay cells. The neural model and the hypothesized age-related increase in inhibitory interactions are consistent with findings     

Interrater agreement for reviews for Developmental Review

Reviewer reliability is examined for the first 2 years of operation of Developmental Review. Using the statistic, Finn's r, summary recommendations on publishability are shown to be higher in reliability than previously reported for other journals. Separate rating scales are shown to be less reliable than summary recommendations. Finn's r is compared with the intraclass correlation coefficient and shown to be a better method for examining reviewer agreement across different journals. Potential causes of high reviewer agreement for Developmental Review are discussed, and the importance of the distinction between reliability and validity of reviews is noted.     

Grip Force-Load Force Coupling Is Influenced by Altered Visual Feedback about Object Kinematics

Abstract

Recent evidence suggests that visual feedback influences the adjustment of grip force to the changing load force exerted by a grasped object as it is manipulated. The current project investigated how visual feedback of object kinematics affects the coupling of grip force to load force by scaling the apparent displacements of the object viewed in virtual reality. Participants moved the object to manually track a moving virtual target. The predictability of the changing load force exerted by the object was also manipulated by altering the nature of target trajectories (and therefore the nature of object motions). When apparent object displacements increased in magnitude, grip force became more tightly coupled to load force over time. Furthermore, when load force variations were less predictable, the magnitude of apparent object displacements affected the relative degree of continuous versus intermittent coupling of grip force to load force. These findings show that visual feedback of object motion affects the ongoing dynamical coupling between grip force control and load force experienced during manipulation of a grasped object.     

Perceiving tongue position.

Two experiments on perceiving the tongue position were conducted in which naive human subjects pointed to gingival targets, or to extensions of their fingertip, with their tongue. The aim in experiment 1 was to inquire about the existence and accuracy of the perception of the horizontal position of the tongue inside and outside the mouth, and whether kinesthetic elements other than the skin might contribute to perceiving tongue position. Vertical positioning and the calibration of the sensory map that can be presumed to underlie position sense in the tongue were examined in experiment 2. It was found that position sense is equally good in the presence and absence of anesthesia of the mucosa, suggesting that the muscles, tendons, and corollary discharge contribute to position sense in the tongue. Perception of the tongue position both inside and outside the mouth is accurate, with the error in tongue positioning being about 2 degrees. Feedback improved naive subjects' accuracy very little.