Mechanisms of simple and choice reaction to changes in direction of visual motion

Abstract

Experiments are presented in which a random dot pattern moved vertically upwards (velocity vector V(1)) and then abruptly changed its direction of motion by the angle alpha (velocity vector V(2)), either to the left or to the right, without changing the speed. Subjects performed simple reactions to the direction change, disregarding its sign. In another experiment choice reactions to the same stimuli were performed: the subjects pushed a left button when the direction change was to the left and a right button when the change was to the right. The simple reaction time decreased monotonically with alpha increasing from 11 degrees to 169 degrees, whereas, within the same range of angles, a U-shaped curve described the function of the choice reaction time versus alpha. Both types of reaction time increased with decreasing the base speed. Difficulties are outlined which occur when the angle of change alpha is considered as 'intensity' of the stimulus. Instead, the parameter mid R:V(2)-V(1)mid R:, the absolute value of the difference between the velocity vectors before and after the change, is shown to be a meaningful 'intensity' parameter for the simple reaction task. The parameter V(2N), the speed of the velocity component normal to the initial velocity vector V(1), is suggested as an 'intensity' parameter for the choice reaction task. It is shown that the simple and choice reactions to changes in direction of visual motion are performed by two distinct mechanisms which seem to work in parallel and may be nearly equally fast for small angles of change, when mid R:V(2)-V(1)mid R: approximately V(2N).

The Speed of Neural Visual Motion Perception and Processing Determines the Visuomotor Reaction Time of Young Elite Table Tennis Athletes

“…The results on EMG onset and VMRT indicate a faster VMRT in response to fast when compared to slow visual motion onset stimuli. These findings are in line with numerous previous studies using motion onset as well as motion direction change paradigms likewise indicating an acceleration of reaction time with increasing stimulus speed (Genova et al, 2000; Kreegipuu and Allik, 2007). When considering the identical motor time for both stimulus velocity conditions this study confirms previous research suggesting the VMRT is primarily determined by the signal processing speed in the central nervous system (Ando et al, 2001; Zwierko, 2008; Hülsdünker et al, 2017).…”

“…Finally, while our previous research focused on a single visual motion speed (Hülsdünker et al, 2017, 2018a), this study will evaluate two motion velocity conditions thus allowing to draw conclusion not only about the generalizability for different disciplines but also motion speeds. Changes in visual motion speed have previously been shown to affect the latency of activation in the complex of area MT/MST (Kawakami et al, 2002; Maruyama et al, 2002; Hülsdünker et al, 2017) as well as behavioral reaction speed (Kawano et al, 1994; Genova et al, 2000; Kreegipuu and Allik, 2007) in both animals and humans. Specifically, a higher speed of the visual motion stimulus was associated with an earlier N2 component and faster visuomotor reactions.…”

Integration across Time Determines Path Deviation Discrimination for Moving Objects

“…In one experiment, Tripathy and Barrett [7] examined thresholds for path deviation of a single dot and observed thresholds of approximately 2°, provided dot velocity was high. Several studies have examined path deviation in terms of reaction time (RT, [8]–10). Observers are presented with a moving object which undergoes a suprathreshold deviation in path direction and observers are required to make a simple or choice reaction to the event.…”

Visual Analysis of Changes of Motion in Reaction-Time Tasks

“…Instead, Mateeff et al (1999) employed equation 2and established that it can approximate the SRT to direction changes. Later Genova et al (2000) confirmed that equation (2) could be applied to data obtained with two different base speeds V 1 , 4 and 12 deg s À1 .…”

“…Note that equation 2should be also able to account for SRT data in the most complex, but also most common, case when motion changes simultaneously in both speed and direction. This has not been tested yet; the experiments of Mateeff et al (1999) and Genova et al (2000) were carried out with motions that changed only in direction rather than in speed. As a matter of fact, there are indications that equation 2may fail to describe the SRT to such changes.…”