Motor system may be involved in selection of perceptual targets, PhD student paper suggests
School of Psychology PhD student Phil Woodgate is lead author on a new paper published in Behavioural Brain Research on the topic of visual attention.
Although seemingly effortless, interacting with our day-to-day environment is a hugely complex task. Imagine searching for a red pen in a draw full of stationary or picking out a familiar face in an old school photograph. The brain must quickly sort through a large amount of incoming visual information, select the region that seems most likely to contain our item of interest, and possibly perform a motor action (e.g. reaching to pick up the pen).
Traditionally, theories have separated these stages of selection, attention, and action into discrete sections. This recent paper by Phil and colleagues suggests that the motor system, a brain area involved in programming and executing motor responses, is also involved in the selection of perceptual targets. During the experiment, participants were asked to reach and touch a green target amongst red distractors, or vice versa. Whilst they completed the task, electrical stimulation was applied over the motor cortex. The fact that selection of the target was improved by stimulating the motor cortex suggests that this brain area is normally involved in target selection.
There are two important things to note, however. Firstly, in order to show motor cortex involvement the target must be predictable: Stimulation affected selection only when the target predictably repeated (red-red-red-red), and not when it switched randomly between red and green. Secondly, the target had to form the end-point of a reaching movement rather than signify a key-press response for the motor system to be activated.
These findings fit with recent evidence that suggests that the motor system may be at the head of a continuous processing pipeline originating in earlier neural areas.
Woodgate, Strauss, Sami, & Heinke (2015). Motor cortex guides selection of predictable movement targets. Behavioural Brain Research, 287, 238-246.