Causal computations of supplementary motor area on spatial impulsivity

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Human Behavior

Background:

• Impulsive behavior is often triggered by the spatial proximity of stimuli.
• Adaptive behavior relies on overcoming impulsive tendencies.
• The supplementary motor area (SMA) is implicated in motor control and decision-making.

Purpose of the Study:

• To investigate the causal relationship between spatial proximity of stimuli and supplementary motor area (SMA) functions.
• To examine the role of the SMA in modulating spatial impulsivity using virtual reality and brain stimulation.

Main Methods:

• Two experiments utilizing a virtual reality environment with close (21 cm) and distant (360 cm) stimuli.
• Experiment 1: Go/no-go task to measure the influence of stimulus proximity on behavior (N=93).
• Experiment 2: Transcranial static magnetic stimulation (tSMS) over the SMA to assess its causal role in spatial impulsivity (N=28).

Main Results:

• Close stimuli led to faster responses but higher error rates, particularly commission errors, compared to distant stimuli (Experiment 1).
• Real SMA stimulation slowed response latencies, mediated by increased decision thresholds (a) (Experiment 2).
• EZ model parameters (a, v, Ter, MDT) were computed to further analyze decision-making processes.

Conclusions:

• Spatial proximity of stimuli can modulate impulsivity, leading to quicker but less accurate actions towards nearby objects.
• The supplementary motor area (SMA) is crucial in regulating spatial impulsivity.
• This study provides initial evidence for the SMA's role in controlling impulsive tendencies influenced by spatial factors.