Using 1/f noise to examine planning and control in a discrete aiming task

Area of Science:

• Motor control and biomechanics
• Human movement analysis
• Cognitive neuroscience

Background:

• 1/f noise, characterized by long-range dependence, is observed in various biological systems.
• Understanding the underlying processes generating 1/f noise in human motor control is crucial for explaining movement variability.
• Previous research has explored 1/f noise in handwriting and gait, but its role in aiming movements remains less understood.

Purpose of the Study:

• To investigate the influence of spatial, physical, and timing constraints on planning and control in aiming movements.
• To quantify 1/f noise during aiming tasks under different speed conditions.
• To explore the relationship between 1/f noise characteristics and the interplay between motor planning and online control.

Main Methods:

• Participants performed aiming movements with objects of varying mass to different distances at preferred and maximal speeds.
• 1/f noise was quantified using power spectral density, standardized dispersion, rescaled range, and an autoregressive fractionally integrated moving average (ARFIMA) model selection.
• Movement data, including peak velocity, were analyzed to identify temporal patterns of 1/f noise.

Main Results:

• Analyses using four different methods showed consistent quantification of 1/f noise.
• More long-range (ARFIMA) models were selected at peak velocity during preferred-speed movements (Experiment 1) compared to fast movements (Experiment 2).
• A trend suggested increased 1/f noise at peak velocity during preferred-speed movements, indicating potential overlap of planning and control, which diminished during fast movements.

Conclusions:

• The findings suggest that 1/f noise in aiming movements may arise from the summation of short-range processes operating at different timescales.
• Sufficient time for both planning (slower process) and control (faster process) to interact appears to facilitate the emergence of 1/f noise.
• The results contribute to understanding the complex interplay of cognitive and motor processes underlying human movement variability.