Distinct dynamical patterns that distinguish willed and forced actions

Abstract

The neural pathways for generating willed actions have been increasingly investigated since the famous pioneering work by Benjamin Libet on the nature of free will. To better understand what differentiates the brain states underlying willed and forced behaviours, we performed a study of chosen and forced actions over a binary choice scenario. Magnetoencephalography recordings were obtained from six subjects during a simple task in which the subject presses a button with the left or right finger in response to a cue that either (1) specifies the finger with which the button should be pressed or (2) instructs the subject to press a button with a finger of their own choosing. Three independent analyses were performed to investigate the dynamical patterns of neural activity supporting willed and forced behaviours during the preparatory period preceding a button press. Each analysis offered similar findings in the temporal and spatial domains and in particular, a high accuracy in the classification of single trials was obtained around 200 ms after cue presentation with an overall average of 82%. During this period, the majority of the discriminatory power comes from differential neural processes observed bilaterally in the parietal lobes, as well as some differences in occipital and temporal lobes, suggesting a contribution of these regions to willed and forced behaviours.

Single trial classification of magnetoencephalographic recordings using Granger causality

“…A previous analysis of the same dataset with the goal of obtaining the best classification rates obtained a mean accuracy of 82% (Dominguez et al, 2011) suggesting that superior methods exists if the goal of the study is to obtain a high classification accuracy but even these do not perform much better. Among possible reasons for the relatively low classification rates are that signals were analyzed in the original sensor space and are of a very short length.…”

“…This study used an existing MEG dataset from the experiments described by Dominguez et al (2011) in which subjects performed left-and right-handed button presses in response to cues belonging to two conditions. The forced cue specifically instructed the subject which hand to use for the button press and the free cue instructed the subject to press a button with the hand of their choosing.…”

Libertad y ética: el trabajo de Benjamin Libet

“…Otros más han modificado el experimento en otro sentido, utilizando magnetoencefalografía y distinguiendo comportamientos forzados (utilizar un dedo para presionar un botón) y comportamientos libres (escoger el dedo), encontrando diferencias en el potencial de preparación en ambos grupos de eventos, y otras áreas corticales involucradas 30 .…”

An exploration of spatial auditory BCI paradigms with different sounds: music notes versus beeps

“…In view of this, some studies have focused on auditory-based-BCI systems, which can be used by these patients. Although an auditory P300 speller tested with four locked-in patients showed worse performance compared with a visual P300 speller (Kübler et al 2009), later studies have shown the practicality of the auditory BCI paradigm (Dominguez et al 2011;Wang and Chang 2008).…”