| Popis: |
A flexible repertoire of motor actions is necessary for everyday life. Even target- driven actions have the potential to be carried out in many different ways. This flexibility of action execution even within biological systems implies some mechanism by which one motor plan becomes promoted to the stage of execution of a particular task. The focus of this work is an investigation of the generation of action, by looking at the process of automatic inhibition of primed motor plans. Automatic inhibition is phenomenon wherein motor responses to visual stimuli are inhibited under certain conditions. It has been conceived of as a process to control action generation automatically, preventing the execution of actions that are no longer indicated by the sensory environment. However it is not yet known whether automatic inhibition can operate in all types of actions. Boundary conditions for the emergence of automatic inhibition were examined through both behavioural and neuro-cognitive investigation. A possible neural locus for automatic inhibition was examined via the application of rTMS. Although implicated in the generation of actions, and in the generation of voluntary actions in particular, it does not appear that activity in the SMA is necessary for the operation of automatic inhibition. Automatic inhibition was shown to operate only in terms of voluntary actions, although its precursor, automatic response priming, may be more ubiquitous in action generation. The perceptual salience, or conscious awareness, of the action cue or target may determine, along with the perceptual strength of the prime stimulus, whether or not automatic inhibition operates. It is possible that the presence or absence of automatic inhibition may be a defining feature of voluntary and involuntary actions. |
