Titolo della tesi: Cognitive Control Dynamics: A complex interplay of cognitive variables in actions.
In the present study, we focused on response inhibition as a fundamental aspect of cognitive control, emphasizing its significance in dynamic environments and ensuring goal-directed behaviors. The "Stop Signal Task" (SST) is introduced as a behavioral paradigm for investigating inhibitory control, with a detailed description of its execution and outcomes. Subsequently, the "horse race" model is presented, offering a conceptual framework to understand SST paradigm results. The model highlights the dynamic competition between response initiation and response inhibition, underscoring the temporal independence of these processes, crucial for accurately estimating the "Stop Signal Reaction Time" (SSRT). In the first experiment, we explored motor control in a context requiring the selective inhibition of an effector which movement started paired with a second effector. In this experiment, we modeled a situation where acting a motor decision corresponding to stopping or continuing a prepared movement could be linked to the foreknowledge of the effector involved to be recruited in the movement. The distinction between non-selective and selective stopping contexts emphasized the complexity of selective inhibitory responses in a multi-component context. The motor stage of this decision process underscores how selective inhibitory responses involve the specific suppression of components of a multi-component action. In a second study, we investigated the selective control of movements by manipulating the degree of difficulty in interpreting a perceptual stimulus as informative for executing or canceling prepared actions. In our manipulation, the degree of difficulty was manipulated by cognitive variables involving engaging a numerical comparison, rather than the comparison between perceptual characteristics of the stimuli as in previous experiments. The results of this study show the influence of cognitive variables on motor decision processes. By behavioral neurophysiology experiment, we further analyzed the neuronal correlates of this form of decision-making. In this third study, attention was focused on the activity of the dorsal premotor cortex, a brain area supporting motor decision both by selecting the appropriate motor action depending on contextual demands and which activity has been observed to be modulated by cognitive variables. In this study, we focused on the modulation of different frequency bands of neural activity in response to varying task difficulty, modulated by cognitive operations, within a computational framework focused on processing incoming information for decision-making.
Overall, here we explored a framework for understanding cognitive control, examining both motor and cognitive aspects through behavioral paradigms and neural studies. It contributes to the understanding of the underlying dynamics of cognitive control and inhibitory responses.