Modulation of attention by motor interaction: A study in a visual discrimination task

Most of the traditional neuroscience research has considered attention as a superior cognitive function mainly oriented to perceptual processes and away from sensorimotor functions. Alternatively, the “Attention for Action” framework proposes a close relationship between cognitive and sensorimotor processes, where attention would act as an integrative mechanism. There is empirical evidence suggesting that the processes of preparation and motor execution have a positive impact on the attentional and perceptual processes, but there is no consensus if the interaction of these processes produces interference or improvement in them. The aim of this thesis is to contribute to a better understanding of the interactions between attentional and motor processes. In this thesis we propose that the functional coupling between attentional and motor processes positively modulates attention processes. To evaluate this proposition we designed an ocular pursuit dual task that required sustained attention and discrimination of a visual stimulus (visual condition). By adding a motor relevant act to the task (motor condition) we were able to evaluate if this produced a modulating effect on the attention and if differences were observed between both experimental conditions. Task performance was measured using behavioral, electro physiological (ERPs) and pupil diameter variation parameters in both, a group of healthy children (Control group) and another group of children with attentional deficit (ADHD group). Behavioral results showed that the Control group had a better overall performance in the task than the ADHD group, with better performance in visual condition than in motor condition, but that differentiating effect between groups disappeared when comparing them within motor condition, that means the motor effect favored the performance of the ADHD group. Electrophysiology showed that in motor condition a modulating effect was produced on CNV, P1 and N1 compared with the visual condition for both groups, it being larger in the Control group. Finally, Control group showed a progressive increase in pupillary diameter along the trial in the motor condition, while in the visual condition this increase was stabilized 400 ms. prior to the appearance of visual stimulus and remained so until the end of the trial. ADHD group, however, showed a progressive increase in pupillary diameter along the trial for both conditions, which could reflect a greater attentional load of these subjects in the task. These results suggest that in the analyzed task there would be a positive modulatory effect of the motor component on the attentional processes, which despite not being clear in behavioral performance, is consistent at electrophysiological level and in the pupil diameter variation, which would reflect positive interaction between these processes.