Dottorato in NEUROSCIENZE DEL COMPORTAMENTO

Titolo della tesi: Beyond the visuo-spatial attention: Behavioural and neural correlates of physiological and pathological conditions.

In the last four decades, visuo-spatial attention has been one of the most investigated cognitive domains in neuroscience. Here we further investigated visuo-spatial attention using an integrated approach based: on a combination of “classical” attention tasks that might shed new lights on this multifaceted function (Aim 1); and on the simultaneous evaluation of the impact of other cognitive processes (namely, emotion and memory) on the deployment of visuo-spatial attentional resources (Aim 2). Specifically, for Aim 1 we used a visual search task, a bilateral stimulus task, and landmark task to investigate the neural correlates of visuo-spatial attention both in neurologically-intact subjects and patients with hemispatial neglect syndrome. A large literature investigated the specific activations elicited by each of these tasks in neurologically-intact, healthy subjects. Here we found a common substrate, namely the intraparietal sulcus, that was consistently engaged during the performance of the three tasks. By contrast, much less is known regarding the neural correlates of these tasks in neglect patients. Hence, we observed specific brain activations mainly in the left hemisphere, suggesting the existence of a compensatory mechanism in this syndrome. For Aim 2, we designed an experimental paradigm to assess the neural correlates of the interplay between emotion and long-term memory in the guidance of attention during a visual search task. We found that (negative) emotion enhanced the effect of long-term memory in guiding visuo-spatial attention, thus improving target detection at the visual search task. This effect was supported by a circuit of regions involving dorsal and ventral fronto-parietal, insular and parahippocampal activations. Moreover, we observed that the activation of the dorsomedial prefrontal cortex was further mediated by heart rate variability (namely, an index of the efficiency of “brain-heart connections”) during the interplay between emotion and memory in guiding visuo-spatial attention.