Action in self-awareness: evidence from anosognosia for hemiplegia and from somatoparaphrenia

Conscious awareness is a fascinating psychological function of the human mind. It describes a subjective first-person phenomenon (Damasio, 1998), that consists in both the cognitive processes of the self and its interactions with the external world. Therefore the construction of the self-awareness includes all the experiences re-lated to the body (James, 1980), in order to process and to represent the perceptual, motor, emotional and cognitive states as own bodily states. This function results to be impaired in several neuropsychological and neurologi-cal disorders (Flashman, 2002), causing interferences with the personal identity or the awareness about ourselves (Orfei, et al., 2007). These pathological conditions reveal insight to scientifically investigate the cognitive processes and the neuroanatomical networks involved in awareness of the bodily self (Fotopoulou, 2012). The self-awareness include both the 'sense of agency' as the feelings of the authorship and control of our actions and of the following changes on the external world and the 'sense of ownership' as the appreciation of the body as belonging to me (Gallagher, 2000) and they can be selectively or simultaneously impaired. The specific disorder of body agency is the Anosognosia for hemiplegia (Babinski, 1914), as the apparent unawareness of own sensorimotor deficits or the inability to acknowledge and appreciate the severity of the paralysis and other sensorimotor deficits following stroke (Cocchini, Beschin, Cameron, Fotopoulou, & Della Sala, 2009) Indeed the disturbances affecting the body ownership are the inability to recognize one's own body ('asomatognosia', Cutting, 1978) and the misattribution of ownership of own arm to another person ('somatoparaphrenia', Gerstmann, 1942). This thesis aims to investigate the possible influences of bodily aspects in self-awareness, by focusing on the specific role of actions. In Chapter 1 and 2, I introduced the disturbances of self-awareness of the Anosognosia for Hemipleia, and Somatoparaphrenia with neuropsychological and neuroanatomical accounts. Subsequently I wanted to highlight the importance of planning an action in these deficits in order to enhance the degree of motor awareness through both bottom-up and top-down mechanisms. My main projects focused on the investigation of the role of the Action in Anosognosia for Hemiplegia. In details in Chapter 3, 4 and 5 my experiments based on evaluating the fluctuations of motor awareness in patients with Anosognosia for Hemiplegia during the request to execute an action. I investigated this issue in some different tasks: in the attempts to act, in third-perspective view and in automatic bodily activation by measuring skin conductance responses. In addition I modulated the affective resonance of these tasks by using dangerous stimuli, so that I could evaluate the influences of both bottom-up sensorimotor and top-down emotional and cognitive components in awareness' fluctuations. I also integrated brain lesion-analyses to understand the neural networks underneath. In Chapter 6, I integrated the thesis with a single-case study of a patient with Crossed Somatoparaphrenia. This rare disorder gave me the possibility to investi-gate some aspects related to the body image and the body schema. I studied this patient in different situations assessing: multisensory integration and spatial components of proprioception and third-perspective view, in order to evaluate both sensorial and higher-order possible effects relating to the body representation. In addition, I also enclosed two single-case studies. The first was a young patient with Balint's syndrome, which was evaluated in a cross-modal task, the second a man affected by Tactile Agnosia, whit whom I applied a rehabilitation program with transcranical direct-current stimulation. These studies are included as extra experiemental studies not belonging to the main PhD topic.