Computational Psychiatry and Psychometrics Based on Non-Conscious Stimuli Input and Pupil Response Output

摘要

It is well known from the technical literature that non-conscious perception of emotional stimuli\udaffects behavior, perception, and even decision making [e.g., see Ref. (1) for a comprehensive\udreview]. Non-conscious perception can be obtained by inducing sensory unawareness, e.g., through\udbackward masking and binocular rivalry (1). Experiments adopting such paradigms have evidenced\udthat non-consciously perceived emotional stimuli elicit activity in the amygdala, superior colliculus,\udbasal ganglia, and pulvinar. More specifically, it has been shown that a subcortical fast route exists\udbetween the thalamus and the amygdala, which, in turn, project onto different cortical and subcortical\udstructures [e.g., onto the nucleus accumbens, NAcc, when appetitive stimuli are perceived (2)].\udThese findings agree with the hypothesis about amygdala functionality proposed by LeDoux (3, 4).\udIn fact, LeDoux has hypothized the existence of a thalamic pathway to the amygdala; such a pathway\udwould allow to automatically detect evolutionary prepared visual stimuli (such as emotional faces,\udsexual-related stimuli, spiders, snakes, and injuries). Note that this model is also supported by other\udresults acquired by different researchers that have employed masking in normal participants (5, 6)\udor have observed brain activity in patients affected by cortical blindness (7, 8). According to this\udmodel about amygdala functionality, the superior colliculus stimulates the pulvinar nucleus of the\udthalamus, which then arouses the amygdala (4, 9, 10). This suggests that salient features representing\udbiologically prepared stimuli could be stored in the amygdala since birth. From an evolutionary perspective,\udthis can be related to the fact that fast and implicit (or unconscious) reactions are needed in\uddangerous and highly dynamical environments. Moreover, even ontogenetic stimuli (e.g., weapons)\udare encoded within the amygdala through implicit learning during life (11, 12). These data evidence\udthe importance of subcortical regions associated with implicit emotional processing. In fact, since\udthe brain structure works like a hierarchical network (13) in which the limbic system represents a\udlower hierarchical level with respect to the higher cortical structure, it is likely that the overall perception\udand emotional appraisal are influenced by low-level evaluations. More specifically, the signals\udcoming from lower and higher hierarchical levels determine prediction errors (or error signals) at\udintermediate levels; such error signals propagate through the entire hierarchical structure, determining\udcognitive perception, causes attributions, emotional evaluations, actions, and behaviors (14).\udHence, if subcortical limbic-brainstem regions are defective, all the network hierarchy functioning\udwill be compromised. As a matter of fact, a dysfunction in the limbic-brainstem regions is associated\udwith various psychiatric disorders with higher cognitive deficits including autism, schizophrenia,\udposttraumatic stress disorders (PTSD), attention deficits/hyperactivity disorder (ADHD), neurosis,\udphobia, and others.