Neural bases of the non-conscious perception of emotional signals

Abstract

| Many emotional stimuli are processed without being consciously perceived. Recent evidence indicates that subcortical structures have a substantial role in this processing. These structures are part of a phylogenetically ancient pathway that has specific functional properties and that interacts with cortical processes. There is now increasing evidence that non-consciously perceived emotional stimuli induce distinct neurophysiological changes and influence behaviour towards the consciously perceived world. Understanding the neural bases of the non-conscious perception of emotional signals will clarify the phylogenetic continuity of emotion systems across species and the integration of cortical and subcortical activity in the human brain.

From affective blindsight to emotional consciousness

“…Under the assumption that the special role of faces is not fixed by their physical properties but by their functional ones, the findings reported above converge with the idea that nonconscious emotion processing in blindsight is not specific for faces, but rather for biologically primitive emotional expressions that are clearly associated with action tendencies and to which we are evolutionary prepared to respond (Tamietto & de Gelder, 2010).…”

“…Contemporary neuroscience is replete with examples of social and affective processes that occur without or outside conscious experience (de Gelder, de Haan, & Heywood, 2001; de Gelder, Hortensius, & Tamietto, 2012;Tamietto & de Gelder, 2010;Vuilleumier, 2005). This evidence has contributed significantly to the burgeoning field of social and affective neuroscience.…”

“…As we will discuss in detail later, approaching consciousness, and its absence, from the vantage point of emotion processing may help to reconcile these two aspects of consciousness that have been barely considered within the same framework. In fact, the intersection between emotion and consciousness seems more radical than what was initially envisaged: not only do emotional signals have a privileged access to consciousness, but several subcortical structures that are important for emotion processing partly overlap with structures involved in the maintenance of state consciousness (Craig, 2009;Critchley, 2005;Damasio, 1999;Mitchell & Greening, 2012;Panksepp, 2005;Park & Tallon-Baudry, 2014;Tamietto & de Gelder, 2010;Tamietto et al, 2005;Tsuchiya & Adolphs, 2007;Vuilleumier, 2005). Seen from an evolutionary perspective, this is consistent with the thesis that consciousness evolved in the process, and as a consequence, of the demands of the social and emotional environment (Humphrey, 1983).…”

Facial emotion recognition in Parkinson's disease: A review and new hypotheses

“…For instance, showing that the ability to discriminate graded intensities of angry faces was positively correlated with the ability to discriminate unperfect/perfect circles (radial frequency patterns), Marneweck and Hammon indicated that impaired ability to perceive visual forms could contribute to FER deficit in PD 38. It is noteworthy that visual and emotional systems are extensively interconnected; for example, the amygdala is connected to the superior colliculus via the pulvinar, to the OFC, and the anterior cingulate cortex, as well as to cortical visual regions in the temporal cortex 41. Furthermore, the idea that FER deficit in PD could be secondary to executive dysfunction is an old one.…”

“…Like Gray and Tickle‐Degnen,12 we noted that FER deficit in PD affected all the basic emotions but was greater for negative emotions (64% of studies highlighted a global deficit, 44% for anger, 27% for happiness; Table 1). This could echo the subcortical pathway involving the pulvinar, the amygdala, and the striatum, which may lead to a coarse but fast visual information processing 40, 41. Indeed, because of its evolutionary relevance, this preserved route may induce a preattentive and autonomic bias toward threatening stimuli like angry faces 42, 43.…”