Awareness and consciousness in humans and animals – neural and behavioral correlates in an evolutionary perspective

Abstract

Awareness or consciousness in the context of stimulus perception can directly be assessed in well controlled test situations with humans via the persons’ reports about their subjective experiences with the stimuli. Since we have no direct access to subjective experiences in animals, their possible awareness or consciousness in stimulus perception tasks has often been inferred from behavior and cognitive abilities previously observed in aware and conscious humans. Here, we analyze published human data primarily on event-related potentials and brain-wave generation during perception and responding to sensory stimuli and extract neural markers (mainly latencies of evoked-potential peaks and of gamma-wave occurrence) indicating that a person became aware or conscious of the perceived stimulus. These neural correlates of consciousness were then applied to sets of corresponding data from various animals including several species of mammals, and one species each of birds, fish, cephalopods, and insects. We found that the neural markers from studies in humans could also successfully be applied to the mammal and bird data suggesting that species in these animal groups can become subjectively aware of and conscious about perceived stimuli. Fish, cephalopod and insect data remained inconclusive. In an evolutionary perspective we have to consider that both awareness of and consciousness about perceived stimuli appear as evolved, attention-dependent options added to the ongoing neural activities of stimulus processing and action generation. Since gamma-wave generation for functional coupling of brain areas in aware/conscious states is energetically highly cost-intensive, it remains to be shown which animal species under which conditions of lifestyle and ecological niche may achieve significant advantages in reproductive fitness by drawing upon these options. Hence, we started our discussion about awareness and consciousness in animals with the question in how far these expressions of brain activity are necessary attributes for perceiving stimuli and responding in an adaptive way.

Neuro-functional modeling of near-death experiences in contexts of altered states of consciousness

“…The NDE definition by Charland-Verville et al (2020) and the consideration that some situations of NDEs may refer to disconnected consciousness as, for example, observed in dreaming during rapid-eye-movement sleep ( Martial et al, 2020a ) do not only acknowledge a psychological basis of NDEs ( Lange et al, 2004 ) but also, and primarily, a neurophysiological basis becoming noticeable in ASCs. This NDE definition opens the door to the understanding of NDEs via the knowledge of the neurophysiological bases of the generation of wakefulness and awareness and of changes in these basic attributes of consciousness (e.g., Sperry, 1968 ; Crick and Koch, 1990 ; Edelman, 1992 ; Baars, 1993 ; Aru et al, 2012 ; Damasio, 2012 ; Dehaene, 2014 ; Tononi et al, 2016 ; Gazzaniga, 2018 ; Ehret and Romand, 2022 ). The definition of an authentic NDE or RED by listing necessary presence and absence of components in the NDE reports has been criticized ( Evrard et al, 2022 ) as “ a very risky strategy, which truncates the NDE phenomenon to avoid confronting what the last decades of research have revealed.”…”

“…Here, we will open the perspective to scientifically address and validate NDEs in the context of brain functions. Their relationship to consciousness has been a major subject of studies in the neurosciences for a long time (e.g., Ehret and Romand, 2022 ). Such a neuro-functional approach may offer valuable ideas for psychiatric and psychologic learning- and/or medication-based treatment of persons who suffer from their experiences.…”

“…Brain waves were analyzed with regard to the temporal occurrence and spatial cortical distribution of the various waves, especially gamma-waves. Gamma-waves are associated with brain activity during states, for example, of sensory perception, memory retrieval, waking, dreaming, meditation ( Llinás and Paré, 1991 ; Steriade et al, 1996 ; Llinás et al, 1998 ; Fries, 2009 ; Bosman et al, 2014 ) and aware perception and conscious action planning (e.g., Ehret and Romand, 2022 ). The data showed coupling of brain waves and long-range communication via gamma-waves in a well-coordinated way between sensory, motor, and association areas of the brain.…”

“…Further terms of consciousness concern, for example, access consciousness , the memory- and cognition-based action planning and execution ( Block, 2005 ) and self-consciousness or self-awareness (e.g., Vogeley and Fink, 2003 ; Morin, 2006 ; Singer, 2019 ). Phenomenal consciousness and access consciousness can be characterized by different neural correlates of consciousness in activity recordings of the brain (e.g., Ehret and Romand, 2022 ). Opposite to wakefulness and awareness, loss of consciousness (LOC) corresponds to the absence of subjective experience and refers to a state in which an individual lacks the normal awareness of the self and the surrounding environment (e.g., Laureys, 2005 ; Bonhomme et al, 2019 ).…”

De la peur à la confiance: les neurosciences comme soubassements d’une pratique méditative basée sur la pleine conscience et l’autocompassion

“…On l'a lu et sans doute aussi constaté : durant les deux dernières années, les jeunes ont subi de plein fouet les mesures politico sanitaires. A l'âge de la transformation radicale, de la projection existentielle, de la césure avec l'univers connu de l'enfance et de l'ouverture quelques exceptions de moments de conscience près (Ebner & Hameroff, 2011;Ehret & Romand, 2022;Eriksson, 2017;Frigato, 2021;Hutchinson, 2019;Koch et al, 2016;Polak & Marvan, 2018;Tononi & Koch, 2008;Yaron et al, 2022). (Kohler et al, 2002).…”