INTRODUCTION:There appears to be a fundamental difference between the two ways of how an object becomes perceptually experienced. One occurs when preconscious object-specifying sensory data processing crosses a certain threshold so that sensory constituents of object depiction become consciously experienced. The other occurs when the already consciously experienced sensory features of the object become interpreted as belonging to a certain visual object category. Surprisingly, experimental facts about neural markers of conscious access gathered so far do not allow us to distinguish mechanisms responsible for these two varieties. METHODS:A cortical multicompartment layer-5 pyramidal neuron-based generic processing model is presented in order to conceptualize a possible mechanistic solution for the explanatory cul-de-sac. To support the argument, a review of pertinent research is compiled as associated with data from studies where physically invariant perceptual stimuli have underwent alternative interpretation(s) by the brain. RESULTS:Recent developments in the newly emerging field of cellular psycho(physio)logy are introduced, offering a hypothetical solution for distinguishing the mechanisms subserving sensory content experience and conscious interpretation. CONCLUSION:The multicompartment single cell-based mechanistic approach to brain process correlates of conscious perception appears to have an added value beyond the traditional inter-areal connectivity-based theoretical stances.

'Cellular psychology' is a new field of inquiry that studies dendritic mechanisms for adapting mental events to the current context, thus increasing their coherence, flexibility, effectiveness, and comprehensibility. Apical dendrites of neocortical pyramidal cells have a crucial role in cognition - those dendrites receive input from diverse sources, including feedback, and can amplify the cell's feedforward transmission if relevant in that context. Specialized subsets of inhibitory interneurons regulate this cooperative context-sensitive processing by increasing or decreasing amplification. Apical input has different effects on cellular output depending on whether we are awake, deeply asleep, or dreaming. Furthermore, wakeful thought and imagery may depend on apical input. Highresolution neuroimaging in humans supports and complements evidence on these cellular mechanisms from other mammals.

The search for the neural correlates of consciousness has brought many theories of consciousness with it. The abundance of theories points to the need to examine the empirical background supporting each particular theory. This research identified the most common theories of consciousness (global neuronal workspace theory [GNWT], integrated information theory [IIT], and predictive processing) and the most widely used experimental paradigms in consciousness research: masking, filling-in, ambiguous figures, dichotic listening, tip-of-the-tongue phenomenon, binocular rivalry, attentional blink, inattentional blindness, change blindness, biological motion, phosphenes, no-report paradigm, the effect of expectations on perception, and ensemble perception. The selected theories and the underlying neurobiology were reviewed and the extent to which the theories have been supported by experiments using the selected experimental paradigms was investigated through a systematic search. Forty-one empirical articles were found in support of GNWT, 36 in support of predictive processing, and three in support of IIT. Different theories mostly used different experimental paradigms and partly different measuring instruments, which somewhat restricts the theories when aspiring for universality. The possible impact of these differences on the generalizability of theories is presented in the discussion, and the results are compared (a) with other empirical works not specifically targeted here and (b) with a similar systematic review.

This primer aims to provide a concise description of the Dendritic Integration Theory (DIT) of consciousness. We consider the motivation for DIT, the evidence for it, and how it fits with other theories of consciousness.

Progress in the science of consciousness depends on the experimental paradigms and varieties of contrastive analysis available to researchers. Here we highlight paradigms where the object is represented in consciousness as a set of its features but the interpretation of this set alternates in consciousness. We group experimental paradigms with this property under the label "conscious interpretation". We compare the paradigms studying conscious interpretation of the already consciously perceived objects with other types of experimental paradigms. We review previous and recent studies investigating this interpretative aspect of consciousness and propose future directions. We put forward the hypothesis that there are types of stimuli with a hierarchy of interpretations for which the rule applies: conscious experience is drawn towards higher-level interpretation and reverting back to the lower level of interpretation is impossible. We discuss how theories of consciousness might incorporate knowledge and constraints arising from the characteristics of conscious interpretation.

Ambiguous figures (aka bistable, multistable, or reversible images) have fascinated scientists as well as laypersons for centuries. It may be surprising indeed how one and the same physical depiction can be experienced in perceptual awareness in cardinally different ways. In the most well-known examples of such illusions of multistability, the phenomenal change relates just to visual organization. Much less common are perceptions of alternating emotional content in the ambiguous visual image. Here, I introduce one such example.

COPYRIGHT © 2022 Bachmann. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Within-object element ambiguity allows for a strange illusion of alternating facial expression and structure

OPINION article Front. Neurosci., 07 September 2021 | https://doi.org/10.3389/fnins.2021.731600

Abstract Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.

We present a theoretical view of the cellular foundations for network-level processes involved in producing our conscious experience. Inputs to apical synapses in layer 1 of a large subset of neocortical cells are summed at an integration zone near the top of their apical trunk. These inputs come from diverse sources and provide a context within which the transmission of information abstracted from sensory input to their basal and perisomatic synapses can be amplified when relevant. We argue that apical amplification enables conscious perceptual experience and makes it more flexible, and thus more adaptive, by being sensitive to context. Apical amplification provides a possible mechanism for recurrent processing theory that avoids strong loops. It makes the broadcasting hypothesized by global neuronal workspace theories feasible while preserving the distinct contributions of the individual cells receiving the broadcast. It also provides mechanisms that contribute to the holistic aspects of integrated information theory. As apical amplification is highly dependent on cholinergic, aminergic, and other neuromodulators, it relates the specific contents of conscious experience to global mental states and to fluctuations in arousal when awake. We conclude that apical dendrites provide a cellular mechanism for the context-sensitive selective amplification that is a cardinal prerequisite of conscious perception.

Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.

Attention distractibility in a low load visual search experiment with a rare irrelevant distractor could be an objective continuous measure in adulthood that correlates well with the symptoms of attention deficit throughout lifespan. This was studied using a birth cohort representative sample in a longitudinal study. The expected correlations were not found between the distractor cost measured in the experiment in adulthood and the inattention questionnaire scores from ages 15-33. However, the coefficient of variability for RT (CVRT) correlated negatively with self-reported motor restlessness (age 15) and attention deficit (age 25). We suggest that hyperactivity in childhood improved motor control at age 33. Associations with the gene KTN1 rs945270 (found to affect putamen size) were explored. CVRT, motor restlessness at age 15 and attention deficit scores at age 25 were especially low for male C-allele carriers. A possible association with the volume of putamen of individual participants is considered.

People prone to mood disorders and anxiety typically show increased sensitivity to task‑irrelevant stimulation signifying threat. Better knowledge about the brain mechanisms mediating this sensitivity as well as about individual inherited differences in how these mechanisms function is a precondition for developing improved vulnerability screening, resilience building and treatment methods. The chances to have affective disorders are known to depend, among other factors, on the functioning of the brain serotonin systems developed under influence from common genetic variability. However, the extent and directions of the effects of SNPs involved in serotonergic regulation on the propensity for suboptimal threat‑sensitivity are poorly understood. This applies also to HTR1A rs6295 polymorphism. Assisted by our custom developed emotional attentional blink task, we found that nonclinical subjects carrying the G allele (compared to C allele homozygotes) had higher sensitivity to threat‑depicting distractor stimuli, expressed as an increase in the blink magnitude. We also disrupted right‑hemisphere dorsolateral prefrontal cortex by rTMS (repetitive transcranial magnetic stimulation) to look for the possible role of DLPFC (dorsolateral prefrontal cortex; known to be involved in cognitive control of responses to affective stimuli) in serotonergic regulation mediated by the HTR1A rs6295 polymorphism. No main effects or interactions with rTMS being involved were found.

The relationship between expectation-induced hallucination proneness and self-confidence in performance was studied in a visual perception task. Participants were prompted either to recognize briefly shown faces as male or female or to rate the subjective vividness of a square surrounding the face. Importantly, in a few critical trials, the square was absent. Upon completion, participants rated their performance in the face recognition task; they were also asked whether they were sure that their estimation was correct. Out of 35 participants, 33 "hallucinated" on at least one trial, rating the square as visible when it was actually absent. Negative correlation between hallucination proneness and self-confidence in performance (metacognitive rating) was found: The more hallucinations a participant experienced, the less confident he/she was in his/her performance in the face recognition task. Most subjects underestimated their performance; higher ratings were also more accurate. Thus, higher hallucination proneness was associated with more inaccurate ratings of one's own perception. However, confidence in self-ratings as measured by the second follow-up question was unrelated to both, hallucination proneness and self-confidence in performance, supporting the view that there is no unitary mechanism of metacognitive evaluations and extending this view to the domain of visual hallucinatory perception.

OPINION article Front. Psychol., 23 June 2020 | https://doi.org/10.3389/fpsyg.2020.01293

This review is set to present the gist of the theoretical account of consciousness recently presented by Christof Koch and pose a couple of questions instigated by this account. The expected answers to these questions would hopefully help to advance our understanding of the basic nature of the conscious mind.