Consciousness, plasticity, and connectomics: the role of intersubjectivity in human cognition

From Lung to Brain: Respiration Modulates Neural and Mental Activity

Respiration protocols have been developed to manipulate mental states, including their use for therapeutic purposes. In this systematic review, we discuss evidence that respiration may play a fundamental role in coordinating neural activity, behavior, and emotion. The main findings are: (1) respiration affects the neural activity of a wide variety of regions in the brain; (2) respiration modulates different frequency ranges in the brain's dynamics; (3) different respiration protocols (spontaneous, hyperventilation, slow or resonance respiration) yield different neural and mental effects; and (4) the effects of respiration on the brain are related to concurrent modulation of biochemical (oxygen delivery, pH) and physiological (cerebral blood flow, heart rate variability) variables. We conclude that respiration may be an integral rhythm of the brain's neural activity. This provides an intimate connection of respiration with neuro-mental features like emotion. A respiratory-neuro-mental connection holds the promise for a brain-based therapeutic usage of respiration in mental disorders.

Towards an animal model of consciousness based on the platform theory

The evolution of intellectual capacities has brought forth a continuum of consciousness levels subserved by neuronal networks of varying complexity. Brain pathologies, neurodegenerative, and mental diseases affect conscious cognition and behavior. Although impairments in consciousness are among the most devastating consequences of neurological and mental diseases, valid and reliable animal models of consciousness, that could be used for preclinical research are missing. The platform theory holds that the brain enters a conscious operation mode, whenever mental representations of stimuli, associations, concepts, memories, and experiences are effortfully maintained (in working memory) and actively manipulated. We used the platform theory as a framework and evaluation standard to categorize behavioral paradigms with respect to the level of consciousness involved in task performance. According to the platform theory, a behavioral paradigm involves conscious cognitive operations, when the problem posed is unexpected, novel or requires the maintenance and manipulation of a large amount of information to perform cognitive operations on them. Conscious cognitive operations are associated with a relocation of processing resources and the redirection of attentional focus. A consciousness behavioral test battery is proposed that is composed of tests which are assumed to require higher levels of consciousness as compared to other tasks and paradigms. The consciousness test battery for rodents includes the following tests: Working memory in the radial arm maze, episodic-like memory, prospective memory, detour test, and operant conditioning with concurrent variable-interval variable-ratio schedules. Performance in this test battery can be contrasted with the performance in paradigms and tests that require lower levels of consciousness. Additionally, a second more comprehensive behavioral test battery is proposed to control for behavioral phenotypes not related to consciousness. Our theory could serve as a guidance for the decryption of the neurobiological basis of consciousness.

Voxel-based asymmetry of the regional gray matter over the inferior temporal gyrus correlates with depressive symptoms in medicated patients with major depressive disorder

The number of patients suffering from major depressive disorder (MDD) is increasing worldwide. Imbalanced hemispherical brain activity may be an underlying factor of MDD; however, whether structural asymmetry also contributes to the symptoms experienced in MDD has been scarcely investigated. In this study, we aimed to examine cortical asymmetry in association with the severity of depressive and cognitive symptoms observed in MDD during stable medication. The association between the affective and cognitive symptoms and gray matter asymmetry was evaluated in 17 MDD patients using voxel-wise gray matter asymmetry analysis on high-resolution T1-weighted MR images. Asymmetry index values in the inferior temporal gyrus (ITG) correlated with the scores of the 17-item Hamilton Depression Rating Scale (HDRS), but no association was found with the Beck Hopelessness Scale, and performance on the 1-, 2- and 3-back task. Our results indicate that the asymmetry of gray matter content in the ITG might be associated with higher depression severity. Our findings might help to better understand how structural changes contribute to depression severity in patients with MDD.

Brain-heart interaction in perseverative cognition

The move from the concept of homeostasis to that of allostasis has led reactivity stress research to widen the object of its investigation: from the brief physiological response that occurs when one is facing a stressor to what happens when one is anticipating or recovering from a stressor. A paradigmatic example is represented by perseverative cognition, during which human beings react "as if" they were constantly facing a concrete stressor. The core idea behind this review is that the cognitive inflexibility that characterizes perseverative cognition is reflected in both our body (by increased autonomic nervous system rigidity assessed by heart rate variability; HRV) and our brain (by reduced prefrontal-amygdala functional connectivity). This is a review of studies conducted in different settings (laboratory, daily life), populations (healthy, major depression, generalized anxiety), location (United States, Europe), and age groups (children, adults) that consistently replicated the association between autonomic, subjective, and behavioral measures of cognitive inflexibility during perseverative cognition. Moreover, compelling neuroimaging data suggest that HRV reduction from pre- to post-induction of perseverative cognition is associated with both structural and functional brain abnormalities reflecting impaired prefrontal inhibitory control over subcortical structures (e.g., diminished prefrontal-amygdala functional connectivity). The integration of neuroscience techniques with clinical autonomic research has advanced our understanding of the neurobiology of brain-heart interaction during perseverative cognition, potentially yielding to more effective treatment packages. This is clinically relevant if one considers that perseverative cognition is a pervasive transdiagnostic factor that carries prognostic risk for both psychological and somatic health.

Modeling Psychological Attributes in Psychology - An Epistemological Discussion: Network Analysis vs. Latent Variables

Network Analysis is considered as a new method that challenges Latent Variable models in inferring psychological attributes. With Network Analysis, psychological attributes are derived from a complex system of components without the need to call on any latent variables. But the ontological status of psychological attributes is not adequately defined with Network Analysis, because a psychological attribute is both a complex system and a property emerging from this complex system. The aim of this article is to reappraise the legitimacy of latent variable models by engaging in an ontological and epistemological discussion on psychological attributes. Psychological attributes relate to the mental equilibrium of individuals embedded in their social interactions, as robust attractors within complex dynamic processes with emergent properties, distinct from physical entities located in precise areas of the brain. Latent variables thus possess legitimacy, because the emergent properties can be conceptualized and analyzed on the sole basis of their manifestations, without exploring the upstream complex system. However, in opposition with the usual Latent Variable models, this article is in favor of the integration of a dynamic system of manifestations. Latent Variables models and Network Analysis thus appear as complementary approaches. New approaches combining Latent Network Models and Network Residuals are certainly a promising new way to infer psychological attributes, placing psychological attributes in an inter-subjective dynamic approach. Pragmatism-realism appears as the epistemological framework required if we are to use latent variables as representations of psychological attributes.

Toward a neural basis for peer-interaction: what makes peer-learning tick?

Many of the instructional practices that have been advanced as intrinsically motivating are inherent in socio-constructivist learning environments. There is now emerging scientific evidence to explain why interactive learning environments promote the intrinsic motivation to learn. The "two-body" and "second person" approaches have begun to explore the "dark matter" of social neuroscience: the intra- and inter-individual brain dynamics during social interaction. Moreover, studies indicate that when young learners are given expanded opportunities to actively and equitably participate in collaborative learning activities they experienced feelings of well-being, contentment, or even excitement. Neuroscience starts demonstrating how this naturally rewarding aspect is strongly associated with the implication of the mesolimbic dopaminergic pathway during social interaction. The production of dopamine reinforces the desire to continue the interaction, and heightens feelings of anticipation for future peer-learning activities. Here we review how cooperative learning and problem-solving interactions can bring about the "intrinsic" motivation to learn. Overall, the reported theoretical arguments and neuroscientific results have clear implications for school and organization approaches and support social constructivist perspectives.

Nursing and the new biology: towards a realist, anti-reductionist approach to nursing knowledge

As a system of knowledge, nursing has utilized a range of subjects and reconstituted them to reflect the thinking and practice of health care. Often drawn to a holistic model, nursing finds it difficult to resist the reductionist tendencies in biological and medical thinking. In this paper I will propose a relational approach to knowledge that is able to address this issue. The paper argues that biology is not characterized by one stable theory but is often a contentious topic and employs philosophically diverse models in its scientific research. Biology need not be seen as a reductionist science, but reductionism is nonetheless an important current within biological thinking. These reductionist currents can undermine nursing knowledge in four main ways. Firstly, that the conclusions drawn from reductionism go far beyond their data based on an approach that prioritizes biological explanations and eliminates others. Secondly, that the methods employed by biologists are sometimes weak, and the limitations are insufficiently acknowledged. Thirdly, that the assumptions that drive the research agenda are problematic, and finally that uncritical application of these ideas can be potentially disastrous for nursing practice. These issues are explored through an examination of the problems reductionism poses for the issue of gender, mental health, and altruism. I then propose an approach based on critical realism that adopts an anti-reductionist philosophy that utilizes the conceptual tools of emergence and a relational ontology.

Observational themes of social behavioral disturbances in frontotemporal dementia

ABSTRACT Background: Caregivers report early disturbances in social behavior among patients with behavioral variant frontotemporal dementia (bvFTD); however, there are few direct observational studies of these social behavioral disturbances. This study aimed to identify social behavioral themes in bvFTD by direct observation in naturalistic interactions. The identification of these themes can help caregivers and clinicians manage the social behavioral disturbances of this disease. Methods: Researchers observed 13 bvFTD patients in their homes and community-based settings and recorded field notes on their interpersonal interactions. A qualitative analysis of their social behavior was then conducted using ATLAS.ti application and a constant comparison method. Results: Qualitative analysis revealed the following themes: (1) diminished relational interest and initiation, indicating failure to seek social interactions; (2) lack of social synchrony/intersubjectivity, indicating an inability to establish and maintain interpersonal relationships; and (3) poor awareness and adherence to social boundaries and norms. These themes corresponded with changes from caregiver reports and behavioral scales. Conclusion: This analysis indicates that real-world observation validates the diagnostic criteria for bvFTD and increases understanding of social behavioral disturbances in this disorder. The results of this and future observational studies can highlight key areas for clinical assessment, caregiver education, and targeted interventions that enhance the management of social behavioral disturbances in bvFTD.

Fine-granularity functional interaction signatures for characterization of brain conditions

In the human brain, functional activity occurs at multiple spatial scales. Current studies on functional brain networks and their alterations in brain diseases via resting-state functional magnetic resonance imaging (rs-fMRI) are generally either at local scale (regionally confined analysis and inter-regional functional connectivity analysis) or at global scale (graph theoretic analysis). In contrast, inferring functional interaction at fine-granularity sub-network scale has not been adequately explored yet. Here our hypothesis is that functional interaction measured at fine-granularity sub-network scale can provide new insight into the neural mechanisms of neurological and psychological conditions, thus offering complementary information for healthy and diseased population classification. In this paper, we derived fine-granularity functional interaction (FGFI) signatures in subjects with Mild Cognitive Impairment (MCI) and Schizophrenia by diffusion tensor imaging (DTI) and rs-fMRI, and used patient-control classification experiments to evaluate the distinctiveness of the derived FGFI features. Our experimental results have shown that the FGFI features alone can achieve comparable classification performance compared with the commonly used inter-regional connectivity features. However, the classification performance can be substantially improved when FGFI features and inter-regional connectivity features are integrated, suggesting the complementary information achieved from the FGFI signatures.

The Interacting Body: Intra- and Interindividual Processes During Imitation

Cognition involving others, or social cognition, is often conceptualized as the solitary, third-person computation of mental states. Relatively, little attention has been paid to how individuals use their cognitive capacities at the behavioral and brain levels in social exchanges. We introduce imitation as a valuable model of dynamic social interactive phenomena and describe laboratory procedures for studying it in behavioral and neuroimaging contexts. We review research that reveals behavioral and neural synchronization of individuals engaged in imitation. In the latter case, brain activity is correlated in imitative partners, but the pattern expressed by an individual depends on the individual’s role (i.e., model or imitator). We link these findings to theoretical notions about mirroring and mentalizing brain systems and then describe how mirroring and mentalizing support the notion of prospective cognition, even in basic forms of communication such as reciprocal imitation.

The balanced mind: the variability of task-unrelated thoughts predicts error monitoring

Self-generated thoughts unrelated to ongoing activities, also known as "mind-wandering," make up a substantial portion of our daily lives. Reports of such task-unrelated thoughts (TUTs) predict both poor performance on demanding cognitive tasks and blood-oxygen-level-dependent (BOLD) activity in the default mode network (DMN). However, recent findings suggest that TUTs and the DMN can also facilitate metacognitive abilities and related behaviors. To further understand these relationships, we examined the influence of subjective intensity, ruminative quality, and variability of mind-wandering on response inhibition and monitoring, using the Error Awareness Task (EAT). We expected to replicate links between TUT and reduced inhibition, and explored whether variance in TUT would predict improved error monitoring, reflecting a capacity to balance between internal and external cognition. By analyzing BOLD responses to subjective probes and the EAT, we dissociated contributions of the DMN, executive, and salience networks to task performance. While both response inhibition and online TUT ratings modulated BOLD activity in the medial prefrontal cortex (mPFC) of the DMN, the former recruited a more dorsal area implying functional segregation. We further found that individual differences in mean TUTs strongly predicted EAT stop accuracy, while TUT variability specifically predicted levels of error awareness. Interestingly, we also observed co-activation of salience and default mode regions during error awareness, supporting a link between monitoring and TUTs. Altogether our results suggest that although TUT is detrimental to task performance, fluctuations in attention between self-generated and external task-related thought is a characteristic of individuals with greater metacognitive monitoring capacity. Achieving a balance between internally and externally oriented thought may thus aid individuals in optimizing their task performance.

Toward a second-person neuroscience

In spite of the remarkable progress made in the burgeoning field of social neuroscience, the neural mechanisms that underlie social encounters are only beginning to be studied and could – paradoxically – be seen as representing the “dark matter” of social neuroscience. Recent conceptual and empirical developments consistently indicate the need for investigations that allow the study of real-time social encounters in a truly interactive manner. This suggestion is based on the premise that social cognition is fundamentally different when we are in interaction with others rather than merely observing them. In this article, we outline the theoretical conception of a second-person approach to other minds and review evidence from neuroimaging, psychophysiological studies, and related fields to argue for the development of a second-person neuroscience, which will help neuroscience to really “go social”; this may also be relevant for our understanding of psychiatric disorders construed as disorders of social cognition.

The mind-brain relationship as a mathematical problem

This paper aims to frame certain fundamental aspects of the human mind (content and meaning of mental states) and foundational elements of brain computation (spatial and temporal patterns of neural activity) so as to enable at least in principle their integration within one and the same quantitative representation. Through the history of science, similar approaches have been instrumental to bridge other seemingly mysterious scientific phenomena, such as thermodynamics and statistical mechanics, optics and electromagnetism, or chemistry and quantum physics, among several other examples. Identifying the relevant levels of analysis is important to define proper mathematical formalisms for describing the brain and the mind, such that they could be mapped onto each other in order to explain their equivalence. Based on these premises, we overview the potential of neural connectivity to provide highly informative constraints on brain computational process. Moreover, we outline approaches for representing cognitive and emotional states geometrically with semantic maps. Next, we summarize leading theoretical framework that might serve as an explanatory bridge between neural connectivity and mental space. Furthermore, we discuss the implications of this framework for human communication and our view of reality. We conclude by analyzing the practical requirements to manage the necessary data for solving the mind-brain problem from this perspective.

Interaction vs. observation: distinctive modes of social cognition in human brain and behavior? A combined fMRI and eye-tracking study

Human cognition has usually been approached on the level of individual minds and brains, but social interaction is a challenging case. Is it best thought of as a self-contained individual cognitive process aiming at an "understanding of the other," or should it rather be approached as an collective, inter-personal process where individual cognitive components interact on a moment-to-moment basis to form coupled dynamics? In a combined fMRI and eye-tracking study we directly contrasted these models of social cognition. We found that the perception of situations affording social contingent responsiveness (e.g., someone offering or showing you an object) elicited activations in regions of the right posterior temporal sulcus and yielded greater pupil dilation corresponding to a model of coupled dynamics (joint action). In contrast, the social-cognitive perception of someone "privately" manipulating an object elicited activation in medial prefrontal cortex, the right inferior frontal gyrus and right inferior parietal lobus, regions normally associated with Theory of Mind and with the mirror neuron system. Our findings support a distinction in social cognition between social observation and social interaction, and demonstrate that simple ostensive cues may shift participants' experience, behavior, and brain activity between these modes. The identification of a distinct, interactive mode has implications for research on social cognition, both in everyday life and in clinical conditions.

Anatomical connectivity influences both intra- and inter-brain synchronizations

Recent development in diffusion spectrum brain imaging combined to functional simulation has the potential to further our understanding of how structure and dynamics are intertwined in the human brain. At the intra-individual scale, neurocomputational models have already started to uncover how the human connectome constrains the coordination of brain activity across distributed brain regions. In parallel, at the inter-individual scale, nascent social neuroscience provides a new dynamical vista of the coupling between two embodied cognitive agents. Using EEG hyperscanning to record simultaneously the brain activities of subjects during their ongoing interaction, we have previously demonstrated that behavioral synchrony correlates with the emergence of inter-brain synchronization. However, the functional meaning of such synchronization remains to be specified. Here, we use a biophysical model to quantify to what extent inter-brain synchronizations are related to the anatomical and functional similarity of the two brains in interaction. Pairs of interacting brains were numerically simulated and compared to real data. Results show a potential dynamical property of the human connectome to facilitate inter-individual synchronizations and thus may partly account for our propensity to generate dynamical couplings with others.

Introspective minds: using ALE meta-analyses to study commonalities in the neural correlates of emotional processing, social & unconstrained cognition

Previous research suggests overlap between brain regions that show task-induced deactivations and those activated during the performance of social-cognitive tasks. Here, we present results of quantitative meta-analyses of neuroimaging studies, which confirm a statistical convergence in the neural correlates of social and resting state cognition. Based on the idea that both social and unconstrained cognition might be characterized by introspective processes, which are also thought to be highly relevant for emotional experiences, a third meta-analysis was performed investigating studies on emotional processing. By using conjunction analyses across all three sets of studies, we can demonstrate significant overlap of task-related signal change in dorso-medial prefrontal and medial parietal cortex, brain regions that have, indeed, recently been linked to introspective abilities. Our findings, therefore, provide evidence for the existence of a core neural network, which shows task-related signal change during socio-emotional tasks and during resting states.

Towards a two-body neuroscience

Recent work from our interdisciplinary research group has revealed the emergence of inter-brain synchronization across multiple frequency bands during social interaction.1 Our findings result from the close collaboration between experts who study neural dynamics and developmental psychology. The initial aim of the collaboration was to combine knowledge from these two fields in order to move from a classical one-brain neuroscience towards a novel two-body approach. A new technique called hyperscanning has made it possible to study the neural activity of two individuals simultaneously. However, this advanced methodology was not sufficient in itself. What remained to be found was a way to promote real-time reciprocal social interaction between two individuals during brain recording and analyze the neural and behavioral phenomenon from an inter-individual perspective. Approaches used in infancy research to study nonverbal communication and coordination, between a mother and her child for example, have so far been poorly applied to neuroimaging experiments. We thus adapted an ecological two-body experiment inspired by the use of spontaneous imitation in preverbal infants. Numerous methodological and theoretical problems had to be overcome, ranging from the choice of a common time-unit for behavioral and brain recordings to the creation of algorithms for data processing between distant brain regions in different brains. This article will discuss the underlying issues and perspectives involved in elucidating the pathway from individual to social theories of cognition.