The neural bases of human cognition are studied in their most integrated aspects, such as mind wandering and mindfulness meditation, the ability to infer others’ emotions or the emergence of symbolic thought. To do this, we will use two innovative approaches, the analysis of resting-state brain networks and neuroarchaeology.
Understanding integrated cognition from resting-state brain activity
Intrinsic functional connectivity networks, known as “resting-state networks”, correspond to groups of regions whose activity is synchronous while one lets one’s thoughts flow freely. These resting-state networks are not randomly organized, but closely resemble existing cognitive function networks such as spatial attention orientation, language or action. It is therefore possible, on the basis of a simple acquisition of functional magnetic resonance imaging (fMRI) data lasting about ten minutes, to identify all the functional brain networks of a person even though he or she does not perform any particular cognitive task.
A first objective consists in characterizing the modifications of the “default mode network”, and its relationships with other rest networks, according to the content and form of thoughts (emotional, memory, image, language, …etc).
Within the broad repertoire of cognitive functions, mental activity which operates on representations (sensory or motor mental images, inner language…) is singularly developed in the human species. The particularity of this activity is that it does not depend on information directly from the external environment and does not necessarily lead to action on the latter. Unlike other species, humans have the ability to carry out this mental activity without being goal-oriented. This mind-wandering combines an evocation and contemplation of past events, in the form of mental images or comments, with the imagination and planning of future events, whether or not they have a chance to happen. This psychic state corresponds to half of our awakened mental activity.
Resting-state networks are directly modulated by the variability of the nature of mind-wandering, in relation to the person’s cognitive and emotional skills. At the cerebral level, mind-wandering results in the activation of a specific resting-state network, called the “default mode network”.
The neural bases of mind-wandering are studied from the fMRI measurement of resting brain activity. Using a computerized questionnaire developed in the laboratory, thoughts that occurred during this period are collected. In this way, the emotional tonality of thoughts, their prospective or retrospective nature, their imagery or verbal form can be collected. The analysis of neuroimaging data combined with these qualitative data makes it possible to relate mental content and brain activity within the “default mode network” and to better characterize the role of the different brain regions that make it up.
A second objective is to study the link between stress reduction through mindfulness meditation training and changes in resting networks.
Mindfulness is defined as intentionally paying attention to the present moment without judging one’s physical feelings or the content of one’s thoughts. Its application as a health care service appeared in the 1970s with the MBSR (Mindfulness Based Stress Reduction) program, a program that takes place in groups over a period of 8 weeks. MBSR was first developed to reduce anxiety and depressive symptoms in the clinical population but also in individuals free of pathologies. It is assumed that the improvement in emotional regulation it brings, is at the root of many of the benefits of mindfulness meditation. Emotional regulation refers to strategies that influence the nature of the emotions that occur, when and how long they occur, and how these emotions are experienced and expressed.
In our research program, a population known to be under stress, composed of medical and surgical residents, will benefit from an MBSR program. A measurement of intrinsic functional connectivity is performed before and after the MBSR program. We assume that emotional regulation, also measured before and after the program, is improved by the MBSR program and that these improvements are associated with changes in the “default mode network”, particularly for the brain regions involved in emotional regulation (anterior cingulate cortex, medial frontal cortex, amygdala). In addition, these changes in brain connectivity are related to different cognitive and emotional states (anxiety, burnout, attention processes, decision-making, empathy) measured using questionnaires and/or psychometric tests.
A third objective is to find a marker of the ability to infer others’ emotions in resting state networks.
The human being is eminently social and communicative and his abilities to infer the intentions of others (theory of the mind) are particularly developed. The ability to adopt the point of view of others is in constant interaction with the emotional system and allows for empathy and compassion. Like cognitive functioning, the ability to discriminate others’ emotions is variable from one individual to another, and the neural bases of the variability of this aspect of emotional intelligence remain largely unknown.
Indeed, while emotional skills interact with cognitive skills, the neural bases of the variability of the ability to recognize emotions have still been little explored,. A particularly important expression of this strong proximity between emotional and cognitive skills is seen in the fact that neural networks of emotion and their modifications are involved in many developmental (autism) and psychiatric (depression, anxiety) pathologies that are also characterized by cognitive disorders.
To characterize the relationships between the ability to infer emotions and intrinsic functional connectivity, we conduct a detailed characterization of emotional competencies evaluated by the Geneva Emotion Recognition Test (GERT).
These skills are then related to the inter-individual variability of connections between resting state networks. It is thus possible to establish how the connectivity of regions known for their involvement in emotional behaviour varies according to the ability to recognize the emotions of others.
We are particularly interested in the connectivity of the amygdala, hippocampus, insula and frontal regions that are altered in certain psychiatric disorders such as autism and schizophrenia. We also study how their connectivity is modulated by psychological states such as anxiety, depression, impulsivity, self-esteem…
Understanding the emergence of symbolic thought
At the beginning of 2019, some twenty worldwide scientific publications concerned the new field of study of neuroarchaeology. This disciplinary approach between neuroimaging and archaeology makes it possible to study brain functionning in its evolutionary aspects. With the expertise of a team of archaeologists from the PACEA laboratory (laboratory “from Prehistory to the Present: Culture, Environment and Anthropology”, UMR 5199) specialized in the study of the emergence of behaviour and symbolic productions in the Paleolithic, we are developing a totally pioneering approach in understanding the emergence of symbolic thought in human beings.
How does the brain treat the abstract patterns produced by our ancestors?
The objective is to identify the neural bases of the cognitive skills necessary for the production and recognition of symbolic representations with fMRI techniques.
The intellectual capacities of modern man are the result of an evolution of cognitive functions that have led to the emergence of behaviours that distinguish him from other species. While this evolution was long considered to have been abrupt and relatively recent, many archaeologists now argue for a much older origin, which involved human species that have now disappeared. This is particularly the case of symbolic thought, which seems to be expressed through the production of abstract engravings, the oldest and most recently discovered would date back several hundred thousand years. From rock paintings to the invention of writing 5000 years ago, graphic, figurative or symbolic production is a major aspect of human cognitive abilities. The discovery of abstract engravings dating back 500,000 years ago suggests that this activity not only interested the first specimens of Homo sapiens but also hominids belonging to other species such as Homo erectus and Homo neanderthalensis. The “ArchéoNeuro” research project seeks to provide neural support for the hypothesis proposed by anthropologists that these abstract motifs mark the emergence of symbolic production in the behavioural repertoire of hominines.
A difficulty in this approach is that it concerns modern humans who are not familiar with these engravings, unlike our ancestors who produced them. This is why, in an extension of this work, the brain response of archaeologists as they perceive these engravings is collected., making it possible to establish brain regions involved in the perception and recognition of these traces by experts.
Is the culturalized body perceived as a symbolic object?
What about the perception of the culturalized body, that is, the body carrying communication devices such as ornaments and drawings. Could it be perceived as a symbolic object? At the cerebral level, faces and body parts are treated by specialized visual regions. To identify the transition from a “simple” anatomical perception to a symbolic and social perception, we study in fMRI how the visual processing of body paintings and ornaments alters the neural networks related to the recognition of faces and different body parts.