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International audience; The PeriPersonal Space (PPS) has been defined as the space surrounding the body, where physical interactions with elements of the environment take place. As our world is social in nature, recent evidence revealed the complex modulation of social factors onto PPS representation. In light of the growing interest in the field, in this review we take a close look at the experimental approaches undertaken to assess the impact of social factors onto PPS representation. Our social world also influences the personal space (PS), a concept stemming from social psychology, defined as the space we keep between us and others to avoid discomfort. Here we analytically compare PPS and PS with the aim of understanding if and how they relate to each other. At the behavioral level, the multiplicity of experimental methodologies, whether well-established or novel, lead to somewhat divergent results and interpretations. Beyond behavior, we review physiological and neural signatures of PPS representation to discuss how interoceptive signals could contribute to PPS representation, as well as how these internal signals could shape the neural responses of PPS representation. In particular, by merging exteroceptive information from the environment and internal signals that come from the body, PPS may promote an integrated representation of the self, as distinct from the environment and the others. We put forward that integrating internal and external signals in the brain for perception of proximal environmental stimuli may also provide us with a better understanding of the processes at play during social interactions. Adopting such an integrative stance may offer novel insights about PPS representation in a social world. Finally, we discuss possible links between PPS research and social cognition, a link that may contribute to the understanding of intentions and feelings of others around us and promote appropriate social interactions.

International audience; Background/objectives: While excessive food consumption represents a key factor in the development of obesity, the underlying mechanisms are still unclear. Ghrelin, a gut-brain hormone involved in the regulation of appetite, is impaired in obesity. In addition to its role in eating behavior, this hormone was shown to affect brain regions controlling reward, including the striatum and prefrontal cortex, and there is strong evidence of impaired reward processing in obesity. The present study investigated the possibility that disrupted reward-related brain activity in obesity relates to ghrelin deficiency.Subjects/methods: Fifteen severely obese subjects (BMI > 35 kg/m(2)) and fifteen healthy non-obese control subjects (BMI < 30 kg/m(2)) were recruited. A guessing-task paradigm, previously shown to activate the ventral striatum, was used to assess reward-related brain neural activity by functional magnetic resonance imaging (fMRI). Fasting blood samples were collected for the measurement of circulating ghrelin.Results: Significant activations in the ventral striatum, ventromedial prefrontal cortex and extrastriate visual cortex were elicited by the fMRI task in both obese and control subjects. In addition, greater reward-related activations were present in the dorsolateral prefrontal cortex, and precuneus/posterior cingulate of obese subjects compared to controls. Obese subjects exhibited longer choice times after repeated reward and lower circulating ghrelin levels than lean controls. Reduced ghrelin levels significantly predicted slower post-reward choices and reward-related hyperactivity in dorsolateral prefrontal cortices in obese subjects.Conclusion: This study provides evidence of association between circulating ghrelin and reward-related brain activity in obesity and encourages further exploration of the role of ghrelin system in altered eating behavior in obesity.

The objects located straight-ahead of the body are preferentially processed by the visual system. They are more rapidly detected and evoke stronger BOLD responses in early visual areas than elements that are retinotopically identical but located at eccentric spatial positions. To characterize the dynamics of the underlying neural mechanisms, we recorded in 29 subjects the EEG responses to peripheral targets differing solely by their locations with respect to the body. Straight-ahead stimuli led to stronger responses than eccentric stimuli for several components whose latencies ranged between 70 and 350 ms after stimulus onset. The earliest effects were found at 70 ms for a component that originates from occipital areas, the contralateral P1. To determine whether the straight-ahead direction affects primary visual cortex responses, we performed an additional experiment (n = 29) specifically designed to generate two robust components, the C1 and C2, whose cortical origins are constrained within areas V1, V2 and V3. Our analyses confirmed all the results of the first experiment and also revealed that the C2 amplitude between 130 and 160 ms after stimulus onset was significantly stronger for straight-ahead stimuli. A frequency analysis of the pre-stimulus baseline revealed that gaze-driven alterations in the visual hemi-field containing the straight-ahead direction were associated with a decrease in alpha power in the contralateral hemisphere, suggesting the implication of specific neural modulations before stimulus onset. Altogether, our EEG data demonstrate that preferential responses to the straight-ahead direction can be detected in the visual cortex as early as about 70 ms after stimulus onset. Electronic supplementary material The online version of this article (10.1007/s00429-019-01988-5) contains supplementary material, which is available to authorized users.

Introduction In a previous study exploring central pain modulation with heterotopic stimuli in healthy volunteers, we found that transitions between sustained noxious and innocuous thermal stimulations on the foot activated the “salience matrix”. Knowing that central sensory processing is abnormal in migraine, we searched in the present study for possible abnormalities of these salient transitional responses in different forms of migraine and at different time points of the migraine cycle. Methods Participants of both sexes, mostly females, took part in a conditioned pain modulation experiment: Migraineurs between (n = 14) and during attacks (n = 5), chronic migraine patients with medication overuse headache (n = 7) and healthy volunteers (n = 24). To evoke the salience response, continuous noxious cold or innocuous warm stimulations were alternatively applied on the right foot. Cerebral blood oxygenation level dependent responses were recorded with fMRI. Results Switching between the two stimulations caused a significant transition response in the “salience matrix” in all subject groups (effect of the condition). Moreover, some group effects appeared on subsequent post-hoc analyses. Augmented transitional blood oxygenation level dependent responses in the motor cortex and superior temporal sulcus were found in two patient groups compared to healthy controls: chronic migraine with medication overuse headache patients and migraineurs recorded during an attack. In chronic migraine with medication overuse headache patients, salience-related responses were moreover greater in the premotor cortex, supplementary motor area, lingual gyrus and dorso-medial prefrontal cortex and other “salience matrix” areas, such as the anterior cingulate and primary somatosensory cortices. Conclusion This study shows salience-related hyperactivation of affective and motor control areas in chronic migraine with medication overuse headache patients and, to a lesser extent, in episodic migraine patients during an attack. The greater extension of exaggerated blood oxygenation level dependent responses to unspecific salient stimuli in chronic migraine with medication overuse headache than during a migraine attack could be relevant for headache chronification.

Статичні електричні потенціали (СТЕП) у біологічно активних зонах шкіри (БАЗ) відображають рівень фонової активації мозкових структур і рівень психічного стресу. Мета дослідження – виявити зв’язки СТЕП у симетричних біологічно активних зонах шкіри обличчя з рівнем емоційного вигорання в студентів. Виявлена зворотна кореляція між формуванням емоційного вигорання й рівнем електричного потенціалу шкіри в правих білявушних БАЗ (r s = - .43, р < .05) відносно долоні як референтної ділянки. Знайдено кореляції між розвитком стадії опору вигоранню та фоновими СТЕП у правих і лівих лобних БАЗ (відповідно, r s = - .44 і r s = - .47, р < .05) і СТЕП у лівій лобній БАЗ після впливу негативних кадрів телевізійних новин (r s = - .50, р < .01). Це вказує на те, що формування емоційного вигорання знижує передпускову (до початку експерименту) емоційну напругу й відповідь, тобто силу реакції, на «зовнішні» негативні емоційні стимули. Отримані дані свідчать про те, що електродермальні потенціали можуть служити об’єктивними критеріями формування емоційного вигорання. Emotional burnout syndrome sees as a reaction to stress in interpersonal communication in the form of full or partial shutdown of emotions. V. Boyko dynamic model of burnout that was used as basis of this study classified in 3 stages in accordance with the mechanism of stress. There exist 3 phases: Anxiety Tension, Resistance, and Exhaustion. Strengthening of stressful factors in everyday life triggers the formation of emotional burnout (Anxiety Tension stage). The respondents with «Resistance» stage begin to economize emotion and characterize by emotional and moral disorientation. The central nervous activity reduction and the fall in energy tone are evident in the «Exhaustion» stage. Inadequate reactions to the different stimulus are associated with the hyperreactivity of the nervous system. The skin potential level (SPL) of facial biologically active zones (BAZs) reflects the level of background activation of brain structures and the level of mental stress. That is why skin potential level reflects the formation of emotional burnout. Purpose. The aim of the study was to detect the changes of SPL in symmetric biologically active zones of face skin (frontal, superciliary, paranasal, temporal, periotic and postaural) depending on the level of emotional burnout. Methods. 31 healthy volunteers (women and men) – first-third year students (Mage = 19.07, SD = 1.91 years, from 17 to 23 years) were recruited from the Taras Shevchenko National University of Kyiv, Educational and Scientific Centre «Institute of Biology and Medicine» and Faculty of Psychology, and participated for course credit during preexam period. Skin potential level was recorded via nonpolarizable silver electrodes from the symmetric biologically active zones of face skin (frontal, superciliary, paranasal, temporal, periotic and postaural) with the palm as a reference area. To determine the stages of burnout we used the Boyko «Syndrome of emotional burnout» test adapted for students by Tukaiev and Vasheka. The value of each of Burnout stages was measured on a scale from 0 to 120 points: 0 to 36 points – the stage was not formed, 37 to 60 points – the stage was under development, 61 to 120 points – the stage was formed. The Speerman rank test was carried out for the correlation analysis. Results. Inverse correlation was found between the formation of emotional burnout and the skin potential level in right periotic BAZ (parotid BAZ) (r = - .43, p < .05). We found correlation between the development of the Resistance stage of burnout and background SPL in the right and left frontal BAZ (respectively r = - .44 and r = - .47, p < .05) and SPL in the left frontal BAZ after the exposure of negative frames of documentaries (r = - .50, p < .01). Conclusion. Our data indicates that the formation of burnout reduced the prestarting initial emotional tension and response strength to «external» negative emotional stimuli. It indicates that electrodermal potentials can serve as objective criteria of formation of emotional burnout.

International audience; The mechanisms underlying conditioned pain modulation (CPM) are multifaceted. We searched for a link between individual differences in prefrontal cortex activity during multi-trial heterotopic noxious cold conditioning and modulation of the cerebral response to phasic heat pain. In 24 healthy female subjects, we conditioned laser heat stimuli to the left hand by applying alternatively ice-cold or lukewarm compresses to the right foot. We compared pain ratings with cerebral fMRI BOLD responses. We also analyzed the relation between CPM and BOLD changes produced by the heterotopic cold conditioning itself, as well as the impact of anxiety and habituation of cold-pain ratings. Specific cerebral activation was identified in precuneus and left posterior insula/SII, respectively, during early and sustained phases of cold application. During cold conditioning, laser pain decreased (n=7), increased (n=10) or stayed unchanged (n=7). At the individual level, the psychophysical effect was directly proportional to the cold-induced modulation of the laser-induced BOLD response in left posterior insula/SII. The latter correlated with the BOLD response recorded 80s earlier during the initial 10-s phase of cold application in anterior cingulate, orbitofrontal and lateral prefrontal cortices. High anxiety and habituation of cold pain were associated with greater laser heat-induced pain during heterotopic cold stimulation. The habituation was also linked to the early cold-induced orbitofrontal responses. We conclude that individual differences in conditioned pain modulation are related to different levels of prefrontal cortical activation by the early part of the conditioning stimulus, possibly due to different levels in trait anxiety.