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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.

International audience; Residing at high altitude may lead to reduced blood oxygen saturation in the brain and altered metabolism in frontal cortical brain areas, probably due to chronic hypobaric hypoxia. These changes may underlie the increased rates of depression and suicidal behavior that have been associated with life at higher altitudes. To test the hypothesis that hypobaric hypoxia is responsible for development of mood disorders due to alterations in neurochemistry, we assessed depression-like behavior in parallel to levels of brain metabolites in rats housed at simulated altitude. 32 female Sprague Dawley rats were housed either in a hypobaric hypoxia chamber at 10,000 ft of simulated altitude for 1 week or at local conditions (4500 ft of elevation in Salt Lake City, Utah). Depression-like behavior was assessed using the forced swim test (FST) and levels of neurometabolites were estimated by in vivo proton magnetic resonance spectroscopy in the frontal cortex, the striatum and the hippocampus at baseline and after a week of exposure to hypobaric hypoxia. After hypoxia exposure the animals demonstrated increased immobility behavior and shortened latency to immobility in the FST. Elevated ratios of myo-inositol, glutamate, and the sum of myo-inositol and glycine to total creatine were observed in the frontal cortex of hypoxia treated rats. A decrease in the ratio of alanine to total creatine was also noted. This study shows that hypoxia induced alterations in frontal lobe brain metabolites, aggravated depression-like behavior and might be a factor in increased rates of psychiatric disorders observed in populations living at high altitudes.

The influence of fluctuations of atmospheric pressure on the functional state of the humans was studied during spring, autumn and winter seasons. Sensory-motor reaction time and selfreported wellbeing, activity and mood were used for evaluation of functional state. The inter-individual variations of those parameters were compared to meteorological parameters using rank order correlation and general linear model. It was found that atmospheric pressure fluctuations have a stronger negative effect with periods of 120-1200 s and 20-120 s on psychological self-assessment and with periods of 10-20 s and 5-10 s on sensory-motor reaction time than the fluctuations with other periods.

Anxiety disorders are known to be comorbid with migraine, and cortical spreading depression (CSD) is the most likely cause of the migraine aura. To search for possible correlations between susceptibility to CSD and anxiety we used the open field test in male Sprague-Dawley rats chronically treated with the preventive anti-migraine drugs valproate or riboflavin. Animals avoiding the central area of the open field chamber and those with less exploratory activity (i.e. rearing) were considered more anxious. After 4 weeks of treatment CSDs were elicited by application of 1 M KCl over the occipital cortex and the number of CSDs occurring over a 2 hour period was compared to the previously assessed open field behaviour. Higher anxiety-like behaviour was significantly correlated with a higher frequency of KCl-induced CSDs. In saline-treated animals, fewer rearings were found in animals with more frequent CSDs (R= −1.00). The duration of ambulatory episodes in the open field center correlated negatively with number of CSDs in the valproate group (R= −0.83; p

The reletaionship between the individual level of empathy and skin potential level as autonomic index of human arousal was investigated. Empathy belongs to higher psychical processes of perception and processing of the emotional information. It is considered that the empathy level is related also to the arousal level and not only to modulation of emotional reactions, due the same brain areas were shown activated for object and subject persons during processes of emotion identification and sympathy depending on type of emotions which were investigated. The aim of this work was to describe the relationship of personal empathy level (defined by psychological question­naire), subjective mood and emotional tension with the arousal of individuals (defined by an objective index of skin potential level). Palmar skin potential level was recorded for 60 volunteers before, during and after affective videostimulation. It was shown that subjective mood, emotional tension and skin potential level is statistically significant changed during stimulation meanwhile empathy level related to the dynamics of skin potential during subjects switching from one type of activity to other.

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.

Atmospheric pressure fluctuations (APF) might induce mechanical effects in the pars flaccida (PF) of the eardrum. To clarify these effects, different kinds of pressure oscillations (PO), chosen within the range of naturally occurring APF, were applied to the middle ears (ME) of gerbils. The linear displacement of the PF during a PO in the ME was measured by laser interferometry. The compliance of the PF to PO was calculated as the ratio of the amplitude of a PF oscillation to the amplitude of a PO. The displacement of the PF traced the PO in the entire range of frequencies (from 10 mHz to 200 mHz) and amplitudes (from 10 Pa to 110 Pa) applied to the ME. Moreover, the PF is found to be displaced by pressure pulses of a few pascals only using a PO with a complex shape. The differences found in the compliance of the PF due to PO with low (less than 20 Pa) and high (more than 90 Pa) amplitude point out that the mechanism of pressure regulation in the ME through the mechanical reaction of the PF in gerbil ears is better adapted to ordinary levels of natural APF than to extraordinary levels. The implications of these findings for the physiology of the human ME with respect to adaptation to natural APF are discussed.

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.

International audience; The migraine headache involves activation and central sensitization of the trigeminovascular pain pathway. The migraine aura is likely due to cortical spreading depression (CSD), a propagating wave of brief neuronal depolarization followed by prolonged inhibition. The precise link between CSD and headache remains controversial. Our objectives were to study the effect of CSD on neuronal activation in the periaqueductal grey matter (PAG), an area known to control pain and autonomic functions, and to be involved in migraine pathogenesis. Fos-immunoreactive nuclei were counted in rostral FAG and Edinger-Westphal nuclei (PAG-EWn bregma -6.5 mm), and caudal PAG (bregma -8 mm) of 17 adult male Sprague-Dawley rats after KCl-induced CSD under chloral hydrate anesthesia. Being part of a pharmacological study, six animals had received, for the preceding 4 weeks daily, intraperitoneal injections of lamotrigine (15 mg/kg), six others had been treated with saline, while five sham-operated animals served as controls. We found that the number of Fos-immunoreactive nuclei in the PAG decreased after CSD provocation. There was no difference between lamotrigine- and saline-treated animals. The number of CSDs correlated negatively with Fos-immunoreactive counts. CSD-linked inhibition of neuronal activity in the FAG might play a role in central sensitization during migraine attacks and contribute to a better understanding of the link between the aura and the headache.

International audience; Background: Alexithymia, the inability to describe one's own emotions, is linked to deficits in empathy, manifesting as a diminished capacity to recognize or understand the emotions and mental states of others. Several brain centers of autonomic control and interoception that are activated in empathy are thought to misfunction in alexithymia. We hypothesized that individual differences in autonomic changes under affective stimulation might be associated with differences in alexithymia and empathy. Methods: We studied 21 healthy volunteers, comparing their alexithymia and empathy scores with changes in their sympathetic autonomic arousal, indexed by the palmar skin potential level, during 3 tasks: playing a computer game, performing mental arithmetic, and watching a negative emotional valence video. Results: Both autonomic and subjective sense of arousal increased at the beginning of each task and then gradually subsided over the course of the task. Higher autonomic arousal at the onset of the computer game was associated with higher empathy scores, and at the onset of the negative video with higher scores for both empathy and alexithymia. Alexithymia delayed the habituation of autonomic arousal during the computer game, while the empathy score was related to a faster decline in arousal during the negative video task. Conclusions: High alexithymia and high empathy scores were linked to increased autonomic arousal at the onset of emotional stimulation, but were distinguishable in the rates of habituation of the evoked arousal. Our data provide insight into the relationships among interacting psychological traits, physiologic regulation, and the arousal dimension of emotional experience.

This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72–11.07 Pa, n = 87) compared to the low DHA (0.7–3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21–1.64, n = 229) compared to the high Rdn (1.65–7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.

This study was designed to clarify whether the pars flaccida (PF) as a flexible part of the tympanic membrane is capable of reacting to pressure oscillations (PO) with amplitudes and frequencies typical for natural atmospheric pressure fluctuations in the far infrasound frequency range (APF). If so, the PF mechanical reactions to APF might be involved in the overall physiologic regulation processes, which make organisms susceptible to APF. The displacements of the PF in response to PO were measured in vitro in ears of gerbils and rabbits by means of laser Doppler vibrometry. The index of the PF reactivity (R(a)) was determined as the ratio of the amplitude of the PF oscillations (PFO) to the amplitude of the PO. All kinds of PO applied caused PFO. The amplitude of the PFO increased when the amplitude of the PO was increased. In gerbils, a decrease in R(a) with the increase in amplitude of the PO was observed. In the range of PO lowest amplitudes (4-20 Pa) R(a) proved to be 1.4 times higher than in the range of highest amplitudes (90-105 Pa). Considering that the natural APF are usually within the range of +/-20 Pa, this fact points to an important contribution of the PF to the pressure dynamics in the middle ear (ME) of gerbils. In rabbit ears, R(a) was lower and recovery from plastic deformation was slower than in gerbils. Our findings are in line with the suggestion that the PF might play an important role in respect of adaptation to natural APF.

Pain responses can be suppressed by heterotopic continuous noxious conditioning, e.g. continuous noxious cold stimulation.

Background Migraine is characterized pathophysiologically by an interictal habituation deficit of information processing, responsible for cortical hyperresponsiveness, which normalizes during attacks [1]. Furthermore, descending pain control systems (DPCSs) can be impaired in episodic and chronic migraine [3,4]. Noninvasive neuromodulation of the cerebral cortex may be effective in migraine prophylaxis [2] including, in chronic migraine, modulation of the dorsolateral prefrontal cortex (DLPFC) that is part of the DPCSs [5].

To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration.Gastric lesions were induced in rats using restraint cold stress. To investigate the effect of oxidative and nitrosative cell stress on tyrosine phosphorylation during wound repair, total activity of protein tyrosine kinase (PTK), protein tyrosine phosphatase (PTP), antioxidant enzymes, nitric oxide synthase (NOS), 2',5'-oligoadenylate synthetase, hydroxyl radical and zinc levels were assayed in parallel.Ulcer provocation induced an immediate decrease in tyrosine kinase (40% in plasma membranes and 56% in cytosol, P0.05) and phosphatase activity (threefold in plasma membranes and 3.3-fold in cytosol), followed by 2.3-2.4-fold decrease (P0.05) in protein phosphotyrosine content in the gastric mucosa. Ulceration induced no immediate change in superoxide dismutase (SOD) activity, 30% increase (P0.05) in catalase activity, 2.3-fold inhibition (P0.05) of glutathione peroxidase, 3.3-fold increase (P0.05) in hydroxyl radical content, and 2.3-fold decrease (P0.05) in zinc level in gastric mucosa. NOS activity was three times higher in gastric mucosa cells after cold stress. Following ulceration, PTK activity increased in plasma membranes and reached a maximum on day 4 after stress (twofold increase, P0.05), but remained inhibited (1.6-3-fold decrease on days 3, 4 and 5, P0.05) in the cytosol. Tyrosine phosphatases remained inhibited both in membranes and cytosol (1.5-2.4-fold, P0.05). NOS activity remained increased on days 1, 2 and 3 (3.8-, 2.6-, 2.2-fold, respectively, P0.05). Activity of SOD increased 1.6 times (P0.05) days 4 and 5 after stress. Catalase activity normalized after day 2. Glutathione peroxidase activity and zinc level decreased (3.3- and 2-fold, respectively, P0.05) on the last day. Activity of 2',5'-oligoadenylate synthethase increased 2.8-fold (P0.05) at the beginning, and 1.6-2.3-fold (P0.05) during ulcer recuperation, and normalized on day 5, consistent with slowing of inflammation processes.These studies show diverse changes in total tyrosine kinase activity in gastric mucosa during the recovery process. Oxidative and nitrosative stress during lesion formation might lead to the observed reduction in tyrosine phosphorylation during ulceration.