It's cool to be stressed: body surface temperatures track sympathetic nervous system activation during acute stress

The use of infra-red thermography to study emotions of wild crested macaques (Macaca nigra) in their natural habitat

Infra-red thermography (IRT) has been validated across a range of taxa as a non-invasive method to quantify physiological changes (variation in skin temperature) that serve as a proxy for emotional arousal in humans and other animals. While its effectiveness has been demonstrated in captivity, its application in wild animals under natural conditions remains underexplored. This study validates IRT in wild crested macaques (Macaca nigra), observed in their natural habitat, to assess its potential for studying short-term emotions as proximate mechanisms of behavior of wild animals. Seventy-five playback experiments and predator model presentations were conducted on 14 adult females, exposing them to stimuli including affiliative grunts, contact calls, aggressive screams, alarm calls, and python models. The objectives were to: (1) evaluate whether environmental and physical factors, such as atmospheric conditions and camera-subject distance, impact thermal measurements; (2) determine whether facial skin temperature variations reliably indicate emotional arousal and valence in response to ecologically relevant stimuli; and (3) explore correlations between temperature changes and behavioral indicators of arousal, such as physical activity and self-directed behaviors. Results showed that: (1) environmental and physical factors did not significantly affect thermal measurements when following our protocol; (2) facial skin temperature changes reliably reflected the intensity of emotional arousal elicited by different stimuli; and (3) temperature variation was associated with behavioral indicators of arousal and anxiety. These findings establish IRT as a reliable tool for investigating emotion-driven skin temperature changes in wild primates, providing valuable insights into the role of short-term emotions in shaping behavior.

Crohn's disease, irritable bowel syndrome, and chronic fatigue: the importance of communication and symptom management-a case report

BACKGROUND

Crohn's disease and irritable bowel syndrome may both cause abdominal pain and diarrhea. Irritable bowel syndrome not only is an important differential diagnosis for Crohn's disease but also occurs in one out of three patients with Crohn's disease in remission in parallel. If not adequately diagnosed and treated, additional functional symptoms such as fatigue and/or muscle pain may develop, indicating a more severe course.

CASE PRESENTATION

A 64-year-old Caucasian male with long-standing, widely inactive Crohn's disease presented with persistent diarrhea, bloating, abdominal pain, general fatigue, unexplained hip pain, and frequent shivering with cold extremities, which had worsened following a gastrointestinal infection and psychological stress. A plausible explanation of his symptoms, based on an understanding of mind-body interactions, the autonomic nervous system, and temperature regulation, combined with symptom relief, was associated with rapid and sustainable improvement. After 2.5 years of follow-up, the patient is almost symptom-free.

CONCLUSIONS

This case report exemplifies the interrelation between organic (Crohn's disease) and functional diseases (irritable bowel syndrome, chronic fatigue syndrome, and somatoform pain). It further demonstrates that these connections may be overlooked in daily practice and that providing a plausible explanation in combination with symptom relief may be important for patients with functional syndromes.

Surface temperatures are influenced by handling stress independently of corticosterone levels in wild king penguins (Aptenodytes patagonicus)

Assessing the physiological stress responses of wild animals opens a window for understanding how organisms cope with environmental challenges. Since stress response is associated with changes in body temperature, the use of body surface temperature through thermal imaging could help to measure acute and chronic stress responses non-invasively. We used thermal imaging, acute handling-stress protocol and an experimental manipulation of corticosterone (the main glucocorticoid hormone in birds) levels in breeding king penguins (Aptenodytes patagonicus), to assess: 1. The potential contribution of the Hypothalamo-Pituitary-Adrenal (HPA) axis in mediating chronic and acute stress-induced changes in adult surface temperature, 2. The influence of HPA axis manipulation on parental investment through thermal imaging of eggs and brooded chicks, and 3. The impact of parental treatment on offspring thermal's response to acute handling. Maximum eye temperature (Teye) increased and minimum beak temperature (Tbeak) decreased in response to handling stress in adults, but neither basal nor stress-induced surface temperatures were significantly affected by corticosterone implant. While egg temperature was not significantly influenced by parental treatment, we found a surprising pattern for chicks: chicks brooded by the (non-implanted) partner of corticosterone-implanted individuals exhibited higher surface temperature (both Teye and Tbeak) than those brooded by glucocorticoid-implanted or control parents. Chick's response to handling in terms of surface temperature was characterized by a drop in both Teye and Tbeak independently of parental treatment. We conclude that the HPA axis seems unlikely to play a major role in determining chronic or acute changes in surface temperature in king penguins. Changes in surface temperature may primarily be mediated by the Sympathetic-Adrenal-Medullary (SAM) axis in response to stressful situations. Our experiment did not reveal a direct impact of parental HPA axis manipulation on parental investment (egg or chick temperature), but a potential influence on the partner's brooding behaviour.

ENDOCANNABINOID SYSTEM IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS MODULATES AUTONOMIC AND CARDIOVASCULAR CHANGES BUT NOT VASOPRESSIN RESPONSE IN A RAT HEMORRHAGIC SHOCK MODEL

ABSTRACT

We evaluated the participation of the endocannabinoid system in the paraventricular nucleus of the hypothalamus (PVN) on the cardiovascular, autonomic, and plasma vasopressin (AVP) responses evoked by hemorrhagic shock in rats. For this, the PVN was bilaterally treated with either vehicle, the selective cannabinoid receptor type 1 antagonist AM251, the selective fatty acid amide hydrolase amide enzyme inhibitor URB597, the selective monoacylglycerol-lipase enzyme inhibitor JZL184, or the selective transient receptor potential vanilloid type 1 antagonist capsazepine. We evaluated changes on arterial pressure, heart rate, tail skin temperature (ST), and plasma AVP responses induced by bleeding, which started 10 min after PVN treatment. We observed that bilateral microinjection of AM251 into the PVN reduced the hypotension during the hemorrhage and prevented the return of blood pressure to baseline values in the posthemorrhagic period. Inhibition of local 2-arachidonoylglycerol metabolism by PVN treatment with JZL184 induced similar effects in relation to those observed in AM251-treated animals. Inhibition of local anandamide metabolism via PVN treatment with URB597 decreased the depressor effect and ST drop induced by the hemorrhagic stimulus. Bilateral microinjection of capsazepine mitigated the fall in blood pressure and ST. None of the PVN treatments altered the increased plasma concentration of AVP and tachycardia induced by hemorrhage. Taken together, present results suggest that endocannabinoid neurotransmission within the PVN plays a prominent role in cardiovascular and autonomic, but not neuroendocrine, responses evoked by hemorrhage.