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Unpredictable stressors have been used to assess the effect of stress on energy metabolism in obesity-prone (C57BL6J) and obesity-resistant (AJ) mice. Mice were exposed for 25 days to a stress protocol. Both strains of mice were divided into groups of control and stressed mice, which had access to either a high-fat or a high-carbohydrate diet. Twenty-four hours after the last session of stress, mice were sacrificed for blood and brain collections. Insulin, corticosterone, and glucose concentrations in plasma were measured, and expressions of corticotropin-releasing factor (CRF) in the paraventricular hypothalamic nucleus (PVH) and the central amygdala (CeA) were determined by in situ hybridization. Stressed mice in all groups had lower body fat contents than control mice, and all mice fed with the high-fat diet had heavier retroperitoneal and inguinal fat pads than mice fed with carbohydrate. CRF mRNA level in the CeA was lower in B6 mice than in AJ mice. Stressed mice had a lower expression of CRF in the CeA than control mice. In conclusion, chronic stress reduces body fat content in obesity-prone as well as in obesity-resistant mice.

Control theory is concerned mainly with the treatment of signals. This article takes into account that living beings not only treat information, but they are open systems traversed by flows of energy and mass. A block diagram of the regulation process is proposed, taking into account this fundamental difference between engineered and living systems. This new diagram is used to describe the stability of body weight. The ponderostat is hypothesized to work as a regulation of blood glucocorticoids with a hypothalamic set-point related to CRH concentration.

A hypothesis is presented according to which structure of consciousness is quadri-dimensional. The four dimensions are duration, quality, intensity, and affectivity. One may reach this conclusion by introspection alone, or by deduction along the following steps: (1) consciousness should be examined from the point of view of evolutionary psychology; (2) this leads to the following postulate--consciousness evolved from sensation; (3) the postulate entails a corollary-- consciousness has kept the quadri-dimensional structure of sensation. The above postulate could explain the phylogenetic origin of pleasure as the common currency, and in turn the tradeoffs for access to the behavioral final common path. It would also entail that joy is the transient sign of a useful conscious event, whereas happiness is the indifferent experience of a satisfied mind.

The skin of the face is reputed not to vasoconstrict in response to cold stress because the face skin temperature remains steady during hypothermia. The purpose of the present work was to measure the vasomotor response of the human face to whole-body hypothermia, and to compare it with hyperthermia. Six male subjects were immersed in cold and in warm water to obtain the two conditions. Skin blood flow, evaporation, and skin temperature (Tsk) were recorded in three loci of the face, the forehead, the infra orbital area, and the cheek. Tympanic (Tty) and oesophageal (Toes) temperatures were also recorded during the different thermal states. Normothermic measurements served as control. Blood flow was recorded with a laser-Doppler flowmeter, evaporation measured with an evaporimeter. Face Tsk remained stable between normo-, hypo-, and hyperthermia. Facial blood flow, however, did not follow the same pattern. The facial blood flow remained at minimal vasoconstricted level when the subjects' condition was changed from normo- to hypothermia. When the condition changed from hypo- to hyperthermia a 3 to 9-fold increase in the blood flow was recorded. From these results it was concluded that a vasoconstriction seems to be the general vasomotor state in the face during normothermia.

Juvenile green iguanas were placed in a situation of conflict between two motivations: a thermoregulatory drive and the attraction of a palatable bait. To be able to reach the bait (lettuce), they had to leave a warm refuge, provided with standard food, and venture into a cold environment. In experiment 1 the time interval between sessions with bait, ranging from 1 to 8 days, had no effect on the duration of stay on the bait. This result shows that the lettuce was not a necessary food, deprivation of which would have had to be compensated for. In experiment 2 as the ambient temperature at the bait decreased the lizards spent less time feeding on lettuce, and they visited the bait less frequently. This result shows that the lizards traded off the palatability of the bait with the disadvantage of the cold. These findings support the hypothesis that a common currency makes it possible for lizards to compare two sensory modalities.

An increase of body temperatures by about 1.0 °C in humans at rest increases the ventilation rate (8). Recently in humans we reported that passive hyperthermia, above thresholds of tympanic (Tty) and esophageal temperatures (Tes), induced an increase in ventilation rate that was proportional to the increase in core temperatures (4). This increased ventilation during hyperthermia leads to a small but significant increase respiratory heat loss (10) and this thermally induced hyperventilation in humans (3), as it does in other species (1), appears to be a thermolytic mechanism that could be contributing to selective brain cooling (SBC). SBC in hyperthermic humans occurs when the Tty is lower than Tes. During exercise, however, the relationship between ventilation and core temperatures is not so clear.

Fever as a condition of increased body heat associated with disease in humans has been known since Antiquity, but the notion that there is a physiological thermostat, which is reset during fever is generally attributed to Liebermeister (1875). Fever, being a long recognized symptom in human disease, has been studied mostly in humans and in other endothermic vertebrates (DuBois 1948; Atkins and Bodel 1979). The capacity to regulate body temperature, however, is not limited to endothermic mammals and birds. That reptiles can modify their core temperature by several degrees through behavioral means has been known since the beginning of this century (Krehl and Soetbeer 1899; Langlois 1902) but it has been shown only quite recently (Vaughan et al. 1974) that an ectothermic reptile, Dipsosaurus dorsalis, will select a warmer environment after being injected with pyrogens, and thereby raise its body temperature. This was then shown to occur also in fish (Reynolds et al. 1976). In febrile humans (Cabanac 1969; Guieu and Hellon 1980) and dogs (Cabanac et al. 1970) changes in behavior are likewise used to reduce heat loss, and thereby to defend an elevated thermoregulatory set-point.

Several historians thing that the legendary runner who brought the new of the Greek victory over the Persian army landed at Marathon, and who died after delivering his message, was only a legend because Herodotus did not mention the ruuner in his relation of the battle. However, other historians from Antiquy mentioned him and the local tradition was strong enough for the local organizers to accept a marathon race in Athen's first modern Olympic games. In addition, collapse and death, although rare, are not exceptional in long distance foot and bicycle races, especially in hot and humid weather. A hypothesis, based on experimental results obtained in healthy subjects, is presented here to explain these deaths as well as that of the legendary runner. It is proposed that the death might have been caused by sudded brain hyperthermia resulting from a loss of selective brain cooling when the patient stoping moving, thus ending the convective-evaporative heat loss from the head. Understanding its pathogeny may help prevent this dramatic accident in the future

Ten adult men were exposed to four different conditions of noise—low noise (70 dB), loud noise (90 dB), loud music (90 dB) and a silence control—while they tasted sweet or salty solutions. In the first experiment, they rated the pleasure/displeasure aroused by ten gustatory stimuli (five sucrose and five sodium chloride from 0.15 to 2.35 m /l). The median affective rating for sucrose was significantly higher in loud noise and with loud music. No change was observed for salt. In the second experiment, the subjects were invited to mix solutions in order to obtain the most pleasant concentration of sucrose or sodium chloride. Subjects' preferred concentrations of sucrose or sodium chloride did not vary with auditory conditions.

Rats were trained to feed 2 h daily. Each rat was presented during three 10-day-long alimentary periods with each of the following diets: control (C), low calorie (L), and high calorie (H). The food was placed at an ambient temperature of -15 degrees C at 16 m from a warm refuge. It was found that the rats ingested similar amounts of food, regardless of energy density of the diet, and therefore did not compensate for variations in the caloric density of a diet. This was despite the recognition of a novel diet on the first day of its presentation as manifested by a change in rats' meal pattern. L diet was eaten slowly, suggesting that it was less palatable than the C or H diets. The results suggest that the rat placed in a closed economy with only short-term access to food imposed by a hostile environment does not adjust its food intake in accordance with energy value of the food. Its momentary food intake appears to be controlled by the gustatory properties of the food.

The mammalian brain has poor tolerance to increased temperature. However, when body core temperature rises during exercise or heat stress, the temperature of the brain can remain at a lower level, somewhat independent of the rest of the body. In several mammals the cooling of the brain is related to anatomically well-defined countercurrent heat exchangers. Humans lack these distinct anatomic structures, but significant cooling of the brain can nevertheless occur. Such selective cooling of the brain may have important medical implicantions.

A matrix of 25 gustatory stimuli combined five sucrose concentrations (0.15 to 2.35 mole/l) with five temperatures (10 to 50 degrees C) or sournesses (pH 1.8 to 5.7). On four different days at the same time of day ten healthy young men served as subjects. Sweet pleasure/displeasure vs. temperature pleasure/displeasure was studied in four subjects and sweet pleasure/displeasure vs. sourness pleasure/displeasure in six subjects. Throughout the first session the 25 stimuli were presented for 5 s each and the subject gave a magnitude estimate of his pleasure or displeasure in response to one dimension of the matrix (e.g. sweetness) regardless of the other. Similarly, throughout the second session, the same stimuli were presented and the subject rated his pleasure or displeasure in response to the second dimension of the matrix (e.g. sourness or temperature) regardless of the first. For the third session however, the subject himself was invited to mix samples, this to allow a behavioural choice in one dimension of the matrix the other being imposed (e.g. he could mix sucrose and water ad libitum for five imposed temperatures). For the last session the subject could adjust the previously imposed dimension, the other previously adjustable dimension being now imposed (e.g. he could modify temperature for five imposed sucrose concentrations). The results of the first two sessions showed that pleasure/displeasure resulted from a two-dimensional combination of the taste modalities offered. The results of the last two sessions showed that the subjects tended to maximize their sensory pleasure. The operant choices coincided with the ratings obtained in the first two sessions. Whether a dimension of the matrix was imposed or operantly adjustable made no difference on the results; the subjects tended to maximize sensory pleasure in the imposed dimension as well as in the adjustable dimension. The subjects therefore maximized their pleasure in the two-dimensional space offered.

In response to a stimulus, a sensation is tridimensional: qualitative, quantitative, and affective. The affective part of sensation, pleasure or displeasure, depends on the qualities of the stimulus. Within a narrow range of intensity, chemical, thermal, and mechanical stimuli are able to arouse pleasure. In addition, pleasure depends on the internal state of the subject. This is easily observed in the case of temperature: pleasure is aroused by a warm stimulus in a hypothermic subject and by a cold stimulus in a hyperthermic subject. This property of a given stimulus to arouse pleasure or displeasure according to the internal state of the subject is termed alliethesia. Alliesthesia is also produced by chemical and mechanical stimuli. Acquired preferences or aversions for alimentary stimuli represent a case of alliesthesia. In the same way, the capacity of any indifferent stimulus to become rewarding, or punishing, by association with some reward or punishment, is also a case of alliethesia. In all cases, pleasure is a sign of a stimulus useful to the subject; displeasure a sign of danger. Usefulness and danger are judged by the central nervous system with reference to homeostasis and the set point of the implied regulation. Pleasure and displeasure thus appear to motivate useful behaviors.

The postprandial changes in resting metabolic rate (RMR) were measured in eight subjects after the ingestion of 735 kcal taken in the form of a meal or fed by stomach tube. A much larger increase in RMR was found with meal feeding (MF) as compared with tube feeding (TF). Measurements of respiratory quotient (RQ) indicated that the increase in RMR with MF is related to increased glucose oxidation, whereas with TF it is possibly explained primarily by the cost of energy storing. Determination of plasma norepinephrine (NE) indicated that the sympathetic nervous system is activated by MF but not by TF. Similarly, plasma glucose and insulin determinations have shown that the secretion of insulin is increased during food ingestion but only with the MF situation. Thus in the 30 min after the beginning of the meal, an increased glucose oxidation was observed that is possibly related to an enhanced NE and insulin secretion; such effects were nonexistent in the TF situation. These results would not substantiate the notion of the specific dynamic action of food and would indicate that independent of the composition of the ingested nutrients, the postprandial increase in RMR is also influenced by sensory and cognitive stimulations.

Gryllus bimaculatus were infected with an intracellular prokaryote, Rickettsiella grylli, then reared either at fixed temperatures or in a temperature gradient (22-36 degrees C) where they could select the temperature they preferred. Only 50% of the infected insects reared at 28 degrees C or less survived after 20 days, against 75% of those reared at 30 degrees C or more and 90% of those in the temperature gradient. Examination of smears of insect tissue showed that all (100%) of the infected insects reared between 23 and 29 degrees C had developed a strong rickettsial infection. Only 20% of the insects reared in a gradient of temperature showed signs of strong infection. Body temperature of crickets in the temperature gradient, recorded using thin thermocouples, was 33 degrees C in infected crickets and 26.6 degrees C in controls. It is concluded that thermoregulatory behavior was used by the insects to produce a fever when infected with Rickettsiella grylli. This protected them and increased survival capacity.

The influence of water temperature on intake and affective ratings was explored in human subjects. Dehydration whether by profuse sweating (body weight loss: 289 +/- 11 g, N = 20) or mountain climbing (body weight loss: 1660 +/- 58 g, N = 20) resulted in the same intake. Maximal intake was observed for water at 15 degrees C with respectively 199.0 +/- 17.0 ml and 222.7 +/- 17.4 ml. Colder and warmer water was ingested to a lesser extent. When 20 subjects were allowed to mix water to their preferred temperature, they chose 14.9 +/- 1 degree C and drunk 211.0 +/- 19.5 ml. Votes on a pleasure/displeasure scale increased from 50 degrees C to 0 degree C. Cold water was therefore both more pleasureable and less drunk. Dehydration resulted in a negative alliesthesia for warm water. Positive alliesthesia for cold water was probably the result of hyperthermia rather than dehydration.

1. Scorpions Buthus occitanus and Androctonus australis were placed in a temperature gradient where they could select their thermopreferendum. Intrathoracic temperature was recorded continuously. 2. Both species selected 24.8 +/- 1.0 degrees C as their preferred body temperature. No nycthemeral cycle of preference was observed in the experimental conditions. Saline injection did not modify this thermopreferendum. 3. Prostaglandin E1 (PGE1) produced a fever. Duration and magnitude of fevers were related to PGE1 doses in a bell-shaped curve. The longest and highest fevers were obtained with 4 microgram . g-1 PGE1. 4. These results show that there is an ability to produce fever and, thus, indirectly, that there is a set point in body temperature regulation in arthropods, among the oldest known terrestrial animals.

1. Four human subjects were rendered hyperthermic and hypothermic by immersion in warm and cool water, at 02.00, 08.00, 14.00 and 20.00 hr. Bath and oesophageal temperatures and pulse rate were recorded. Temperature preference was determined by operant behaviour and vote. The core temperature set-point for behavioural thermoregulation was estimated from the behavioural results. 2. The results are in accord with those of previous studies of the nyethemeral cycling of autonomic responsiveness to heat and cold with a heating up phase before noon and a cooling down phase during the early night. 3. Subjective sensations and behavioural responses were also found to follow a nycthemeral cycle with a minimum before noon and a maximum at 20.00 hr. 4. The core temperature set point was 0-7 degrees C higher after noon than before noon with a small phase advance from resting core temperature. This result suggests that the nycthemeral cyclic change in body temperature is due to a nycthemeral cyclic change in the set-point near to which body temperature is kept by both autonomic and behavioural thermoregulatory responses.

Rats were chronically implanted with a hypothalamic thermode. After recovery the thermode was heated and the rats were exposed to 4 ambient temperatures (Ta) 20, 30, 35 and 40 °C. For each Ta they were subjected to 3 conditions: (1) they could press a bar which provided them with a cool wind; (2) they could press a bar which cooled the hypothalamic thermode; and (3) both bars were active and the rat could press either one. Skin, hypothalamic, and rectal temperatures were recorded at the same time. The results indicate that when rats had either only or by choice access to the lever that cooled their hypothalamus, they used it in such a way as to prevent their hypothalamus from overheating. A lower priority was given to the maintenance of skin temperature.

1. Subcutaneous injection of capsaicin (6–11 mg, or 21–66 mg cumulative), permanently reduced the capacity of rats to withstand a hot environment, as described by Jancso-Gabor et al. (1970). 2. The treated rats thermoregulatory behaviour was not different from that of control rats, both in hot and cold environments. 3. Saliva secretion was decreased in a hot environment, and the weight of the submaxillary glands was reduced in capsaicinized rats. 4. It is concluded that hyperthermia present in treated rats when subjected to a warm environment is not due to a disruption ofsensu stricto temperature regulation, but rather to a decreased salivary secretion. Whether this decrease has a central or a peripheral origin is not known.

Juvenile Tupinambis teguixin were placed in a conflicting situation: feeding vs. cold environment. To feed they had to leave a warm refuge (\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{wasysym} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document}$T_{{\mathrm{op}}}$\end{document} 44-45 C) and go 1.5 m to where food was presented at an ambient temperature (\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{wasysym} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document}$T_{{\mathrm{a}}}$\end{document}) varying from 25 to 0 C. When \documentclass{aastex} \usepackage{amsbsy}...

1. Four subjects were immersed in a stirred water-bath maintained at either 30 or 40° C. The left hand was placed out of the bath in a glove receiving water at a temperature selected by the subject as most pleasurable. Experiments were conducted during the euthermic state and during either spontaneous or induced fever. 2. The results of control experiments confirm a previous observation using the same method, that preferred hand skin temperature was a linear function of internal temperature but also indicated an influence by mean skin temperature. 3. The general pattern of response during fever was identical to that when fever was absent except that the regulated steady state internal temperature was higher and the slopes of preferred temperature plotted against internal temperature were steeper. 4. The results seem to support the concept of a change in set point rather than that of a change in the gain of the thermoregulatory processes during fever.

Resume Chez 10 sujets une injection de 30 g de glucose dans l'artere mesenterique est pratiquee sous forme de serum glucose a 30%. Chez 10 autres sujets, 50 g de glucose sont ainsi injectes. L'evolution de la reponse gustative a diverses solutions sucrees est suivie avant et apres cette injection, grâce a la presentation des stimulations sucrees selon un certain protocole, les reponses affectives obtenues sont donnees d'apres une echelle arbitraire. L'injection de glucose dans l'artere mesenterique n'a pas ete suivie de modification de la reponse affective, il n'y a pas eu d'alliesthesie. On en conclut que l'alliesthesie ne tire pas son origine des gluco-recepteurs hepatiques.

Resume A dix sujets sains on propose des stimulations gustatives sucrees avant et apres injection intragastrique de glucose. Chaque sujet au cours de 4 experiences recoit 0 g. 25 g, 50 g et 100 g de glucose. On suit l'evolution de la sensation dans les deux heures suivantes. Les resultats montrent une alliesthesie negative (diminution du plaisir donne par le saccharose) apparaissant en 15 min croissant jusqu'a un maximum vers la 55ieme minute puis decroissant. L'effet est d'autant plus marque que la dose de glucose ingere est importante. Ces resultats sont compatibles avec une intervention de l'alliesthesie negative dans la perception consciente de la satiete.

Resume Dans un bac de 2 m de long un gradient thermique aqueux lineaire a ete cree entre 0°C et 40°C. On l'utilise pour determiner le thermopreferendum de 2 poissons marins Chromis chromis ( n = 36) et Scorpena scorfa ( n = 36) et d'un batracien Rana esculenta ( n = 48). En l'absence de gradient thermique, il existe un thigmotactisme positif. En presence du gradient thermique Chromis chromis et Scorpena scorfa montrent une preference pour 20°C, mais restent disperses de 8°C a 26°C. Chez Rana esculenta il existe un thermopreferendum etroit limite entre 25°C et 28°C. Chez Rana esculenta le rechauffement intra-abdominal a l'aide d'une resistance chauffante isolee entraine de facon repetee un deplacement vers les zones froides du bac, suivi d'un retour a 25°C apres l'interruption du rechauffement.

Dogs were placed in a climatic chamber with adjustable temperature. They had the possibility to open an infrared heater and/or an air-conditioner. Normal dogs responded to ambient temperature with linear behavior both for cold and for warm reinforcements. During fever the dogs responded to ambient temperature with more heater and less air-conditioner. During thyroxin load the dogs responded with less heater and more air-conditioner. These observations suggest that behavior is controlled by temperature regulation and adapted to the thermoregulatory set point.

3 dogs could behaviourally modify their own spinal cord temperature (Tspin. cord). In a hot environment, 2 dogs did not cool their spinal cord, 1 dog warmed it. The higher the environmental temperature, the higher the chosen Tspin. cord. These results seem to imply that this latter dog tended, in warm environment, to behaviourally reduce: Ts greater than Tspin. cord (Ts mean skin temperature). Data obtained previously support this explanation.

In human subjects, bradycardia was produced by immersing the subjects' faces in water at 15 degrees C when they were hyperthermic. When they were hypothermic, the same face cooling produced tachycardia. It is suggested that the difference in cardiac response originates in selective brain cooling during hyperthermia, by venous return from the face to the brain, via ophthalmic veins.

Publisher Summary This chapter focuses on physiological signals for thermal comfort. There is a close correlation between thermoregulatory behavior and the motivation for this behavior, if the subject has no other priorities. While it is unlikely that behavior occurs without motivation, motivation can occur in the absence of behavior; this divorce may occur even in well-planned experiments. Such dissociation between motivation and its behavioural expression has been emphasized in other types of behaviors, such as food intake. Thermal comfort, as other conscious perceptions, is a mental phenomenon; it is, therefore, a function of the nervous system in the human, as in other species. This system, which permits the perception of thermal comfort, is shown in greatly simplified forms. The strong influence of internal temperature on the perception of thermal comfort is shown by responses and ratings given by subjects immersed in a water bath. One of the primary components of thermal comfort is the pleasure aroused by a peripheral stimulus; this, in turn, depends on internal temperature.

In numerous species, saliva secretion is an important thermolytic response to hyperthermia. The aim of the present work was to look for a thermolytic saliva secretion in human beings. Saliva collected by cannulation was not secreted more during active or passive hyperthermia than during control periods. Therefore, it can be concluded that saliva secretion has no thermoregulatory role in human beings.

In some isolated parts of North Africa, there persists an ancient Berber custom of imposing an overfeeding regimen on young girls before marriage, to achieve an obesity which is regarded as aesthetically pleasing. We have studied the effect of such a regimen, lasting 12–16 weeks, on blood lipids and on the affective reactions to sweet tastes in nine subjects. It is known that the pleasantness of alimentary cues i.e., the feeding behaviour, depends on the subject's nutritional state. Only three subjects gained weight (by 3, 5 and 8 kg), in spite of the strong pressure to overeat. No change in plasma lipid concentrations were observed. Nevertheless, at the end of the regimen every subject showed a highly significant decrease in the rated pleasantness of sweet stimuli when they were tested fasting. However, the reduction in sweet pleasantness induced by ingestion of a 200 ml load of 1·4 M glucose solution was not changed by the overfeeding. Thus, pressure to overfeed can reduce hunger, as seen in the attractiveness of sweet foods in fasted subjects, without modifying glucose-induced satiety.

In 100 adult men the area of the face and neck where beard was growing was measured and compared to that of glabrous skin on the forehead and calvaria. In the population as a whole, forehead area was found to be proportional to bearded area. Forehead and calvaria sweat rate was measured on 10 baldheaded male subjects and compared with that of 10 hairy control subjects during mild hyperthermia. Bald skin was found to sweat more than twice as much as hairy skin. In the light of these results the hypothesis that baldness is a thermoregulatory adaptative process is proposed.

An experiment has been set up to explore the hypothesis according to which behaviour is determined by the trend to maximize pleasure. Twelve subjects were placed individually in a situation of conflict where the pleasure of playing a videogame clashed with the increasing discomfort of a cold environment. The time lapse tolerated could be predicted from the algebraic sum of the rating of displeasure aroused by the cold environment and the rating of pleasure aroused by the videogame, obtained in other sessions. This result supports the working hypothesis and allows to conclude that pleasure is the common currency of tradeoffs among various motivations.

Publisher Summary This chapter discusses the effect of salicylate in emotional fever. In a study described in the chapter, eight adult male Sprague–Dawley rats were used. Each animal had a blind stainless steel guide tube permanently implanted into its hypothalamus. Intracranial temperature was recorded continuously by inserting into the tube a copper–constantan thermocouple fitted to a cutoff plastic syringe tip. Simultaneously, the ear skin temperature was recorded with a thermocouple affixed to the ear with adhesive tape. The animals were kept in the room where the experiments were carried out. The procedure consisted of taking the rat out of its home cage, inserting the intracranial thermocouple into the guide tube, affixing the ear thermocouple, and placing the rat in an experimental wire-mesh cage. In addition to this, at intervals not shorter than 2 days, and in a random order, each animal received, 1 h before temperatures were recorded, some i.p. injections. It was found that under control conditions, the core temperature increased immediately after the rat was placed in the experimental cage. At the same time, the skin temperature decreased, which indicated vasoconstriction and diminution of heat loss.

Though the same symptoms are observed in either hyper- or hypothermia, the etiology may be of four different types: 1) the thermoregulatory mechanisms may be insufficient to adapt to temperature extremes in normal subjects; 2) there may be modifications in peripheral thermoregulatory responses, when the patient compensates for the deficiency or excess by other thermoregulatory responses: the internal temperature is then not distrubed but is not stable; 3) a central lesion causing loss of ability to oppose low temperatures results in hypothermia with coma as soon as the subject is exposed to cold. Loss of ability to oppose heat is not encountered: it is superimposable on the hyperexcitation of the centers that oppose heat; 4) modifications in thermoregulatory responses are mainly evident as fever, a protective defense reaction of the organism wich should be supported rather than fought. The inverse syndrome, if it exists, is difficult to distinguish from the loss of ability to oppose cold. The term of "anapyrexia" is suggested for this latter condition. Whatever the diagnosis, measurment of rectal temperature is insufficient for diagnosis, and thermoregulatory responses have to be evaluated. Therapy for the same symptom may, in fact, be inversed depending on the etiology. It may well be that thermoregulatory function is poorly understood because of its true importance. Possessing no specific organs, it uses the various reactions that have appeared during phytogenetic development to ensure thermal homeostasis. It acts permanently through multiple, independent, regulatory loops allowing many compensatory mechanisms. This underlines, in an indirect manner, the need for the organism to maintain at all costs a constant temperature. This permanent thermal homeostasis implies that only severe disorders result in hyper- or hypothermia, that major disturbances are rapidly fatal, which emphasizes the fundamental importance of thermorgulation.

It is as though the body weight, or a variable correlated closely with body weight, was submitted to regulation. This regulation is analyzed from known human studies. This short bibliography study reviews interrelations between palatability of food stuffs and ponderostat. Findings show that palatability elevates ingestion rate, metabolic output rate and ponderostat set point. Reciprocally, ingestion and the set point modulate food palatability.

Four human subjects were fed ad lib with a bland diet for a period of 3 weeks. Their body weight decreased by 3.13 kg during this period. It was observed that the shift of the palatability response to sucrose solutions induced by a gastric glucose load (alliesthesia) was not affected by such a reduction of body weight. This result was compared to a previous experiment showing a decreased alliesthesia after a body weight loss due to the restriction of a palatable diet. These results confirm the role of the palatability of the diet on the maintenance of a body weight level and provide evidence for an interaction between the two factors in determining the oral satiation process.

The principle of behavioural therapy was used in anti-tobacco treatment. An assessment of the first 100 patients is given here. From the beginning of treatment, which was individual and lasted for one week, the subjects, with three exceptions, stopped smoking between the treatment sessions. After treatment was completed, 93 subjects maintained this abstinence for at least 15 days; 74 patients have not started to smoke again, with a follow-up period ranging from 2 to 18 months. The degree of motivation of the patients would seem to be the only parameter related to relapse.

Direction of blood flow in angularis oculi veins was recorded in humans. In mild hypothermia, blood flow was weak and directed from brain to face. In hyperthermia, however, blood flowed rapidly in the opposite direction, angularis oculi vein collecting cool facial blood and supplying cavernous sinus. Therefore selective cooling of human brain is possible.

Three healthy young adult males were placed on a treadmill geared to five speeds and five slopes in combination. At minute 16 they gave estimates of displeasure for sensations aroused in their chest and lower limbs. These estimates were compared to the operant choice of the subjects when they were given the task, in other sessions, of climbing up 300 m on the treadmill at varying speeds and slopes. When speed was imposed, they could adjust slope and reciprocally. The were instructed that the session would end when they had reached the 300 m elevation. The results showed that the subjects adjusted slope and speed inversally; time for climbing up 300 m was almost constant, i.e. they tended to work at constant power in various conditions. Such performance could be predicted from the sum of ratings of displeasure aroused in the lower limbs and in the chest. These results suggest that optimalization of behaviour was obtained by minimization of bidimensional displeasure.