Neural Mechanisms of Feeding Behavior and Its Disorders

There are two forms of feeding behavior. The hypothalamus and the lower brainstem monitor the internal environment of the body and are involved in the control of feeding behavior to maintain energy balance and homeostasis (homeostasis-dependent feeding behavior). On the other hand, humans and animals, when placed in an environment similar to modern society (e.g., cafeterias), where organisms can easily ingest highly preferred foods, consume more than necessary (homeostasis-independent feeding behavior). The emotion/reward system, including the amygdala and nucleus accumbens, is involved in this type of feeding behavior. These two control systems interact in the lateral hypothalamic area (LHA), where feeding behavior is controlled by systems with higher activity. In modern society, there is abundant information on food, and high-calorie foods such as snacks are readily available. Thus, in modern society, the homeostasis-independent control system easily surpasses the homeostasis-dependent control system, which results in obesity. Various feeding and eating disorders might be ascribed to dysregulations in the two control systems. In the future, more effective treatments for feeding and eating disorders can be developed by elucidating the mechanisms of these two control systems

摂食リズムの視床下部性統御

金沢大学医学部研究課題/領域番号:X00090----257027, 研究期間(年度):1977出典：「摂食リズムの視床下部性統御」研究成果報告書　課題番号X00090----257027（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00090----257027/）を加工して作

摂食中枢と皮質運動野の機能的及び解剖学的関係の解明

金沢大学医学部研究課題/領域番号:X00090----157033, 研究期間(年度):1976出典：「摂食中枢と皮質運動野の機能的及び解剖学的関係の解明」研究成果報告書　課題番号X00090----157033（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00090----157033/）を加工して作

視床下部外側野と皮質運動野間相互連絡様式の神経生理学的研究

金沢大学医学部研究課題/領域番号:X00040----222109, 研究期間(年度):1977出典：「視床下部外側野と皮質運動野間相互連絡様式の神経生理学的研究」研究成果報告書　課題番号X00040----222109（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00040----222109/）を加工して作

Lysine and Arginine Reduce the Effects of Cerebral Ischemic Insults and Inhibit Glutamate-Induced Neuronal Activity in Rats

Intravenous administration of arginine was shown to be protective against cerebral ischemic insults via nitric oxide production and possibly via additional mechanisms. The present study aimed at evaluating the neuroprotective effects of oral administration of lysine (a basic amino acid), arginine, and their combination on ischemic insults (cerebral edema and infarction) and hemispheric brain swelling induced by transient middle cerebral artery occlusion/reperfusion in rats. Magnetic resonance imaging and 2,3,5-triphenyltetrazolium chloride staining were performed 2 days after ischemia induction. In control animals, the major edematous areas were observed in the cerebral cortex and striatum. The volumes associated with cortical edema were significantly reduced by lysine (2.0 g/kg), arginine (0.6 g/kg), or their combined administration (0.6 g/kg each). Protective effects of these amino acids on infarction were comparable to the inhibitory effects on edema formation. Interestingly, these amino acids, even at low dose (0.6 g/kg), were effective to reduce hemispheric brain swelling. Additionally, the effects of in vivo microiontophoretic (juxtaneuronal) applications of these amino acids on glutamate-evoked neuronal activity in the ventromedial hypothalamus were investigated in awake rats. Glutamate-induced neuronal activity was robustly inhibited by microiontophoretic applications of lysine or arginine onto neuronal membranes. Taken together, our results demonstrate the neuroprotective effects of oral ingestion of lysine and arginine against ischemic insults (cerebral edema and infarction), especially in the cerebral cortex, and suggest that suppression of glutamate-induced neuronal activity might be the primary mechanism associated with these neuroprotective effects

Neuronal response sto face-like and facial stimuli in the monkey superior colliculus

The superficial layers of the superior colliculus (sSC) appear to function as a subcortical visual pathway that bypasses the striate cortex for the rapid processing of coarse facial information. We investigated the responses of neurons in the monkey sSC during a delayed non-matching-to-sample (DNMS) task in which monkeys were required to discriminate among five categories of visual stimuli [photos of faces with different gaze directions, line drawings of faces, face-like patterns (three dark blobs on a bright oval), eye-like patterns, and simple geometric patterns]. Of the 605 sSC neurons recorded, 216 neurons responded to the visual stimuli. Among the stimuli, face-like patterns elicited responses with the shortest latencies. Low-pass filtering of the images did not influence the responses. However, scrambling of the images increased the responses in the late phase, and this was consistent with a feedback influence from upstream areas. A multidimensional scaling (MDS) analysis of the population data indicated that the sSC neurons could separately encode face-like patterns during the first 25-ms period after stimulus onset, and stimulus categorization developed in the next three 25-ms periods. The amount of stimulus information conveyed by the sSC neurons and the number of stimulus-differentiating neurons were consistently higher during the 2nd to 4th 25-ms periods than during the first 25-ms period. These results suggested that population activity of the sSC neurons preferentially filtered face-like patterns with short latencies to allow for the rapid processing of coarse facial information and developed categorization of the stimuli in later phases through feedback from upstream areas

Population coding of facial information in the monkey superior colliculus and pulvinar

The superior colliculus (SC) and pulvinar are thought to function as a subcortical visual pathway that bypasses the striate cortex and detects fundamental facial information. We previously investigated neuronal responses in the SC and pulvinar of monkeys during a delayed nonmatching-to-sample task, in which the monkeys were required to discriminate among 35 facial photos of five models and other categories of visual stimuli, and reported that population coding by multiple SC and pulvinar neurons well discriminated facial photos from other categories of stimuli (Nguyen et al., 2013, 2014). However, it remains unknown whether population coding could represent multiple types of facial information including facial identity, gender, facial orientation, and gaze direction. In the present study, to investigate population coding of multiple types of facial information by the SC and pulvinar neurons, we reanalyzed the same neuronal responses in the SC and pulvinar; the responses of 112 neurons in the SC and 68 neurons in the pulvinar in serial 50-ms epochs after stimulus onset were reanalyzed with multidimensional scaling (MDS). The results indicated that population coding by neurons in both the SC and pulvinar classified some aspects of facial information, such as face orientation, gender, and identity, of the facial photos in the second epoch (50–100 ms after stimulus onset). The Euclidean distances between all the pairs of stimuli in the MDS spaces in the SC were significantly correlated with those in the pulvinar, which suggested that the SC and pulvinar function as a unit. However, in contrast with the known population coding of face neurons in the temporal cortex, the facial information coding in the SC and pulvinar was coarse and insufficient. In these subcortical areas, identity discrimination was face orientation-dependent and the left and right profiles were not discriminated. Furthermore, gaze direction information was not extracted in the SC and pulvinar. These results suggest that the SC and pulvinar, which comprise the subcortical visual pathway, send coarse and rapid information on faces to the cortical system in a bottom-up process

Physiological effects of natural flagrance of “CEDROL” and cedrol for application to aromatherapy

匂い物質は，嗅覚神経系を介して行動発現や自律神経機能の調節などに関与する神経系（大脳辺縁系および視床下部）を賦活することにより，アロマセラピーの効果発現に関与していることが示唆されている．セドロールは，セダーウッド油から抽出した天然香料であり，セドロールを含むセダーウッドエッセンスはアロマセラピーに用いられていることから，自律神経機能に及ぼす作用が期待される．そこでセドロールを実験的に健常人に上気道から吸入させると，副交感神経の活動が有意に増大し，交感神経系の活動が有意に低下した．さらに，喉頭全摘除術を受けた被験者を用いて，上気道を介さずに下気道からセドロールを直接吸入させると，同様の効果が認められた．以上から，セドロールは嗅覚神経系だけでなく肺の迷走神経系を介して，交感神経系の活動や精神緊張を低下させる作用を有することが示唆された．これらのことは，セドロールがアロマセラピーに有用であることを示唆する．Odor substance is suggested to induce clinical effects of aromatherapy by stimulating the brain areas（limbic system and hypothalamus）involved in emotion and autonomic control through the olfactory system. Effects of pure compound （Cedrol） extracted from cedar wood oil on the cardiovascular system were investigated since cedar wood essence, which includes Cedrol, has been applied to aromatherapy. Vaporized Cedrol were presented to healthy human subjects via a face mask, which decreased sympathetic activity and increased parasympathetic activity. In the subsequent experiment, vaporized Cedrol was directly inhaled through the lower airway from a hole in the trachea of the totally laryngectomized subjects, but not through the upper airway. The experiment using the totally laryngectomized subjects replicated the similar results in healthy subjects who inhaled Cedrol through the nose. These results suggest that Cedrol acts on the peripheral nervous system （vagus nerve） innervating the lower airway and pulmonary system as well as the olfactory system in the upper airway. These results suggest usefulness of Cedrol for aromatherapy

Snakes elicit earlier, and monkey faces, later, gamma oscillations in macaque pulvinar neurons

Gamma oscillations (30–80 Hz) have been suggested to be involved in feedforward visual information processing, and might play an important role in detecting snakes as predators of primates. In the present study, we analyzed gamma oscillations of pulvinar neurons in the monkeys during a delayed non-matching to sample task, in which monkeys were required to discriminate 4 categories of visual stimuli (snakes, monkey faces, monkey hands and simple geometrical patterns). Gamma oscillations of pulvinar neuronal activity were analyzed in three phases around the stimulus onset (Pre-stimulus: 500 ms before stimulus onset; Early: 0–200 ms after stimulus onset; and Late: 300–500 ms after stimulus onset). The results showed significant increases in mean strength of gamma oscillations in the Early phase for snakes and the Late phase for monkey faces, but no significant differences in ratios and frequencies of gamma oscillations among the 3 phases. The different periods of stronger gamma oscillations provide neurophysiological evidence that is consistent with other studies indicating that primates can detect snakes very rapidly and also cue in to faces for information. Our results are suggestive of different roles of gamma oscillations in the pulvinar: feedforward processing for images of snakes and cortico-pulvinar-cortical integration for images of faces