To examine the cerebral activity of the motor cortex during maximum movement, we measured regional cerebral blood flow (rCBF) in twelve normal volunteers, using near infrared spectroscopy (NIRS). Repetitive tapping of the right index finger was performed at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, and 4.5 Hz, and during maximum effort (ME). The relative increase rate of rCBF during movement beginning with a resting condition was calculated for each movement condition. The left primary sensorimotor cortex showed significant activation during ME compared to the other frequencies. The rapid increase of rCBF was seen immediately after the initiation of finger tapping at all the tested frequencies but showed no increase following that. However, the rCBF during ME continued to increase until the end of the task. Change of the integrated electromyogram (iEMG) for the frequency and change of rCBF for the frequency at all the tested frequencies showed similar tendencies.
Dietary restriction is known to prolong life in laboratory animals. However, little is known about the effects of dietary restriction on physical performance. To evaluate physical performance, we measured four item indices: time to climb out of obstacles, time to escape restraint by gummed tape, time hanging from a bar, and ability to resist slipping every week. The diets of ICR mice were restricted from the age of 7 weeks through 24 weeks. Body weight of the diet-restricted mice decreased during the 7th to 9th weeks of age. After the 10th week, weight gain resumed. In response to assigned tasks, the diet-restricted mice performed better in all activities: they climbed out of obstacles faster, freed themselves sooner from restraint by gummed tape, hung from a bar longer, and better resisted slipping down a slope. These results suggest that diet-restricted mice have superior physical abilities, such as those required to overcome or avoid risks to life, than do ad-libitum-fed mice.
The present study sought to determine if the postural sway of a subject required to grasp a tray (motor task) holding a cup filled with water and prevent spilling (mental task), would be reduced by consciously redirecting attention to maintain the tray in a horizontal position. We hypothesized the mental task would increase the stabilization of standing postural balance. Postural sway was measured in 17 normal subjects under the following conditions: 1) holding a 100 g weight in each hand (total 200 g; no mental task), 2) holding with both hands a tray on which 200 g was placed (tray-holding task), and 3) holding with both hands a tray on which a cup filled with water weighing 200 g was placed in the center (mental task). Postural sway was significantly reduced during the mental task versus other tasks. Standing posture balance was stabilized when a mental task was added. Thus, we concluded that higher brain functions such as attention and consciousness exerted a significant influence over the control of standing posture.
The present study examined the relationship between sex-role identity (SRI) and functional cerebral lateralization (FCL) in right-handed males. Two tasks (figure task and location task) were used to assess FCL. The figure task required the identification of shape stimuli, while the location task involved identification of the position of stimuli. SRI was assessed by the Bem Sex Role Inventory (BSRI). Males with higher masculine scores in the BSRI indicated greater differences in the reaction time between right and left visual-fields in the location task. This finding suggests that males with higher masculinity in SRI might have greater FCL.
As one way of thinking about physiological anthropology, let us survey it from a historical viewpoint. At the beginning of the 19th century, Blumenbach, considered the father of Physical Anthropology, wrote his “Handbook of Comparative Anatomy and Physiology.” The subsequent research conducted and papers written by researchers such as Broca and Martin pointed in the direction of physiological anthropology; furthermore, the research carried out by the American researchers Demon and Baker had a physiological anthropology “feel.” The courses in Physiological Anthropology taught by Tokizane exerted a major influence on physiological anthropology in Japan. The precursor of the Japan Society of Physiological Anthropology, organized by Sato in 1978, was extremely significant in the effect that it had on the subsequent development of physiological anthropology. The holding of the biennial International Congress of Physiological Anthropology, along with the allocation of the Research sub-field of Physiological Anthropology in the Grant-in-Aid for Scientific Research, would seem to suggest that the field of physiological anthropology is set to increasingly grow and evolve.
The methodology of physiological anthropology has been defined in the capacity of an independent academic field by five keywords: environmental adaptability, technological adaptability, physiological polymorphism, whole-body coordination and functional potentiality, clearly suggesting the direction of approach to human beings in the field of physiological anthropology. Recently, these keywords have attracted a great deal of attention from physiological anthropologists in Japan. Physiological anthropology is based on a biological framework. From the viewpoint of biology, it is essential to discuss the biological function of human behavior. In this brief conceptual manuscript, the biological aspects of physiological anthropology are discussed in relation to the five keywords.
The environmental adaptability of human beings has progressed according to various environments experienced in the course of evolution. Therefore, various phenotypes for environmental adaptability exist and are considered to be physiological polymorphism. Physiological polymorphism in thermoregulation is influenced by genotype, individual characteristics, environmental factors, cultural factors, etc. Moreover, it is thought that physiological polymorphism is evidenced more clearly in physiological responses to extreme situations and/or changing conditions than in environments where homeostasis is easily maintained. In the field of physiological anthropology, I think that it is important not only to discover the physiological responses that demonstrate polymorphism, but also to hypothesize about the mechanisms and the processes by which such polymorphisms were formed, and their meaning for human beings. Such discussions may be supposed to lead to an evaluation of the environmental adaptability of humans from the viewpoint of physiological anthropology.
The term “adaptability” or “capacity of adaptation” is the central concept in the general advancement and promotion of research in physiological anthropology. Throughout the history of Homo sapiens, mankind has adapted itself to environmental stress. As a result, numerous physiological polymorphisms in humans are present in our planet-wide distribution. Totally regulated physiological function by integration and coordination is referred to as whole-body coordination and is associated with a high degree of adaptability in humans. Functional potentiality also affects environmental adaptability. Thus, whole-body coordination and functional potentiality are necessary for adaptation to environmental changes. There is an interrelationship among functional potentiality, whole-body coordination, physiological polymorphisms, and environmental adaptability.
Certain perspectives of morphological and functional diversities molded to adapt to highly technological environments remain to be evaluated, which leads us to consider what a truly healthy and comfortable environment is by focusing on the diversity of human adaptability based on the keywords of physiological anthropology, or physiological polymorphism, functional potentiality and whole body coordination. Each of the three keywords is outlined here, as well as the mutual relationship between them. A re-evaluation of the significance of polymorphism in the current living environment is also discussed here.