Environmental stresses cause changes in physiological variables which affect the psychological state. For example, severe hyperthermia or hypoxia can induce cognitive impairments. We provide an overview of methodologies to evaluate brain cognitive function recorded from biological signals, and briefly summarize the effects of hyperthermia or hypoxia on cognitive function.
In this paper, flowering dates of the Japanese Hydrangea macrophylla were examined to clarify temporal and spatial variations from 1987 to 2016 on climatological approach, including effects of warming from winter to spring in recent years and in winter. By linear regression analysis of the flowering dates against the year, phenological trend from 1987 to 2016 on average at 54 stations was shown to be negative, i.e., advancing flowering. Many stations showed earlier flowering in north-eastern Japan, however, the flowering dates were delayed at 13 stations mainly in south-western Japan, located in warm areas, showing spatial variation. Trends in flowering dates indicated to be slightly delayed in both 1987-1996 and 1997-2006, and to be earlier in 2007-2016. Results of correlation analysis from 1987 to 2016 at 54 stations indicated that there were significant relationships between advancing flowering and spring warming. On the other hand, delayed flowering in phenological trend from 1997 to 2006 at 13 stations was dependent more on spring temperature than warming in winter. With respect to the spatial variations, trend in flowering dates from 1987 to 2016 indicated to be negative, i.e., advancing flowering for all 5 areas in Japan, showing the earliest in Hokkaido area and the least early in Kyushu area.
To elucidate the brain activity characteristics regarding cold sense in people with hypersensitivity to the cold, we examined electroencephalogram (EEG) responses during local and whole-body skin cooling in young adult women with and without a cold constitution. EEG responses were measured at the parietal area under an eyes-closed condition, and the spectral power of four frequency bands (θ, α1, α2, β) was analyzed. In the local cooling experiment, local temperatures at dorsal feet were reduced from 33°C to 23°C using local temperature controlling devices with peltier elements. In the whole-body cooling experiment, whole-body skin temperature was reduced from 36-36.5°C to 34-34.5°C using a water-perfused suit. EEG responses in women with a cold constitution were characterized by 1) a lower appearance of low-frequency α waves during local and whole-body skin cooling, and 2) a higher appearance of β waves during whole-body skin cooling but not during local skin cooling.
It is generally believed that the skin moisture levels tend to decline with aging. We followed age-related changes in the skin moisture by examining some biophysical properties of skin in winter in five women in their early forties over a 4-year period from 2011 to 2014. Sebum contents, transepidermal water loss (TEWL), and skin conductance were measured on the forehead, the lateral outer canthus, and the cheek in a climate chamber (24°C, relative humidity: 35%). The subjects’ sebum contents declined with increasing age at all measurement sites. The decline was more prominent in the lateral canthus and in the cheek than in the forehead, and the decline became more apparent in all of the sites in the latter half of the 4 years. On the other hand, the TEWL nor the skin conductance did not change over the 4 years. In conclusion, in women in their early forties, the decrease in the sebum amount with aging was not considered to have any influence in the facial skin moisture level. Taking the fact that lipids from the sebaceous glands having smaller water -holding capacity constitute the major and those from the epidermal cells having the larger holding capacity do the minor portion of the sebum into consideration, it will be needed to study further through the analysis of components of sebum with increasing number of the subjects and precision in order to establish effective measures to maintain moisture of skin in middle-aged women.