The human brain deteriorates as we age, and the rate and the trajectories of these changes significantly vary among brain regions and among individuals. Because neuroimaging data are potentially important indicators of individual's brain health, they are commonly used in brain age prediction. In this review, we summarize brain age prediction model from neuroimaging-based studies in the last ten years. The studies are categorized based on their image modalities and feature types. The results indicate that the prediction frameworks based on neuroimaging holds promise toward individualized brain age prediction. Finally, we addressed the challenges in brain age prediction and suggested some future research directions.
Aging ; Brain ; diagnostic imaging ; physiology ; Humans ; Neuroimaging

OBJECTIVE: To build a physiological aging scale for healthy people.
 METHODS: We collected age-related physiologic items through literature screening and expert interview. Two rounds of Delphi were implemented. The importance, feasibility and the degree of authority for the physiological index system were graded. Using analytic hierarchy process, we determined the weight of dimensions and items.
 RESULTS: Using Delphy mothod, 17 physiological and other professional experts offered the results as follow: coefficient of expert authorities Cr was 0.86±0.03, coordination coefficients for the first and second round were 0.264(χ2=229.691, P<0.001) and 0.293(χ2=228.474，P<0.001), respectively. The consistency was good. The aging scale for healthy people included 3 dimensions, namely physical form, feeling movement and functional status. Each dimension had 8 items. The weight coefficients for the 3 dimensions were 0.54, 0.16, and 0.30, respectively. The Cronbach's α coefficient of the scale was 0.893, the reliability was 0.796, and the variance of the common factor was 58.17%.
 CONCLUSION The improved Delphi method or physiological aging scale is satisfied, which can provide reference for the evaluation of aging.
Aging ; physiology ; Delphi Technique ; Humans ; Reproducibility of Results

In this research, we compared the visual neuron responses for LGN, A18 and PMLS of old and young cats with extracellular single-neuron recording techniques. We used firing rate vector to characterize information, and response irregularity of cells to evaluate the degeneration of visual characters. Response irregularity is characterized by means of the two coefficients of variation of firing rate vectors: Cv and Cv2. We found that there was no significant change of the response irregularity in LGN areas during the aging process from young to old cats. But in the other two areas, neurons of old cats exhibited significantly larger response irregularity than those of young cats. The result indicated that the information processing function of advanced visual cortex was impaired by aging. This result also provids a reference for the research of the other neuronal system changes during aging process.
Action Potentials ; physiology ; Aging ; physiology ; Animals ; Cats ; Neural Conduction ; Neurons ; physiology ; Visual Cortex ; physiology

Melanoblasts, the precursors to melanocytes, originate in the neural crest. Some melanoblasts can travel to the hair follicle and further differentiate into pigment melanin-producing melanocytes. Hair follicles contain a pool of undifferentiated melanocyte stem cells (MSCs), which are sources of differentiated melanocytes, and functional melanocytes exhist in the hair bulb. The volume, life, and activity of melanocytes in a hair follicle is closely related with the growth cycle of follicle. Appearance of gray hair gray results from incomplete MSCs maintenance.
Aging ; physiology ; Cell Differentiation ; Hair Follicle ; cytology ; physiology ; Humans ; Melanocytes ; physiology ; Stem Cells ; physiology

BACKGROUND: This study evaluated dynamic changes in eyebrow position related to aging. METHODS: Female participants were recruited and separated into two groups aged 20–30 years (the younger group, n=20; mean age, 24.8 years) and 50–70 years (the older group, n=20; mean age, 55.8 years). Photogrammetry was used to determine the eyebrow position at the medial canthus (MC), lateral limbus, lateral canthus, and lateral end point (EP) for 6 actions: smooth opening (the reference action) and closing of the eye, forward gaze, maximum opening and closing of the eye, and maximum frown. Videos were also recorded. RESULTS: No differences in eyebrow position were detected at the MC when opening or closing the eyes smoothly, gazing straight ahead, or closing the eyes maximally. For all 6 actions, the position of the lateral EP in the older group was significantly lower than in the younger group (P=0.003), and the smallest degree of vertical movement at this point was found in both age groups (P<0.001). Vertical movement at the 4 landmarks of the eyebrows decreased with aging. CONCLUSIONS: Eyebrow position was unchanged at the MC with aging, except at maximal eye opening and maximal frown. No differences in eyebrow position were observed between the younger and older groups when eyes were maximally closed, except at the EP. It is important to focus on correction of the lateral EP for periorbital rejuvenation.
Aging* ; Anthropometry ; Eyebrows* ; Female ; Humans ; Lacrimal Apparatus ; Photogrammetry ; Physiology ; Rejuvenation

Aging is a process of the progressive functional decline with time, leading to disability, dependence, morbidity, and mortality. While the organ function in the elderly is relatively uncompromised under basal conditions, their ability to tolerate increased physiologic stress is reduced. And the extent and onset of the deterioration in functional reserve is quite diverse from patient to patient. The aging population is rapidly growing and their medical management is becoming one of the greatest challenges to anesthesiologists. The understanding of the normal physiologic changes with aging is essential to frame any discussion of perioperative management in the elderly. In this review, we will focus on the physiologic changes in neurologic, cardiac, pulmonary, renal, and hepatic function, and thermoregulation.
Aged ; Aging* ; Body Temperature Regulation ; Humans ; Mortality ; Physiology

Studies on nocturnal penile tumescence characteristics in normal men have advantages of further investigations of erection physiology and of impotence research. We conducted a study of nocturnal penile tumescence in 30 Korean healthy males aged 21 to 68 (divided into 5 groups, from 20s to 60s) by means of polysomnographic monitoring to provide normative data on how it is related to man`s sexual function with aging and its range of characteristics for the management of impotence. Analyses of 60 sleep data showed that with aging from 20s to 60s, there was steady decrease in mean values of total tumescence time, total tumescence time/total sleep period time, total tumescence time/total REM period time, amount of maximum REM-related tumescence episodes, frequency of REM-related tumescence, frequency of maximum REM-related tumescence episode, as well as of penile circumferential change and penile rigidity in maximum tumescence episode. These results indicate that there is steady decrease in the quality of nocturnal penile tumescence including frequency, duration, amount and degree with aging from 20s to 60s, which reflects changes of sexual capacity and function in psychosexul aspect. We suppose these normative data will contribute to further clinical investigations of nocturnal penile tumescence and male sexual dysfunction.
Adult* ; Aging* ; Erectile Dysfunction ; Humans ; Male ; Penile Erection* ; Physiology

The Biological characteristic of aging is a process which is irreversible, universal and detrimental. Knowledge about the normal morphologic and physiologic changes that accompany aging and the ability to discriminate between normal and pathologic states become increasingly important issues. Echocardiography is able to provide detailed information about cardiac anatomy and physiology, and is a cheap, safe, non-invasive procedure, particularly suitable for elderly people. Its non-invasive nature makes it convenient as a means of investigating aging changes during follow-up, and repeated measurements may be made over the course of many years. The information obtained often provides the clinician with sufficient detail to formulate a management plan, and serial studies may be conveniently performed to monitor progression of aging process, increasingly common in an elderly population.
Aged* ; Aging ; Echocardiography* ; Follow-Up Studies ; Humans ; Physiology ; Population Characteristics

Acupuncture Therapy ; methods ; Aging ; blood ; physiology ; Animals ; Humans ; Mice ; Qi

Aging ; physiology ; Cardiovascular Diseases ; complications ; Humans ; Phenotype ; Progeria ; complications