Emotion recognition is known to change with age, but associations between the change and brain atrophy are not well understood. In the current study atrophied brain regions associated with emotion ...recognition were investigated in elderly and younger participants. Group comparison showed no difference in emotion recognition score, while the score was associated with years of education, not age. We measured the gray matter volume of 18 regions of interest including the bilateral precuneus, supramarginal gyrus, orbital gyrus, straight gyrus, superior temporal sulcus, inferior frontal gyrus, insular cortex, amygdala, and hippocampus, which have been associated with social function and emotion recognition. Brain reductions were observed in elderly group except left inferior frontal gyrus, left straight gyrus, right orbital gyrus, right inferior frontal gyrus, and right supramarginal gyrus. Path analysis was performed using the following variables: age, years of education, emotion recognition score, and the 5 regions that were not different between the groups. The analysis revealed that years of education were associated with volumes of the right orbital gyrus, right inferior frontal gyrus, and right supramarginal gyrus. Furthermore, the right supramarginal gyrus volume was associated with the emotion recognition score. These results suggest that the amount of education received contributes to maintain the right supramarginal gyrus volume, and indirectly affects emotion recognition ability.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Electronic devices have become an indispensable part of our daily lives, while their negative aspects have been reported. One disadvantage is that reading comprehension is reduced when reading from ...an electronic device; the cause of this deficit in performance is unclear. In this study, we investigated the cause for comprehension decline when reading on a smartphone by simultaneously measuring respiration and brain activity during reading in 34 healthy individuals. We found that, compared to reading on a paper medium, reading on a smartphone elicits fewer sighs, promotes brain overactivity in the prefrontal cortex, and results in reduced comprehension. Furthermore, reading on a smartphone affected sigh frequency but not normal breathing, suggesting that normal breathing and sigh generation are mediated by pathways differentially influenced by the visual environment. A path analysis suggests that the interactive relationship between sigh inhibition and overactivity in the prefrontal cortex causes comprehension decline. These findings provide new insight into the respiration-mediated mechanisms of cognitive function.
Change in body perception requires recalibration of various sensory inputs. However, it is less known how information other than sensations relates to the recalibration of body perception. Here, we ...focused on the relationship between respiration and cognition and investigated whether respiratory rhythms are related to the recalibration of hand perception. We built a visual feedback environment, in which a mannequin hand moved in conjunction with its own respiratory rhythm, and participants performed an experiment under conditions in congruency/incongruency for spatial and temporal factors. The temporal and spatial congruency between own respiratory rhythm and the mannequin hand markedly facilitated the phenomenon of hand ownership sense transfer to the mannequin hand, while incongruency had little effect on the change in hand ownership. The finding suggests that an internal model in the brain allows respiratory rhythms to be involved in the adaptation of the body's neural representations.
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•3D-kinematic analysis determined fine gait and joint movements of hindlimbs in mice.•Unilateral brain damage (BD) affected the gait and trajectory of ankles in both limbs.•BD with ...exercise mice improved movements without compensatory operation.
Motor dysfunction, such as gait impairment, is a major disability induced by traumatic brain injury or stroke. Treadmill running is often used as a physical exercise (Ex) clinically and experimentally for the recovery of patients. In animal experiments, although dynamic behavioral deficits can be evaluated using scoring systems, local and minor behaviors are difficult to determine. This study aims to evaluate motor dysfunction and recovery after brain damage (BD) with/without mild-intensity running Ex in mice using three-dimensional (3D) kinematic analysis. To determine exercise intensity, C57/BL6-strain male young adult mice were examined in an incremental running test while the pulmonary gas exchange of O2 and CO2 were measured. The animals were then subjected to left hemidecortication as BD, and some mice performed Ex (10 m/min for 30 min 5 times/wk) for 4 weeks. The BD with Ex and BD or sham-operated mice (sham) without (w/o) Ex had their gait recorded by four synchronized cameras, and gait was evaluated via 3D-kinematic analysis. The BD w/o Ex mice significantly differed in stride, step, and stride width for both limbs compared to the sham w/o Ex mice. The BD with Ex mice showed improvement. The BD w/o Ex mice had restricted ankle movements and impairment in dorsal/planter flexing using trajectory analysis. Consistent with these impairments, the nonaffected side also exhibited a different trajectory, suggesting compensatory movements. These results suggest that the appropriate Ex after BD recovered motor function. Furthermore, the present study suggested that 3D-kinematic analysis is a powerful tool for detecting minor behavioral alterations owing to the impairment of the affected side and the compensation of the unaffected side.
New neurons are constantly generated in the olfactory bulb and the dentate gyrus of the hippocampus. The number of new cells depends on sensory experiences; an enriched odor environment increases ...neurogenesis and neural survival. The aim of this study was to investigate whether enriched olfactory stimuli affect neurogenesis of mitral and granule cells of the olfactory bulb and dentate gyrus, and whether respiratory activity accompanied by olfactory stimuli is associated with new cells in these regions. To this end, respiratory activity during enriched odor stimuli was continuously measured in mice and new cells were stained with 5-bromo-2′-deoxyuridine, which selectively labels proliferating cells. An enriched olfactory environment significantly increased neurogenesis of mitral and granule cells in the olfactory bulb, but not in the dentate gyrus. Additionally, an increase of new granule cells under the enriched odor condition was correlated to sniffing frequency power, which had a significantly different pattern from the no-odor condition. A high respiratory frequency with frequent odor stimuli may be associated with activation of granule cells to form inhibitory neurons and this active state might increase granule cell neurogenesis.
•Enriched odor environment increases granule cell neurogenesis in the olfactory bulb.•Enriched odor environment increases mitral cell neurogenesis in the olfactory bulb.•The increase in new granule cells was correlated with sniffing frequency.•Animals with a high sniff frequency in response to odor had increased granule cell neurogenesis.
Cognitive function declines with age and has been shown to be associated with atrophy in some brain regions, including the prefrontal cortex. However, the details of the relationship between aging ...and cognitive dysfunction are not well understood.
Across a wide range of ages (24- to 85-years-old), this research measured the gray matter volume of structural magnetic resonance imaging data in 39 participants, while some brain regions were set as mediator variables to assess the cascade process between aging and cognitive dysfunction in a path analysis.
Path analysis showed that age affected the left hippocampus, thereby directly affecting the left superior frontal gyrus. Furthermore, the gyrus directly affected higher order flexibility and maintenance abilities calculated as in the Wisconsin card sorting test, and the two abilities affected the assessment of general cognitive function.
Our finding suggests that a cascade process mediated by the left hippocampus and left superior frontal gyrus is involved in the relationship between aging and cognitive dysfunction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Specific odors can induce memories of the past, especially those associated with autobiographical and episodic memory. Odors associated with autobiographical memories have been found to elicit ...stronger activation in the orbitofrontal cortex, hippocampus, and parahippocampus compared with odors not linked to personal memories. Here, we examined whether continuous odor stimuli associated with autobiographical memories could activate the above olfactory areas in older adults and speculated regarding whether this odor stimulation could have a protective effect against age-related cognitive decline. Specifically, we used functional magnetic resonance imaging to investigate the relationship between blood oxygen levels in olfactory regions and odor-induced subjective memory retrieval and emotions associated with autobiographical memory in older adults. In our group of healthy older adults, the tested odors induced autobiographical memories that were accompanied by increasing levels of retrieval and the feeling of being “brought back in time.” The strength of the subjective feelings, including vividness of the memory and degree of comfort, impacted activation of the left fusiform gyrus and left posterior orbitofrontal cortex. Further, our path model suggested that the strength of memory retrieval and of the emotions induced by odor-evoked autobiographical memories directly influenced neural changes in the left fusiform gyrus, and impacted left posterior orbitofrontal cortex activation through the left fusiform response.
Introduction
Pathological abnormalities first appear in the medial temporal regions including entorhinal cortex and parahippocampus in patients with Alzheimer's disease. Previous studies showed that ...olfactory decline in elderly subjects was associated with volume reductions in the left hippocampus and left parahippocampus without cognitive impairment. The aim of this study is to investigate the link between olfaction and volume reductions in the medial temporal regions including the parahippocampus, entorhinal cortex, and hippocampal subfields.
Method
27 elderly subjects and 27 young controls were measured olfaction acuity, cognitive function, and structural magnetic resonance imaging. Image processing and gray matter volumetric segmentation were performed with FreeSurfer. Volume data were analyzed with SPSS Statistics software.
Results
Interesting results of this study were that volume reduction in the entorhinal cortex was not directly linked with declining olfactory ability. Volume reduction in the left entorhinal cortex was correlated with volume reduction in the left parahippocampus and dentate gyrus. However, left parahippocampus volume reduction had the greatest impact on olfactory decline, and the entorhinal cortex and dentate gyrus might additionally contribute to olfactory decline.
Conclusion
Our results indicate that olfactory decline may be directly reflected in the medial temporal regions as reduced parahippocampus volumes, rather than as morphological changes in the entorhinal cortex and hippocampus. The parahippocampus may play an important role in the association between memory retrieval and olfactory identification.
Left: Visualization of brain segmentation in a single subject with FreeSurfer. The entorhinal cortex (ENT) is indicated in red, and the parahippocampus (para‐HI) is indicated in green. Right: Visualization of hippocampal subfield segmentation in a single subject with each subfield represented by a different color.
This study aimed to clarify the differential exercise capacity between 2-month-old and 10-month-old mice using an incremental running test. Metabolic and ventilatory responses and blood lactate ...concentration were measured to evaluate exercise capacity. We examined whether incremental running test results reflected metabolic and ventilatory responses and blood lactate concentration observed during the steady-state running test. Metabolic response significantly declined with age, whereas ventilatory response was similar between the groups. A low-intensity/moderate exercise load of 10/min in an incremental running test was performed on both mice for 30 min. They showed a characteristic pattern in ventilatory response in 10-month mice. The results of incremental running tests didn’t necessarily reflect the steady-state metabolic and ventilatory responses because some parameters showed an approximation and others did not in incremental and steady-state tests, which changed with age. Our study suggests metabolic and ventilatory responses depending on age and provides basic knowledge regarding the objective and quantitative assessment of treadmill running in an animal model.
•The physiological data during running exercise was evaluated in different aged mice.•The ventilatory response during exercise was measured and clarified.•A specific response of ventilation was revealed during exercise in aged animals.•This study provided quantitative information for animal exercise prescription.
We reported that estradiol (E2) affects the medial preoptic area in the hypothalamus, a thermoregulatory center, decreases the Tskn (skin temperature) of the tail, and maintains the Tb (body ...temperature) in the cold in ovariectomized rats. E2 facilitates the thermoregulatory behavior, evaluated by the tail-hiding behavior of rats hiding their tails under their bodies, and suppressed neural activity in the insula of the brain. These results indicate that E2 centrally affects and facilitates autonomic and behavioral thermoregulation in the cold. The effect of E2 on thermoregulatory responses through cold receptors, transient receptor potential melastatin-8 (TRPM8) and transient receptor potential ankyrin 1 (TRPA1), were investigated. E2 suppressed the elevation of Tb by the application of menthol, a TRPM8 agonist; however, it did not affect Tb or Tskn of the tail after the application of cinnamaldehyde, a TRPA1 agonist. Thus, E2 modifies thermoregulation via TRPM8. In young women, Tskn decreased in all phases of the menstrual cycle after menthol application to the dorsum of the foot; however, cold unpleasantness occurred only in the preovulatory phase, the higher E2 concentration phase. Thus, E2 induces mental hypersensitivity to the cold through TRPM8. In ovariectomized rats, the effect of E2 on thermoregulation was investigated through the TWIK-related K+ channel (TREK), a new cold receptor. E2 administration increased Tb after the administration of ostruthin, a TREK agonist. These results indicate that E2 modulates thermoregulation in the cold through TRPM8, TREK, and centrally.
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