The reduction of the body facilitation effect in the paretic limb suggests the decline of body-specific attention to the paretic one in patients with chronic hemiparesis. This decline of body-specific attention, leading to neglect for the paretic limb, will be one of the most serious problems for rehabilitation based on use-dependent plasticity.

Learned nonuse is a major problem in upper limb (UL) rehabilitation after stroke. Among the various factors that contribute to learned nonuse, recent studies have focused on body representation of the paretic limb in the brain. We previously developed a method to measure body-specific attention, as a marker of body representation of the paretic limb and revealed a decline in body-specific attention to the paretic limb in chronic stroke patients by a cross-sectional study. However, longitudinal changes in body-specific attention and paretic arm use in daily life (real-world arm use) from the onset to the chronic phase, and their relationship, remain unknown. Here, in a longitudinal, prospective, observational study, we sought to elucidate the longitudinal changes in body-specific attention to the paretic limb and real-world arm use, and their relationship, by using accelerometers and psychophysical methods, respectively, in 25 patients with subacute stroke. Measurements were taken at baseline (TBL), 2 weeks (T2w), 1 month (T1M), 2 months (T2M), and 6 months (T6M) after enrollment. UL function was measured using the Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT). Real-world arm use was measured using accelerometers on both wrists. Body-specific attention was measured using a visual detection task. The UL function and real-world arm use improved up to T6M. Longitudinal changes in body-specific attention were most remarkable at T1M. Changes in body-specific attention up to T1M correlated positively with changes in real-world arm use up to T6M, and from T1M to T6M, and the latter more strongly correlated with changes in real-world arm use. Changes in real-world arm use up to T2M correlated positively with changes in FMA up to T2M and T6M. No correlation was found between body-specific attention and FMA scores. Thus, these results suggest that improved body-specific attention to the paretic limb during the early phase contributes to increasing long-term real-world arm use and that increased real-world use is associated with the recovery of UL function. Our results may contribute to the development of rehabilitation strategies to enhance adaptive changes in body representation in the brain and increase real-world arm use after stroke.

Introduction: The disabling effects of dementia, an incurable disease with little effect on mortality, affect society far more than many other conditions. Objective: The aim of this study was to stop or delay the onset of dementia using lowcost methods such as physical exercise. Methods: Senescence-accelerated model-prone (SAMP) 10 mice were made to perform a user-friendly shaking exercise for 25 weeks. The motor function and hippocampal functions (learning, spatial cognition) of the mice were evaluated using behavioral experiments. The degree of hippocampal aging was evaluated based on brain morphology. The association between behavioral performance of the mice and the degree of hippocampal aging was then evaluated. Results: The behavioral test results showed that the shaking group had higher motor coordination (p < 0.01) and motor learning (p < 0.05). Significantly higher performances in the learning ability were observed in the shaking group at a middle-period experiment (p < 0.05); the spatial cognitive functions also improved (p < 0.05). The shaking group showed delayed ageing of cells in the dentate gyrus (DG; area: p < 0.01) and cornu Ammonis (CA; area: p < 0.01) regions of the hippocampus. Conclusions: The shaking exercise enhances the activity of mice and reduces age-associated decreases in learning and spatial cognitive functions. Regarding hippocampal morphology, shaking exercise can prevent non-functional protein accumulation, cell atrophy, and cell loss. Specifically, shaking exercise protects cell growth and regeneration in the DG area and enhances the learning function of the hippocampus. Furthermore, shaking exercise maintained the spatial cognitive function of cells in the CA3 and CA1 regions, and prevented the chronic loss of CA2 transmission that decreased the spatial memory decline in mice.

<b><i>Introduction:</i></b> Patients with dementia show reduced adaptive, behavioral, and physiological responses to environmental threats. Physical exercise is expected to delay brain aging, maintain cognitive function and, consequently, help dementia patients face threats and protect themselves skillfully. <b><i>Methods:</i></b> To confirm this, we aimed to investigate the effects of the shaking exercise on the avoidance function in the senescence-accelerated mouse-prone strain-10 (SAMP-10) model at the behavioral and tissue levels. SAMP-10 mice were randomized into 2 groups: a control group and a shaking group. The avoidance response (latency) of the mice was evaluated using a passive avoidance task. The degree of amygdala and hippocampal aging was evaluated based on the brain morphology. Subsequently, the association between avoidance response and the degree of amygdala-hippocampal aging was evaluated. <b><i>Results:</i></b> Regarding the passive avoidance task, the shaking group showed a longer latency period than the control group (<i>p</i> &#x3c; 0.05), even and low intensity staining of ubiquitinated protein, and had a higher number of and larger neurons than those of the control group. The difference between the groups was more significant in the BA region of the amygdala and the CA1 region of the hippocampus (staining degree: <i>p</i> &#x3c; 0.05, neuron size: <i>p</i> &#x3c; 0.01, neuron counts: <i>p</i> &#x3c; 0.01) than in other regions. <b><i>Conclusions:</i></b> The shaking exercise prevents nonfunctional protein (NFP) accumulation, neuron atrophy, and neuron loss; delays the aging of the amygdala and hippocampus; and maintains the function of the amygdala-hippocampal circuit. It thus enhances emotional processing and cognition functions, the memory of threats, the skillful confrontation of threats, and proper self-protection from danger.

To execute the intended movement, the brain directs attention, called body-specific attention, to the body to obtain information useful for movement. Body-specific attention to the hands has been examined but not to the feet. We aimed to confirm the existence of body-specific attention to the hands and feet, and examine its relation to motor and sensory functions from a behavioral perspective. The study included two groups of 27 right-handed and right-footed healthy adults, respectively. Visual detection tasks were used to measure body-specific attention. We measured reaction times to visual stimuli on or off the self-body and calculated the index of body-specific attention score to subtract the reaction time on self-body from that off one. Participants were classified into low and high attention groups based on each left and right body-specific attention index. For motor functions, Experiment 1 comprised handgrip strength and ball-rotation tasks for the hands, and Experiment 2 comprised toe grip strength involved in postural control for the feet. For sensory functions, the tactile thresholds of the hands and feet were measured. The results showed that, in both hands, the reaction time to visual stimuli on the hand was significantly lesser than that offhand. In the foot, this facilitation effect was observed in the right foot but not the left, which showed the correlation between body-specific attention and the normalized toe gripping force, suggesting that body-specific attention affected postural control. In the hand, the number of rotations of the ball was higher in the high than in the low attention group, regardless of the elaboration exercise difficulty or the left or right hand. However, this relation was not observed in the handgripping task. Thus, body-specific attention to the hand is an important component of elaborate movements. The tactile threshold was higher in the high than in the low attention group, regardless of the side in hand and foot. The results suggested that more body-specific attention is directed to the limbs with lower tactile abilities, supporting the sensory information reaching the brain. Therefore, we suggested that body-specific attention regulates the sensory information to help motor control.