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Focal damage due to stroke causes widespread abnormal changes in brain function and hemispheric asymmetry. In this study, functional near‐infrared spectroscopy (fNIRS) was used to collect resting‐state hemoglobin data from 85 patients with subacute stroke and 26 healthy controls, to comparatively analyze the characteristics of lateralization after stroke in terms of cortical activity, functional networks, and hemodynamic lags. Higher intensity of motor cortical activity, lower hemispheric autonomy, and more abnormal hemodynamic leads or lags were found in the affected hemisphere. Lateralization metrics of the three aspects were all associated with the Fugl‐Meyer score. The results of this study prove that three lateralization metrics may provide clinical reference for stroke rehabilitation. Meanwhile, the present study piloted the use of resting‐state fNIRS for analyzing hemodynamic lag, demonstrating the potential of fNIRS to assess hemodynamic abnormalities in addition to the study of cortical neurological function after stroke. [ABSTRACT FROM AUTHOR]

Background: To explore the neural changes of brain activity in rats with circumscribed capsular infarcts to find a new therapeutic target for promoting the functional recovery. Methods: A total of 18 capsular infarct rats and 18 normal rats were conducted in this study. All animal use procedures were strictly in accordance with the guide for the care and use of laboratory animals. After establishing the photothrombotic capsular infarct model, the functional magnetic resonance imaging (fMRI) data were collected and analyzed. Results: The fMRI results indicated that the passive movement would induce strong activation in caudate, putamen, frontal association somatosensory cortex, thalamus dorsolateral, and thalamus midline dorsal in control group, and the passive movement would only induce limited activation mostly in somatosensory cortex, thalamus dorsolateral, and thalamus midline dorsal in capsular infarct models. Capsular infarct makes the cortical activity weaken in sensory‐related cortex and subcortical nuclei, including capsular area and thalamus. Conclusions: Such findings imply that the posterior limb of internal capsule (PLIC) is connected to these structures in function, interacts together with them, and, accordingly, the lesion of PLIC manifests the related symptoms. [ABSTRACT FROM AUTHOR]

Sleep pressure that builds up gradually during the extended wakefulness results in sleep rebound. Several lines of evidence, however, suggest that wake per se may not be sufficient to drive sleep rebound and that rapid eye movement (REM) and non‐rapid eye movement (NREM) sleep rebound may be differentially regulated. In this study, we investigated the relative contribution of brain versus physical activities in REM and NREM sleep rebound by four sets of experiments. First, we forced locomotion in rats in a rotating wheel for 4 hr and examined subsequent sleep rebound. Second, we exposed the rats lacking homeostatic sleep response after prolonged quiet wakefulness and arousal brain activity induced by chemoactivation of parabrachial nucleus to the same rotating wheel paradigm and tested if physical activity could rescue the sleep homeostasis. Third, we varied motor activity levels while concurrently inhibiting the cortical activity by administering ketamine or xylazine (motor inhibitor), or ketamine + xylazine mixture and investigated if motor activity in the absence of activated cortex can cause NREM sleep rebound. Fourth and finally, we manipulated cortical activity by administering ketamine (that induced active wakefulness and waking brain) alone or in combination with atropine (that selectively inhibits the cortex) and studied if cortical inhibition irrespective of motor activity levels can block REM sleep rebound. Our results demonstrate that motor activity but not cortical activity determines NREM sleep rebound whereas cortical activity but not motor activity determines REM sleep rebound. [ABSTRACT FROM AUTHOR]

The effects of physical activity on brain function can be assessed through event-related potentials ( P300) that reflect cortical activities related to cognitive functions. P300 latency represents the information processing time; longer latencies represent slower processing. P300 amplitude is associated with the attentional system and working memory, with higher amplitudes representing more preserved functions. This systematic review summarizes the literature concerning the effects of physical activity and exercise on P300 in the elderly. Databases, including Web of Science, Scopus, Psyc INFO, MEDLINE/ PubMed, and Biological Abstracts, were searched for articles up to November 2015. Articles were considered for inclusion if they were studies of the elderly, assessed P300, and evaluated the influence of physical activity on P300 or the effect of physical exercise training on P300. Of the 1227 articles found, 14 investigations matched the inclusion criteria. Nine analyzed the influence of physical activity on P300 in the elderly, and five examined the effects of physical exercise on P300 in the elderly. The obtained results showed that physically active elderly people have shortened P300 latency and higher amplitude. Physical exercise, especially those involving aerobic or resistance training, seems to have marked beneficial effects on P300 in the elderly. Evidence shows that physical activity and physical exercise positively influence cortical activities related to cognitive functions, as indicated by P300, in elderly people. [ABSTRACT FROM AUTHOR]

The baroreflex consists of a negative feedback loop adjusting heart activity to blood pressure fluctuations. This review is concerned with interactions between baroreflex function and behavior. In addition to changes in baroreflex cardiac control subject to behavioral manipulations, interindividual differences in reflex function predicted psychological and central nervous features. The sensitivity of the reflex was inversely related to cognitive performance, evoked potential amplitudes, experimental pain sensitivity, and the severity of clinical pain. Possible variables moderating the strength of the associations are tonic blood pressure, gender, and psychiatric disease. It is suggested that these observations reflect inhibition of higher brain function by baroreceptor afferents. While in many cases increased baroreflex function implies stronger inhibition, individual and situational factors modulate the behavioral impact of cardiac regulation. [ABSTRACT FROM AUTHOR]

After reconstruction of the anterior cruciate ligament (ACL) afferent proprioceptive information from the knee joint may be altered. In order to examine changes in central activation patterns, spectral features of the electroencephalography (EEG) were measured. Patients after ACL reconstruction and healthy controls carried out an knee-angle reproduction task in a groups × limbs × trials design. Cortical activity was recorded using international standards. FFT were conducted to determine power at Theta, Alpha-1, Alpha-2 and Beta-1. Statistics show significantly larger aberrations in the reconstructed limbs compared with the controls whereas there are no differences between the uninvolved land controls. Brain activity demonstrates significantly higher frontal Theta-power (F3, F4, F8) in both limbs of the ACL group vs the controls and a significantly higher Alpha-2 power was shown in the ACL-reconstructed limb compared with controls at parietal positions (P3, P4). No such differences were found between the uninvolved side and the controls. The EEG was able to measure a change in joint position sense at the cortical level after the reconstruction of the ACL. The results of these findings might indicate differences in focused attention with involvement of the anterior cingulate cortex (frontal Theta) and sensory processing in the parietal somatosensory cortex (Alpha-2). [ABSTRACT FROM AUTHOR]

Abstract When people divide attention between two sensory modalities and respond rapidly to stimuli in either modality, the reaction times (RTs) are longer than when they selectively attend and respond to one sensory modality. There is a further increase in RT when subjects use different fingers to respond to stimuli from different modalities as compared to when they use the same finger for both modalities. Here we use functional magnetic resonance imaging to show that division of attention bilaterally activates the caudal prefrontal areas near the precentral sulcus and areas in the intraparietal sulcus. All RT tasks, whether different fingers for different modalities or one finger for both modalities was used, activated identical motor areas 4a, 4p, supplementary and cingulate, the basal ganglia and the ventral anterior thalami. The increased blood oxygen level-dependent signal from motor cortical areas was anatomically distinct from the prefrontal/parietal areas. These anatomically dissociable neural substrates of division of attention and motor control may be responsible for the different types of RT delays that we have found. In the brain, there were no differences in the BOLD signal irrespective of whether the effector was specified a priori or was specified only after the sensory signal was received. [ABSTRACT FROM AUTHOR]

We investigated the neuromagnetic responses to mechanical stimulation of the oesophagus. In six healthy right-handed volunteers (mean age 31.6 years) the proximal and distal oesophagus were stimulated by electronically controlled pump-inflation of a silicone balloon once every 4.5–5.5 sec (dwell time 145 msec). The balloon volume was adjusted to induce different sensation levels (i) just above threshold of perception, (ii) strong sensation and (iii) painful sensation. Evoked magnetic brain responses were recorded time-locked to stimulus onset with a Neuromag-122TM whole-head neuromagnetometer and modelled as equivalent current diploe (ECD) sources. ECDs were superimposed on individual magnetic resonance imaging (MRI) scans. Magnetic brain responses following distal oesophageal stimulation were adequately explained by a time-varying 2–4 dipole model with unilateral or bilateral sources in second somatosensory cortex and later sources in the frontal cortex. With increasing stimulus intensities, latencies of the sources decreased and amplitudes increased. Proximal oesophageal stimulation led to activation of source areas spatially similar to those of distal oesophageal stimulation but with shorter response latencies. Both painful and nonpainful mechanical stimulation of the oesophagus activate the second somatosensory cortex (SII). Evidence for topographic organization of oesophageal afferents in SII is poor. [ABSTRACT FROM AUTHOR]