On the Power of Constructive Criticism.

The editorial discusses the practice of peer review for SPIE Neurophotonics.

Regional brain activity and neural network changes in cognitive-motor dual-task interference: A functional near-infrared spectroscopy study.

Previous neuroimaging studies have reported dual-task interference (DTi) and deterioration of task performance in a cognitive-motor dual task (DT) compared to that in a single task (ST). Greater frontoparietal activity is a neural signature of DTi; nonetheless, the underlying mechanism of cortical network in DTi still remains unclear. This study aimed to investigate the regional brain activity and neural network changes during DTi induced by highly demanding cognitive-motor DT.

Correlation of diabetic renal hypoperfusion with microvascular responses of the skeletal muscle: a rat model study using diffuse correlation spectroscopy.

Using diffuse correlation spectroscopy, we assessed the renal blood flow and thigh muscle microvascular responses in a rat model of type 2 diabetes. The blood flow index at the renal surface decreased significantly with arterial clamping, cardiac extirpation, and the progression of diabetic endothelial dysfunction. Renal blood flow measured in diabetic and nondiabetic rats also showed a significant correlation with the reactive hyperemic response of the thigh muscle.

Differential changes in blood flow and oxygen utilization in active muscles between voluntary exercise and electrical muscle stimulation in young adults.

The physiological effects on blood flow and oxygen utilization in active muscles during and after involuntary contraction triggered by electrical muscle stimulation (EMS) remain unclear, particularly compared with those elicited by voluntary (VOL) contractions. Therefore, we used diffuse correlation and near-infrared spectroscopy (DCS-NIRS) to compare changes in local muscle blood flow and oxygen consumption during and after these two types of muscle contractions in humans. Overall, 24 healthy young adults participated in the study, and data were successfully obtained from 17 of them.

Deep-learning-based separation of shallow and deep layer blood flow rates in diffuse correlation spectroscopy.

Diffuse correlation spectroscopy faces challenges concerning the contamination of cutaneous and deep tissue blood flow. We propose a long short-term memory network to directly quantify the flow rates of shallow and deep-layer tissues. By exploiting the different contributions of shallow and deep-layer flow rates to auto-correlation functions, we accurately predict the shallow and deep-layer flow rates (RMSE = 0.

Gait-combined closed-loop brain stimulation can improve walking dynamics in Parkinsonian gait disturbances: a randomised-control trial.

Objective: Gait disturbance lowers activities of daily living in patients with Parkinson's disease (PD) and related disorders. However, the effectiveness of pharmacological, surgical and rehabilitative treatments is limited. We recently developed a novel neuromodulation approach using gait-combined closed-loop transcranial electrical stimulation (tES) for healthy volunteers and patients who are post-stroke, and achieved significant entrainment of gait rhythm and an increase in gait speed.

Case report: Backward gait training combined with gait-synchronized cerebellar transcranial alternating current stimulation in progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is characterized by recurrent falls caused by postural instability, and a backward gait is considered beneficial for postural instability. Furthermore, a recent approach for rehabilitation combined with gait-oriented synchronized stimulation using non-invasive transcranial patterned stimulation could be promising for balance function. Here, we present a case of PSP with backward gait training combined with gait-synchronized transcranial alternating current stimulation (tACS).

Case report: A novel approach of closed-loop brain stimulation combined with robot gait training in post-stroke gait disturbance.

Most post-stroke patients have long-lasting gait disturbances that reduce their daily activities. They often show impaired hip and knee joint flexion and ankle dorsiflexion of the lower limbs during the swing phase of gait, which is controlled by the corticospinal tract from the primary motor cortex (M1). Recently, we reported that gait-synchronized closed-loop brain stimulation targeting swing phase-related activity in the affected M1 can improve gait function in post-stroke patients.

Emotional modulation of cortical activity during gum chewing: A functional near-infrared spectroscopy study.

Distinct brain regions are known to be associated with various emotional states. Cortical activity may be modulated by emotional states that are triggered by flavors during food intake. We examined cortical activity during chewing with different flavors and assessed the emotional modulation of cortical activity using multichannel near-infrared spectroscopy.

Theta activity in semantic priming under visual crowding as revealed by magnetoencephalography.

Crowding refers to impaired object recognition of peripheral visual targets caused by nearby flankers. It has been shown that the response to a word was faster when it was preceded by a semantically related than unrelated crowded prime, demonstrating that semantic priming survives crowding. This study examines neural correlates of semantic priming under visual crowding using magnetoencephalography with four conditions: prime (isolated, crowded) x prime-target relationship (related, unrelated).

Altered metabolic connectivity between the amygdala and default mode network is related to pain perception in patients with cancer.

We investigated the neural correlates for chronic cancer pain conditions by retrospectively analyzing whole brain regions on 18F-fluoro-2-deoxyglucose-positron emission tomography images acquired from 80 patients with head and neck squamous cell carcinoma and esophageal cancer. The patients were divided into three groups according to perceived pain severity and type of analgesic treatment, namely patients not under analgesic treatment because of no or minor pain, patients with good pain control under analgesic treatment, and patients with poor pain control despite analgesic treatment. Uncontrollable cancer pain enhanced the activity of the hippocampus, amygdala, inferior temporal gyrus, and temporal pole.

Evaluation of Local Skeletal Muscle Blood Flow in Manipulative Therapy by Diffuse Correlation Spectroscopy.

Manipulative therapy (MT) is applied to motor organs through a therapist's hands. Although MT has been utilized in various medical treatments based on its potential role for increasing the blood flow to the local muscle, a quantitative validation of local muscle blood flow in MT remains challenging due to the lack of appropriate bedside evaluation techniques. Therefore, we investigated changes in the local blood flow to the muscle undergoing MT by employing diffuse correlation spectroscopy, a portable and emerging optical measurement technology that non-invasively measures blood flow in deep tissues.

Development of Virtual Reality-based Gait Training System Simulating Personal Home Environment.

We developed a virtual reality (VR)-based gait training system, which could be used by inpatients to train their gait function in a simulated home environment, to reduce the risk of falling after discharge. The proposed system simulates the home environment on a head-mounted display, in which a user can walk around freely. The system provides visual feedback in the event of a collision with an indoor object such as a wall or furniture, prompting the user to modify his or her gait pattern.

Bidirectional Connectivity Between Broca's Area and Wernicke's Area During Interactive Verbal Communication.

This investigation aims to advance the understanding of neural dynamics that underlies live and natural interactions during spoken dialogue between two individuals. The underlying hypothesis is that functional connectivity between canonical speech areas in the human brain will be modulated by social interaction. Granger causality was applied to compare directional connectivity across Broca's and Wernicke's areas during verbal conditions consisting of interactive and noninteractive communication.

Rapid vasodilation within contracted skeletal muscle in humans: new insight from concurrent use of diffuse correlation spectroscopy and Doppler ultrasound.

Previous studies showed that conduit artery blood flow rapidly increases after even a brief contraction of muscles within the dependent limb. Whether this rapid hyperemia occurs within contracted skeletal muscle in humans has yet to be confirmed, however. We therefore used diffuse correlation spectroscopy (DCS) to characterize the rapid hyperemia and vasodilatory responses within the muscle microvasculature induced by single muscle contractions in humans.

Neurobiological influence of comorbid conditions in young patients diagnosed with gaming disorder: A whole-brain functional connectivity study based on a data driven method.

Gaming disorder, which is characterized by multiple cognitive and behavioral symptoms, often has comorbid psychiatric conditions such as depression and attention-deficit hyperactivity disorder. Neurobiological effects of the comorbid disorders so far reported are not converging, exhibiting positive and negative alterations of the connectivity in brain networks. In this study, we conducted resting-state functional magnetic-resonance imaging and whole brain functional connectivity analyses for young participants consisting of 40 patients diagnosed with the gaming disorder, with and without comorbid conditions, and 29 healthy controls.

Real-Time Eye-to-Eye Contact Is Associated With Cross-Brain Neural Coupling in Angular Gyrus.

Direct eye contact between two individuals is a salient social behavior known to initiate and promote interpersonal interaction. However, the neural processes that underlie these live interactive behaviors and eye-to-eye contact are not well understood. The Dynamic Neural Coupling Hypothesis presents a general theoretical framework proposing that shared interactive behaviors are represented by cross-brain signal coherence.

Detection of Music Preferences using Cerebral Blood Flow Signals.

Music has been used for entertainment as well as for medical treatments that remedies physical conditions or psychiatric disorders. It is reported that better outcome can be expected when the music was selected along with personal preferences for these therapies. However it is difficult to find out personalized favorite music if the patient has difficulty in verbal communication due to ageing or developmental disorders.

The effect of masticatory behaviour on generalized attention in heathy volunteers.

Aim: As our society ages, the number of people living with dementia also steadily increases. Some work has focused on masticatory behaviour as a form of daily health care that could help prevent cognitive impairment and dementia. However, it is not yet clear how masticatory behaviour influences various cognitive functions.

The Possibility of Urinary Liver-Type Fatty Acid-Binding Protein as a Biomarker of Renal Hypoxia in Spontaneously Diabetic Torii Fatty Rats.

Background: Renal hypoxia is an aggravating factor for tubulointerstitial damage, which is strongly associated with renal prognosis in diabetic kidney disease (DKD). Therefore, urinary markers that can detect renal hypoxia are useful for monitoring DKD.

Objective: To determine the correlation between urinary liver-type fatty acid-binding protein (L-FABP) and renal hypoxia using a novel animal model of type 2 diabetes.

Prefrontal activation related to spontaneous creativity with rock music improvisation: A functional near-infrared spectroscopy study.

Understanding how the brain modulates improvisation has been the focus of numerous studies in recent years. Models have suggested regulation of activity between default mode and executive control networks play a role in improvisational execution. Several studies comparing formulaic to improvised sequences support this framework and document increases in activity in medial frontal lobe with decreased activity in the dorsolateral prefrontal cortex (DLPFC).

Co-localization of theta-band activity and hemodynamic responses during face perception: simultaneous electroencephalography and functional near-infrared spectroscopy recordings.

Face-specific neural processes in the human brain have been localized to multiple anatomical structures and associated with diverse and dynamic social functions. The question of how various face-related systems and functions may be bound together remains an active area of investigation. We hypothesize that face processing may be associated with specific frequency band oscillations that serve to integrate distributed face processing systems.

Remote photonic sensing of cerebral hemodynamic changes via temporal spatial analysis of acoustic vibrations.

A novel photonic method for remote monitoring of task-related hemodynamic changes in human brain activation is presented. Physiological processes associated with neural activity, such as nano-vibrations due to blood flow and tissue oxygenation in the brain, are detected by remote sensing of nano-acoustic vibrations using temporal spatial analysis of defocused self-interference random patterns. Temporal nanometric changes of the speckle pattern due to visual task-induced hemodynamic responses were tracked by this method.

Difference in the integrated effects of sympathetic vasoconstriction and local vasodilation in human skeletal muscle and skin microvasculature.

We investigated the integration of sympathetic vasoconstriction and local vasodilation in the skeletal muscle and skin microvasculature of humans. In 39 healthy volunteers, we simultaneously measured the blood flow index in the flexor carpi radialis muscle using diffuse correlation spectroscopy and the skin using laser-Doppler flowmetry. We examined the effects of acute sympathoexcitation induced by forehead cooling on relatively weak and robust vasodilatory responses during postocclusive reactive hyperemia (PORH) induced by 70-sec and 10-min arterial occlusion in the upper arm.