Development of a dual wavelength 32-channel functional near-infrared spectroscopy based neuroimaging system

M. Atif Yaqub,M. Raheel Bhutta,Jongseo Park,Keum-Shik Hong 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

Advancements in the field of neuroscience is essential for our society as the fatality rate due to brain degenerative diseases is quite high. Various modalities have been in use for a long time for brain monitoring. The inexpensive, portable, and easy to operate nature of functional near-infrared spectroscopy (fNIRS) has demonstrated that it can be used to measure the concentration changes in the blood chromophores during an activity. In this paper, we have demonstrated our developed fNIRS system that is able to determine the concentration changes in oxy-hemoglobin and deoxy-hemoglobin and display them in real-time as well as record the data for future use. Our system is composed of a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a serial communication module, and a battery. To test the functionality of the system, phantom brain model was used. During the experiment, the fNIRS system showed the acquired intensity values as well as corresponding hemoglobin changes for 32 channels. The results, obtained during the testing of our system, show that the acquired signal intensity values decrease with increase in the separation between the near-infrared light transmitter and emitter.

Development of a High Density Neuroimaging System Using Functional Near-Infrared Spectroscopy

M. Atif Yaqub,Amad Zafar,Usman Ghafoor,Keum-Shik Hong 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

The progress in the field of neuroscience is critical in our rapidly aging society as the fatality rate due to brain degenerative diseases is rising. Recently, functional near-infrared spectroscopy (fNIRS) has established its application in measuring the blood chromophores’ concentration changes during an activity. In this developmental study, we have introduced our lab-developed fNIRS system that is able to compute the concentration changes in oxy-hemoglobin and deoxy-hemoglobin from the optical NIR light signals. We have employed 128 dual wavelength light emitting diodes (LEDs) of 735 nm and 850 nm in the designed system. LED driving circuit was designed by using serial peripheral interface based output expansion chips. A single photodiode (PD) was used for measuring the NIR light intensity received after passing through the brain tissue and getting absorbed and scattered in the process. Our system uses a battery for supplying power to the system. A wireless communication module was interfaced with the system for transferring the fNIRS data to our developed software running on a host computer. The software is capable of displaying the real-time data and record it for future processing. To test the functionality of the system, a phantom brain model was used. The LED and PD were attached to the phantom and multiple combinations of LEDs were tested to provide robust data. Our lab-developed fNIRS system showed the acquired intensity values for both wavelengths which corresponds to hemoglobin changes in 128 channels.

Effects of HD-tDCS on Resting-State Functional Connectivity in the Prefrontal Cortex: An fNIRS Study

Yaqub, M. Atif,Woo, Seong-Woo,Hong, Keum-Shik Hindawi Limited 2018 Complexity Vol.2018 No.-

<P>Functional connectivity is linked to several degenerative brain diseases prevalent in our aging society. Electrical stimulation is used for the clinical treatment and rehabilitation of patients with many cognitive disorders. In this study, the effects of high-definition transcranial direct current stimulation (HD-tDCS) on resting-state brain networks in the human prefrontal cortex were investigated by using functional near-infrared spectroscopy (fNIRS). The intrahemispheric as well as interhemispheric connectivity changes induced by 1 mA HD-tDCS were examined in 15 healthy subjects. Pearson correlation coefficient-based correlation matrices were generated from filtered time series oxyhemoglobin (ΔHbO) signals and converted into binary matrices. Common graph theory metrics were computed to evaluate the network changes. Systematic interhemispheric, intrahemispheric, and intraregional connectivity analyses demonstrated that the stimulation positively affected the resting-state connectivity in the prefrontal cortex. The poststimulation connectivity was increased throughout the prefrontal region, while focal HD-tDCS effects induced an increased rate of connectivity in the stimulated hemisphere. The graph theory metrics clearly distinguished the prestimulation and poststimulation networks for a range of thresholds. The results of this study suggest that HD-tDCS can be used to increase functional connectivity in the prefrontal cortex. The increase in functional connectivity can be explored clinically for neurorehabilitation of patients with degenerative brain diseases.</P>

Enhancement in classification accuracy of motor imagery signals with visual aid: An fNIRS-BCI Study

Usman Ghafoor,Amad Zafar,M. Atif Yaqub,Keum-Shik Hong 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

One of the most promising brain activity utilized in brain-computer interface (BCI) is motor imagery (MI). Due to weak hemodynamic response (HR) signal, the achieved classification accuracies using MI are not sufficiently high. In this study, the enhancement in HR was investigated during motor imagery tasks of ball squeezing with the right hand. Brain signals in the form of concentration changes in oxy-hemoglobin (ΔHbO) and deoxy-hemoglobin (ΔHbR) from the left sensorimotor cortex were obtained using functional near-infrared spectroscopy (fNIRS). The experiment was separated in two sessions: In the first session the MI task was performed without a visual aid, and in the second session of the same task, the visual aid was provided: A video was played on a screen that showed a person continuously squeezing the ball, which can help in enhancing the imagination, thus improvement in HR. Later the features of averaged ΔHbO were used for classification. The active channels were selected on the basis of t-values and trials of those channels were mean to obtain averaged ΔHbO. Consistent with literature, imagery task with visual aid, showed increased activation in ΔHbO. Moreover, linear discriminant analysis was used to classify signals by taking the mean and peak of the averaged ΔHbO resulting in average classification accuracies of approximately 66% and 77% for MI task, with and without visual aid, respectively. These results are convincing that showed improvement in MI ability which will be useful for fNIRS-based BCI applications.

Determination of the parameters in the designed hemodynamic response function using Nelder-Mead algorithm

Amad Zafar,Usman Ghafoor,M. Atif Yaqub,Keum-Shik Hong 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

In this paper, we have investigated the use of the Nelder-Mead algorithm in determining the parameters of a designed hemodynamic response function (dHRF) instead of using fixed parameters for functional near-infrared spectroscopy (fNIRS). The hemodynamic response (HR) is supposed to be a linear combination of the baseline, the dHRF, and physiological noises (Mayer, cardiac, and respiration). The linear combination of three gamma functions is used to model the dHRF including the initial dip, the conventional HR, and the undershoot afterward. In this formulation, fifteen parameters (9 for dHRF and 6 for physiological noises) are unknown. An objective function is designed and solved using the iterative optimization Nelder-Mead algorithm to determine the unknown parameters of dHRF and physiological noises. The performance of the algorithm is tested using simulated and experimental datasets. The fNIRS experimental data were acquired from five healthy subjects during right-hand thumb finger flexion/extension tasks from the left motor cortex. The results demonstrate that inter-subject differences existed in the dHRF parameters. Therefore, it will be worthwhile to use subject-dependent dHRF parameters for a better estimation of the cortical activation using fNIRS.

Effect of binder and composition ratio on electrochemical performance of silicon/graphite composite battery electrode

Farooq, U.,Choi, J.H.,Atif Pervez, S.,Yaqub, A.,Kim, D.H.,Lee, Y.J.,Saleem, M.,Doh, C.H. North-Holland 2014 Materials letters Vol.136 No.-

A comparative study was conducted to examine the effect of two different polymer binders and composition ratio of active material on electrochemical performance of silicon-graphite (Si-Gr) composite electrode in rechargeable lithium-ion batteries (LIBs). Polyacrylic acid (PAA) and polyvinylidene fluoride (PVDF) were utilized as binders for composite electrode that was fabricated using Si powder, graphite and super P black (SPB) by varying composition ratios of active material. The electrochemical performance was investigated by galvanostatic charge/discharge tests at room temperature. The results revealed that composite electrode fabricated with PAA binder using maximum contents of Si powder (20wt%) showed high specific capacity around 1000mAhg<SUP>-1</SUP> with excellent capacity retention. The enhanced electrochemical performance can be attributed to high mechanical strength and adhesive capability provided by PAA binder to composite electrode.

Probing the role of hydrolytically stable, 3-aminopropyl triethoxysilane crosslinked chitosan/graphene oxide membrane towards Congo red dye adsorption

Jadoon Aniqa,Ali Zarshad,Farooq W.A.,Ali Farman,Price Gareth J.,Taimur Shaista,Atif M.,AlMutairi Mona A.,Yaqub Nafeesah,Bibi Saira 한국물리학회 2022 Current Applied Physics Vol.40 No.-

In this investigation, the practicability of utilizing 3-aminopropyl triethoxysilane (3-APTES) crosslinked chitosan (Ch)/graphene oxide (GO) membranes were explored for adsorptive removal of anionic dyes from aqueous medium. Membranes were successfully fabricated through solution casting technique. Strong interactions amongst matrix (chitosan), 3-APTES, polyvinylpyrrolidone (PVP) and GO were confirmed by Infrared spectroscopy. Thermal stability of the chitosan was improved by adding graphene oxide and results were verified via thermogravimetric (TGA) analysis. Swelling and hydrolytic results confirmed that 2 %-Ch/PVP was a stable membrane while increasing the amount of 3-APTES in the chitosan nanocomposites membrane decreased its stability in aqueous medium. The adsorption characteristics of the membranes were evaluated by the adsorption of Congo red (CR) dye from aqueous medium. The adsorbent can remove 80% of CR from aqueous medium and follows second order kinetics. This study outlines the possibility of exploring green membranes which can be easily fit in various flow systems.