Weng-Tink Chooi

Brain activation during cognitive tasks: An overview of EEG and fMRI studies

Brain controls all body functions that enable us to perform daily life events dynamically. Memory is an important part of brain that controls and processes our present and past information and interconnects with future plans to assist corresponding dynamic activities of whole body. In cognitive psychology, human memory processes are functionally divided into three categories namely encoding, retention, and recalling. This paper provides an overview of memory processes and brain regions that are activated during these processes using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). We discussed issues related to cognitive tasks design that may be helpful in future memory research to conduct experiment with EEG and fMRI in a better way.

EEG mean power and complexity analysis during complex mental task

The aim of this study was to investigate the association between EEG measures (mean power and sample entropy) and complex mental reasoning task (IQ test). Six healthy university students participated voluntarily in the experiment. EEG was recorded at resting states (eye open and eye closed) and during performing IQ test and analyzed over 12 regions across the scalp. EEG mean power measure of delta and theta frequency significantly (p<;0.025) discriminated the IQ test from resting states at frontal regions and alpha frequency at parietal, occipital and parieto-occipital regions. Highly reduced mean power of beta frequency was found during IQ test at parietal, occipital and parieto-occipital regions as compared to frontal regions. Results of Sample Entropy (SE) showed high complexity in EEG signal during IQ test than resting state eye closed. Our findings showed high cortical activation and increased EEG complexity during IQ test than resting states.

Brain Behavior in Learning and Memory Recall Process: A High-Resolution EEG Analysis

Learning is a cognitive process, which leads to create new memory. Today, multimedia contents are commonly used in classroom for learning. This study investigated brain physiological behavior during learning and memory process using multimedia contents and Electroencephalogram (EEG) method. Fifteen healthy subjects voluntarily participated and performed three experimental tasks: i) Intelligence task, ii) learning task, and iii) recall task. EEG was recorded duration learning and memory recall task using 128 channels Hydro Cel Geodesic Net system (EGI Inc., USA) with recommended specifications. EEG source localization showed that deep brain medial temporal region was highly activated during learning task. EEG theta band in frontal and parietal regions and gamma band at left posterior temporal and frontal regions differentiated successful memory recall. This study provide additional understanding of successful memory recall that complements earlier brain mapping studies.

Dynamics of Scalp Potential and Autonomic Nerve Activity during Intelligence Test

The main objective of this study was to examine the changes in autonomic nervous system (ANS) and scalp potential during intelligence test (IQ). Electroencephalogram (EEG) and Electrocardiogram (ECG) signals were recorded simultaneously from eight healthy participants during IQ and resting states (eyes–closed and eyes-open). Heart rate (HR) and heart rate variability (HRV) were derived from ECG signal. EEG mean power was computed for five frequency bands (delta, theta, alpha, beta, and gamma) and analyzed in 12 regions across the scalp. The EEG frequency bands showed significant (p<0.025) changes between IQ test and rest states. Delta and theta at frontal (PF, AF, F) and temporal regions (FT, T, TP) and alpha activity at parietal (P), parieto-occipital (PO) and occipital (O) regions were significant. In beta and gamma bands, highly reduced mean power was found at P, PO, and O regions as compared to PF, AF, and F regions in IQ test. HR and low frequency in normalized unit (LFnu) were increased significantly (p<0.05 and p<0.025, respectively) in IQ test. Further, high frequency in normalized unit (HFnu) was decreased (p<0.11). Results showed parallel changes in scalp potential and automatic nervous activity during IQ test compared to rest conditions.

Emerging Drug Use Trends in Kelantan, Malaysia

ABSTRACT The primarily rural and agrarian Kelantan province of Malaysia has high rates of drug use and is characterized by unique sociocultural factors. Combining qualitative and ethnographic methods, we investigated drug use and treatment needs of people who use drugs (PWUD) in rural areas of Kelantan. In February 2014, field visits, participant observation, and focus group discussions (FGDs) with 27 active PWUD were conducted in rural areas surrounding the capital city of Kelantan. The findings indicate a high prevalence of opiate and amphetamine type stimulants (ATS) use in these areas. FGD participants reported initiating drug use at early ages due to peer influences, to relieve boredom, to cope with problems, and a high saturation of villages with other PWUD was reported as a major contributor to their own continued drug use. They reported a trend of drug use initiation at younger ages and increased drug use among females. Participants were interested in treatment; however, their limited knowledge about treatment options and perceived limited availability of services were barriers to treatment seeking. Easy access to drugs, primarily from Thailand and facilitated by the use of mobile phones, resulted in an expanding prevalence of drug use that underscores the need to bolster education and prevention efforts and accessibility of treatment services in Kelantan.

Brain behavior during reasoning and problem solving task: An EEG study

The capacity of relational reasoning is to find relationships, comprehend implications, analyze novel problems and draw conclusions. This study has investigated brain behavior and dynamic neural activity during Ravens Advance Progressive Matrices (RAPM), which requires strong cognitive reasoning to select a solution, by using an electroencephalogram (EEG). The EEGs were recorded all over the scalps of eight healthy volunteers using the 128-channel Hydro-Cel Geodesic (EGI Inc.) system. Brain activation was dominant during the reasoning and problem solving process in the pre-frontal lobe and parietal lobe as compared to the baseline conditions in all of the subjects, consistently. The theta band (3.5-7.5Hz) was significantly (p<;0.025) higher during the reasoning process at the frontal lobe as compared to eye-closed and eye-open conditions. Results showed high frontal theta activity in problem solving, which requires substantial reasoning and thinking skills.

Atomoxetine for amphetamine-type stimulant dependence during buprenorphine treatment: A randomized controlled trial

BACKGROUND Amphetamine type stimulants (ATS) use is highly prevalent and frequently co-occurs with opioid dependence in Malaysia and Asian countries. No medications have established efficacy for treating ATS use disorder. This study evaluated the safety, tolerability, and potential efficacy of atomoxetine for treating ATS use disorder. METHODS Participants with opioid and ATS dependence (N = 69) were enrolled in a pilot, double-blind, placebo-controlled randomized clinical trial; all received buprenorphine/naloxone and behavioral counseling and were randomized to atomoxetine 80 mg daily (n = 33) or placebo (n = 33). The effect size of the between-group difference on the primary outcome, proportion of ATS-negative urine tests, was estimated using Cohens d for the intention-to-treat (ITT) sample and for higher adherence subsample (≥60 days of atomoxetine or placebo ingestion). RESULTS Participants were all male with mean (SD) age 39.4 (6.8) years. The proportion of ATS-negative urine tests was higher in atomoxetine- compared to placebo-treated participants: 0.77 (0.63-0.91) vs. 0.67 (0.53-0.81, d = 0.26) in the ITT sample and 0.90 (0.75-1.00) vs. 0.64 (0.51-0.78, d = 0.56) in the higher adherence subsample. The proportion of days abstinent from ATS increased from baseline in both groups (p < 0.001) and did not differ significantly between atomoxetine- and placebo-treated participants (p = 0.42). Depressive symptoms were reduced from baseline in both groups (p < 0.02) with a greater reduction for atomoxetine- than placebo-treated participants (p < 0.02). There were no serious adverse events or adverse events leading to medication discontinuation. CONCLUSIONS The findings support clinical tolerability and safety and suggest potential efficacy of atomoxetine for treating ATS use disorder in this population.