Basic and Clinical Neuroscience
Volume:15 Issue: 1, Jan-Feb 2024

Alzheimer’s disease (AD) is characterized by progressive loss of cognition and a gradual decrease in memory. Although AD is considered the most persistent form of dementia and a global concern, no complete cure or agents that can completely halt the progression of AD have been found. In the past years, significant progress has been made in understanding the cellular and molecular changes associated with AD, and numerous drug targets have been identified for the development of drugs for this disease. Amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) are the major attributes of AD. Symptomatic relief is the only possible treatment available at present and a disease-modifying drug is of utmost importance. The development of drugs that can inhibit different targets responsible for the formation of plaques is a potential area in AD research. This review is not a complete list of all possible targets for AD but serves to highlight the targets related to Aβ pathology and pathways concerned with the formation of Aβ fragments. This shall serve as a prospect in the identification of Aβ plaque inhibitors and pave the strategies for newer drug treatments. Nevertheless, substantial research is done in this area but to bridle, the clinical difficulty remains a concern.

Growing evidence indicates that adolescent substance abuse is now an alarming concern that imposes a considerable socio-economic burden on societies. On the other hand, numerous studies have shown that due to specific neurophysiological features, the brain is more vulnerable to the adverse effects of psychoactive drugs at an early age. Unfortunately, these negative effects are not limited to the period of drug use, but can persistently affect the brain’s responsiveness to future exposures to the same or other types of drug. For researchers to develop pharmacological strategies for managing substance abuse disorders, they need to gain a deep understanding of the differences in behavioral outcomes associated with each type of drug across different age groups. The present study was conducted to review the experimental evidence revealing the mentioned differential effects with an emphasis on common drugs of abuse, including cocaine, nicotine, cannabis, and opioids. Although the cellular mechanisms underlying age-related effects have not been exclusively addressed for each drug, the most recent results are presented and discussed. Future studies are required to focus on these mechanisms and reveal how molecular changes during brain development can result in differential responses to drugs at the behavioral level.

The apolipoprotein E (APOE) genotype has a heterogeneous distribution throughout the world. The present study aimed to characterize the APOE genotype (rs429358, rs7412) in healthy individuals compared with Alzheimer cases in Kerman, southeastern Iran, by two standard mutation scanning methods. 

In this case-control study, 90 Alzheimer patients as a case group and 90 healthy individuals as a control group were examined. APOE genotyping was carried out using high-resolution melting (HRM) analysis assay and multiplex tetra-primer amplification-refractory mutation system polymerase chain reaction (T-ARMS PCR) techniques.

In contrast to Multiplex T-ARMS PCR, HRM analysis was not efficient in rs7412 genotyping. The results of multiplex T-ARMS showed that ε2ε3 genotype (P=0.006, odd ratio [OR]=0.119) and ε2 allele (P=0.004, OR=0.129) were more prevalent in the control group compared with the case ones, whereas ε4 allele was associated with borderline risk of Alzheimer disease (P=0.099, OR=1.76). 

We concluded that Multiplex T-ARMS PCR could be considered as a better option than HRM analysis for APOE genotyping in terms of speed, accuracy, simplicity, and cheapness in large-scale use. Also, the present study revealed that ε2 ε3 genotype and ε2 allele are protective against Alzheimer whereas the ε4 allele cannot be strongly considered as Alzheimer genetic risk factor in Kerman, Iran. The results may help to choose a better technique for APOE genotyping.

This study aimed to investigate the age trends in various types of memory, including priming, working memory (WM), episodic memory (EM), and semantic memory (SM) from adulthood to old age, as well as the mediating role of inhibition control (IC) in the relationship between age and memory.

A total of 796 healthy adults aged between 25 and 83 years participated in this cross-sectional study. They underwent assessment using a comprehensive battery of memory tests (adapted from the Betula battery), digit span tasks (to measure WM), and the Stroop color-word test (to measure IC). 

The scatter plot with locally estimated scatterplot smoothing (LOESS) fitting line showed EM and WM declined steadily from age 25, while SM exhibited a mild increase up to age 55 followed by a decline. Priming did not show significant changes with age. Mediation analysis and bootstrap tests indicated that IC mediated the relationship between age and EM (β=–0.097, P=0.002) and between age and SM (β=-0.086, P=0.001).

Our results showed that age affects various types of memory differently, and inhibition control plays a fundamental mediating role in explaining age-related declines in SM and EM.

Parkinson disease is a neurodegenerative disease that disrupts functional brain networks. Many neurodegenerative disorders are associated with changes in brain communication patterns. Resting-state functional connectivity studies can distinguish the topological structure of Parkinson patients from healthy individuals by analyzing patterns between different regions of the brain. Accordingly, the present study aimed to determine the brain topological features and functional connectivity in patients with Parkinson disease, using a Bayesian approach. 

The data of this study were downloaded from the open neuro site. These data include resting-state functional magnetic resonance imaging (rs-fMRI) of 11 healthy individuals and 11 Parkinson patients with mean ages of 64.36 and 63.73, respectively. An advanced nonparametric Bayesian model was used to evaluate topological characteristics, including clustering of brain regions and correlation coefficient of the clusters. The significance of functional relationships based on each edge between the two groups was examined through false discovery rate (FDR) and network-based statistics (NBS) methods. 

Brain connectivity results showed a major difference in terms of the number of regions in each cluster and the correlation coefficient between the patient and healthy groups. The largest clusters in the patient and control groups were 26 and 53 regions, respectively, with clustering correlation values of 0.36 and 0.26. Although there are 15 common areas across the two clusters, the intensity of the functional relationship between these areas was different in the two groups. Moreover, using NBS and FDR methods, no significant difference was observed for each edge between the patient and healthy groups (P>0.05). 

The results of this study show a different topological configuration of the brain network between the patient and healthy groups, indicating changes in the functional relationship between a set of areas of the brain.

Our aim was to investigate the expression of miRNAs, C-reactive protein as a blood inflammation marker, and alanine aminotransferase as a tissue inflammation marker, in recovered and not-recovered COVID-19 patients.

This cross-sectional project was conducted at three medical centers in Iran from December to March 2021. In total, 20 confirmed cases of COVID-19 with grade III severity and 20 healthy subjects were enrolled in the study. Subsequently, the neuroinflammatory expression of miRNAs (miR-199, miR-203, and miR-181), C-reactive protein, and alanine aminotransferase was investigated during hospitalization from week 0 to week 2.

Among COVID-19 subjects who did not recover, the expression levels of miR-199, miR-203, and miR-181 were decreased, while the levels of C-reactive protein and alanine aminotransferase increased during hospitalization. Conversely, in recovered COVID-19 subjects, the relative expression of miR-199, miR-203, and miR-181 increased and the levels of C-reactive protein and alanine aminotransferase decreased during hospitalization.

The expression pattern of neuroinflammatory miRNAs depends on whether the COVID-19 patient is recovering or deteriorating. Their expression is downregulated in COVID-19 patients who do not recover and upregulated in those who do recover.

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. There are several factors that influence the severity of CTS. The purpose of this study was to explore the severity of CTS in hypothyroid patients.

This cross-sectional study was conducted in the university clinic. Seventy-six participants with a clinically and electrophysiological confirmed diagnosis of CTS were included in the study. The demographic data and severity of CTS were analyzed based on the presence (n=38) or the absence (n=38) of primary hypothyroid disease. Thirty-eight hypothyroid patients who were being treated were included in this study. For the assessment of the severity of CTS, the Boston questionnaire (BCTQ) and electrodiagnostic tests were used. For data analysis, an independent sample t-test and chi-squared test were carried out. A P<0.05 was considered significant.

The mean age of hypothyroid and non-hypothyroid CTS patients was 46.21±7.22 and 44.24±8.02 years, respectively. Body mass index (BMI) was >30 kg/m2 in both groups. There was no significant difference in demographic data among the two groups. The mean score of symptom severity in hypothyroid and non-hypothyroid-CTS patients were 30.37±10.84 and 35.89±7.19, and also functional status was 21.71±9.04 and 25.92±6.62, respectively. There was a significant difference between the two groups, in terms of symptom severity scale (P=0.017, 95% CI, 31.14%, 35.48%) and functional status scale (P=0.023, 95% CI, 21.95%, 25.67%). In terms of electrophysiological findings, there was no statistically significant difference between these two groups. 

The results of this study indicated that, contrary to expectation, the severity of CTS is higher in non-hypothyroid patients than in hypothyroid patients.

Although several studies have been published about COVID-19, ischemic stroke is known yet as a complicated problem for COVID-19 patients. Scientific reports have indicated that in many cases, the incidence of stroke in patients with COVID-19 leads to death. 

The obtained mathematical equation in this study can help physicians’ decision-making about treatment and identification of influential clinical factors for early diagnosis. 

In this retrospective study, data from 128 patients between March and September 2020, including their demographic information, clinical characteristics, and laboratory parameters were collected and analyzed statistically. A logistic regression model was developed to identify the significant variables in predicting stroke incidence in patients with COVID-19. 

Clinical characteristics and laboratory parameters for 128 patients (including 76 males and 52 females; with a mean age of 57.109±15.97 years) were considered as the inputs that included ventilator dependence, comorbidities, and laboratory tests, including WBC, neutrophil, lymphocyte, platelet count, C-reactive protein, blood urea nitrogen, alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH). Receiver operating characteristic–area under the curve (ROC-AUC), accuracy, sensitivity, and specificity were considered indices to determine the model capability. The accuracy of the model classification was also addressed by 93.8%. The area under the curve was 97.5% with a 95% CI.

The findings showed that ventilator dependence, cardiac ejection fraction, and LDH are associated with the occurrence of stroke and the proposed model can predict the stroke effectively.

There are studies about polysomnographic (PSG) characteristics of patients with either obesity hypoventilation syndrome (OHS) or addiction. We aimed to investigate the PSG characteristics of obstructive sleep apnea (OSA) patients with opium addiction, those on methadone maintenance treatment (MMT), and non-addicts for the treatment of addiction.

In this cross-sectional study, we enrolled 75 patients with OHS in the Bamdad Respiratory and Sleep Research Center affiliated with the Isfahan University of Medical Sciences between January 2020 and February 2021. The patients were categorized into three groups: Opium addicts (OA), MMT, and non-addicts (NA). All patients completed screening questionnaires for OSA. This included the Epworth sleepiness scale (ESS), stop-bang questionnaire, and Berlin questionnaire and the data analyzed by SPSS software, version 24.

A total of 75 OHS patients (54 men [72%] and 21 women [28%]) were studied in three groups, including OA (n=30), MMT (n=15), and NA (n=30). The apnea hypopnea index was not significantly different between the three groups. The longest apnea duration was higher in the OA than in other groups (P=0.001). Central apnea index (P=0.01), longest hypopnea duration (P=0.04), PaCO2 (P=0.04), and time with SpO2˂90% (T90) (P=0.009) were higher in the MMT than in other groups. Furthermore, the minimum SpO2 was lower in the MMT than in other groups (P=0.03). 

Some of the sleep disturbances were worse in the MMT than in the OA group. This suggests the need for further studies to compare the effects of opium and methadone on sleep in OHS patients.

Antioxidants prevent the progression of neuropsychiatric disorders, such as bipolar disorder (BD). Omega-3 fatty acid supplementation helps prevent lipid peroxidation and improve antioxidant status. This study aims to investigate the effect of omega-3 supplementation on serum levels of antioxidant status in patients with BD. 

In this study, 28 patients with BD received an omega-3 fatty acid supplement (2 g/daily) while the other 28 patients received edible paraffin oil (2 g/daily) for 60 days. The activities of superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAC) were evaluated in pre-intervention and post-intervention. 

The results showed that omega-3 supplementation increased the activities of SOD (12.94±3.84 U/mL vs 17.72±3.59 U/mL) and CAT (5.08±1.61 nmol/min/mL vs 6.43±1.33 nmol/min/mL) in post-intervention compared to pre-intervention (P=0.001). The results also showed that omega-3 supplementation increased the activities of SOD (17.72±3.59 U/mL vs 13.79±3.12 U/mL) and CAT (6.43±1.33 nmol/min/mL vs 4.89±1.45 nmol/min/mL) compared to the control group in post-intervention (P=0.001). Omega-3 supplementation did not have significant effects on the serum concentration of TAC compared to pre-intervention (P=0.373) and control group (P=0.604). 

Omega-3 supplementation increased the activities of SOD and CAT and may decrease the progression of disease via increasing antioxidant status.

This study investigated the effect of autobiographical brand images on false memory formation in adults, using the category associate’s procedure. The study also applied the event-related potential (ERP) approach to explore neural correlates of false memory and gender differences in false memory recall of brand images. 

Eight categories of autobiographical brand images were implied in a category associates’ procedure to investigate false memory recall. ERP data were obtained from 24 participants (12 females and 12 males) using a 32-channel amplifier while subjects were performing the memory task. Subsequently, gender effects on behavioral responses and neural correlates of false and true memory recalls were statistically compared using peak amplitude and latency of P300, late positive complex, and FN400 components. 

The results showed that left frontal areas in women were more activated in response to false memories compared to men, however, the men’s brain responses were faster. In addition, the men’s brain responses to false memories were widely distributed mainly over frontal, parietal, and occipital areas.

Males and females differently process autobiographical brand images. Nevertheless, the differential neural process may not influence their recognition rate or response time.