Basic and Clinical Neuroscience
Volume:12 Issue: 1, Jan-Feb 2021

Human intelligence has always been a fascinating subject for scientists. Since the inception of Spearman’s general intelligence in the early 1900s, there has been significant progress towards characterizing different aspects of intelligence and its relationship with structural and functional features of the brain. In recent years, the invention of sophisticated brain imaging devices using Diffusion-Weighted Imaging (DWI) and functional Magnetic Resonance Imaging (fMRI) has allowed researchers to test hypotheses about neural correlates of intelligence in humans.This review summarizes recent findings on the associations of human intelligence with neuroimaging data. To this end, first, we review the literature that has related brain morphometry to intelligence. Next, we elaborate on the applications of DWI and resting-state fMRI on the investigation of intelligence. Then, we provide a survey of literature that has used multimodal DWI-fMRI to shed light on intelligence. Finally, we discuss the state-of-the-art of individualized prediction of intelligence from neuroimaging data and point out future strategies. Future studies hold promising outcomes for machine learning-based predictive frameworks using neuroimaging features to estimate human intelligence.

Several signaling pathways and transcription factors control the cell fate in its in vitro development and differentiation. The orchestrated use of these factors results in cell specification. In coculture methods, many of these factors secrete from host cells but control the process. Today, transcription factors required for retinal progenitor cells are well known, but the generation of these cells from mesenchymal stem cells is an ideal goal. The purpose of the paper is to review novel methods for retinal progenitor cell production and selecting a set of signaling molecules in the presence of adult retinal pigment epithelium and extraocular mesenchyme acting as inducers of retinal cell differentiation.

Parkinsonchr('39')s disease (PD) presentations comprise frequent movement disorders in the elderly with various symptoms consisting of motor and non-motor complications. Paeonol is a phenolic chemical agent that has shown antioxidant and anti-inflammatory effects in different disorders and promising effects on metabotropic glutamate receptors (mGluR)- and GABAA-mediated neurotransmission. In this research, we tried to show the neuroprotective potential of paeonol in rat PD model induced by intrastriatal 6-hydroxydopamine (6-OHDA).

Rats with intrastriatal 6-OHDA lesioning received with paeonol at a dosage of 100 mg/kg/d for one week. In the end, some biomarkers of oxidative stress, apoptosis, and astrogliosis in nigral and striatal tissues were evaluated in addition to behavioral and Tyrosine Hydroxylase (TH) immunohistochemical analysis.

The obtained data showed that paeonol alleviates apomorphine-induced rotations and reduces the delay time to initiate and the total time in the narrow beam test. However, its beneficial behavioral effect vanished after intracerebroventricular administration of mGluR III or GABAA receptor antagonists. Moreover, paeonol significantly restored striatal malondialdehyde, tissue levels of reactive oxygen species, the activity of the protective and vital enzymes consisting of superoxide dismutase and catalase, Glial Fibrillary Acidic Protein (GFAP), DNA fragmentation, phosphor apoptosis signal-regulating kinase 1, and nigral aquaporin 4 with no significant and proper change of nitrite, interleukin-1β, inducible nitric oxide synthase, and angiotensin II. Additionally, paeonol prevented injury and reduced tyrosine hydroxylase-containing neurons in the midbrain nigral tissue.

These obtained findings evidently designate neuroprotective property of paeonol in 6-OHDA murine model of PD that is exerted via easing of oxidative stress, apoptosis, astrogliosis, and its advantageous effect is to some extent mediated via mGluR III/GABAA pathway.

Parkinson Disease (PD), the second most common chronic neurodegenerative disorder, is characterized by tremor, bradykinesia, rigidity, and postural instability. SHANK3 (SH3 and multiple ankyrin repeat domain 3) belongs to the extremely conserved ProSAP/ Shank family of synaptic scaffolding proteins. Meanwhile, rs9616915 is a non-synonymous SNP (T>C) located in the exon 6 of the SHANK3 gene, which induces substitution of isoleucine to threonine and affects the function of the resulted protein. The present study aimed to evaluate whether rs9616915 polymorphism of SHANK3 is involved in the susceptibility to PD.

The study subjects were 100 patients diagnosed with PD and 100 control volunteers. The obtained samples were evaluated by the polymerase chain reaction-restriction fragment length polymorphism method.

A significant association was found in genotype distribution between cases and controls. Individuals with TC genotype had increased risk of PD (P=0.035, OR=1.98, 95% CI=1.04 - 3.74). No significant difference was found in allele distribution (P=0.7).

The findings suggest that the SHANK3 rs9616915 polymorphism is associated with an increased risk of PD in the population. Further studies are needed to confirm the role of the SHANK3 gene in PD.

Recent studies have shown that Polyunsaturated Fatty Acids (PUFAs), including Eicosapentaenoic Acid (EPA), and Arachidonic Acid (AA), are associated with cognitive functions in patients with Coronary Artery Disease (CAD). Nevertheless, controversial results have been reported, too. The current study aimed to clarify the association of serum EPA and AA levels with cognitive decline in an Iranian sample with CAD.

We evaluated cognitive function with the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), in relation to serum levels of EPA and AA, in 179 CAD patients. The associations between the MMSE and MoCA scores and the other demographic parameters were evaluated.

Patients with CAD generally had mild cognitive impairment. But we could not find any significant correlation between PUFAs and cognitive function. However, BMI was associated with EPA/MoCA; age was associated with MMSE/MoCA and BMI. Finally, the correlation between sex and MMSE/MoCA was significant. 

Subjects generally had mild cognitive impairment, but we could not find any significant correlation between serum EPA and AA levels with cognitive function.

Freezing of gait, a common PD motor symptom, could increase the risk of falling. This study aimed to investigate the clinimetric attributes of the Freezing of Gait Questionnaire (FOGQ) for people with Parkinson disease in the “off” state.

A total of 115 patients with Parkinson disease (PD; mean age, 60.25 years) were included. Acceptability, internal consistency (by the Cronbach alpha, and test-retest by Intraclass Correlation [ICC]), and reliability of the Persian-translated version of the FOGQ were examined. Dimensionality was estimated by Exploratory Factor Analysis (EFA). Fall efficacy scale-international, unified Parkinson disease rating scale-II, Berg balance scale, functional reach test, and Parkinson disease questionnaire-39 were applied to determine the convergent validity. Diagnostic accuracy for obtaining optimal cutoff point, separating faller and non-faller groups, was analyzed by Receiver Operating Characteristics (ROC) curve analysis and Area Under the Curve (AUC). All tests were carried out in an “off” state.

The Cronbach alpha was high (α=0.92). The test-retest showed high reliability (ICC=0.89). The FOGQ was unidimensional according to the EFA and had acceptable convergent validity with moderate to high correlation with other clinical scales. The optimal cutoff point to discriminate fallers from non-fallers during the “off” state was 9/10, with an AUC of 0.92.

Our results suggest that the FOGQ has appropriate reliability, validity, and discriminative ability for measuring FOG in patients with PD during the “off” state.

Down syndrome as a genetic disorder is a popular research topic in molecular studies. One way to study Down syndrome is via bioinformatics. 

In this study, a gene expression profile from a microarray study was selected for more investigation.

The study of Down syndrome patients shows specific genes with differential expression and network centrality properties. These genes are introduced as RHOA, FGF2, FYN, and CD44, and their level of expression is high in these patients. 

This study suggests that besides chromosomes 21, there are additional contributing chromosomes to the risk of Down syndrome development. Besides, these genes could be used for clinical studies after more analysis.

An impaired sense of smell has a remarkable impact on the quality of life. It is seen in a variety of neurodegenerative diseases such as Parkinson disease. In this study, we assessed the olfactory function in patients with Multiple Sclerosis (MS) by Sniff Magnitude Test (SMT). 

A cross-sectional study was conducted on 48 patients with MS. A questionnaire, including demographic and clinical variables, was completed for each patient. The SMT was used for the evaluation of olfactory function. 

Olfactory dysfunction was found in 14.6% of patients (8.3% hyposmia and 6.3% anosmia). Older age, longer disease duration, higher hospital admission rate, lower mini-mental status examination score, and secondary progressive course of MS were significantly related to olfactory dysfunction. 

Secondary progressive MS and markers of advanced disease toward neurodegenerative phase (including older age, longer disease duration, and lower cognitive function) can be associated with olfactory dysfunction in MS patients.

One of the vital skills which has an impact on emotional health and well-being is the regulation of emotions. In recent years, the neural basis of this process has been considered widely. One of the powerful tools for eliciting and regulating emotion is music. The Anterior Cingulate Cortex (ACC) is part of the emotional neural circuitry involved in Major Depressive Disorder (MDD). The current study uses functional Magnetic Resonance Imaging (fMRI) to examine how neural processing of emotional musical auditory stimuli is changed within the ACC in depression. Statistical inference is conducted using a Bayesian Generalized Linear Model (GLM) approach with an Integrated Nested Laplace Approximation (INLA) algorithm.

A new proposed Bayesian approach was applied for assessing functional response to emotional musical auditory stimuli in a block design fMRI data with 105 scans of two healthy and depressed women. In this Bayesian approach, Unweighted Graph-Laplacian (UGL) prior was chosen for spatial dependency, and autoregressive (AR) (1) process was used for temporal correlation via pre-weighting residuals. Finally, the inference was conducted using the Integrated Nested Laplace Approximation (INLA) algorithm in the R-INLA package.

The results revealed that positive music, as compared to negative music, elicits stronger activation within the ACC area in both healthy and depressed subjects. In comparing MDD and Never-Depressed (ND) individuals, a significant difference was found between MDD and ND groups in response to positive music vs negative music stimuli. The activations increase from baseline to positive stimuli and decrease from baseline to negative stimuli in ND subjects. Also, a significant decrease from baseline to positive stimuli was observed in MDD subjects, but there was no significant difference between baseline and negative stimuli.

Assessing the pattern of activations within ACC in a depressed individual may be useful in retraining the ACC and improving its function, and lead to more effective therapeutic interventions.

Patients with cancer may have many complications involving their psychosomatic systems, such as sleep disturbance, depression, and anxiety. Thus, many research studies were conducted to reduce these complications. Zolpidem, as a short-term non-benzodiazepine treatment of insomnia, and melatonin as a chronobiological function-regulatory hormone, are commonly used for improving sleep quality. This randomized clinical trial aims to compare the effects of zolpidem and melatonin on sleep quality, depression, and anxiety in patients with colorectal cancer.

In this single-blinded trial, 90 patients with colorectal cancer undergoing chemotherapy who had obtained a score of 5 or higher on the Pittsburgh Sleep Quality Index (PSQI) were randomly divided into two groups (n=45). One group was treated with 10 mg zolpidem at bedtime, and the other group received 6 mg melatonin at bedtime for 30 days. PSQI on weeks 0, 4, 8, Groningen sleep quality scale, Hamilton rating scale for depression, and Hamilton anxiety rating scale questionnaires were performed to assess patients on weeks 0, 4, and 8. The outcome was then analyzed, and P≤0.05 was considered statistically significant.

Both zolpidem and melatonin had significant impacts on sleep quality in week 4 (P<0.05). After stopping the treatments, the conditions were noticeably reversed on week 8 (P<0.05). Zolpidem and melatonin were relatively similar in affecting sleep duration, latency, efficiency, and disturbance. None of the two study medications had any considerable influence on anxiety and depression.

Melatonin and zolpidem are promising agents for treating sleep complications and, to some extent, depression, and anxiety in cancer patients, according to the present study. However, further clinical trials are recommended to confirm the results of this study.

The Iranian Brain Imaging Database (IBID) was initiated in 2017, with 5 major goals: provide researchers easy access to a neuroimaging database, provide normative quantitative measures of the brain for clinical research purposes, study the aging profile of the brain, examine the association of brain structure and function, and join the ENIGMA consortium. Many prestigious databases with similar goals are available. However, they were not done on an Iranian population, and the battery of their tests (e.g. cognitive tests) is selected based on their specific questions and needs. 

The IBID will include 300 participants (50% female) in the age range of 20 to 70 years old, with an equal number of participants (#60) in each age decade. It comprises a battery of cognitive, lifestyle, medical, and mental health tests, in addition to several Magnetic Resonance Imaging (MRI) protocols. Each participant completes the assessments on two referral days.

The study currently has a cross-sectional design, but longitudinal assessments are considered for the future phases of the study. Here, details of the methodology and the initial results of assessing the first 152 participants of the study are provided. 

IBID is established to enable research into human brain function, to aid clinicians in disease diagnosis research, and also to unite the Iranian researchers with interests in the brain.

Corticotropin-Releasing Hormone (CRH) is involved in stress and energy homeostasis. On the other hand, CRH receptors also exist within the paraventricular nucleus (PVN) and Central Amygdala (CeA) nuclei. The present study compared the effect of CRH microinjections into PVN and CeA on three consecutive hours and cumulative food intake, internal regulatory factors of food intake, such as serum leptin and ghrelin, as well as blood glucose levels in rats under different acute psychological (Social Stress [SS] and Isolation Stress [IS] group) stresses.

Sixty-six male Wistar rats were randomly allocated to 11 groups: Control, Sham, CRH-PVN, CRH-CeA, SS, IS, SS-CRH-PVN, SS-CRH-CeA, IS-CRH-PVN, and IS-CRH-CeA groups. The CRH (2 µg/kg in 0.5 µL saline) was injected into PVN and CeA nuclei in rats under everyday, acute social stress and isolation stress conditions. 

Acute isolation and social stresses did not affect cumulative food intake. Whereas isolation stress led to changes in both leptin and glucose levels, social stress reduced only glucose levels. Cumulative food intake significantly decreased under acute CRH injection into the CeA and particularly into the PVN. Blood glucose significantly reduced in all the groups receiving CRH into their CeA. 

The PVN played a more important role compared to CeA on food intake. These nuclei probably employ different mechanisms for their effects on food intake. Besides, it seems that exogenously CRH injection into the PVN probably had a more anorectic effect than naturally activated CRH by stresses. Acute isolation stress had a greater impact than social stress on leptin level and cumulative food intake. Thus, elevated food intake related to leptin compared to ghrelin and glucose levels in the CRH-PVN group under acute social stress.

Ischemic stroke is one of the leading causes of morbidity and mortality worldwide. Neuroprotective strategies were reported to attenuate cognitive deficits after ischemic incidents. Here we studied the neuroprotective potential of chrysin in a rat model of cerebral Ischemia/Reperfusion (I/R) in the presence or absence of Estrogen Receptors (ERs).

Adult male Wistar rats were pretreated with chrysin (CH) (CH; 30 mg/kg; gavage; for 21 consecutive days) alone or with selective ERs antagonists (ERα antagonist MPP; ERβ antagonist PHTPP; IP) or nonselective ERs antagonist (ICI182780; IP). Then, the bilateral common carotid arteries were occluded for 20 min, which was followed by 72 h reperfusion. Subsequently, cognitive performance was evaluated by Morris Water Maze (MWM) and shuttle box tasks, and afterward, their hippocampi were removed for ELISA assays and H&E staining. Oxidative indicators Malondialdehyde (MDA) and Glutathione Peroxidase (GPx), as well as inflammation mediators interleukin (IL)-1β and tumor necrosis factor-alpha (TNFα), were measured using commercial kits.

Results of the current study showed that the anti-oxidative and anti-inflammatory properties of CH are possible mechanisms that could improve cognitive deficits and prevent neuronal cell death following I/R (P<0.001). These effects were reversed by ICI182780 (P>0.05). Furthermore, when chrysin was co-treated with ERβ antagonist, PHTPP showed a weak neuroprotective effect in I/R rats. However, these parameters were not significantly different when chrysin was combined with ERα antagonist MPP.

Our data confirm that chrysin could potentially serve as a neuroprotective agent against devastating effects of cerebral I/R injury, which may be mediated via its interaction with ERs, especially ERβ.