The Volumetric Changes of the Pineal Gland with Age: An Atlas-based Structural Analysis.

INTRODUCTION: There are numerous reports on the facilitatory role of the pineal gland (PG) in brain function, and the size this structure is suggested to be associated with its proper functionality. Previous works which studied the volume of the PG were mostly based on manual delineation of this region. In a recent work, we developed an MRI atlas for the PG in the standard space, with one of its applications being in volumetric studies. METHODS: In this study, using structural MRI data from 295 healthy participants in the age range of 19 to 76 years old, and using robust volumetric methods which included the above-mentioned atlas, we estimated the association of ageing with the changes of the PG volume, along with the volume of 48 other brain structures. RESULTS: We observed a linear decline (r= -0.42) over this age range for the PG volume, which showed similarity to the ageing profile of most of the other brain structures. Also, the PG volume showed significant associations with the scores of 9 cognitive tests. CONCLUSION: This study is the first work with an automated approach to estimate the PG volume, and could be a help to better understand the functionality of the PG in older ages.

Citizens of the world: National stereotypes do not affect empathic response in the presence of individuating information.

Stereotyping is defined as generalising an attribute to a whole group and overlooking individual differences. In this study, we investigated whether Iranians' stereotypes of nations affected their empathy for the citizens of those nations. First, in a pilot study we explored common national stereotypes by using the stereotype content model (SCM) based on which six countries with different perceived warmth and competence scores were selected as nationalities of the protagonists of the vignettes in our experiment. In the next phase, 21 participants were asked to rate the degree of sadness associated with each vignette in an fMRI scanner. The results showed no significant differences in brain activity while participants were exposed to scenarios in which negative events befell people from different nations. This may be due to the individuation of victims by providing personal information about them.

Fully automatic 3D segmentation of the thoracolumbar spinal cord and the vertebral canal from T2-weighted MRI using K-means clustering algorithm.

STUDY DESIGN: Method development. OBJECTIVES: To develop a reliable protocol for automatic segmentation of Thoracolumbar spinal cord using MRI based on K-means clustering algorithm in 3D images. SETTING: University-based laboratory, Tehran, Iran. METHODS: T2 structural volumes acquired from the spinal cord of 20 uninjured volunteers on a 3T MR scanner. We proposed an automatic method for spinal cord segmentation based on the K-means clustering algorithm in 3D images and compare our results with two available segmentation methods (PropSeg, DeepSeg) implemented in the Spinal Cord Toolbox. Dice and Hausdorff were used to compare the results of our method (K-Seg) with the manual segmentation, PropSeg, and DeepSeg. RESULTS: The accuracy of our automatic segmentation method for T2-weighted images was significantly better or similar to the SCT methods, in terms of 3D DC (p < 0.001). The 3D DCs were respectively (0.81 ± 0.04) and Hausdorff Distance (12.3 ± 2.48) by the K-Seg method in contrary to other SCT methods for T2-weighted images. CONCLUSIONS: The output with similar protocols showed that K-Seg results match the manual segmentation better than the other methods especially on the thoracolumbar levels in the spinal cord due to the low image contrast as a result of poor SNR in these areas.

A 65-year-old woman with ALS and bilateral precentral motor band sign.

Advanced MRI techniques, including SWI, MinIP, and QSM, are instrumental in detecting the "motor band sign" in ALS, aiding in the early diagnosis and assessment of upper motor neuron involvement, which is critical for therapeutic interventions.

Quantitative susceptibility mapping in amyotrophic lateral sclerosis: automatic quantification of the magnetic susceptibility in the subcortical nuclei.

Objective: Previous studies have suggested a link between dysregulation of cortical iron levels and neuronal loss in amyotrophic lateral sclerosis (ALS) patients. However, few studies have reported differences in quantitative susceptibility mapping (QSM) values in subcortical nuclei between patients with ALS and healthy controls (HCs). Methods: MRI was performed using a 3 Tesla Prisma scanner (64-channel head coil), including 3D T1-MPRAGE and multi-echo 3D GRE for QSM reconstruction. Automated QSM segmentation was used to measure susceptibility values in the subcortical nuclei, which were compared between the groups. Correlations with clinical scales were analyzed. Group comparisons were performed using independent t-tests, with p < 0.05 considered significant. Correlations were assessed using Pearson's correlation, with p < 0.05 considered significant. Cohen's d was reported to compare the standardized mean difference (SMD) of QSM. Results: Twelve patients with limb-onset ALS (mean age 48.7 years, 75% male) and 13 age-, sex-, and handedness-matched HCs (mean age 44.6 years, 69% male) were included. Compared to HCs, ALS patients demonstrated significantly lower susceptibility in the left caudate nucleus (CN) (SMD = -0.845), right CN (SMD = -0.851), whole CN (SMD = -1.016), and left subthalamic nucleus (STN) (SMD = -1.000). Susceptibility in the left putamen (SMD = -0.857), left thalamus (SMD = -1.081), and whole thalamus (SMD = -0.968) was significantly higher in the patients. The susceptibility of the substantia nigra (SN), CN, and pulvinar was positively correlated with disease duration. Conclusions: QSM detects abnormal iron accumulation patterns in the subcortical gray matter of ALS patients, which correlates with disease characteristics, supporting its potential as a neuroimaging biomarker.

Volume loss in the left anterior-superior subunit of the hypothalamus in amyotrophic lateral sclerosis.

BACKGROUND AND OBJECTIVE: Amyotrophic lateral sclerosis (ALS) causes motor neuron loss and progressive paralysis. While traditionally viewed as motor neuron disease (MND), ALS also affects non-motor regions, such as the hypothalamus. This study aimed to quantify the hypothalamic subregion volumes in patients with ALS versus healthy controls (HCs) and examine their associations with demographic and clinical features. METHODS: Forty-eight participants (24 ALS patients and 24 HCs) underwent structural MRI. A deep convolutional neural network was used for the automated segmentation of the hypothalamic subunits, including the anterior-superior (a-sHyp), anterior-inferior (a-iHyp), superior tuberal (supTub), inferior tuberal (infTub), and posterior (posHyp). The neural network was validated using FreeSurfer v7.4.1, with individual head size variations normalized using total intracranial volume (TIV) normalization. Statistical analyses were performed for comparisons using independent sample t-tests. Correlations were calculated using Pearson's and Spearman's tests (p < 0.05). The standard mean difference (SMD) was used to compare the mean differences between parametric variables. RESULTS: The volume of the left a-sHyp hypothalamic subunit was significantly lower in ALS patients than in HCs (p = 0.023, SMD = -0.681). No significant correlation was found between the volume of the hypothalamic subunits, body mass index (BMI), and ALSFRS-R in patients with ALS. However, right a-sHyp (r = 0.420, p = 0.041) was correlated with disease duration, whereas right supTub (r = -0.471, p = 0.020) and left postHyp (r = -0.406, p = 0.049) were negatively correlated with age. There was no significant difference in the volume of hypothalamic subunits between males and females, and no significant difference was found between patients with revised ALS Functional Rating Scale (ALSFRS-R) scores ≤41 and >41 and those with a disease duration of 9 months or less. DISCUSSION AND CONCLUSION: The main finding suggests atrophy of the left a-sHyp hypothalamic subunit in patients with ALS, which is supported by previous research as an extra-motor neuroimaging finding for ALS.

Seven Ambiguities in Explaining the Human Memory System in the Principles of Neural Science Book.

Memory is probably one of the most complex human cognitive functions, and in many years, thousands of studies have helped us better recognize this brain function. Professor Kandel and his colleagues have written one of the reference textbooks in neuroscience, which has also elaborated on the memory function. In this book, I encountered several ambiguities while explaining the memory system. Here, I share those points, either to find an answer to them or to let them be a suggestion for our future works. Professor Kandel has spent most of his meritorious lifetime studying the memory system; however, the brain is extremely complex, and as a result, we still have many years to comprehensively understand the neural mechanisms of brain functions. Highlights: The human memory system is not yet well identified.Imaging studies are not able to locate the memory storage sites of the brain.Current theories cannot explain the huge amount of memory storage in the brain.Episodic memories of animals should be different with a human episodic memory? Plain Language Summary: The human memory system is very complex, and we still have many questions on that. One of the questions is about the location of episodic memory storage in humans. Is that really happening in the brain? One other question is about studying the episodic memory in animals: do they really have an episodic memory similar to the humans? Prof. Kandel in his very valuable book has explained the memory system; however, many ambiguities are still unsolved. For example, the neuroimaging methods are nearly never able to speak of the site of memory "storage" in the brain, whereas many of their results are used as evidence for identifying the location of memory storage in the brain. Also, the hippocampus is emphasized to be responsible for the storage of episodic memories in animals, whereas a human whore hippocampus is resected is still able to retrieve his memories from before the surgery. As a result, we speculate that, despite all the very precious findings of Prof. Kandel, we still have to work in this field to reveal its mysteries.

Fronto-Cerebellar Neurometabolite Alterations After Methylphenidate in Children and Adolescents With ADHD: A Proton Magnetic Resonance Spectroscopy Study.

OBJECTIVE: The fronto-cerebellar circuit is involved in ADHD pathophysiology. Methylphenidate, as a first-line medication for ADHD, affects different brain regions, however, its effect on the fronto-cerebellar circuit is not investigated sufficiently. We aimed to investigate the effect of 8-week treatment with methylphenidate on neurometabolite ratios in the fronto-cerebellar circuit in ADHD participants using magnetic resonance spectroscopy (MRS). METHODS: Fifteen drug-naïve ADHD children and adolescents were enrolled in the present study. Two single-voxel MR spectra were acquired from the right dorsolateral prefrontal cortex (DLPFC) and left Crus 1, before and after the medication. Also, neuropsychological and behavioral assessments were administered. RESULTS: After medication, the glutamate/creatine in the DLPFC and the choline/creatine in the Crus 1 decreased in the ADHD participants. CONCLUSION: These findings propose that methylphenidate-induced metabolite changes in the fronto-cerebellar circuit could be associated with improvement in cognitive/behavioral characteristics in ADHD. Also, results highlighted cerebellar engagement in ADHD pathophysiology.

MRI biomarkers for memory-related impairment in amyotrophic lateral sclerosis: a systematic review.

Introduction: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder associated with cognitive and behavioral impairments and motor symptoms. Magnetic resonance imaging (MRI) biomarkers have been investigated as potential tools for detecting and monitoring memory-related impairment in ALS. Our objective was to examine the importance of identifying MRI biomarkers for memory-related impairment in ALS, motor neuron disease (MND), and ALS frontotemporal dementia (FTD) (ALS-FTD) patients. Methods: PubMed and Scopus databases were searched. Keywords covering magnetic resonance imaging, ALS, MND, and memory impairments were searched. There were a total of 25 studies included in our work here. Results: The structural MRI (sMRI) studies reported gray matter (GM) atrophy in the regions associated with memory processing, such as the hippocampus and parahippocampal gyrus (PhG), in ALS patients. The diffusion tensor imaging (DTI) studies showed white matter (WM) alterations in the corticospinal tract (CST) and other tracts that are related to motor and extra-motor functions, and these alterations were associated with memory and executive function impairments in ALS. The functional MRI (fMRI) studies also demonstrated an altered activation in the prefrontal cortex, limbic system, and other brain regions involved in memory and emotional processing in ALS patients. Conclusion: MRI biomarkers show promise in uncovering the neural mechanisms of memory-related impairment in ALS. Nonetheless, addressing challenges such as sample sizes, imaging protocols, and longitudinal studies is crucial for future research. Ultimately, MRI biomarkers have the potential to be a tool for detecting and monitoring memory-related impairments in ALS.

Iron quantification in basal ganglia using quantitative susceptibility mapping in a patient with ALS: a case report and literature review.

Background: Quantitative susceptibility mapping (QSM) is a magnetic resonance imaging (MRI) technique that can measure the magnetic susceptibility of tissues, which can reflect their iron content. QSM has been used to detect iron accumulation in cortical and subcortical brain regions. However, its application in subcortical regions such as the basal ganglia, particularly the putamen, is rare in patients with amyotrophic lateral sclerosis (ALS). Case presentation and literature review: We present the case of a 40-year-old male patient with ALS who underwent an MRI for QSM. We compared his QSM images with those of a control subject and performed a quantitative analysis of the magnetic susceptibility values in the putamen regions. We also reviewed the literature on previous QSM studies in ALS and summarized their methods and findings. Our QSM analysis revealed increased magnetic susceptibility values in the bilateral putamen of the ALS patient compared to controls, indicating iron overload. This finding is consistent with previous studies reporting iron dysregulation in subcortical nuclei in ALS. We also discussed the QSM processing techniques used in our study and in the literature, highlighting their advantages and limitations. Conclusion: This case report demonstrates the potential of QSM as a sensitive MRI biomarker for evaluating iron levels in subcortical regions of ALS patients. QSM can provide quantitative information on iron deposition patterns in both motor and extra-motor areas of ALS patients, which may help understand the pathophysiology of ALS and monitor disease progression. Further studies with larger samples are needed to validate these results and explore the clinical implications of QSM in ALS.

Examining the Dominant Presence of Brain Grey Matter in Autism During Functional Magnetic Resonance Imaging.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder with symptoms appearing from early childhood. Behavioral modifications, special education, and medicines are used to treat ASD; however, the effectiveness of the treatments depends on early diagnosis of the disorder. The primary approach in diagnosing ASD is based on clinical interviews and valid scales. Still, methods based on brain imaging could also be possible diagnostic biomarkers for ASD. Methods: To identify the amount of information the functional magnetic resonance imaging (fMRI) reveals on ASD, we reviewed 292 task-based fMRI studies on ASD individuals. This study is part of a systematic review with the registration number CRD42017070975. Results: We observed that face perception, language, attention, and social processing tasks were mainly studied in ASD. In addition, 73 brain regions, nearly 83% of brain grey matter, showed an altered activation between the ASD and normal individuals during these four tasks, either in a lower or a higher activation. Conclusion: Using imaging methods, such as fMRI, to diagnose and predict ASD is a great objective; research similar to the present study could be the initial step.

The heritability of brain metabolites on proton magnetic resonance spectroscopy in older individuals.

Twin studies have shown that many aspects of brain structure are heritable, suggesting a strong genetic contribution to brain structure. Less is known about functional aspects of the brain, in particular biologically relevant metabolites in the brain such as those measured by proton magnetic resonance spectroscopy (((1))H MRS), N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho) and myoinositol (ml), which have been suggested as possible markers of brain aging and early dementia. We examined 296 (56 male/108 female monozygotic and 43 male/89 female dizygotic) older twins (mean age 72.2 ± 5.5 years, range 65-88), for the levels of these metabolites relative to the H(2)O signal in the posterior cingulate cortex using ((1))H MRS. All metabolites showed substantial heritability, which was greatest for the neuronal integrity marker NAA (72%), and less so for the others - Cr (51%), Cho (33%) and ml (55%). The heritability of these markers did not change significantly with age or sex. The genetic determination of NAA, along with the evidence that NAA levels change in aging and neurodegenerative diseases suggest that it is a potential endophenotype of brain aging and dementia.

Evaluation of fronto-cerebellar neurometabolites in youth with ADHD compared to the healthy group and their associations with cognitive and behavioral characteristics: A proton magnetic spectroscopy study.

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent neurodevelopmental disorders, characterized by specific cognitive and behavioral symptoms. A fronto-cerebellar circuit is implicated in ADHD, and despite its role in cognitive/behavioral aspects, the neurochemical alterations in this circuit are not well understood. The present study aimed to compare neurometabolite ratios of the fronto-cerebellar circuit between ADHD and control participants, using proton magnetic resonance spectroscopy (1H MRS), and investigate whether neurometabolites related to cognitive/behavioral characteristics. Fifteen children and adolescents with ADHD and 19 healthy control participants were enrolled in this study. Two single voxel spectra localized in the right dorsolateral prefrontal cortex (DLPFC) and left Crus 1 were taken using PRESS sequence. Also, neuropsychological performance and behavioral characteristics were evaluated. Results revealed that ADHD group had different choline/creatine and glutamate/creatine ratios in the fronto-cerebellar circuit, compared to healthy controls. The current study also found significant correlations between neurometabolite ratios in the both region of interests (ROIs) and cognitive/behavioral characteristics. These results suggest that alterations in fronto-cerebellar metabolites may be related to cognitive and behavioral deficits in ADHD, and also, our findings highlight that the cerebellum may be involved in the pathophysiology of ADHD.

How do cannabis users mentally travel in time? Evidence from an fMRI study of episodic future thinking.

RATIONALE: Episodic future thinking (EFT) is a cognitive function that allows individuals to imagine novel experiences that may happen in the future. Prior studies show that EFT is impaired in different groups of substance users. However, there is no evidence regarding the neurobiological mechanisms of EFT in cannabis users. OBJECTIVES: We aimed to compare brain activations of regular cannabis users and non-using controls during an EFT fMRI task. Exploratory analyses were also conducted to investigate the association between EFT and cannabis use variables (e.g., duration of use, age onset, frequency of use). METHODS: Twenty current cannabis users and 22 drug-naïve controls underwent an fMRI scanning session while completing a task involving envisioning future-related events and retrieval of past memories as a control condition. The EFT fMRI task was adapted from the autobiographical interview and composed of 20 auditory cue sentences (10 cues for past and 10 cues for future events). Participants were asked to recall a past or generate a future event, in response to the cues, and then rate their vividness after each response. RESULTS: We found that cannabis users compared to non-user controls had lower activation within the cerebellum, medial and superior temporal gyrus, lateral occipital cortex, and occipital fusiform gyrus while envisioning future events. Cannabis users rated the vividness of past events significantly lower than non-users (P < 0.005). There were marginal group differences for rating the vividness of future events (P = 0.052). Significant correlations were also found between the medial and superior temporal gyrus activities and behavioral measures of EFT and episodic memory. CONCLUSIONS: Cannabis users, compared to drug-naïve controls, have lower brain activation in EFT relevant regions. Thus, any attempts to improve aberrant EFT performance in cannabis users may benefit from EFT training.

Cue-induced craving and negative emotion disrupt response inhibition in methamphetamine use disorder: Behavioral and fMRI results from a mixed Go/No-Go task.

BACKGROUND: Drug-related cue-reactivity, dysfunctional negative emotion processing, and response-disinhibition constitute three core aspects of methamphetamine use disorder (MUD). These phenomena have been studied independently, but the neuroscientific literature on their interaction in addictive disorders remains scant. METHODS: 62 individuals with MUD were scanned when responding to the geometric Go or No-Go cues superimposed over blank, neutral, negative-emotional and drug-related background images. Neural correlates of drug and negative-emotional cue-reactivity, response-inhibition and their interactions were estimated, and methamphetamine cue-reactivity was compared between individuals with MUD and 23 healthy controls. Relationships between behavioral characteristics and observed activations were investigated. RESULTS: Individuals with MUD had longer reaction times and more errors in drug and negative-emotional compared to blank blocks, and more omission errors in drug compared to neutral blocks. They showed higher drug cue-reactivity than controls across prefrontal, fusiform, and visual regions (Z > 3.1, p-corrected<0.05). Response-inhibition was associated with precuneal, inferior parietal, anterior cingulate, temporal, and inferior frontal activations (Z > 3.1, p-corrected<0.05). Response-inhibition in drug cue blocks coincided with higher activations in the visual cortex and lower activations in the paracentral lobule and superior and inferior frontal gyri, while inhibition during negative-emotional blocks led to higher superior parietal, fusiform, and lateral occipital activations (Z > 3.1, p-corrected<0.05). CONCLUSION: Drug cue-reactivity may impair response inhibition partly through activating dis-inhibitory regions, while temporal and parietal activations associated with response-inhibition in negative blocks suggest compensatory activity. Results suggest that drug and negative-emotional cue-reactivity influence response-inhibition, and the study of these interactions may aid mechanistic understanding of methamphetamine use disorder.

The Effect of Cognitive Load on the Retrieval of Long-Term Memory: An fMRI Study.

One of the less well-understood aspects of memory function is the mechanism by which the brain responds to an increasing load of memory, either during encoding or retrieval. Identifying the brain structures which manage this increasing cognitive demand would enhance our knowledge of human memory. Despite numerous studies about the effect of cognitive loads on working memory processes, whether these can be applied to long-term memory processes is unclear. We asked 32 healthy young volunteers to memorize all possible details of 24 images over a 12-day period ending 2 days before the fMRI scan. The images were of 12 categories relevant to daily events, with each category including a high and a low load image. Behavioral assessments on a separate group of participants (#22) provided the average loads of the images. The participants had to retrieve these previously memorized images during the fMRI scan in 15 s, with their eyes closed. We observed seven brain structures showing the highest activation with increasing load of the retrieved images, viz. parahippocampus, cerebellum, superior lateral occipital, fusiform and lingual gyri, precuneus, and posterior cingulate gyrus. Some structures showed reduced activation when retrieving higher load images, such as the anterior cingulate, insula, and supramarginal and postcentral gyri. The findings of this study revealed that the mechanism by which a difficult-to-retrieve memory is handled is mainly by elevating the activation of the responsible brain areas and not by getting other brain regions involved, which is a help to better understand the LTM retrieval process in the human brain.

Overlapping but Language-Specific Mechanisms in Morphosyntactic Processing in Highly Competent L2 Acquired at School Entry: fMRI Evidence From an Alternating Language Switching Task.

Many bilingual individuals acquire their second language when entering primary school; however, very few studies have investigated morphosyntax processing in this population. Combining a whole-brain and region of interest (ROI)-based approach, we studied event-related fMRI during morphosyntactic processing, specifically person-number phi-features, in Turkish (L1) and Persian (L2) by highly proficient bilinguals who learned Persian at school entry. In a design with alternating language switching and pseudorandomized grammaticality conditions, two left-lateralized syntax-specific ROIs and 11 bilateral ROIs involved in executive functions (EF) were analyzed for the intensity of activation relative to a resting baseline. Our findings indicate a strong overlap of neural networks for L1 and L2, suggesting structural similarities of neuroanatomical organization. In all ROIs morphosyntactic processing invoked stronger activation in L1 than in L2. This may be a consequence of symmetrical switch costs in the alternating design used here, where the need for suppressing the non-required language is stronger for the dominant L1 when it is non-required as compared to the non-dominant L2, leading to a stronger rebound for L1 than L2 when the language is required. Both L1 and L2 revealed significant activation in syntax-specific areas in left hemisphere clusters and increased activation in EF-specific areas in right-hemisphere than left-hemisphere clusters, confirming syntax-specific functions of the left hemisphere, whereas the right hemisphere appears to subserve control functions required for switching languages. While previous reports indicate a leftward bias in planum temporale activation during auditory and linguistic processing, the present study shows the activation of the right planum temporale indicating its involvement in auditory attention. More pronounced grammaticality effect in left pars opercularis for L1 and in left pSTG for L2 indicate differences in the processing of morphosyntactic information in these brain regions. Nevertheless, the activation of pars opercularis and pSTG emphasize the centrality of these regions in the processing of person-number phi-features. Taken together, the present results confirm that morphosyntactic processing in bilinguals relates to composite, syntax-sensitive and EF-sensitive mechanisms in which some nodes of the language network are differentially involved.

Along-tract analysis of the white matter is more informative about brain ageing, compared to whole-tract analysis.

Diffusion Tensor Imaging (DTI) enabled the investigation of brain White Matter (WM), both qualitatively to study the macrostructure, and quantitatively to study the microstructure. The quantitative analyses are mostly performed at the whole-tract level, i.e., providing one measure of interest per tract; however, along-tract approaches may provide finer details of the quality of the WM tracts. In this study, using the DWI data collected from 40 young and 40 old individuals, we compared the DTI measures of FA, MD, AD, and RD, estimated by both whole-tract and along-tract approaches in 18 WM bundles, between the two groups. The results of the whole-tract quantitative analysis showed a statistically significant (p-FWER < 0.05) difference between the old and young groups in 6 tracts for FA, 8 tracts for MD, 1 tract for AD, and 7 tracts for RD. On the contrary, the along-tract approach showed differences between the two groups in 10 tracts for FA, 14 tracts for MD, 8 tracts for AD, and 11 tracts for RD. All the differences between the along-tract measures of the two groups had a large effect size (Cohen'd > 0.80). This study showed that the along-tract approach for the analysis of brain WM reveals changes in some WM tracts which had not shown any changes in the whole-tract approach, and therefore this finding emphasizes the utilization of the along-tract approach along with the whole-tract method for a more accurate study of the brain WM.

A Probabilistic Atlas of the Pineal Gland in the Standard Space.

Pineal gland (PG) is a structure located in the midline of the brain, and is considered as a main part of the epithalamus. There are numerous reports on the facilitatory role of this area for brain function; hormone secretion and its role in sleep cycle are the major reports. However, reports are rarely available on the direct role of this structure in brain cognition and in information processing. A suggestion for the limited number of such studies is the lack of a standard atlas for the PG; none of the available MRI templates and atlases has provided parcellations for this structure. In this study, we used the three-dimensional (3D) T1-weighted MRI data of 152 healthy young volunteers, and provided a probabilistic map of the PG in the standard Montreal Neurologic Institute (MNI) space. The methods included collecting the data using a 64-channel head coil on a 3-Tesla Prisma MRI Scanner, manual delineation of the PG by two experts, and robust template and atlas construction algorithms. This atlas is freely accessible, and we hope importing this atlas in the well-known neuroimaging software packages would help to identify other probable roles of the PG in brain function. It could also be used to study pineal cysts, for volumetric analyses, and to test any associations between the cognitive abilities of the human and the structure of the PG.

Iranian Brain Imaging Database: A Neuropsychiatric Database of Healthy Brain.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.