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Purpose: The insula, a cortical structure buried deep within the sylvian fissure, has long posed a surgical challenge. Comprehensive knowledge of the insular anatomy is therefore integral to preoperative planning and safe interventional procedures. Since magnetic resonance imaging (MRI) is a favoured modality for the identification of cerebral structures, this study aimed to investigate the morphology and morphometry of the insula in a South African population, using MRI scans. Methods: One-hundred MRI studies of insulae (n = 200 hemispheres) were retrospectively analysed for morphological features and morphometric parameters. Results: The insulae were predominantly trapezoidal in shape (Laterality: Left: 82%; Right: 78%; Sex: Male: 84%, Female: 76%). The central insular sulcus was almost always "well seen" (Laterality: Left: 97%; Right: 99%; Sex: Male: 99%, Female: 97%). The middle short insular gyrus (MSG) was most variable in visibility, especially when compared across the sexes (p = 0.004). Insular gyri widths were comparable in both cerebral hemispheres; the posterior long gyrus (PLG) presented with the smallest mean widths. Anterior lobule (AL) widths were larger than those of the posterior lobule (PL). Widths of the insular gyri and lobules were generally larger in males than in females. The MSG and PLG widths in the left hemisphere, AL width in the right hemisphere, and the PL width in both hemispheres were significantly larger in males than in females (p = 0.001; p = 0.005; p = 0.041; p = 0.001, p = 0.015, respectively). Conclusion: MRI scans may be used to accurately interpret insular anatomy. The data obtained may aid neurosurgeons to perform safe insula-related surgical procedures. [ABSTRACT FROM AUTHOR]

Abstract Despite extensive studies published on the canine brain, inconsistencies and disagreements in the nomenclature and representation of various cerebral structures continue to exist. This study aimed to create a comprehensive mapping of the external architecture of the mesocephalic canine brain with a focus on the major gyri and sulci. Standardized dissection techniques were used on 20 ethically sourced brains obtained from 6 to 10-year-old dogs that were free of neurological disorders. Distinct gyri and sulci with unique locations and bordering structures were observed. Thus, it was possible to identify the often-ignored subprorean gyrus. In addition, this study was able to illustrate the unique locations and bordering structures of gyri and sulci. The findings can contribute to a consensus among researchers on the canine brain anatomy and assist in clarifying the inconsistencies in cerebral structure representation. Furthermore, the results of this study may hold significant implications for veterinary medicine and neuroscience and serve as a foundation for the development of diagnostic and therapeutic approaches for various neurological diseases in dogs. Our findings offer valuable insights into the unique evolutionary adaptations and specialized behaviors of the canine brain, thereby increasing awareness about the neural structures that enable dogs to demonstrate their unique traits.

Despite extensive studies published on the canine brain, inconsistencies and disagreements in the nomenclature and representation of various cerebral structures continue to exist. This study aimed to create a comprehensive mapping of the external architecture of the mesocephalic canine brain with a focus on the major gyri and sulci. Standardized dissection techniques were used on 20 ethically sourced brains obtained from 6 to 10-year-old dogs that were free of neurological disorders. Distinct gyri and sulci with unique locations and bordering structures were observed. Thus, it was possible to identify the often-ignored subprorean gyrus. In addition, this study was able to illustrate the unique locations and bordering structures of gyri and sulci. The findings can contribute to a consensus among researchers on the canine brain anatomy and assist in clarifying the inconsistencies in cerebral structure representation. Furthermore, the results of this study may hold significant implications for veterinary medicine and neuroscience and serve as a foundation for the development of diagnostic and therapeutic approaches for various neurological diseases in dogs. Our findings offer valuable insights into the unique evolutionary adaptations and specialized behaviors of the canine brain, thereby increasing awareness about the neural structures that enable dogs to demonstrate their unique traits. [ABSTRACT FROM AUTHOR]

The inferior frontal sulcus (ifs) is a prominent sulcus on the lateral frontal cortex, separating the middle frontal gyrus from the inferior frontal gyrus. The morphology of the ifs can be difficult to distinguish from adjacent sulci, which are often misidentified as continuations of the ifs. The morphological variability of the ifs and its relationship to surrounding sulci were examined in 40 healthy human subjects (i.e., 80 hemispheres). The sulci were identified and labeled on the native cortical surface meshes of individual subjects, permitting proper intra‐sulcal assessment. Two main morphological patterns of the ifs were identified across hemispheres: in Type I, the ifs was a single continuous sulcus, and in Type II, the ifs was discontinuous and appeared in two segments. The morphology of the ifs could be further subdivided into nine subtypes based on the presence of anterior and posterior sulcal extensions. The ifs was often observed to connect, either superficially or completely, with surrounding sulci, and seldom appeared as an independent sulcus. The spatial variability of the ifs and its various morphological configurations were quantified in the form of surface spatial probability maps which are made publicly available in the standard fsaverage space. These maps demonstrated that the ifs generally occupied a consistent position across hemispheres and across individuals. The normalized mean sulcal depths associated with the main morphological types were also computed. The present study provides the first detailed description of the ifs as a sulcal complex composed of segments and extensions that can be clearly differentiated from adjacent sulci. These descriptions, together with the spatial probability maps, are critical for the accurate identification of the ifs in anatomical and functional neuroimaging studies investigating the structural characteristics and functional organization of this region in the human brain. [ABSTRACT FROM AUTHOR]

The neuroanatomical changes that underpin cognitive development are of major interest in neuroscience. Of the many aspects of neuroanatomy to consider, tertiary sulci are particularly attractive as they emerge last in gestation, show a protracted development after birth, and are either human- or hominoid-specific. Thus, they are ideal targets for exploring morphological-cognitive relationships with cognitive skills that also show protracted development such as working memory (WM). Yet, the relationship between sulcal morphology and WM is unknown-either in development or more generally. To fill this gap, we adopted a data-driven approach with cross-validation to examine the relationship between sulcal depth in lateral prefrontal cortex (LPFC) and verbal WM in 60 children and adolescents between ages 6 and 18. These analyses identified 9 left, and no right, LPFC sulci (of which 7 were tertiary) whose depth predicted verbal WM performance above and beyond the effect of age. Most of these sulci are located within and around contours of previously proposed functional parcellations of LPFC. This sulcal depth model outperformed models with age or cortical thickness. Together, these findings build empirical support for a classic theory that tertiary sulci serve as landmarks in association cortices that contribute to late-maturing human cognitive abilities.

The third trimester of pregnancy is the most critical period for human brain development, during which significant changes occur in the morphology of the brain. The development of sulci and gyri allows for a considerable increase in the brain surface. In preterm newborns, these changes occur in an extrauterine environment that may cause a disruption of the normal brain maturation process. We hypothesize that a normalized atlas of brain maturation with cerebral ultrasound images from birth to term equivalent age will help clinicians assess these changes. This work proposes a semi-automatic Graphical User Interface (GUI) platform for segmenting the main cerebral sulci in the clinical setting from ultrasound images. This platform has been obtained from images of a cerebral ultrasound neonatal database images provided by two clinical researchers from the Hospital Sant Joan de Déu in Barcelona, Spain. The primary objective is to provide a user-friendly design platform for clinicians for running and visualizing an atlas of images validated by medical experts. This GUI offers different segmentation approaches and pre-processing tools and is user-friendly and designed for running, visualizing images, and segmenting the principal sulci. The presented results are discussed in detail in this paper, providing an exhaustive analysis of the proposed approach's effectiveness. [ABSTRACT FROM AUTHOR]

Background: The surface of the developing human brain undergoes morphological changes with the formation of different sulci during the fetal period. During the first and second-trimester fetal brain surface remain smooth, and between the 28th and 30th weeks of gestation, new gyri and sulci appear due to rapid growth of the fetal brain. Aims and Objectives: To study the time of appearance of sulci in different surfaces of the fetal brain, which will help estimate the gestational age of the fetus from the specimen of the fetal brain. Materials and Methods: About 108 cerebral hemispheres from 54 fetal brains were examined in the Department of Anatomy, Medical College, Kolkata, West Bengal, in 1 year from December 2016 to December 2017. Among 54 fetal brains, 21 were museum specimens of the Department of Anatomy and Forensic Medicine of Medical College, Kolkata, and the rest were fetal cadavers. For brains from fetal cadavers, after brain removal, it was fixed in 10% formalin. Fetal brains were divided into two groups – a) brains from fetuses with bodyweight up to 1000 g with a weight gap of 100 g among the groups. b) brains from fetuses with body weight >1001 g with a weight gap of 250 g among the groups. Sulci in the superolateral, medial, and inferior surfaces of the fetal brain were noted carefully. Results: Comparing the findings of our study with the previous anatomical studies, it is found that we studied a large number of sulci in detail. When we compared the anatomical findings with the findings of USG or MRI it was found that there was 2–4 weeks delay between anatomical appearance and visualization of the same sulcus in fetal brain by imaging (USG and MRI). The development of cerebral sulci was proportional to the bodyweight of the fetus. Conclusion: Embryological appearance of sulci is a crucial important in the Anatomy and radiological study of brain and micro neurosurgery. The study is essential for estimation of the gestational age of the fetus also.

In adult lizards, new neurons are generated from neural stem cells in the ventricular zone of the lateral ventricles. These new neurons migrate and integrate into the main telencephalic subdivisions. In this work we have studied adult neurogenesis in the lizard Podarcis liolepis (formerly Podarcis hispanica) by administering [3H]-thymidine and bromodeoxyuridine as proliferation markers and euthanizing the animals at different survival times to determine the identity of progenitor cells and to study their lineage derivatives. After short survival times, only type B cells are labeled, suggesting that they are neural stem cells. Three days after administration, some type A cells are labeled, corresponding to recently formed neuroblasts. Type A cells migrate to their final destinations, where they differentiate into mature neurons and integrate into functional circuits. Our results after long survival periods suggest that, in addition to actively dividing type B cells, there is also a type B subpopulation with low proliferative activity. We also found that new neurons incorporated into the olfactory bulb are generated both in situ, in the walls of the anterior extension of the lateral ventricle of the olfactory bulbs, but also at more caudal levels, most likely in anterior levels of the sulcus ventralis/terminalis. These cells follow a tangential migration toward the olfactory bulbs where they integrate. We hypothesized that at least part of the newly generated neurons would undergo a specialization process over time. In support of this prediction, we found two neuronal populations in the cellular layer of the medial cortex, which we named type I and II neurons. At intermediate survival times (1 month) only type II neurons were labeled with [3H]-thymidine, while at longer survival times (3, 6, or 12 months) both type I and type II neurons were labeled. This study sheds light on the ultrastructural characteristics of the ventricular zone of P. liolepis as a neurogenic niche, and adds to our knowledge of the processes whereby newly generated neurons in the adult brain migrate and integrate into their final destinations. [ABSTRACT FROM AUTHOR]

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A salient neuroanatomical feature of the human brain is its pronounced cortical folding, and there is mounting evidence that sulcal morphology is relevant to functional brain architecture and cognition. However, our understanding of the relationships between sulcal anatomy, brain activity, and behavior is still in its infancy. We previously found the depth of three small, shallow sulci in lateral prefrontal cortex (LPFC) was linked to reasoning performance in childhood and adolescence (Voorhies et al., 2021). These findings beg the question: what is the linking mechanism between sulcal morphology and cognition? To shed light on this question, we investigated functional connectivity among sulci in LPFC and lateral parietal cortex (LPC). We leveraged manual parcellations (21 sulci/hemisphere, total of 1806) and functional magnetic resonance (fMRI) data from a reasoning task from 43 participants aged 7-18 years (20 female). We conducted clustering and classification analyses of individual-level functional connectivity among sulci. Broadly, we found that 1) the connectivity patterns of individual sulci could be differentiated - and more accurately than rotated sulcal labels equated for size and shape; 2) sulcal connectivity did not consistently correspond with that of probabilistic labels or large-scale networks; 3) sulci clustered together into groups with similar patterns, not dictated by spatial proximity; and 4) across individuals, greater depth was associated with higher network centrality for several sulci under investigation. These results highlight that functional connectivity can be meaningfully anchored to individual sulcal anatomy, and demonstrate that functional network centrality can vary as a function of sulcal depth., Competing Interests: Conflict of interest statement: The authors declare no competing financial interests.

Gyrification is a fundamental property of the human cortex that is increasingly studied by basic and clinical neuroscience. However, it remains unclear if and how the global architecture of cortical folding varies with 3 interwoven sources of anatomical variation: brain size, sex, and sex chromosome dosage (SCD). Here, for 375 individuals spanning 7 karyotype groups (XX, XY, XXX, XYY, XXY, XXYY, XXXXY), we use structural neuroimaging to measure a global sulcation index (SI, total sulcal/cortical hull area) and both determinants of sulcal area: total sulcal length and mean sulcal depth. We detail large and patterned effects of sex and SCD across all folding metrics, but show that these effects are in fact largely consistent with the normative scaling of cortical folding in health: larger human brains have disproportionately high SI due to a relative expansion of sulcal area versus hull area, which arises because disproportionate sulcal lengthening overcomes a lack of proportionate sulcal deepening. Accounting for these normative allometries reveals 1) brain size-independent sulcal lengthening in males versus females, and 2) insensitivity of overall folding architecture to SCD. Our methodology and findings provide a novel context for future studies of human cortical folding in health and disease.

The third trimester of pregnancy is the most critical period for human brain development, during which significant changes occur in the morphology of the brain. The development of sulci and gyri allows for a considerable increase in the brain surface. In preterm newborns, these changes occur in an extrauterine environment that may cause a disruption of the normal brain maturation process. We hypothesize that a normalized atlas of brain maturation with cerebral ultrasound images from birth to term equivalent age will help clinicians assess these changes. This work proposes a semi-automatic Graphical User Interface (GUI) platform for segmenting the main cerebral sulci in the clinical setting from ultrasound images. This platform has been obtained from images of a cerebral ultrasound neonatal database images provided by two clinical researchers from the Hospital Sant Joan de Déu in Barcelona, Spain. The primary objective is to provide a user-friendly design platform for clinicians for running and visualizing an atlas of images validated by medical experts. This GUI offers different segmentation approaches and pre-processing tools and is user-friendly and designed for running, visualizing images, and segmenting the principal sulci. The presented results are discussed in detail in this paper, providing an exhaustive analysis of the proposed approach’s effectiveness.

Objectives: In the human brain, the inferior frontal gyrus (IFG) is comprised of three morphological regions, which include the pars opercularis, pars triangularis, and pars orbitalis. These brains regions are implicated in a number of cognitive and linguistic functions, and the pars opercularis and pars triangularis of the language dominant hemisphere are collectively referred to as Broca's area. Evolution of the morphology of the IFG has been a topic of study in comparative neuroscience. Materials and Methods: Using magnetic resonance images (MRI) from 294 chimpanzees with known pedigrees, we quantified the folding patterns, surface area, and depth of three sulci and their subdivisions that define the IFG. Results: Chimpanzees show considerable individual variation in IFG sulci. A higher proportion of males and chimpanzees with better orofacial motor control had a bifurcation in the dorsal limb of the fronto‐orbital sulcus. For surface area and depth, chimpanzees with better orofacial motor control had greater leftward asymmetries in surface area and increased gyrification for the fronto‐orbital sulcus and greater rightward biases for the inferior precentral sulcus. Quantitative genetic analyses revealed that the average surface area and depth for three of the five sulci subdivisions were significantly heritable. By contrast, we found no evidence for heritability in asymmetries for any of the sulci. Discussion: These findings provide context to understanding evolutionary selection for increasing motor, cognitive and linguistic functions among primates, and contribute an essential comparative framework for interpreting IFG evolution in the human lineage. [ABSTRACT FROM AUTHOR]

Background: The sulcal patterns may be useful in studying the mechanisms of both neuro developmental and neuro degenerative changes that occur during brain maturation and ageing. Magnetic resonance imaging has facilitated the non-invasive study of human cerebral and cognitive development. Aims and Objective: To find out the age related anatomical variations of some of the cerebral cortical sulci and gyri of the brain. Materials and Methods: The study was done using the MRI images of brain of normal healthy adults aged between 20-70 years. A total of 200 images were analysed consisting of that from 119 male subjects and 81 female subjects from the Department of Radiodiagnosis, Government Medical College Kottayam. Results: Using statistical analysis it was found that as the age advances there was decrease in the depth, in case of central sulcus, pre-central sulcus and post-central sulcus. The width of the pre-central sulcus and post-central sulcus was found to increase with age. The changes in the width of the central sulcus were not significant. Conclusion: The observations of the undertaken study indicated that age changes do occur in the sulci of the brain and there was a sequential change in relation to the different periods of adult life. These changes are probably due to the volume loss of the brain due to the atrophy that occurs during aging.

Background: The surface of the developing human brain undergoes morphological changes with the formation of different sulci during the fetal period. During the first and second-trimester fetal brain surface remain smooth, and between the 28th and 30th weeks of gestation, new gyri and sulci appear due to rapid growth of the fetal brain. Aims and Objectives: To study the time of appearance of sulci in different surfaces of the fetal brain, which will help estimate the gestational age of the fetus from the specimen of the fetal brain. Materials and Methods: About 108 cerebral hemispheres from 54 fetal brains were examined in the Department of Anatomy, Medical College, Kolkata, West Bengal, in 1 year from December 2016 to December 2017. Among 54 fetal brains, 21 were museum specimens of the Department of Anatomy and Forensic Medicine of Medical College, Kolkata, and the rest were fetal cadavers. For brains from fetal cadavers, after brain removal, it was fixed in 10% formalin. Fetal brains were divided into two groups - a) brains from fetuses with bodyweight up to 1000 g with a weight gap of 100 g among the groups. b) brains from fetuses with body weight >1001 g with a weight gap of 250 g among the groups. Sulci in the superolateral, medial, and inferior surfaces of the fetal brain were noted carefully. Results: Comparing the findings of our study with the previous anatomical studies, it is found that we studied a large number of sulci in detail. When we compared the anatomical findings with the findings of USG or MRI it was found that there was 2-4 weeks delay between anatomical appearance and visualization of the same sulcus in fetal brain by imaging (USG and MRI). The development of cerebral sulci was proportional to the bodyweight of the fetus. Conclusion: Embryological appearance of sulci is a crucial important in the Anatomy and radiological study of brain and micro neurosurgery. The study is essential for estimation of the gestational age of the fetus also. [ABSTRACT FROM AUTHOR]

Background: liver is a soft, friable and largest gland in the body, occupying the upper part of the abdominal cavity just beneath the right diaphragm. The greater part of it is situated under cover of the ribs, extending to the left to reach the left diaphragm. Objective: to determine gross anatomical variations of liver and their clinical and surgical implications. To study variations in lobes, fissures and accessory lobes were observed. Material And Methods: a total of 50 formalin-fixed adult human livers, irrespective of the sex, were studied over a period of three years from Dr M K shah medical college. These livers were specifically observed for any variant or anomalous surface morphology. Result: out of 50 specimens, 16 were considered normal without any ac-accessory fissures, lobes, or presence of a pones hepatis. 34 livers had one or more morphological variations. 14 liver has accessory fissure, 10 liver are present with riedel’s lobe present in liver, 10 liver are present with pons hepatic. Conclusion: liver being the largest abdominal organ, the knowledge of its normal and variant morphology is essential for the clinicians. In general, accessory hepatic fissures/sulci are potential sources of diagnostic errors during imaging. On ultrasound or computerized tomography, any collection of fluid in these fissures may be mistaken for a liver cyst, intrahepatic hematoma, or liver abscess, which would require further radiologic workup. [ABSTRACT FROM AUTHOR]

We used a surface-based analysis of T2* relaxation rates at 7 T magnetic resonance imaging, which allows sampling quantitative T2* throughout the cortical width, to map in vivo the spatial distribution of intracortical pathology in multiple sclerosis. Ultra-high resolution quantitative T2* maps were obtained in 10 subjects with clinically isolated syndrome/early multiple sclerosis (≤ 3 years disease duration), 18 subjects with relapsing-remitting multiple sclerosis (≥ 4 years disease duration), 13 subjects with secondary progressive multiple sclerosis, and in 17 age-matched healthy controls. Quantitative T2* maps were registered to anatomical cortical surfaces for sampling T2* at 25%, 50% and 75% depth from the pial surface. Differences in laminar quantitative T2* between each patient group and controls were assessed using general linear model (P < 0.05 corrected for multiple comparisons). In all 41 multiple sclerosis cases, we tested for associations between laminar quantitative T2*, neurological disability, Multiple Sclerosis Severity Score, cortical thickness, and white matter lesions. In patients, we measured, T2* in intracortical lesions and in the intracortical portion of leukocortical lesions visually detected on 7 T scans. Cortical lesional T2* was compared with patients normal-appearing cortical grey matter T2* (paired t-test) and with mean cortical T2* in controls (linear regression using age as nuisance factor). Subjects with multiple sclerosis exhibited relative to controls, independent from cortical thickness, significantly increased T2*, consistent with cortical myelin and iron loss. In early disease, T2* changes were focal and mainly confined at 25% depth, and in cortical sulci. In later disease stages T2* changes involved deeper cortical laminae, multiple cortical areas and gyri. In patients, T2* in intracortical and leukocortical lesions was increased compared with normal-appearing cortical grey matter (P < 10(-10) and P < 10(-7)), and mean cortical T2* in controls (P < 10(-5) and P < 10(-6)). In secondary progressive multiple sclerosis, T2* in normal-appearing cortical grey matter was significantly increased relative to controls (P < 0.001). Laminar T2* changes may, thus, result from cortical pathology within and outside focal cortical lesions. Neurological disability and Multiple Sclerosis Severity Score correlated each with the degree of laminar quantitative T2* changes, independently from white matter lesions, the greatest association being at 25% depth, while they did not correlate with cortical thickness and volume. These findings demonstrate a gradient in the expression of cortical pathology throughout stages of multiple sclerosis, which was associated with worse disability and provides in vivo evidence for the existence of a cortical pathological process driven from the pial surface.

Chronic Traumatic Encephalopathy (CTE) affects a significant portion of athletes in contact sports but is difficult to quantify using clinical examinations and modeling approaches. We use an in silico approach to quantify CTE biomechanics using mesoscale Finite Element (FE) analysis that bridges with macroscale whole head FE analysis. The sulci geometry produces complex stress waves that interact with one another to create increased shear stresses at the sulci depth that are significantly larger than in analyses without sulci (from 0.5 to 18.0 kPa). Sulci peak stress concentration regions coincide with experimentally observed CTE sites documented in the literature. Sulci introduce stress localizations at their depth in the gray matter Sulci stress fields interact to produce stress concentration sites in white matter Differentiating brain tissue properties did not significantly affect peak stresses [ABSTRACT FROM AUTHOR]

Background: The sulcal patterns may be useful in studying the mechanisms of both neuro developmental and neuro degenerative changes that occur during brain maturation and aging. Magnetic resonance imaging has facilitated the non-invasive study of human cerebral and cognitive development. Aims and Objective: To find out the age related anatomical variations of some of the cerebral cortical sulci and gyri of the brain. Materials and Methods: The study was done using the MRI images of brain of normal healthy adults aged between 20- 70 years. A total of 200 images were analysed consisting of that from 119 male subjects and 81 female subjects from the Department of Radiodiagnosis, Government Medical College Kottayam. Results: Using statistical analysis it was found that as the age advances there was decrease in the depth, in case of central sulcus, pre-central sulcus and post-central sulcus. The width of the pre-central sulcus and post-central sulcus was found to increase with age. The changes in the width of the central sulcus were not significant. Conclusion: The observations of the undertaken study indicated that age changes do occur in the sulci of the brain and there was a sequential change in relation to the different periods of adult life. These changes are probably due to the volume loss of the brain due to the atrophy that occurs during aging. [ABSTRACT FROM AUTHOR]

The superficial anatomy of the occipital lobe has been described as irregular and highly complex. This notion mainly arises from the variability of the regional sulco-gyral architecture. Our aim was to investigate the prevalence, morphology, and correlative anatomy of the sulci and gyri of the occipital region in cadaveric specimens and to summarize the nomenclature used in the literature to describe these structures. To this end, 33 normal, adult, formalin-fixed hemispheres were studied. In addition, a review of the relevant literature was conducted with the aim to compare our findings with data from previous studies. Hence, in the lateral occipital surface, we recorded the lateral occipital sulcus and the intraoccipital sulcus in 100%, the anterior occipital sulcus in 24%, and the inferior occipital sulcus in 15% of cases. In the area of the occipital pole, we found the transverse occipital sulcus in 88% of cases, the lunate sulcus in 64%, the occipitopolar sulcus in 24%, and the retrocalcarine sulcus in 12% of specimens. In the medial occipital surface, the calcarine fissure and parieto-occipital sulcus were always present. Finally, the basal occipital surface was always indented by the posterior occipitotemporal and posterior collateral sulci. A sulcus not previously described in the literature was identified on the supero-lateral aspect of the occipital surface in 85% of cases. We named this sulcus "marginal occipital sulcus" after its specific topography. In this study, we offer a clear description of the occipital surface anatomy and further propose a standardized taxonomy for clinical and anatomical use. [ABSTRACT FROM AUTHOR]

Endocasts (i.e., replicas of the inner surface of the bony braincase) constitute a critical proxy for qualifying and quantifying variations in brain shape and organization in extinct taxa. In the absence of brain tissues preserved in the fossil record, endocasts provide the only direct evidence of brain evolution. However, debates on whether or not information inferred from the study of endocasts reflects brain shape and organization have polarized discussions in paleoneurology since the earliest descriptions of cerebral imprints in fossil hominin crania. By means of imaging techniques (i.e., MRIs and CT scans) and 3D modelling methods (i.e., surface‐based comparisons), we collected consistent morphological (i.e., shape) and structural (i.e., sulci) information on the variation patterns between the brain and the endocast based on a sample of extant human individuals (N = 5) from the 3D clinical image database of the Steve Biko Academic Hospital in Pretoria (South Africa) and the Hôpitaux Universitaires Pitié Salpêtrière in Paris (France). Surfaces of the brain and endocast of the same individual were segmented from the 3D MRIs and CT images, respectively. Sulcal imprints were automatically detected. We performed a deformation‐based shape analysis to compare both the shape and the sulcal pattern of the brain and the endocast. We demonstrated that there is close correspondence in terms of morphology and organization between the brain and the corresponding endocast with the exception of the superior region. By comparatively quantifying the shape and organization of the brain and endocast, this work represents an important reference for paleoneurological studies. [ABSTRACT FROM AUTHOR]

Electrical dipoles oriented perpendicular to the cortical surface are the primary source of the scalp EEGs and MEGs. Thus, in particular, gyri and sulci structures on the cortical surface have a definite possibility to influence the EEGs and MEGs. This was examined by comparing the spatial power spectral density (PSD) of the upper portion of the human cortex in MRI slices to that of simulated scalp EEGs and MEGs. The electrical activity was modeled with 2,650 dipolar sources oriented normal to the local cortical surface. The resulting scalp potentials were calculated with a finite element model of the head constructed from 51 segmented sagittal MR images. The PSD was computed after taking the fast Fourier transform of scalp potentials. The PSD of the cortical contour in each slice was also computed. The PSD was then averaged over all the slices. This was done for sagittal and coronal view both. The PSD of EEG and MEG showed two broad peaks, one from 0.05 to 0.22 cycles/cm (wavelength 20–4.545 cm) and the other from 0.22 to 1.2 cycles/cm (wavelength 4.545–0.834 cm). The PSD of the cortex showed a broad peak from 0.08 to 0.32 cycles/cm (wavelength 12.5–3.125 cm) and other two peaks within the range of 0.32 to 0.9 cycles/cm (wavelength 3.125–1.11 cm). These peaks are definitely due to the gyri structures and associated larger patterns on the cortical surface. Smaller peaks in the range of 1–3 cycles/cm were also observed which are possibly due to sulci structures. These results suggest that the spatial information was present in the EEG and MEG at the spatial frequencies of gyri. This also implies that the practical Nyquist frequency for sampling scalp EEGs should be 3.0 cycles/cm and an optimal interelectrode spacing of about 3 mm is needed for extraction of cortical patterns from scalp EEGs in humans.

Electrical dipoles oriented perpendicular to the cortical surface are the primary source of the scalp EEGs and MEGs. Thus, in particular, gyri and sulci structures on the cortical surface have a definite possibility to influence the EEGs and MEGs. This was examined by comparing the spatial power spectral density (PSD) of the upper portion of the human cortex in MRI slices to that of simulated scalp EEGs and MEGs. The electrical activity was modeled with 2,650 dipolar sources oriented normal to the local cortical surface. The resulting scalp potentials were calculated with a finite element model of the head constructed from 51 segmented sagittal MR images. The PSD was computed after taking the fast Fourier transform of scalp potentials. The PSD of the cortical contour in each slice was also computed. The PSD was then averaged over all the slices. This was done for sagittal and coronal view both. The PSD of EEG and MEG showed two broad peaks, one from 0.05 to 0.22 cycles/cm (wavelength 20–4.545 cm) and the other from 0.22 to 1.2 cycles/cm (wavelength 4.545–0.834 cm). The PSD of the cortex showed a broad peak from 0.08 to 0.32 cycles/cm (wavelength 12.5–3.125 cm) and other two peaks within the range of 0.32 to 0.9 cycles/cm (wavelength 3.125–1.11 cm). These peaks are definitely due to the gyri structures and associated larger patterns on the cortical surface. Smaller peaks in the range of 1–3 cycles/ cm were also observed which are possibly due to sulci structures. These results suggest that the spatial information was present in the EEG and MEG at the spatial frequencies of gyri. This also implies that the practical Nyquist frequency for sampling scalp EEGs should be 3.0 cycles/cm and an optimal interelectrode spacing of about 3 mm is needed for extraction of cortical patterns from scalp EEGs in humans.

CT imaging is the ideal technique for initial evaluation of neurocritical care patients. It is robust, reliable and relatively easy to interpret. Its ability to diagnose hemorrhage, bony fractures, brain edema and herniation in short scanning times makes it an ideal technique for neurological emergencies. The imaging equipment, normal anatomy and imaging findings in pathologies like infarct, hemorrhage, trauma and hydrocephalus are reviewed in the article. [ABSTRACT FROM AUTHOR]

Highlights • Examination of OFC sulcogyral patterning differences for OCD patients and controls. • Occurrence of Type II and III patterning is associated with OCD illness severity. • Type I pattern expression is associated with general anxiety in OCD patients. Abstract Obsessive–compulsive disorder (OCD) has been consistently associated with structural and functional alteration of the orbitofrontal cortex (OFC) and its subcortical connections. In exploring these alterations, a neurodevelopmental basis to OCD has been suggested. While some studies have examined outcomes of early cortical maturation processes, such as global cortical thickness and gyrification, no work has specifically examined the OFC. Within the OFC, three types of sulcogyral patterns have been identified as a result of variance in cortical folding. The distribution of these patterns has been found to differ in patients of various neuropsychiatric disorders relative to the general population, however no study has yet investigated this distribution in individuals with OCD. Eighty OCD patients and 78 healthy controls were evaluated using magnetic resonance imaging, with identification of the sulcogyral pattern based on the method of Chiavaras and Petrides (2000). While gross changes in OFC sulcogyral patterning did not distinguish OCD patients from healthy controls, expression of both the Type II and Type III patterns was significantly associated with increased OCD illness severity. This finding indicates that early neurodevelopmental factors may influence illness severity. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether sulcal morphology differs between middle age (MA) and older healthy individuals. Furthermore, we sought to determine whether age-related differences in sulcal characteristics were more strongly associated with differences in local or global cortical volumes. Participants (age 44–50, N = 403; age 64–70, N = 390) from the Personality and Total Health Through Life (PATH) study were included. Sulci were 17.3% wider, on average, in old age (OA) compared to MA participants, with the largest difference in the left superior frontal sulcus. Differences in sulcal width were generally higher in males than females. Differences in the width of the superior frontal and central sulci were significantly associated with differences in the volume of adjacent local gyri, while age-related differences in the width of lateral and superior temporal sulci were associated with differences in whole brain cortical volume. These findings suggest that sulcal characteristics provide unique information about changes in local and global brain structure in aging.

The gyri and sulci of the human brain were defined by pioneers such as Louis-Pierre Gratiolet and Alexander Ecker, and extensified by, among others, Dejerine (1895) and von Economo and Koskinas (1925). Extensive discussions of the cerebral sulci and their variations were presented by Ono et al. (1990), Duvernoy (1992), Tamraz and Comair (2000), and Rhoton (2007). An anatomical parcellation of the spatially normalized single high resolution T1 volume provided by the Montreal Neurological Institute (MNI; Collins, 1994; Collins et al., 1998) was used for the macroscopical labeling of functional studies (Tzourio-Mazoyer et al., 2002; Rolls et al., 2015). In the standard atlas of the human brain by Mai et al. (2016), the terminology from Mai and Paxinos (2012) is used. It contains an extensively analyzed individual brain hemisphere in the MNI-space. A recent revision of the terminology on the central nervous system in the Terminologia Anatomica (TA, 1998) was made by the Working Group Neuroanatomy of the Federative International Programme for Anatomical Terminology (FIPAT) of the International Federation of Associations of Anatomists (IFAA), and posted online as the Terminologia Neuroanatomica (TNA, 2017: http://FIPAT.library.dal.ca) as the official FIPAT terminology. This review deals with the various terminologies for the cerebral gyri and sulci, aiming for a common terminology.

The gyri and sulci of the human brain were defined by pioneers such as Louis-Pierre Gratiolet and Alexander Ecker, and extensified by, among others, Dejerine (1895) and von Economo and Koskinas (1925). Extensive discussions of the cerebral sulci and their variations were presented by Ono et al. (1990), Duvernoy (1992), Tamraz and Comair (2000), and Rhoton (2007). An anatomical parcellation of the spatially normalized single high resolution T1 volume provided by the Montreal Neurological Institute (MNI; Collins, 1994; Collins et al., 1998) was used for the macroscopical labeling of functional studies (Tzourio-Mazoyer et al., 2002; Rolls et al., 2015). In the standard atlas of the human brain by Mai et al. (2016), the terminology from Mai and Paxinos (2012) is used. It contains an extensively analyzed individual brain hemisphere in the MNI-space. A recent revision of the terminology on the central nervous system in the Terminologia Anatomica (TA, 1998) was made by the Working Group Neuroanatomy of the Federative International Programme for Anatomical Terminology (FIPAT) of the International Federation of Associations of Anatomists (IFAA), and posted online as the Terminologia Neuroanatomica (TNA, 2017: http://FIPAT.library.dal.ca) as the official FIPAT terminology. This review deals with the various terminologies for the cerebral gyri and sulci, aiming for a common terminology. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether sulcal morphology differs between middle age (MA) and older healthy individuals. Furthermore, we sought to determine whether age-related differences in sulcal characteristics were more strongly associated with differences in local or global cortical volumes. Participants (age 44–50, N = 403; age 64–70, N = 390) from the Personality and Total Health Through Life (PATH) study were included. Sulci were 17.3% wider, on average, in old age (OA) compared to MA participants, with the largest difference in the left superior frontal sulcus. Differences in sulcal width were generally higher in males than females. Differences in the width of the superior frontal and central sulci were significantly associated with differences in the volume of adjacent local gyri, while age-related differences in the width of lateral and superior temporal sulci were associated with differences in whole brain cortical volume. These findings suggest that sulcal characteristics provide unique information about changes in local and global brain structure in aging. [ABSTRACT FROM AUTHOR]

Autism spectrum disorder is associated with an altered early brain development. However, the specific cortical structure abnormalities underlying this disorder remain largely unknown. Nonetheless, atypical cortical folding provides lingering evidence of early disruptions in neurodevelopmental processes and identifying changes in the geometry of cortical sulci is of primary interest for characterizing these structural abnormalities in autism and their evolution over the first stages of brain development. Here, we applied state-of-the-art sulcus-based morphometry methods to a large highly-selective cohort of 73 young male children of age spanning from 18 to 108 months. Moreover, such large cohort was selected through extensive behavioral assessments and stringent inclusion criteria for the group of 59 children with autism. After manual labeling of 59 different sulci in each hemisphere, we computed multiple shape descriptors for each single sulcus element, hereby separating the folding measurement into distinct factors such as the length and depth of the sulcus. We demonstrated that the central, intraparietal and frontal medial sulci showed a significant and consistent pattern of abnormalities across our different geometrical indices. We also found that autistic and control children exhibited strikingly different relationships between age and structural changes in brain morphology. Lastly, the different measures of sulcus shapes were correlated with the CARS and ADOS scores that are specific to the autistic pathology and indices of symptom severity. Inherently, these structural abnormalities are confined to regions that are functionally relevant with respect to cognitive disorders in ASD. In contrast to those previously reported in adults, it is very unlikely that these abnormalities originate from general compensatory mechanisms unrelated to the primary pathology. Rather, they most probably reflect an early disruption on developmental trajectory that could be part of the primary pathology.

The highly convoluted cerebral cortex is characterized by two different topographic structures: convex gyri and concave sulci. Increasing studies have demonstrated that cortical gyri and sulci exhibit different structural connectivity patterns. Inspired by the intrinsic structural differences between gyri and sulci, in this paper, we present a data-driven framework based on sparse representation of fMRI data for functional network inferences, then examine the interactions within and across gyral and sulcal functional networks and finally elucidate possible functional differences using graph theory based properties. We apply the proposed framework to the high-resolution Human Connectome Project (HCP) grayordinate fMRI data. Extensive experimental results on both resting state fMRI data and task-based fMRI data consistently suggested that gyri are more functionally integrated, while sulci are more functionally segregated in the organizational architecture of cerebral cortex, offering novel understanding of the byzantine cerebral cortex. [ABSTRACT FROM AUTHOR]

We explored brain volume recovery in terms of cortical thickness (CTh; gyral, sulcal pattern) and surface area (SA), as well as subcortical volume recovery in the first 2 weeks of abstinence in 49 alcohol-dependent patients (ADPs). A widespread reduction of CTh in ADPs at day 1 of abstinence compared to healthy controls, with more pronounced differences in sulci relative to gyri was found. After 2 weeks of abstinence, partial recovery to varying degrees of CTh loss in ADPs was observed for several regions. The longitudinal CTh changes were greater in sulci than in gyri of affected regions. No longitudinal change in SAs and subcortical volumes was found. Alterations of CTh contribute to brain volume loss in alcoholism and recovery during early abstinence. Sulci seem to be more vulnerable to excessive alcohol consumption and to drive abstinence-induced volume recovery. During the initial 2 weeks of abstinence no subcortical volume regain was observed. Either the time span was too short or the lower subcortical volume could represent a predisposing trait marker. [ABSTRACT FROM AUTHOR]

The recently released Allen Mouse Brain Connectivity Atlas provides a comprehensive mouse brain neuronal connectivity map from brain-wide injection sites via anterograde tracers coupled with serial two-photon tomography. In addition, the Allen Mouse Brain Atlas offers a genome-wide gene expression database built upon a series of in situ hybridization images, covering comprehensive expression energy of over 4,000 genes in coronal sections and over 20,000 genes in sagittal sections across the whole mouse brain. These concurrent and co-registered datasets provide an unparalleled opportunity for systematically analyzing and characterizing spatial neuronal connectivity and gene expression patterns. Inspired by our recent macroscale neuroimaging results showing that there are significantly different structural and functional connectivity patterns on the gyri and sulci of cerebral cortex in primate brains, the present work systematically examines the axonal connectivity and gene expression patterns on gyri and sulci of the cerebellum. Our results demonstrate that the cerebellum gyri and sulci of rodent brains are significantly different in both axonal connectivity and gene expression patterns. This discovery enriches and extends our prior findings in macroscale neuroimaging studies in primates. Additionally, this work offers novel insights on the molecular and structural architectures of the cerebellum in particular and the brain in general. [ABSTRACT FROM AUTHOR]

Certain sulci of the human cerebral cortex hold consistent relationships to cytoarchitectonic areas (e.g. the primary motor cortical area 4 and the somatosensory cortical area 3 occupy the anterior and posterior banks of the central sulcus, respectively). Recent research has improved knowledge of the cortical sulci and their variability across individuals. However, other than the so-called primary sulci, understanding of the precise relationships cortical folds hold with many cytoarchitectonic areas remains elusive. To examine these relationships, the cortex must be blocked, sectioned, and histologically processed in a manner that allows the cytoarchitectonic layers to be clearly observed. The optimal strategy to view the cytoarchitecture is to block and section the cortex perpendicular to the sulcal orientation. Most cytoarchitectonic investigations of the cortex, however, have been conducted on specimens cut along a single axis (e.g. the coronal plane), which distorts the appearance of the cytoarchitectonic layers within parts of the cortical ribbon not sectioned optimally. Thus, to understand further the relationships between sulci and cytoarchitectonic areas, the cortex should be sectioned optimally to the sulci of interest. A novel approach for blocking the cortex optimally using structural magnetic resonance imaging (MRI) and surgical neuronavigation tools is presented here., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The spoken word does not fossilize. Despite this, scientists have long sought to unearth the origins of language within the human lineage. One of the lines of evidence they have pursued is functional brain areas, such as Broca's and Wernicke's areas, which are associated with speech production and comprehension, respectively. Sulcal layout of Broca's area clearly differs between humans and our closest living relatives, the chimpanzees, enabling its homolog in fossil hominins to be deemed more chimpanzee-like (i.e., closer to the ancestral form) or more human-like (i.e., derived form) with relative ease. Yet, no such differences have been found for Wernicke's area. This study compares sulcal and gyral organization of Wernicke's area across extant human brains (n=4), extant chimpanzee brains (n=5) and fossil hominin endocasts (n=4). Some chimpanzee brains had indications of leftward Wernicke's area asymmetry in the form of a shorter Sylvian fissure and/or caudal superior temporal gyral bulging in the left hemisphere. Overlap between the superior and middle temporal sulci in human but not chimpanzee brains may be due to a relatively larger Wernicke's area in humans. Fragmentation of the main body of the superior temporal sulcus exclusively in human left hemispheres was ascribed to a leftward Wernicke's area asymmetry in this species. Endocast examination found that, while Paranthropus robustus exhibit human-like overlap between the superior and middle temporal sulci, Australopithecus africanus do not, although they do exhibit chimpanzee-like caudal superior temporal gyral bulging. Such findings signal, albeit loosely, a more human-like Wernicke's area in Paranthropus than Australopithecus., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective. Numerical implication of sulcal and gyral topography for surgical approaches has not been studied. Methods. Percentage gain of distance using sulci as compared to that of gyri was calculated by measuring distances toward the ventricles in 15 hemispheres. Results. Superior frontal sulcus was closest proving greater than 50% gain in distance compared to superior frontal gyrus; inferior temporal sulcus provided greater gain in the temporal lobe. Conclusion. Sulci provide upto 58% distance gain. For trans-gyral approaches, MFG and ITG were found closer to the respective ventricular area. [ABSTRACT FROM AUTHOR]

Despite technological advances, such as intraoperative MRI, intraoperative sensory and motor monitoring, and awake brain surgery, brain anatomy and its relationship with cranial landmarks still remains the basis of neurosurgery. Our objective is to describe the utility of anatomical knowledge of brain sulci and gyri in neurosurgery. This study was performed on 10 human adult cadaveric heads fixed in formalin and injected with colored silicone rubber. Additionally, using procedures done by the authors between June 2006 and June 2011, we describe anatomical knowledge of brain sulci and gyri used to manage brain lesions. Knowledge of the brain sulci and gyri can be used (a) to localize the craniotomy procedure, (b) to recognize eloquent areas of the brain, and (c) to identify any given sulcus for access to deep areas of the brain. Despite technological advances, anatomical knowledge of brain sulci and gyri remains essential to perform brain surgery safely and effectively. [ABSTRACT FROM AUTHOR]