Cingulate Sulcus Research Articles

Fetal neurosonography at 31-35 weeks reveals altered cortical development in pre-eclampsia with and without small-for-gestational-age fetus.

To explore the pattern of fetal cortical development in pregnancies complicated by pre-eclampsia (PE), with and without a small-for-gestational-age (SGA) fetus, compared to uncomplicated pregnancies. This was a prospective observational study including singleton pregnancies complicated by normotensive SGA (birth weight < 10th centile) (n = 77), PE with an appropriate-for-gestational-age (AGA) fetus (n = 76) or PE with a SGA fetus (n = 67), and 128 uncomplicated pregnancies (normotensive AGA) matched by gestational age at ultrasound. All pregnancies underwent detailed neurosonography, using a transabdominal and transvaginal approach, at 31-35 weeks' gestation to assess the depth of the insula, Sylvian fissure, parieto-occipital sulcus, cingulate sulcus and calcarine sulcus. All measurements were adjusted for biparietal diameter (BPD). In addition, a grading score of cortical development was assigned to each brain structure, ranging from Grade 0 (no development) to Grade 5 (maximum development). Univariate and multiple regression analyses were conducted. Similar to findings in previous studies, normotensive pregnancies with a SGA fetus showed significant differences in cortical development compared with controls, with reduced Sylvian fissure depth adjusted for BPD (14.5 ± 2.4 vs 16.6 ± 2.3; P < 0.001) and increased insula depth adjusted for BPD (33.2 ± 2.0 vs 31.8 ± 2.0; P < 0.001). Interestingly, a similar cortical development pattern was observed in PE pregnancies with a SGA fetus and in PE pregnancies with an AGA fetus, manifested by reduced Sylvian fissure depth adjusted for BPD (14.2 ± 2.3 and 14.3 ± 2.3 vs 16.6 ± 2.3; P < 0.001 for both) and greater insula depth adjusted for BPD (33.2 ± 2.1 and 32.8 ± 1.7 vs 31.8 ± 2.0; P < 0.001 for both) compared with controls. No significant differences were observed in parieto-occipital, cingulate sulcus or calcarine sulcus depth across the study groups. The Sylvian fissure was scored as Grade 4 in significantly more (93.2% vs 59.5%) and as Grade 5 in significantly fewer (2.7% vs 37.3%) PE pregnancies with an AGA fetus compared with controls (P < 0.05 for both). These differences remained significant even after statistical adjustment for potential confounders, including ethnicity, low socioeconomic status, nulliparity, chronic hypertension, pregestational diabetes, assisted reproductive technologies, smoking and fetal gender, with the application of Benjamini-Hochberg procedure for multiple comparisons. PE with or without SGA is associated with a differential fetal cortical development pattern which is similar to that described previously in small fetuses. Future research is warranted to elucidate better the mechanism(s) underlying these changes. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Structural Brain Asymmetries for Language: A Comparative Approach across Primates

Humans are the only species that can speak. Nonhuman primates, however, share some ‘domain-general’ cognitive properties that are essential to language processes. Whether these shared cognitive properties between humans and nonhuman primates are the results of a continuous evolution [homologies] or of a convergent evolution [analogies] remain difficult to demonstrate. However, comparing their respective underlying structure—the brain—to determinate their similarity or their divergence across species is critical to help increase the probability of either of the two hypotheses, respectively. Key areas associated with language processes are the Planum Temporale, Broca’s Area, the Arcuate Fasciculus, Cingulate Sulcus, The Insula, Superior Temporal Sulcus, the Inferior Parietal lobe, and the Central Sulcus. These structures share a fundamental feature: They are functionally and structurally specialised to one hemisphere. Interestingly, several nonhuman primate species, such as chimpanzees and baboons, show human-like structural brain asymmetries for areas homologous to key language regions. The question then arises: for what function did these asymmetries arise in non-linguistic primates, if not for language per se? In an attempt to provide some answers, we review the literature on the lateralisation of the gestural communication system, which may represent the missing behavioural link to brain asymmetries for language area’s homologues in our common ancestor.

Role of Ultrasonography in the Evaluation of Normal Developmental Pattern of Fetal Cerebral Sulci Between 18 and 32 Weeks of Gestational Age.

BackgroundBrain development is a crucial process of intrauterine life and can be readily visualized on ultrasonography. This study aims to visualize developmental patterns of various fetal cerebral sulci using ultrasonography between 18 and 32 weeks of gestation. Sulci are best visualized on images that are taken perpendicular to their expected course of development. Initially, they appear as small dot/dimple on the brain surface and later develop into a V-shaped indentation and finally deepen to form notch and echogenic line into the brain forming a Y-shaped configuration.Material and methodsThis was a cross-sectional observational study conducted on 241 antenatal mothers with a singleton pregnancy between 18 and 32 weeks of gestational age. Demographic and clinical data were obtained. Ultrasonography was performed using PHILIPS EPIQ 5, a curvilinear probe of frequency 2-5MHz. Sulci/fissures that are reported to appear early on anatomical studies were evaluated, specifically the parieto-occipital fissure, calcarine fissure, cingulate sulci, insula/Sylvian fissure, and convexity sulci. Comparison of the categorical outcomes was performed between study groups using the chi-square test. A p-value of <0.05 was considered statistically significant.ResultsThe study included 241 participants. The mean age of antenatal mothers was 24.09 ± 4.13 years, and the mean fetal gestational age was 24.99 ± 4.13 weeks. Parieto-occipital fissure was the first fissure to develop and was present as a V-shaped indentation at 18 weeks and as a Y-shaped configuration by 21-22 weeks. Calcarine fissure was the next fissure to appear; it appeared as a dot by 18 weeks and developed into a V-shaped indentation by 20 weeks and as a Y-shaped configuration by 23 weeks. All fissures except cingulate sulci had appeared by 20 weeks, and calcarine sulci appeared later in the gestation by 21 weeks. Sylvian fissure initially appeared as a smooth surface and later underwent operculization to form obtuse and acute angulations with the adjacent temporal lobe by 20 and 24 weeks, respectively. Convexity sulci appeared later in gestation, beyond 25-26 weeks.ConclusionsUltrasonography, which is the commonest modality used in antenatal assessment of the fetus, can also be used to identify, familiarize, and provide a standard reference to assess normality of fetal sulcations. Neuronal migration disorders result in a wide spectrum of malformations of cortical development whose clinical manifestations include severe psychomotor retardation, developmental delays, motor deficits, seizures, and failure to thrive. Knowledge of normal development patterns of fetal cerebral sulci helps in early suspicion and detection of these cortical malformations, when present.

Investigating the Precise Localization of the Grasping Action in the Mid-Cingulate Cortex and Future Directions.

ObjectiveTo prospectively study the cingulate cortex for the localization and role of the grasping action in humans during electrical stimulation of depth electrodes.MethodsAll the patients (n = 23) with intractable focal epilepsy and a depth electrode stereotactically placed in the cingulate cortex, as part of their pre-surgical epilepsy evaluation from 2015 to 2017, were included. Cortical stimulation was performed and examined for grasping actions. Post-implantation volumetric T1 MRIs were co-registered to determine the exact electrode position.ResultsFive patients (male: female 4:1; median age 31) exhibited contralateral grasping actions during electrical stimulation. All patients had electrodes implanted in the ventral bank of the right cingulate sulcus adjacent to the vertical anterior commissure (VAC) line. Stimulation of other electrodes in adjacent regions did not elicit grasping.ConclusionGrasping action elicited from a localized region in the mid-cingulate cortex (MCC) directly supports the concept of the cingulate cortex being crucially involved in the grasping network. This opens an opportunity to explore this region with deep brain stimulation as a motor neuromodulation target for treatment in specific movement disorders or neurorehabilitation.

Sulcal morphology as cognitive decline predictor in older adults with memory complaints

To determine whether sulcal morphology can predict changes in cognition, we investigated the relationship between width of 20 cerebral sulci and cognitive decline. Sulcal width was measured in T1-weighted MRI images at baseline in 433 adults aged ≥70 years with memory complaints from the MRI-Multidomain Alzheimer Preventive Trial study. Cognition was evaluated at baseline, 6, 12, 24, and 36 months of follow-up with a composite Z score. The composite score variations over time relative to the baseline sulcal width were assessed using linear mixed regression models. We observed a positive association between a greater decline in cognitive composite score and the width of the superior and the anterior inferior temporal sulci, and the cingulate anterior sulcus of the left hemisphere. Sulcal widening in the lateral temporal and the cingulate anterior areas might predict cognitive decline in individuals with memory complaints.

Investigating structural subdivisions of the anterior cingulate cortex in schizophrenia, with implications for treatment resistance and glutamatergic levels.

Background:Abnormalities in the anterior cingulate cortex (ACC) are thought to play an important role in the pathophysiology of schizophrenia. Given regional variations in ACC structure, the present study aimed to examine ACC structural subdivisions and their relationships to treatment resistance and glutamatergic levels in schizophrenia.Methods:This study included 100 patients with schizophrenia and 52 healthy controls from 2 cohorts. We applied non-negative matrix factorization to identify accurate and stable spatial components of ACC structure. Between groups, we compared ACC structural indices in each spatial component based on treatment resistance or response and tested relationships with ACC glutamate + glutamine levels.Results:We detected reductions in cortical thickness and increases in mean diffusivity in the spatial components on the surface of the cingulate sulcus, especially in patients with treatment-resistant and clozapine-resistant schizophrenia. Notably, mean diffusivity in these components was higher in patients who did not respond to clozapine compared to those who did. Furthermore, these ACC structural alterations were related to elevated ACC glutamate + glutamine levels but not related to symptomatology or antipsychotic dose.Limitations:Sample sizes, cross-sectional findings and mixed antipsychotic status were limitations of this study.Conclusion:This study identified reproducible abnormalities in ACC structures in patients with treatment-resistant and clozapine-resistant schizophrenia. Given that these spatial components play a role in inhibitory control, the present study strengthens the notion that glutamate-related disinhibition is a common biological feature of treatment resistance in schizophrenia.

A distal anterior cerebral artery tripod branching to a bihemispheric pericallosal artery.

The anterior cerebral artery (ACA) branching pattern may be particularly complex and variant including bifurcations, trifurcations or quadrifurcations, thus leading to typical or atypical vessels. The bihemispheric ACA (BhACA) variant crosses the midline to supply the contralateral hemisphere. The current case highlights a left-sided ACA trifurcation into a bihemispheric pericallosal artery, and two ipsilateral atypical arteries: a callosomarginal artery of short course and a left-sided pericallosal artery of an aberrant course into the cingulate sulcus. The depicted trifurcation was characterized as a distal ACA tripod. The bihemispheric branch supplied the contralateral pericallosal area and coursed into the cingulate sulcus. Deviations from the typical ACA pattern, especially when they coexist are quite rare and may complicate neurosurgical approaches or raise diagnostic difficulties. The BhACA may be implicated in aneurysm formation and bilateral ischemia after its occlusion. Knowledge of such variants, as well as awareness of the complications they may be related to, is of great significance.

Lesion location and outcome following cingulotomy for obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is among the most debilitating and medically refractory psychiatric disorders. While cingulotomy is an anatomically targeted neurosurgical treatment that has shown significant promise in treating OCD-related symptoms, the precise underlying neuroanatomical basis for its beneficial effects has remained poorly understood. Therefore, the authors sought to determine whether lesion location is related to responder status following cingulotomy. The authors reviewed the records of 18 patients who had undergone cingulotomy. Responders were defined as patients who had at least a 35% improvement in the Yale-Brown Obsessive Compulsive Scale (YBOCS) score. The authors traced the lesion sites on T1-weighted MRI scans and used an anatomical registration matrix generated by the imaging software FreeSurfer to superimpose these lesions onto a template brain. Lesion placement was compared between responders and nonresponders. The placement of lesions relative to various anatomical regions was also compared. A decrease in postoperative YBOCS score was significantly correlated with more superiorly placed lesions (decrease -0.52, p = 0.0012). While all lesions were centered within 6 mm of the cingulate sulcus, responder lesions were placed more superiorly and posteriorly along the cingulate sulcus (1-way ANOVA, p = 0.003). The proportions of the cingulum bundle, cingulate gyrus, and paracingulate cortex affected by the lesions were the same between responders and nonresponders. However, all responders had lesions covering a larger subregion of Brodmann area (BA) 32. In particular, responder lesions covered a significantly greater proportion of the posterior BA32 (1-way ANOVA, p = 0.0064). Lesions in patients responsive to cingulotomy tended to be located more superiorly and posteriorly and share greater coverage of a posterior subregion of BA32 than lesions in patients not responsive to this treatment.

Frontal cortical functional connectivity is impacted by anaesthesia in macaques.

A critical aspect of neuroscience is to establish whether and how brain networks evolved across primates. To date, most comparative studies have used resting-state functional magnetic resonance imaging (rs-fMRI) in anaesthetized nonhuman primates and in awake humans. However, anaesthesia strongly affects rs-fMRI signals. The present study investigated the impact of the awareness state (anaesthesia vs. awake) within the same group of macaque monkeys on the rs-fMRI functional connectivity organization of a well-characterized network in the human brain, the cingulo-frontal lateral network. Results in awake macaques show that rostral seeds in the cingulate sulcus exhibited stronger correlation strength with rostral compared to caudal lateral frontal cortical areas, while more caudal seeds displayed stronger correlation strength with caudal compared to anterior lateral frontal cortical areas. Critically, this inverse rostro-caudal functional gradient was abolished under anaesthesia. This study demonstrated a similar functional connectivity (FC) organization of the cingulo-frontal cortical network in awake macaque to that previously uncovered in the human brain pointing toward a preserved FC organization from macaque to human. However, it can only be observed in awake state suggesting that this network is sensitive to anaesthesia and warranting significant caution when comparing FC patterns across species under different states.

Assessment of normal fetal cortical sulcus development

The aim of our study was to investigate the normal cortical sulcus development in fetuses without central nervous system abnormality with transabdominal ultrasonography. Our study was planned as a cross-sectional study in our clinic between November 2011 and October 2012. The study group was selected among pregnant women who applied to our hospital for routine antenatal follow-up. Singleton pregnancies, between 15th and 32nd gestational weeks, were included in the study. During the routine fetal ultrasonographic examination of these pregnant women, sylvian sulcus, parietooccipital sulcus, calcarine sulcus, and cingulate sulcus length measurements were taken and the correlation of these values with gestational week was evaluated. Three hundred and thirty-two patients were included in the study. Sylvian sulcus length, parietooccipital sulcus length, calcarine sulcus length, and cingulate sulcus length could be first measured respectively, at 15th, 17th, 17th and 25th gestational week. We found a positive correlation between gestational age and sylvian sulcus, parietooccipital sulcus, calcarine sulcus, and cingulate sulcus length measurements (p < 0.001). Sulcal development and cortical maturation can be evaluated prenatally with transabdominal ultrasonography of the central nervous system.

Tormenting thoughts: The posterior cingulate sulcus of the default mode network regulates valence of thoughts and activity in the brain's pain network during music listening.

Many individuals spend a significant amount of their time “mind‐wandering”. Mind‐wandering often includes spontaneous, nonintentional thought, and a neural correlate of this kind of thought is the default mode network (DMN). Thoughts during mind‐wandering can have positive or negative valence, but only little is known about the neural correlates of positive or negative thoughts. We used resting‐state functional magnetic resonance imaging (fMRI) and music to evoke mind‐wandering in n = 33 participants, with positive‐sounding music eliciting thoughts with more positive valence and negative‐sounding music eliciting thoughts with more negative valence. Applying purely data‐driven analysis methods, we show that medial orbitofrontal cortex (mOFC, part of the ventromedial prefrontal cortex) and the posterior cingulate sulcus (likely area 23c of the posterior cingulate cortex), two sub‐regions of the DMN, modulate the valence of thought‐contents during mind‐wandering. In addition, across two independent experiments, we observed that the posterior cingulate sulcus, a region involved in pain, shows valence‐specific functional connectivity with core regions of the brain's putative pain network. Our results suggest that two DMN regions (mOFC and posterior cingulate sulcus) support the formation of negative spontaneous, nonintentional thoughts, and that the interplay between these structures with regions of the putative pain network forms a neural mechanism by which thoughts can become painful.

Multisensory integration in cortical regions responding to locomotion‐related visual and somatomotor signals

During real-world locomotion, in order to be able to move along a path or avoid an obstacle, continuous changes in self-motion direction (i.e. heading) are needed. Control of heading changes during locomotion requires the integration of multiple signals (i.e., visual, somatomotor, vestibular). Recent fMRI studies have shown that both somatomotor areas (human PEc [hPEc], human PE [hPE], primary somatosensory cortex [S-I]) and egomotion visual regions (cingulate sulcus visual area [CSv], posterior cingulate area [pCi], posterior insular cortex [PIC]) respond to either leg movements and egomotion-compatible visual stimulations, suggesting a role in the analysis of both visual attributes of egomotion and somatomotor signals with the aim of guiding locomotion. However, whether these regions are able to integrate egomotion-related visual signals with somatomotor inputs coming from leg movements during heading changes remains an open question. Here we used a combined approach of individual functional localizers and task-evoked activity by fMRI. In thirty subjects we first localized three egomotion areas (CSv, pCi, PIC) and three somatomotor regions (S-I, hPE, hPEc). Then, we tested their responses in a multisensory integration experiment combining visual and somatomotor signals relevant to locomotion in congruent or incongruent trials. We used an fMR-adaptation paradigm to explore the sensitivity to the repeated presentation of these bimodal stimuli in the six regions of interest. Results revealed that hPE, S-I and CSv showed an adaptation effect regardless of congruency, while PIC, pCi and hPEc showed sensitivity to congruency. PIC exhibited a preference for congruent trials compared to incongruent trials. Areas pCi and hPEc exhibited an adaptation effect only for congruent and incongruent trials, respectively. PIC, pCi and hPEc sensitivity to the congruency relationship between visual (locomotion-compatible) cues and (leg-related) somatomotor inputs suggests that these regions are involved in multisensory integration processes, likely in order to guide/adjust leg movements during heading changes.

Interhemispheric Contralateral Transfalcine Approach for Subparacentral Arteriovenous Malformation: 3-Dimensional Operative Video.

Neurovascular procedures along the interhemispheric fissure harbor unique features differentiating them from those arteriovenous malformations (AVMs) located at the lateral surface of the brain.1-4 The aim of this 3-dimensional operative video is to present a microsurgical resection of an AVM in a subparacentral location, operated through an interhemispheric contralateral transfalcine approach.1,3,5 This is a case of a 29-yr-old female, with headaches and history of seizures. The patient presented an interhemispheric bleeding 6 mo before the surgery. The magnetic resonance imaging (MRI) showed a vascular lesion located on the medial surface of the right hemisphere at the confluence between the cingulate sulcus and its ascending sulcus. In the cerebral angiography, a right medial AVM was observed, receiving afference from the right anterior cerebral artery and draining to the superior longitudinal sinus. The patient signed an informed consent for the procedure and agreed with the use of her images and surgical video for research and academic purposes. The patient was in a supine position, and a left interhemispheric contralateral transfalcine approach was performed,1-3 a circumferential dissection of the nidus, and, finally, the AVM was resected in one piece. The patient evolved without neurological deficits after the surgery. The postoperative MRI and angiography showed a complete resection of the AVM. In the case presented, to avoid exposing the drainage vein first and to use the gravity of the exposure, the contralateral transfalcine interhemispheric approach was used,1,2 which finally accomplished the proposed objectives.

False memories activate distinct brain regions in females and males

The constructive process of memory is generally successful; however, it can also lead to memory failures such as false memories. Although true memories and false memories rely on some of the same brain regions, these memory types are also mediated by distinct neural substrates. Of relevance, there is a growing body of evidence that there are sex differences in the brain during true memories. However, no studies have investigated whether there are neural sex differences during false memories. In the current fMRI study, across all subjects, false memories produced activity in the precentral sulcus and superior parietal lobule, replicating previous findings. Males produced greater activity than females in the precuneus, posterior cingulate cortex, parietooccipital sulcus, and fusiform gyrus. Females produced greater activity than males in the medial prefrontal cortex, anterior cingulate cortex, paracentral lobule, supramarginal gyrus, lateral sulcus, cingulate sulcus, the putamen, and V1. An interaction analysis revealed a significant interaction between sex and region with a higher magnitude of activity in the hippocampus for males than females and a higher magnitude of activity in V1 for females than males. The current results suggest that false memories are supported by distinct brain regions and cognitive processes in females and males.

Revisiting the Morphology and Classification of the Paracingulate Gyrus with Commentaries on Ambiguous Cases.

The anterior cingulate cortex is considered to play a crucial role in cognitive and affective regulation. However, this area shows a high degree of morphological interindividual variability and asymmetry. It is especially true regarding the paracingulate sulcus and paracingulate gyrus (PCG). Since the reports described in the literature are mainly based on imaging techniques, the goal of this study was to verify the classification of the PCG based on anatomical material. Special attention was given to ambiguous cases. The PCG was absent in 26.4% of specimens. The gyrus was classified as present in 28.3% of cases. The prominent type of the PCG was observed in 37.7% of the total. Occasionally, the gyrus was well-developed and roughly only a few millimeters were missing for classifying the gyrus as prominent, as it ended slightly anterior the level of the VAC. The remaining four cases involved two inconclusive types. We observed that the callosomarginal artery ran within the cingulate sulcus and provided branches that crossed the PCG. Based on Klingler’s dissection technique, we observed a close relationship of the PCG with the superior longitudinal fascicle. The awareness of the anatomical variability observed within the brain cortex is an essential starting point for in-depth research.

Optic flow selectivity in the macaque parieto-occipital sulcus.

In humans, several neuroimaging studies have demonstrated that passive viewing of optic flow stimuli activates higher-level motion areas, like V6 and the cingulate sulcus visual area (CSv). In macaque, there are few studies on the sensitivity of V6 and CSv to egomotion compatible optic flow. The only fMRI study on this issue revealed selectivity to egomotion compatible optic flow in macaque CSv but not in V6 (Cotterau et al. Cereb Cortex 27(1):330-343, 2017, but see Fan et al. J Neurosci. 35:16303-16314, 2015). Yet, it is unknown whether monkey visual motion areas MT + and V6 display any distinctive fMRI functional profile relative to the optic flow stimulation, as it is the case for the homologous human areas (Pitzalis et al., Cereb Cortex 20(2):411-424, 2010). Here, we described the sensitivity of the monkey brain to two motion stimuli (radial rings and flow fields) originally used in humans to functionally map the motion middle temporal area MT + (Tootell et al. J Neurosci 15: 3215-3230, 1995a; Nature 375:139-141, 1995b) and the motion medial parietal area V6 (Pitzalis et al. 2010), respectively. In both animals, we found regions responding only to optic flow or radial rings stimulation, and regions responding to both stimuli. A region in the parieto-occipital sulcus (likely including V6) was one of the most highly selective area for coherently moving fields of dots, further demonstrating the power of this type of stimulation to activate V6 in both humans and monkeys. We did not find any evidence that putative macaque CSv responds to Flow Fields.

Morphology and morphometry of the human early foetal brain: A three-dimensional analysis.

Morphometric analyses in the early foetal phase (9-13 postconceptional week) are critical for evaluating normal brain growth. In this study, we assessed sequential morphological and morphometric changes in the foetal brain during this period using high-resolution T1-weighted magnetic resonance imaging (MRI) scans from 21 samples preserved at Kyoto University. MRI sectional views (coronal, mid-sagittal, and horizontal sections) and 3D reconstructions of the whole brain revealed sequential changes in its external morphology and internal structures. The cerebrum's gross external view, lateral ventricle and choroid plexus, cerebral wall, basal ganglia and thalamus, and corpus callosum were assessed. The development of the cerebral cortex, white matter microstructure, and basal ganglia can be well-characterized using MRI scans. The insula became apparent and deeply impressed as brain growth progressed. A thick, densely packed cellular ventricular/subventricular zone and ganglionic eminence became apparent at high signal intensity. We detected the emergence of important landmarks which may be candidates in the subdivision processes during the early foetal period; the corpus callosum was first detected in the sample with crown-rump length (CRL) 62mm. A primary sulcus on the medial part of the cortex (cingulate sulcus) was observed in the sample with CRL 114mm. In the cerebellum, the hemispheres, posterolateral fissure, union of the cerebellar halves, and definition of the vermis were observed in the sample with CRL 43.5mm, alongside the appearance of a primary fissure in the sample with CRL 56mm and the prepyramidal fissure in the sample with CRL 75mm. The volumetric, linear, and angle measurements revealed the comprehensive and regional development, growth, and differentiation of brain structures during the early foetal phase. The early foetal period was neither morphologically nor morphometrically uniform. The cerebral proportion (length/height) and the angle of cerebrum to the standard line at the lateral view of the cerebrum, which may reflect the growth and C-shape formation of the cerebrum, may be a candidate for subdividing the early foetal period. Future precise analyses must establish a staging system for the brain during the early foetal period. This study provides insights into brain structure, allowing for a correlation with functional maturation and facilitating the early detection of brain damage and abnormal development.

Asymmetric cortical development and prognosis in fetuses with isolated mild fetal ventriculomegaly: an observational prospective study

BackgroundAssessments of cortical development and identifying factors that may result in a poor prognosis for fetuses with isolated mild ventriculomegaly (IMVM) is a hot research topic. We aimed to perform a constant, detailed assessment of cortical development in IMVM fetuses using ultrasound and determine whether asymmetric cortical development occurred. Moreover, we aimed to estimate the prognosis of IMVM fetuses and compare the difference in the prognosis of IMVM fetuses presenting symmetric and asymmetric cortical maturation.MethodsIMVM was diagnosed by regular ultrasound, neurosonography and fetal MRI. Genetic and TORCH examinations were conducted to exclude common genetic abnormalities and TORCH infection of fetuses. Ultrasound examinations were conducted at an interval of 2–3 weeks to record sulcus development in IMVM fetuses using a scoring system. The neonatal behavioral neurological assessment (NBNA), the Ages and Stages Questionnaire, Third Edition (ASQ-3) and the Bayley Scales of Infant Development, First Edition (BSID-I) were performed after birth.ResultsForty fetuses with IMVM were included: twenty showed asymmetric cortical maturation and twenty showed symmetric cortical maturation. For IMVM fetuses presenting asymmetric cortical maturation, the mean gestational age (GA) at the first diagnosis of relatively delayed development was 24.23 weeks for the parieto-occipital sulcus, 24.71 weeks for the calcarine sulcus, and 26.43 weeks for the cingulate sulcus. All the sulci with delayed development underwent ‘catch-up growth’ and developed to the same grade as the sulci of the other hemisphere. The mean GA at which the two sides developed to the same grade was 29.40 weeks for the parieto-occipital sulcus, 29.30 weeks for the calcarine sulcus and 31.27 weeks for the cingulate sulcus. The NBNA, ASQ-3 and BSID-I scores of all patients were in the normal range.ConclusionsIMVM fetuses may show mild asymmetric cortical maturation in the second trimester, but the relatively delayed sulci undergo ‘catch-up growth’. The neurodevelopment of IMVM fetuses presenting asymmetric cortical maturation and ‘catch-up growth’ is not statistically significantly different from IMVM fetuses presenting symmetric cortical maturation.

The cingulate oculomotor cortex

Knowledge about the relevance and extent of human eye movement control in the cingulate cortex to date is very limited. Experiments in non-human primates brought about evidence for a potentially central role of the dorsal bank of the cingulate sulcus in saccadic eye movements. In humans, a putative cingulate eye field (CEF) in the same region has been proposed; however, its function and location still remain controversial. Another area in the posterior cingulate cortex, the cingulate sulcus visual area (CSv), has been shown to respond to visual motion cues and also ocular motor tasks. In this study we used multi-band neuroimaging (n = 46) to comprehensively characterize oculomotor responses along the entire cingulate cortex during the most common types of eye movements.We were able to robustly localize the CEF to the anterior portion of the midcingulate gyrus. The region gave responses during all oculomotor tasks and is embedded within the ventral attention network. Area CSv, which is located in the anterior portion of the posterior cingulate gyrus, on the other hand responded to smooth pursuit and optokinetic nystagmus only. It likewise represents a node within the ventral attention network but at the same time seems to be a distinctive part of the somatomotor network. Our findings support an executive role of the CEF, suggesting a cognitive control function in maintaining and adapting different kinds of eye movements. CSv on the other hand might be an interface for relaying oculomotor, visual motion and broad sensory signals related to self-motion.

Sex differences in hippocampal connectivity during spatial long‐term memory

Sex differences in brain activity have been reported across various types of long-term memory. To our knowledge, sex differences in functional connectivity during long-term memory have not been investigated. A previous study on the structural connectome identified that female brains have a greater degree of interhemispheric connectivity than males, whereas males have a greater degree of intrahemispheric connectivity than females. The aim of the current investigation was twofold: (a) identify which brain regions were functionally connected to the hippocampus during spatial long-term memory, and (b) determine if there were sex differences in the functionally connected regions. During the study phase, abstract shapes were presented to the left or right of fixation. During the test phase, abstract shapes were presented at fixation and participants classified each item as previously on the "left" or "right". A hippocampal region of interest (ROI) was identified by contrasting spatial memory hits and misses. The peak coordinate from this ROI was used to define the center of a sphere that was used as the seed for the functional connectivity analysis. The connectivity analysis produced many connected activations including the medial posterior frontal cortex, lateral posterior frontal cortex, left inferior frontal gyrus, posterior cingulate cortex, and caudate/putamen. Although there were no regions with greater connectivity in females than males, the male versus female comparison produced connected activations in the medial posterior frontal cortex, anterior prefrontal cortex, precuneus, and cingulate sulcus. Females also had greater interhemispheric connectivity than males. The current findings suggest collapsing across sex in cognitive neuroscience studies may not be warranted.