Anatomical variations of sulci in human fetal cerebrum and its clinical significance

Introduction and Aim: Appearance of sulci and its number in the fetal cerebrum is a signal of growth and development. Chronological appearance and symmetrical development of sulci corresponds to gestational age of fetus. Few sulci can be visualized in the prenatal period to judge the growth of fetus. Any change in chronological appearance, symmetry and number of sulci in fetal cerebrum is of prime importance. Materials and Methods: Hundred and six cerebral hemispheres of 53 fetal brains of different gestational ages were collected from MGM Hospital Kalamboli and Aurangabad after institutional ethical approval to study the pattern of sulci on both sides after fixing in 10% formalin. Results: In 6 (5.6 %) cerebral hemispheres variation in appearance of sulci was observed. It was noted that there is change in number of superior temporal sulcus (STS), superior frontal sulcus (SFS), parieto-occipital sulcus (POS), calcarine sulcus (CS) and occipitotemporal sulcus (OTS) on both the sides in 6 cerebral hemispheres. Remaining 100 cerebral hemisphere showed normal, symmetrical appearance and number of sulci. Conclusion: It was observed that the fetal cerebral hemispheres which showed variations in appearance and number of sulci were associated with mother having eclampsia.

Population-level laterality in foraging finless porpoises

Laterality has been reported in many vertebrates, and asymmetrical cerebral hemisphere function has been hypothesized to cause a left-bias in social behavior and a right-bias in feeding behavior. In this paper, we provide the first report of behavioral laterality in free-ranging finless porpoises, which seems to support the aforementioned hypothesis. We observed the turning behavior of finless porpoises in Omura Bay, Japan, using land-based and unmanned aerial system observations. We found a strong tendency in finless porpoises to turn counterclockwise with their right side down when pursuing and catching fish at the surface of the water. Our results suggest that this population of finless porpoises shows consistent right-biased laterality. Right-biased laterality has been observed in various foraging cetaceans and is usually explained by the dominance of the right eye-left cerebral hemisphere in prey recognition; however, right-biased laterality in foraging cetaceans may have multiple causes.

Population-Level Laterality In Foraging Finless Porpoises

Laterality has been reported in many vertebrates, and asymmetrical cerebral hemisphere function has been hypothesized to cause a left-bias in social behavior and a right-bias in feeding behavior. In this paper, we provide the first report of behavioral laterality in free-ranging finless porpoises, which seemingly supports the aforementioned hypothesis. We observed the turning behavior of finless porpoises in Omura Bay, Japan, using land-based and unmanned aerial system observations. We found a strong tendency in finless porpoises to turn counterclockwise with their right side down when pursuing and catching fish at the surface of the water. Our results suggest that this population of finless porpoises shows consistent right-biased laterality. Right-biased laterality has been observed in various foraging cetaceans and is usually explained by the dominance of the right eye-left cerebral hemisphere in prey recognition; however, right-biased laterality in foraging cetaceans may have multiple causes.

Dural Arteriovenous Fistula with Retrograde Drainage into the Cortical Veins (Case Report)

We present clinical case of a patient who was referred for brain MRI to clarify the cause of a first-time seizure. MRI examination showed cortical and medullary veins ectasia in the left cerebral hemisphere with multiple cerebral microbleeds around the medullary veins. The revealed changes were considered as a manifestation of regional venous hypertension, however, its cause remained unclear. We decided to perform non-contrast 3D-TOF angiography that revealed a dural arteriovenous fistula between the left occipital artery and the sigmoid venous sinus with retrograde drainage into cortical veins (Borden type II, Cognard type IIb). Early diagnosis and treatment of «aggressive» dural arteriovenous fistulas avoids the development of lifethreatening complications (an annual hemorrhage rate of 8,1%).

Visual evoked feedforward-feedback travelling waves organize neural activity across the cortical hierarchy in mice

Sensory processing is distributed among many brain regions that interact via feedforward and feedback signaling. It has been hypothesized that neuronal oscillations mediating feedforward and feedback interactions organize into travelling waves. However, stimulus evoked travelling waves of sufficient spatial scale have never been demonstrated directly. Here, we show that simple visual stimuli reliably evoke two traveling waves with spatial wavelengths that cover much of the cerebral hemisphere in awake mice. 30-50Hz feedforward waves arise in primary visual cortex (V1) and propagate rostrally, while 3-6Hz feedback waves originate in the association cortex and flow caudally. The phase of the feedback wave modulates the amplitude of the feedforward wave and synchronizes firing between V1 and parietal cortex. Altogether, these results provide direct experimental evidence that visual evoked travelling waves percolate through the cerebral cortex and coordinate neuronal activity across broadly distributed networks mediating visual processing.

Reorganization of the Social Brain in Individuals with Only One Intact Cerebral Hemisphere

Social cognition and emotion are ubiquitous human processes that recruit a reliable set of brain networks in healthy individuals. These brain networks typically comprise midline (e.g., medial prefrontal cortex) as well as lateral regions of the brain including homotopic regions in both hemispheres (e.g., left and right temporo-parietal junction). Yet the necessary roles of these networks, and the broader roles of the left and right cerebral hemispheres in socioemotional functioning, remains debated. Here, we investigated these questions in four rare adults whose right (three cases) or left (one case) cerebral hemisphere had been surgically removed (to a large extent) to treat epilepsy. We studied four closely matched healthy comparison participants, and also compared the patient findings to data from a previously published larger healthy comparison sample (n = 33). Participants completed standardized socioemotional and cognitive assessments to investigate social cognition. Functional magnetic resonance imaging (fMRI) data were obtained during passive viewing of a short, animated movie that distinctively recruits two social brain networks: one engaged when thinking about other agents’ internal mental states (e.g., beliefs, desires, emotions; so-called Theory of Mind or ToM network), and the second engaged when thinking about bodily states (e.g., pain, hunger; so-called PAIN network). Behavioral assessments demonstrated remarkably intact general cognitive functioning in all individuals with hemispherectomy. Social-emotional functioning was somewhat variable in the hemispherectomy participants, but strikingly, none of these individuals had consistently impaired social-emotional processing and none of the assessment scores were consistent with a psychiatric disorder. Using inter-region correlation analyses, we also found surprisingly typical ToM and PAIN networks, as well as typical differentiation of the two networks (in the intact hemisphere of patients with either right or left hemispherectomy), based on idiosyncratic reorganization of cortical activation. The findings argue that compensatory brain networks can process social and emotional information following hemispherectomy across different age levels (from 3 months to 20 years old), and suggest that social brain networks typically distributed across midline and lateral brain regions in this domain can be reorganized, to a substantial degree.

Hypoplastic internal carotid artery ending as an ophthalmic artery with multiple cerebral aneurysms, fenestrated Acom and triple A2

A rare case of a hypoplastic internal carotid artery (ICA) terminating in the ophthalmic artery with multiple intracranial saccular aneurysms in the contralateral ICA, anterior communicating artery fenestration and triple A2 was identified. The aetiology and pathogenesis of ICA hypoplasia are subjected to certain hypotheses. Developing several collaterals to preserve the blood supply of the ipsilateral cerebral hemisphere could result in aneurysm formation due to flow overload on the contralateral vasculature, but it could also result in hemicranial hypoplasia, cerebral atrophy and deep watershed infarcts, as in our case.

Cruveilhier’s Unrecognized Case (c1831) of Dyke-Davidoff-Masson Syndrome

In his serially published atlas of pathology, <i>Anatomie Pathologique du Corps Humain</i> (1829–1842), French anatomist and pathologist Jean Cruveilhier (1791–1874) provided an early clinical-pathologic description of Dyke-Davidoff-Masson syndrome. Cruveilhier’s case was initially published around 1830, more than a century before the clinical and radiologic report of Dyke and colleagues in 1933 based on a series of patients studied with pneumoencephalography. Although Dyke and colleagues were apparently unaware of Cruveilhier’s prior description, Cruveilhier’s case manifested all of the key osseous and neuropathological features of Dyke-Davidoff-Masson syndrome as later elaborated by Dyke and colleagues: (1) cerebral hemiatrophy with <i>ex vacuo</i> dilation of the lateral ventricle, (2) ipsilateral thickening of the diploe of the skull, and (3) ipsilateral hyper-pneumatization of the frontal sinuses. In addition, Cruveilhier noted crossed cerebral-cerebellar atrophy in his case and correctly inferred a “crossed effect” between the involved cerebral hemisphere and the contralateral cerebellum. Cruveilhier’s pathological case from 1830 clearly anticipated both the cases reported more than a century later by Dyke and colleagues based on pneumoencephalography and the more recent case reports recognized with computed tomography or magnetic resonance imaging.

Dandy’s hemispherectomies: historical vignette

To better understand Walter Dandy’s intentions and the historical context of his work on hemispherectomy, the authors reviewed his original 1928 publication. Gliomas were considered incurable at that time. Presuming that the loss of motor function denoted a lack of useful tissue in that hemisphere, he pioneered radical removal of the involved cerebral hemisphere. Of the 5 patients operated on by Dandy, 1 died within 48 hours of hemorrhage because of a displaced vascular clip; 1 died of pneumonia in 2 weeks; 2 died of tumor recurrence, at 3 months and 3.5 years, respectively; and a fifth patient was lost to follow-up beyond the 2nd postoperative week. The authors queried the Thomson Reuters Web of Science and Scopus. A total of 88 papers fulfilled inclusion criteria. Half of these papers (44/88) were published after 2012. Only 11% of papers (10/88) quoted Dandy’s paper accurately; half of them were published before 1997. Most publications (76% [67/88]) quoted Dandy incorrectly, all of them from 1997 and later. In the remaining 11 papers (13%), the accuracy of the quotes was unclear. The authors found a trend toward more accurate citation in earlier papers. Critically reviewing Dandy’s report, with an understanding of the historical context, allows a better understanding of his intentions and the value of his contribution.