Mammalian NREM and REM sleep: Why, when and how

This report proposes that fish use the spinal-rhombencephalic regions of their brain to support their activities while awake. Instead, the brainstem-diencephalic regions support the wakefulness in amphibians and reptiles. Lastly, mammals developed the telencephalic cortex to attain the highest degree of wakefulness, the cortical wakefulness. However, a paralyzed form of spinal-rhombencephalic wakefulness remains in mammals in the form of REMS, whose phasic signs are highly efficient in promoting maternal care to mammalian litter. Therefore, the phasic REMS is highly adaptive. However, their importance is low for singletons, in which it is a neutral trait, devoid of adaptive value for adults, and is mal-adaptive for marine mammals. Therefore, they lost it. The spinal-rhombencephalic and cortical wakeful states disregard the homeostasis: animals only attend their most immediate needs: foraging defense and reproduction. However, these activities generate allostatic loads that must be recovered during NREMS, that is a paralyzed form of the amphibian-reptilian subcortical wakefulness. Regarding the regulation of tonic REMS, it depends on a hypothalamic switch. Instead, the phasic REMS depends on an independent proportional pontine control.

Children hydrocephalus in Togo: etiologies, treatment, and outcomes

Background

Hydrocephalus is frequent in sub-Saharan African countries. The postinfectious hydrocephalus tends to decrease. The objective of this study was to identify the etiologies and outcomes of hydrocephalus.

Methods

This was a retrospective study of hydrocephalus cases (0-15 years old) treated in the neurosurgery unit of the Sylvanus Olympio Hospital in Lomé over 10 years (2012-2021). At 1 year, the evolution distinguished in two categories: (1) Good psychomotor development: no delay in the acquisition of walking, language, and school. (2) Psychomotor delay: delay in the acquisition of walking, language, and school.

Results

We reported 305 children treated for hydrocephalus representing 1.8% of all neurosurgery unit patients and 34.2% of pediatric pathologies. There was a male predominance (60.6%). We noted second degree consanguinity in 8.5%. The positive maternal serologies were HIV (12.4%), syphilis (8.2%), and toxoplasmosis (2.6%). A malaria episode had been treated during the first trimester in 36.7% of the mothers. The main clinical sign of hydrocephalus was 91.5% of Macrocephalus. Congenital Malformafions were the most common etiologies of hydrocephalus (68.5%). Ventriculoperitoneal shunt was the main surgical method used and 16 deaths were recorded. The medium-term evolution (1 year) was evaluated in 36.1% and noted 61.8% of psychomotor retardation.

Conclusion

This study confirms the trend of the predominance of congenital causes of hydrocephalus in Africa, even if maternal infections can be involved in the development of some of them. The morbimortality of this pathology remains important, especially concerning neurocognitive outcomes.

Volumetric analysis of cerebrospinal fluid and brain parenchyma in a patient with hydranencephaly and macrocephaly--case report

The aim of this study was to perform for the first time the intracranial volumetric analysis of cerebrospinal fluid (CSF) and brain parenchyma in the supratentorial and infratentorial space in a 30-year-old female patient with hydranencephaly and macrocephaly. A head scan performed using a 3T magnetic resonance was followed by manual segmentation of the brain parenchyma and CSF on T2 coronal brain sections. The volume of CSF and brain parenchyma was measured separately for the supratentorial and infratentorial space. The total volume of the intracranial space was 3645.5 cm³. In the supratentorial space, the volume of CSF was 3375.2 cm³ and the volume of brain parenchyma was 80.3 cm³. In the infratentorial space, the volume of CSF was 101.3 cm³ and the volume of the brain parenchyma was 88.7 cm³. In the supratentorial space, there was severe malacia of almost all brain parenchyma with no visible remnants of the choroid plexuses. Infratentorial structures of the brainstem and cerebellum were hypoplastic but completely developed. Since our patient had no choroid plexuses in the supratentorial space and no obstruction between dural sinuses and CSF, development of hydrocephalus and macrocephaly cannot be explained by the classic hypothesis of CSF physiology with secretion, unidirectional circulation, and absorption as its basic postulates. However, the origin and turnover of the enormous amount of intracranial CSF volume, at least 10-fold larger than normal, and the mechanisms of macroencephaly development could be elucidated by the new hypothesis of CSF physiology recently published by our research team.

Canine neonatal transcranial ultrasonography from birth until closure of bregmatic fontanelle

Ultrasonography is a valuable diagnostic tool that has been used for diagnosis of neonatal brain diseases. The purpose of the present study was to describe the sequential ultrasonographic appearance of the normal canine neonatal brain from birth till closure of the bregmatic fontanelle. In total, 16 clinically normal neonates of mixed breed dogs were used. The bregmatic fontanelle was used as an acoustic window to record 5 transcranial scans (3 transverse, 1 sagittal, and 1 parasagittal scans) at 3, 10, 20, and 30 days of age. The appearance, echogenicity, and developmental differentiation of the structures within the cranium were described. Good images were obtained at 10 and 20 days of age. At 30 days of age, the obtained images presented poor details, as the fontanelle was small. Data obtained from this study represent the basis of brain ultrasound in neonates until 30 days of age, which could be beneficial in diagnosing congenital brain diseases.

Looking at the missing brain: hydranencephaly case series and literature review

Hydranencephaly is a severe congenital condition where most of the cerebral hemispheres are replaced by a membranous sac. Despite the growing amount of case reports, most pathogenic, phenotypic, and prognostic aspects of hydranencephaly remain controversial. By matching the recent literature data with the findings of our own series (four cases: two fetuses at the twelfth gestational week, a 32-year-old man, and a 14-year-old female), we attempted to date back the insult leading to hydranencephaly to understand its pathogenesis and to explain the basis of its protean phenotype. The variable detection of cerebral remnants seems to mirror the developmental pathway of cerebral arteries. Moreover, fetal and postnatal neuroimaging data and histopathologic findings point toward an early bilateral internal carotid artery occlusion, mostly occurring between the eighth and twelfth gestational weeks, as the main pathogenic mechanism of hydranencephaly.

Delayed diagnosis of hydranencephaly in a nine-month-old child

We present a case of a child suffering of hydranencephaly. The interesting fact in the case is that there were no embryological examinations during pregnancy and therefore could the anomaly, which would have been easily avoided by regular visits to the obstetrician, not be diagnosed timely. Education of mothers is always necessary irrespective on how developed a country is and how good the medical treatment and diagnostic tools are. Every pregnant woman needs to be well educated in matters of pregnancy monitoring.