History, Anatomy, Histology, and Embryology of the Ventricles and Physiology of the Cerebrospinal Fluid

Cerebrospinal fluid is an essential, clear, and colorless liquid for the homeostasis of the brain and neuronal functioning. It circulates in the brain ventricles, the cranial and spinal subarachnoid spaces. The mean cerebrospinal fluid volume is 150 ml, with 125 ml in subarachnoid spaces and 25 ml in the ventricles. Cerebrospinal fluid is mainly secreted by the choroid plexuses. Cerebrospinal fluid secretion in adults ranges between 400 and 600 ml per day and it is renewed about four or five times a day. Cerebrospinal fluid is mainly reabsorbed from arachnoid granulations. Any disruption in this well-regulated system from overproduction to decreased absorption or obstruction could lead to hydrocephalus.

The Epic of the Thalamus in Anatomical Language

Understanding the origin of Greek and Latin words used as metaphors to label brain structures gives a unique window into how scientific and medical knowledge was produced, preserved, and transmitted through generations. The history of the term thalamus exemplifies the complex historical process that led to the current anatomical terminology. From its first mention by Galen of Pergamon in the 2nd century A.D. to its definitive and current use by Thomas Willis in 1664, the thalamus had an epical journey through 1500 years across Europe, the Middle East, and the North of Africa. The thalamus was confusingly described by Galen, in the Greek language, as a chamber to the brain ventricles. The term thalamus was transferred from Greek to Syriac through the translations of Galen’s books done in Baghdad and also from Syriac to Arabic. Then, it was translated in Europe during the Middle Ages from the Arabic versions of Galen’s books to Latin. Later, during the Early Renaissance, it was translated again to Latin directly from the Greek versions of Galen’s books. Along this epical journey through languages, the term thalamus switched from referring to a hollow structure connected to brain ventricles to naming a solid structure at the rostral end of the brainstem. Finally, the thalamus was translated from Latin to modern languages, where it is used, until today, to name a nuclear complex of subcortical gray matter in the lateral walls of the third ventricle.

The localization of amyloid precursor protein to ependymal cilia in vertebrates and its role in ciliogenesis and brain development in zebrafish

Amyloid precursor protein (APP) is expressed in many tissues in human, mice and in zebrafish. In zebrafish, there are two orthologues, Appa and Appb. Interestingly, some cellular processes associated with APP overlap with cilia-mediated functions. Whereas the localization of APP to primary cilia of in vitro-cultured cells has been reported, we addressed the presence of APP in motile and in non-motile sensory cilia and its potential implication for ciliogenesis using zebrafish, mouse, and human samples. We report that Appa and Appb are expressed by ciliated cells and become localized at the membrane of cilia in the olfactory epithelium, otic vesicle and in the brain ventricles of zebrafish embryos. App in ependymal cilia persisted in adult zebrafish and was also detected in mouse and human brain. Finally, we found morphologically abnormal ependymal cilia and smaller brain ventricles in appa−/−appb−/− mutant zebrafish. Our findings demonstrate an evolutionary conserved localisation of APP to cilia and suggest a role of App in ciliogenesis and cilia-related functions.

Does the Prevalence of Anatomical Variants of the Brain Ventricles vary according to Socioeconomic Status? A Cross-sectional Imaging Survey in 2 Brazilian Private Hospitals

Background: Anatomical variants of brain ventricles are a known marker for abnormal central nervous system development. They seem to be more prevalent in several neuropsychiatric disorders, e.g. schizophrenia, personality disorders, and psychosis. However, knowledge about the risk factors and their overall prevalence in the general population, especially in developing countries is still limited. Methods: We evaluated the prevalence of prevalence of anatomical ventricular variants [Cavum septum pellucidum (CSP), Cavum vergae (CV), and Cavum velum interpositi (CVI)] in 1467 multislice head CTs from two large private hospitals in the city of Fortaleza, Ceará – Brazil. Results: Hospital one had a higher percentage of patients with low-cost health insurance, strokes, and neurocysticercosis (P<0.05). 15.1% of participants in hospital one versus 7.1% in hospital two had at least one type of cerebral cavum, including vestigial CSP. The rarest types of cava (CV and CVI) were twice more common in hospital one (P<0.05). Logistic regression analysis confirmed that patients from hospital one, older patients, and men were more likely to have any type of cerebral cavum and CSP. Conclusions: Anatomical brain ventricular variants (including vestigial CSP) were present in about 12% of participants of this middle-class Brazilian sample while also being more prevalent in male elderly and participants from lower socioeconomic strata. Further studies are necessary to prospectively investigate the association between socioeconomic variables and how they relate to the prevalence of anatomical brain ventricular variants and other known risk factors for developmental disorders.Trial registration: This study was approved by the Institutional Review Board from both participants institutions- Research Ethics Committee (CEP) - Unichristus (Protocols 099/11 and CAAE: 58763716.3.0000.5049).

Amyloid precursor protein localises to ependymal cilia in vertebrates and is required for ciliogenesis and brain development in zebrafish

Amyloid precursor protein (APP) is ubiquitously expressed in human, mice and in zebrafish. In zebrafish, there are two orthologues, Appa and Appb. Interestingly, some cellular processes associated with APP overlap with cilia-mediated functions. Whereas the localization of APP to primary cilia of in vitro-cultured cells has been reported, we addressed the presence of APP in motile and in non-motile sensory cilia and its potential implication for ciliogenesis using zebrafish, mouse, and human samples. We report that Appa and Appb are expressed by ciliated cells and become localized at the membrane of cilia in the olfactory epithelium, otic vesicle and in the brain ventricles of zebrafish embryos. App in ependymal cilia persisted in adult zebrafish and was also detected in mouse and human brain. Finally, we found morphologically abnormal ependymal cilia and smaller brain ventricles in appa-/-appb-/- mutant zebrafish. Our findings demonstrate an evolutionary conserved localisation of APP to cilia and suggest a role of App in ciliogenesis and cilia-related functions.

Amyloid precursor protein localises to ependymal cilia in vertebrates and is required for ciliogenesis and brain development in zebrafish

Amyloid precursor protein (APP) is ubiquitously expressed in human, mice and in zebrafish. In zebrafish, there are two orthologues, Appa and Appb. Interestingly, some cellular processes associated with APP overlap with cilia-mediated functions. Whereas the localization of APP to primary cilia of in vitro-cultured cells has been reported, we addressed the presence of APP in motile and in non-motile sensory cilia and its potential implication for ciliogenesis using zebrafish, mouse, and human samples. We report that Appa and Appb are expressed by ciliated cells and become localized at the membrane of cilia in the olfactory epithelium, otic vesicle and in the brain ventricles of zebrafish embryos. App in ependymal cilia persisted in adult zebrafish and was also detected in mouse and human brain. Finally, we found morphologically abnormal ependymal cilia and smaller brain ventricles in appa-/-appb-/- mutant zebrafish. Our findings demonstrate an evolutionary conserved localisation of APP to cilia and suggest a role of App in ciliogenesis and cilia-related functions.

Hydrocephalus Revisited: New Insights Into Dynamics of Neurofluids on Macroand Microscales

New experimental and clinical findings question the historic view of hydrocephalus and its 100-year-old classification. In particular, real-time MRI evaluation of CSF flow and detailed insights into brain water regulation on the molecular scale indicate the existence of at least three main mechanisms that determine the dynamics of neurofluids. (i) Inspiration is a major driving force (ii) Adequate filling of brain ventricles by balanced cerebrospinal fluid upsurge is sensed by cilia (iii) The perivascular glial network connects the ependymal surface to the pericapillary Virchow-Robin spaces. Hitherto, these aspects have not been considered a common physiologic framework improving knowledge and therapy for severe disorders of normal-pressure and post-haemorrhagic hydrocephalus, spontaneous intracranial hypotension and spaceflight disease.