Log in/Sign up
Arts & Humanities
Biology & Life Sciences
Business & Economics
Chemistry & Materials Science
Computer Science & Mathematics
Environmental & Earth Sciences
Medicine & Pharmacology
Public Health & Healthcare
Virtual Anthropology and Paleoneurology
Advances in neuroscience have made it possible to obtain increasing information on the anatomy of the brain, at ever-higher resolutions, with different imaging techniques, on ever-larger samples. At the same time, paleoanthropology has to deal with partial reflections on the shape of the brain, on fragmentary specimens and small samples in an attempt to approach the morphology of the brain of past human species. Paleoanthropology has much to gain from interacting more with the field of neuroimaging. Improving our understanding of the morphology of the endocast necessarily involves studying the external surface of the brain and the link it maintains with the internal surface of the skull. The contribution of neuroimaging will allow us to better define the relationship between brain and endocast. Models of intra- and inter-species variability in brain morphology inferred from large neuroimaging databases will help make the most of the rare endocasts of extinct species. Moreover, exchanges between these two disciplines will also be beneficial to our knowledge of the Homo sapiens brain. Documenting the anatomy among other human species and including the variation over time within our own species are approaches that offer us a new perspective through which to appreciate what really characterizes the brain of humanity today.
09 Nov 2021
Vertebrate Cutaneous Sensory Corpuscles
Vertebrate cutaneous sensory corpuscles are specialized sensory nerve formations located in the skin of all vertebrates and responsible for tactile sensation. Functionally, they are mechanoreceptors transducing external mechanical stimuli into electrical signals which will be later led to the Central Nervous System. The afferent innervation of vertebrate skin is supplied by nerve fibers (Aβ, Aδ, C) which are originated from peripheral neurons localized in the dorsal root ganglia (DRG). Aβ nerve fibers end at the dermis level forming several morphotypes of sensory corpuscles with capacity of detecting different stimuli: Merkel cell–neurite complexes, Ruffini corpuscles, Meissner’s corpuscles and Pacinian corpuscles are present in the glabrous skin; while pilo-neural complexes are found in hairy skin. The structure of sensory corpuscles is formed by an axon, non-myelinating Schwann-like cells, a capsule of endoneurial and/or perineurial origin and extracelullar matrix molecules. The vertebrate skin contains sensory corpuscles that are receptors for different qualities of mechanosensitivity like light brush, touch, pressure, stretch or vibration. These specialized sensory organs are linked anatomically and functionally to mechanosensory neurons, which function as low-threshold mechanoreceptors connected to peripheral skin through Aβ nerve fibers. Furthermore, low-threshold mechanoreceptors associated with Aδ and C nerve fibers have been identified in hairy skin. The process of mechanotransduction requires the conversion of a mechanical stimulus into electrical signals (action potentials) through the activation of mechanosensible ion channels present both in the axon and the periaxonal cells of sensory corpuscles (i.e., Schwann-, endoneurial- and perineurial-related cells). Most of those putative ion channels belong to the degenerin/epithelial sodium channel (especially the family of acid-sensing ion channels), the transient receptor potential channel superfamilies, and the Piezo family.
07 Sep 2020
Vascular Endothelial Growth Factors
Vascular endothelial growth factors (VEGFs) are primary regulators of blood and lymphatic vessels. Hemangiogenic VEGFs (VEGF-A, PlGF, and VEGF-B) target mostly blood vessels, while the lymphangiogenic VEGFs (VEGF-C and VEGF-D) target mostly lymphatic vessels. Blocking VEGF-A is used today to treat several types of cancer (“antiangiogenic therapy”). However, in other diseases, it would be beneficial to do the opposite, namely to increase the activity of VEGFs. For example, VEGF-A could generate new blood vessels to protect from heart disease, and VEGF-C could generate new lymphatics to counteract lymphedema. Clinical trials that tried to stimulate blood vessel growth in ischemic diseases have been disappointing so far, and the first clinical trials targeting the lymphatic vasculature have progressed to phase II. Antiangiogenic drugs targeting VEGF-A such as bevacizumab or aflibercept neutralize the growth factor directly. However, since VEGF-C and VEGF-D are produced as inactive precursors, novel drugs against the lymphangiogenic VEGFs could also target the enzymatic activation of VEGF-C and VEGF-D. Because of the delicate balance between too much and too little vascular growth, a detailed understanding of the activation of the VEGF-C and VEGF-D is needed before such concepts can be converted into safe and efficacious therapies.
30 Mar 2021
The Subretinal Space of the Eye
The subretinal space is located between the retinal pigment epithelium (RPE) and the photoreceptive cells. The majority of the retina is a delicate matrix of photoreceptive cells and their support network which are responsible for human vision. These cells are separated from the cornea by a layer of pigment epithelium. The RPE has tight junctions, effectively insulating the inside of the retina from systemic circulation; the contents of the retina can then be controlled by transcellular transport.
05 May 2022
The Subconjunctival Space of the Eye
The subconjunctival space is the hydrophilic, fluid-filled space between the conjunctiva and the sclera. Additionally, the subconjunctival space has access to all the blood vessels found in the conjunctiva, which can help to further distribute substances throughout the whole eye. The subconjunctival space is located superior to the cornea and optimally located to distribute drugs to several different parts of the eye through minimally invasive means while limiting the development of scar tissue.
05 May 2022
The Na+/H+ Exchangers in Cardiac Physiology Regulation
The Na+/H+ exchangers (NHEs) are membrane transporters that exchange one intracellular pro-ton for one extracellular Na+. The first discovered NHE isoform, NHE1, is expressed almost ubiquitously in all tissues, especially in the myocardium. During myocardial ische-mia-reperfusion, NHE1 catalyzes increased uptake of intracellular Na+, which in turn leads to Ca2+ overload and subsequently myocardial injury. Numerous preclinical research has shown that NHE1 is involved in cardiac hypertrophy and heart failure, but the exact molecular mecha-nisms remain elusive.
27 Sep 2022
The Microbiota–Gut–Brain Axis
The microbiota–gut system can be thought of as a single unit that interacts with the brain via the “two-way” microbiota–gut–brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. The modification of the composition of the microbiota destroys the bottom-to-top communication that ultimately influences brain motor, sensory, and cognitive functions, maintains brain homeostasis and/or contributes to the onset of pathological conditions. Elucidating the interplay between the gut microbiota and the central nervous system, and the role of microbiota in neuroinflammation, will lead to a better understanding of many neurodegenerative diseases pathogeneses, and, hopefully, to the development of new preventing or therapeutic strategies.
11 Oct 2021
The Intravitreal Space of the Eye
The intravitreal space comprises the majority of the eye’s volume and is located behind the lens of the eye. The vitreous chamber of the eye is mostly filled with a gel-like solution called the vitreous body. The vitreous body is 98.5–99.7% water containing salt soluble proteins and hyaluronic acid.
05 May 2022
The Cat Mandible
The cat mandible is small and has some peculiarities relative to the dentition (only three incisors, a prominent canine, two premolars and one molar); a conical and horizontally oriented condyle, and a protudent angular process in its ventrocaudal part. Most of the body of the mandible is occupied by the mandibular dental roots and the mandibular canal that protects the neurovascular supply: the inferior alveolar artery and vein, and the inferior alveolar nerve that exits the mandible rostrally as the mental nerves. They irrigate and innervate all the teeth and associated structures such as the lips and gingiva. Tooth roots and the mandibular canal account for up to 70% of the volume of the mandibular body. Consequently, when fractured it is difficult to repair without invading the dental roots or vascular structures.
01 Mar 2021
The Biological Basis for Antioxidant Therapy
Reactive oxygen species (ROS) are a class of highly reactive free radicals, such as hydroxyl radical (•OH), the superoxide radical (O2•−) and hydrogen peroxide (H2O2). The high intracellular ROS level-induced oxidative stress leads to the upregulation of antioxidant capacity to maintain redox homeostasis by metabolic rerouting or activation of genetic programs.
06 Jul 2022
Featured Entry Collections
Encyclopedia of Social Sciences
Encyclopedia of ZEMCH Research and Development
Encyclopedia of Engineering
Encyclopedia of COVID-19
Log in/Sign up
Terms and Conditions
Browse our user manual, common Q&A, author guidelines, etc.
Rate your experience
Let us know your experience and what we could improve.
Report an error
Is something wrong? Please let us know!
Other feedback you would like to report.
Did you find what you were looking for?
Do you agree to share your valuable feedback publicly on
Yes, I agree. Encyclopedia can post it.
No, I do not agree. I would not like to post my testimonial.
Upload a screenshot
(Max file size 2MB)