scholarly journals Small within the largest: brain size and anatomy of the extinct Neoepiblema acreensis , a giant rodent from the Neotropics

2020 ◽  
Vol 16 (2) ◽  
pp. 20190914 ◽  
Author(s):  
José D. Ferreira ◽  
Francisco R. Negri ◽  
Marcelo R. Sánchez-Villagra ◽  
Leonardo Kerber
Keyword(s):  
Brain Size ◽  
Imaging Techniques ◽  
Cranial Nerves ◽  
Ecological Factors ◽  
Energetic Cost ◽  
Brain Anatomy ◽  
Non Invasive ◽  
Adaptive Value ◽  
Caviomorph Rodents ◽  
The Brain

The ecomorphological diversity of caviomorph rodents in South America included giant forms, such as the chinchilloid Neoepiblema acreensis from the Upper Miocene of Brazil. The evolution of the brain anatomy and size of these animals can be now studied with non-invasive imaging techniques and exceptional fossils. Caviomorphs show diversity in the traits of the olfactory bulbs, cerebrum, cerebellum, cranial nerves, and blood vessels. Neoepiblema acreensis had a gyrencephalic brain, with an expansion of the frontal lobe, lacking an evident paraflocculus. Compared to the predictions based on extant taxa, even when considering taphonomical effects, N. acreensis , a rodent that weighted almost 80 kg, had a very low encephalization quotient compared to other rodents. The adaptive value of a low energetic cost and other ecological factors could explain the presence of a small brain in this giant rodent––a pattern we also hypothesize for other Neogene giant rodents.

On the anatomic relation of choroid plexus to brain: a comparative study

1980 ◽  
Vol 238 (1) ◽  
pp. R76-R81 ◽  
Author(s):  
H. F. Cserr ◽  
M. Bundgaard ◽  
J. K. Ashby ◽  
M. Murray
Keyword(s):  
Choroid Plexus ◽  
Brain Volume ◽  
Brain Size ◽  
Ventricular Volume ◽  
Brain Weight ◽  
Air Breathing ◽  
Original Proposal ◽  
Adaptive Value ◽  
Choroid Plexuses ◽  
The Brain

The size of choroid plexuses and cerebral ventricles relative to brain varies widely among vertebrates. The functional significance of this variability has attracted little attention since Herrick's original proposal that large choroid plexuses might enhance oxygen delivery to the brain and therefore be of adaptive value in the transition of vertebrates from water to air breathing. We compared choroid plexus and brain weight or ventricular and brain volume in 40 species from nine vertebrate groups. Both choroid plexus weight and ventricular volume were unrelated to brain size. Plexus weight ranged from 0 to 5.2% of brain weight and ventricular volume from 0.9 to 132% of brain volume. Amid this diversity the dipnoans, chondrosteans, holosteans, amphibians, and crossopterygian examined in this study are exceptional in uniformly having large plexuses. The adaptive significance of large choroid plexuses may lie in the presence of specific homeostatic mechanisms and their role in the response to the increases in PCO2 that accompany the transition to air breathing.

Brain Basics from a Computational Perspective

2017 ◽  
Author(s):  
Martin V. Butz ◽  
Esther F. Kutter
Keyword(s):  
Current Knowledge ◽  
Imaging Techniques ◽  
Processing System ◽  
Predictive Processing ◽  
Brain Anatomy ◽  
Internal Structures ◽  
Computational Perspective ◽  
Central Nervous Systems ◽  
The Brain ◽  
Human Nervous System

This chapter provides a crude overview of current knowledge in neuroscience about the human nervous system and its functionality. The distinction between the peripheral and central nervous systems is introduced. Next, brain anatomy is introduced, as well as nerve cells and the information processing principles that unfold in biological neural networks. Moreover, brain modules are covered, including their interconnected communication. With modularizations and wiring systematicities in mind, functional and structural systematicities are surveyed, including neural homunculi, cortical columnar structures, and the six-layered structure of the cerebral cortex. Finally, different available brain imaging techniques are contrasted. In conclusion, evidence is surveyed that suggests that the brain can be viewed as a highly modularized predictive processing system, which maintains internal activity and produces internal structures for the purpose of maintaining bodily needs in approximate homeostasis.

scholarly journals Sepsis-Associated Brain Dysfunction: A Review of Current Literature

2020 ◽  
Vol 17 (16) ◽  
pp. 5852
Author(s):  
Piotr F. Czempik ◽  
Michał P. Pluta ◽  
Łukasz J. Krzych
Keyword(s):  
Imaging Techniques ◽  
Screening Method ◽  
Specific Treatment ◽  
Brain Dysfunction ◽  
Non Invasive ◽  
Clinical Neurological Examination ◽  
Electrographic Seizures ◽  
The Moment ◽  
And Function ◽  
The Brain

Sepsis-associated brain dysfunction (SABD) may be the most common type of encephalopathy in critically ill patients. SABD develops in up to 70% of septic patients and represents the most frequent organ insufficiency associated with sepsis. It presents with a plethora of acute neurological features and may have several serious long-term psychiatric consequences. SABD might cause various pathological changes in the brain through numerous mechanisms. Clinical neurological examination is the basic screening method for SABD, although it may be challenging in subjects receiving with opioids and sedative agents. As electrographic seizures and periodic discharges might be present in 20% of septic patients, screening with electroencephalography (EEG) might be useful. Several imaging techniques have been suggested for non-invasive assessment of structure and function of the brain in SABD patients; however, their usefulness is rather limited. Although several experimental therapies have been postulated, at the moment, no specific treatment exists. Clinicians should focus on preventive measures and optimal management of sepsis. This review discusses epidemiology, clinical presentation, pathology, pathophysiology, diagnosis, management, and prevention of SABD.

scholarly journals Endocranial Morphology of the Extinct North American Lion (Panthera atrox)

2016 ◽  
Vol 88 (3-4) ◽  
pp. 213-221 ◽  
Author(s):  
Andrew R. Cuff ◽  
Christopher Stockey ◽  
Anjali Goswami
Keyword(s):  
North American ◽  
Brain Size ◽  
Cranial Nerves ◽  
Ct Scans ◽  
Brain Anatomy ◽  
Encephalization Quotient ◽  
Ear Morphology ◽  
La Brea Tar Pits ◽  
Brain Shape ◽  
Panthera Atrox

The extinct North American lion (Panthera atrox) is one of the largest felids (Mammalia, Carnivora) to have ever lived, and it is known from a plethora of incredibly well-preserved remains. Despite this abundance of material, there has been little research into its endocranial anatomy. CT scans of a skull of P. atrox from the Pleistocene La Brea Tar pits were used to generate the first virtual endocranium for this species and to elucidate previously unknown details of its brain size and gross structure, cranial nerves, and inner-ear morphology. Results show that its gross brain anatomy is broadly similar to that of other pantherines, although P. atrox displays less cephalic flexure than either extant lions or tigers, instead showing a brain shape that is reminiscent of earlier felids. Despite this unusual reduction in flexure, the estimated absolute brain size for this specimen is one of the largest reported for any felid, living or extinct. Its encephalization quotient (brain size as a fraction of the expected brain mass for a given body mass) is also larger than that of extant lions but similar to that of the other pantherines. The advent of CT scans has allowed nondestructive sampling of anatomy that cannot otherwise be studied in these extinct lions, leading to a more accurate reconstruction of endocranial morphology and its evolution.

scholarly journals Aspects of the gorgonopsian paleobiology: insights from the basicranium, occiput, osseous labyrinth and neuroanatomy of the immature gorgonopsian skull of Aloposaurus gracilis (Therapsida: Theriodontia: Gorgonopsia)

2016 ◽  
Author(s):  
Ricardo M Araujo ◽  
Vincent Fernandez ◽  
Michael J Polcyn ◽  
Jörg Fröbisch ◽  
Rui M.S. Martins
Keyword(s):  
Computed Tomography ◽  
Semicircular Canal ◽  
Phase Contrast ◽  
Cranial Nerves ◽  
Brain Anatomy ◽  
Micro Computed Tomography ◽  
Horizontal Semicircular Canal ◽  
Head Posture ◽  
The Past ◽  
The Brain

Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy remains poorly known, and aspects of their brain anatomy, cranial nerves and vasculature, osseous labyrinth persist unknown. By using propagation phase contrast synchrotron micro-computed tomography, we scanned GPIT/RE/7124, a specimen previously reported as Aloposaurus gracilis. We explored the anatomy of the braincase and rendered the anatomy of the various skull cavities. Notably, we found that there is a separate ossification between what was previously referred as the “parasphenoid” and the basioccipital. This element is reinterpreted as a posterior ossification of the basisphenoid, the basi-postsphenoid. Additionally the previously called “parasphenoid” is in fact the co-ossification of the dermal parasphenoid and the endochondral basi-presphenoid. The anatomy of the osseous labyrinth is rendered in detail, revealing a unique discoid morphology of the horizontal semicircular canal, rather than toroidal, probably due to architectural contraints of the ossification of the opisthotic and supraoccipital. In addition, the orientation of the horizontal semicircular canal suggests an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.

Non-convulsive brain stimulation

2020 ◽  
pp. 291-310
Author(s):  
Kevin A. Caulfield ◽  
Mark S. George
Keyword(s):  
Brain Stimulation ◽  
Vagus Nerve Stimulation ◽  
Imaging Techniques ◽  
Functional Neuroanatomy ◽  
Non Invasive ◽  
Positron Emission ◽  
Transcranial Alternating Current Stimulation ◽  
Catch Up ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Before 1990, neurologists and psychiatrists could not readily image or examine (except at death) their main organ of study, the brain, causing clinical neuroscience to lag behind the rest of medicine. In the past 30 years, new brain-imaging techniques (positron emission tomography (PET) and magnetic resonance imaging (MRI)) have allowed neuropsychiatrists to play catch-up, equipped with a more detailed and complex understanding of functional neuroanatomy. Researchers could then theorize about how circuit-based dysfunction might cause psychiatric diseases. In addition to the tools of electroconvulsive therapy (ECT) and brain surgery, we now have a rapidly expanding therapeutic toolkit of non-invasive brain-stimulation devices. This chapter presents a representative landmark imaging paper from the functional imaging revolution, and four device-based papers (two on transcranial magnetic stimulation (TMS), and one each on transcranial alternating current stimulation (tACS) and vagus nerve stimulation (VNS)). These papers broadly cover the path that led to the exciting current and future possibilities for therapeutic non-invasive brain stimulation.

scholarly journals The evolution of a placenta is not linked to increased brain size in poeciliid fishes

2020 ◽  
Author(s):  
P. K. Rowiński ◽  
J. Näslund ◽  
W. Sowersby ◽  
S. Eckerström-Liedholm ◽  
B. Rogell
Keyword(s):  
Brain Size ◽  
General Pattern ◽  
Somatic Growth ◽  
Maternal Investment ◽  
Brain Growth ◽  
Non Invasive ◽  
Poeciliid Fish ◽  
Total Brain ◽  
Nutrient Provisioning ◽  
The Brain

ABSTRACTMaternal investment is considered to have a direct influence on the size of energetically costly organs, including the brain. In placental organisms, offspring are supplied with nutrients during pre-natal development, potentially modulating brain size. However, the coevolution of the placenta and brain size remains largely unknown in non-mammalian taxa. Here, using eight poeciliid fish species, we test if species with placental structures invest more resources into offspring brain development than species without placental structures. We predict that matrotrophy may entail higher nutrient provisioning rates to the developing embryo than lecithotrophy, resulting in larger brain sizes in offspring of matrotrophic species, and that a relatively larger part of the total brain growth would occur at younger ages (leading to a shallower ontogenetic brain size allometry). We took non-invasive brain size measurements during the first four weeks of life, and compared these to somatic growth measurements. Contrary to our expectations, we did not find any differences in brain size between the two maternal strategies. Furthermore, we did not find any differences in how relative brain size changed over ontogenetic development, between placental and non-placental species. In contrast to the marsupial/placental transition, the species investigated here only exhibit pre-natal provisioning, which may reduce the potential for maternal investment into brain size. Consequently, our results suggest that coevolution between placental structures and juvenile brain size is not a general pattern.

MRI and MRA Diagnosis of Intracranial Aneurysms

2011 ◽  
Vol 140 ◽  
pp. 178-182
Author(s):  
Guang Qian Ji ◽  
Jun Wei ◽  
Yu Tian
Keyword(s):  
Magnetic Resonance ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Imaging Techniques ◽  
Non Invasive ◽  
Line Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Arteries And Veins ◽  
The Brain ◽  
Diagnostic Pitfalls

With the development of modern medical imaging technology, computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), digital subtraction angiography (DSA) and other ways widely used, more and more intracranial aneurysms were diagnosed. In the imaging methods described above, MRI is a non-invasive diagnostic method for intracranial aneurysm which shows in detail the aneurysm and its relationship to the brain, and it has become first-line imaging techniques in assessment of the patient with suspected intracranial aneurysm. MRA can show the arteries and veins of the brain as well as the aneurysm. Nowadays, MRI and MRA are extensively used in the diagnosis of intracranial aneurysms, intracranial aneurysms after treatment and intracranial aneurysms inflammation. This review describes the advantages of MRI and MRA for diagnosis and describes diagnostic pitfalls.

Integration Between Computed Tomography and Nuclear Medicine for Non-invasive Assessment of Coronary Anatomy and Myocardial Perfusion

2009 ◽  
Vol 5 (2) ◽  
pp. 15
Author(s):  
Wanda Acampa ◽  
Mario Petretta ◽  
Carmela Nappi ◽  
Alberto Cuocolo ◽  
◽  
...  
Keyword(s):  
Computed Tomography ◽  
Coronary Heart Disease ◽  
Blood Flow ◽  
Heart Disease ◽  
Myocardial Perfusion ◽  
Myocardial Blood Flow ◽  
Imaging Techniques ◽  
Emission Computed Tomography ◽  
Coronary Anatomy ◽  
Non Invasive

Many non-invasive imaging techniques are available for the evaluation of patients with known or suspected coronary heart disease. Among these, computed-tomography-based techniques allow the quantification of coronary atherosclerotic calcium and non-invasive imaging of coronary arteries, whereas nuclear cardiology is the most widely used non-invasive approach for the assessment of myocardial perfusion. The available single-photon-emission computed tomography flow agents are characterised by a cardiac uptake proportional to myocardial blood flow. In addition, different positron emission tomography tracers may be used for the quantitative measurement of myocardial blood flow and coronary flow reserve. Extensive research is being performed in the development of non-invasive coronary angiography and myocardial perfusion imaging using cardiac magnetic resonance. Finally, new multimodality imaging systems have recently been developed bringing together anatomical and functional information. This article provides a description of the available non-invasive imaging techniques in the assessment of coronary anatomy and myocardial perfusion in patients with known or suspected coronary heart disease.

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