Mammalian brains

Extracted Attributes

Isolated brain

An isolated brain is a brain kept alive in vitro, either by perfusion or by a blood substitute, often an oxygenated solution of various salts, or by submerging the brain in oxygenated artificial cerebrospinal fluid (CSF). It is the biological counterpart of brain in a vat. A related concept, attaching the brain or head to the circulatory system of another organism, is called a brain transplant or a head transplant. An isolated brain, however, is more typically attached to an artificial perfusion device rather than a biological body. The brains of many different organisms have been kept alive in vitro for hours, or in some cases days. The central nervous system of invertebrate animals is often easily maintained as they need less oxygen and to a larger extent get their oxygen from CSF; for this reason their brains are more easily maintained without perfusion. Mammalian brains, on the other hand, have a much lesser degree of survival without perfusion and an artificial blood perfusate is usually used. For methodological reasons, most research on isolated mammalian brains has been done with guinea pigs. These animals have a significantly larger basilar artery compared to rats and mice, which make cannulation (to supply CSF) much easier.

Web Search Results

• Brain (comparative anatomy) | Anatomy and Physiology | Research Starters | EBSCOhost

  Mammalian brains have convolutions on the surface of the cerebrum and cerebellum, with the neural cortex following and covering every “hill” and “valley” of the convolutions. This provides a much greater surface area occupied by gray matter, especially in humans, the species in which the convolutions and cerebral cortex are most extensive. Below the gray matter surface is white matter, myelinated neuron fibers that carry information from one area of gray matter to another. Deep in this white matter are basal nuclei, gray matter centers that help regulate subconscious and involuntary control of body functions. [...] Mammalian brains have convolutions on the surface of the cerebrum and cerebellum, with the neural cortex following and covering every “hill” and “valley” of the convolutions. This provides a much greater surface area occupied by gray matter, especially in humans, the species in which the convolutions and cerebral cortex are most extensive. Below the gray matter surface is white matter, myelinated neuron fibers that carry information from one area of gray matter to another. Deep in this white matter are basal nuclei, gray matter centers that help regulate subconscious and involuntary control of body functions. [...] Primates, the order of animals that includes monkeys, apes, and humans, contains species that show a higher level of brain development than most other mammals. Primate brains, especially in humans, are among the largest in the animal kingdom compared to the animal's body size. For many decades, scientists believed brain size was associated with the animal's body size, but later research revealed that brain and body size have a non-linear, curved relationship. This discovery explains why very large animals sometimes have smaller brains than expected. The primate brain retains in its structure the earlier forms and functions that have developed in lower vertebrates over evolutionary time, such as the brainstem and limbic system, but higher areas give new and more complex possibilities for

• Mammalian Brains Seen through the Lens of Evolution

  by SM Sherman · 2026 · Cited by 1 — mammalian brains are organized as layered systems in which newer cortical circuits interact with older subcortical motor networks.

• Understanding the Evolution of Mammalian Brain Structures

  by R Willemet · 2012 · Cited by 30 — Abstract. The mammalian brain varies in size by a factor of 100,000 and is composed of anatomically and functionally distinct structures.

• Comparative Mammalian Brain Collections

  | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wally Welker, John Irwin Johnson, Adrianne Noe This web site provides browsers with images and information from one of the world's largest collection of well-preserved, sectioned and stained brains of mammals. Viewers can see and download photographs of brains of over 100 different species of mammals (including humans) representing over 20 Mammalian Orders. Also available are examples of stained sections from a wide variety of brains of special interest, including Humans, Chimpanzees, Monkeys, various Rodents and Carnivores, California Sealion, Florida Manatee, Big Brown Bat, American Badger, American Raccoon, Yellow Mongoose, Zebra, Cow, and the Atlantic Bottlenose Dolphin. A [...] Zebra, Cow, and the Atlantic Bottlenose Dolphin. A complete list of all available specimens is available. How brain evolution has occurred is discussed. Viewers will learn why these collections are important, why and how they were assembled, and why it is important to protect, preserve and maintain them. Moreover, a variety of issues in brain science are discussed. For users who are interested in using any of our images for educational or research purposes, you have our permission to use them. But, they are not to be published and copyrighted since this would prohibit others from using the same images. At any rate, we request that you identify them as from the University of Wisconsin and Michigan State Comparative Mammalian Brain Collections, as well as from those at the National [...] | | | | | | | | | | --- --- --- ---

• Brain

  Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure. The cerebral cortex is the part of the brain that most strongly distinguishes mammals. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple three-layered structure called the pallium "Pallium (neuroanatomy)"). In mammals, the pallium evolves into a complex six-layered structure called neocortex or isocortex. Several areas at the edge of the neocortex, including the hippocampus and amygdala, are also much more extensively developed in mammals than in other [...] The first vertebrates appeared over 500 million years ago (Mya "Mya (unit)")) during the Cambrian period, and may have resembled the modern jawless fish (hagfish and lamprey) in form. Jawed vertebrates appeared by 445 Mya, tetrapods by 350 Mya, amniotes by 310 Mya and mammaliaforms by 200 Mya (approximately). Each vertebrate clade has an equally long evolutionary history, but the brains of modern fish, amphibians, reptiles, birds and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence. All of these brains contain the same set of basic anatomical structures, but many are rudimentary in the hagfish, whereas in mammals the foremost part (forebrain, especially the telencephalon) is greatly developed and expanded. [...] The brains of humans and other primates contain the same structures as the brains of other mammals, but are generally larger in proportion to body size. The encephalization quotient (EQ) is used to compare brain sizes across species. It takes into account the nonlinearity of the brain-to-body relationship. Humans have an average EQ in the 7-to-8 range, while most other primates have an EQ in the 2-to-3 range. Dolphins have values higher than those of primates other than humans, but nearly all other mammals have EQ values that are substantially lower.