Instruct: Given a question, retrieve documents that answer the question.
Query: How large is a cat's brain?
The brain of the domesticated cat is about five centimetres (2.0in) long, and weighs 25–30g (0.88–1.06oz).[1][2] If a typical cat is taken to be 60cm (24in) long with a weight of 3.3kg (7.3lb), then the brain would be at 0.91%[3] of its total body mass, compared to 2.33%[3] of total body mass in the average human. Within the encephalization quotient proposed by Jerison in 1973,[3][4] values above 1 are classified big brained, while values lower than 1 are small brained.[5] The domestic cat is attributed a value of between 1–1.71 relative to human value that is 7.44–7.8.[1][3] The largest brains in the Felidae family are those of the tigers in Java and Bali, of which the largest relative brain size within the panthera is the tigris.[6] It is debated whether there exists a causal relationship between brain size and intelligence in vertebrates. Correlations have been shown between these factors in a number of experiments. However, correlation does not imply causation. Most experiments involving the relevance of brain size to intelligence hinge on the assumption that complex behavior requires a complex (and therefore intelligent) brain; however, this connection has not been consistently demonstrated.[7][8][9][10][11]
Their discovery occurred accidentally. In 1962, Hubel and Wiesel were attempting to discover that triggered neurophysiological activity in a cat's brain. The cat they were testing showed no results until they displayed a "crack" to the cat, whereupon the cat's brain starting reacting to the stimulus. This began a long series of discoveries which continues to the present day. Hubel and Wiesel received the Nobel Prize for their discovery.
The skull is longer and more narrow than that of a domestic cat. When compared to the leopard cat's skull, the Iriomote cat's is roughly the same size but thicker. Because of this, the Iriomote cat's brain is smaller; a male leopard cat's brain is about 42 grams, whereas a male Iriomote cat's brain is about 30 grams. The occipital bone of the skull and the auditory capsule are not connected. The mandibular symphysis is short.
According to researchers at Tufts University School of Veterinary Medicine, the physical structure of the brains of humans and cats is very similar.[14] The human brain and the cat brain both have cerebral cortices[15] with similar lobes.[16]
Burgess’ studies revealed how the dendrites of brain neurons grow during development. Together with Richard Coss at the University of California, Davis, Burgess was the first to show that sensory stimuli, including social stressors, can cause long-lasting changes in brain cell anatomical structure in just a few minutes. Together with Jaime Villablanca at UCLA, Burgess discovered that early brain injury resembling childhood congenital disorders and adult traumatic brain injury can heal naturally and that rehabilitative exercise improves brain healing. He helped clarify the rôle of the caudate nucleus in aggression and found that, without input from this nucleus, usually aggressive cats are friendly and affiliative. Burgess also contributed to our understanding of how the nervous system responds to morphine, especially during early development.
Large scale brain networks are collections of widespread brain regions showing functional connectivity by statistical analysis of the fMRI BOLD signal or other signal fluctuations. An emerging paradigm in neuroscience is that cognitive tasks are performed not by individual brain regions working in isolation, but by networks consisting of several discrete brain regions that are said to be "functionally connected" due to tightly coupled activity. Functional connectivity may be measured as long-range synchronization of the EEG, MEG, or other dynamic brain signals. Synchronized brain regions may also be identified using spatial independent component analysis. The set of identified brain areas that are linked together in a large-scale network varies with cognitive function. When the cognitive state is not explicit (i.e., the subject is at "rest"), the large scale brain network is a resting state network (RSN). As a physical system with graph-like properties, a large scale brain network has both nodes and edges, and cannot be identified simply by the co-activation of brain areas. In recent decades, the analysis of brain networks was made feasible by advances in imaging techniques as well as new tools from graph theory and dynamical systems. Large scale brain networks are identified by their function, and provide a coherent framework for understanding cognition by offering a neural model of how different cognitive functions emerge when different sets of brain regions join together as self-organized coalitions. Disruptions in activity in various networks have been implicated in neuropsychiatric disorders such as depression, Alzheimer's, autism spectrum disorder, schizophrenia and bipolar disorder. 
In November 2009, scientists claimed to simulate a cat's brain using a supercomputer[91] containing 24,576 processors.[92][93] This experiment did not simulate the function of the individual neurons in the brain, nor their synaptic patterns. It was intended to demonstrate that the problem of simulating a biological brain could be scaled to very large supercomputer platforms.[94] However, the approach has been criticised as flawed.[95][96]
Sperry first became interested in "split-brain" research when he was working on the topic of interocular transfer, which occurs when "one learns with one eye how to solve a problem then, with that eye covered and using the other eye, one already knows how to solve the problem". Sperry asked the question: "how can the learning with one eye appear with the use of the other?" Sperry cut nerves in the eyes of cats so the left eye was connected to the left hemisphere and the right eye was connected to the right hemisphere; he also cut the corpus callosum. The cats were then taught to distinguish a triangle from a square with the right eye covered. Then the cats were presented the same problem with the left eye covered; the cats had no idea what they had just learned with the right eye and because of this could be taught to distinguish a square from a triangle. Depending on which eye was covered, the cats would either distinguish a square from a triangle or a triangle from a square, demonstrating that the left and right hemispheres learned and remembered two different events. This led Sperry to believe that the left and right hemispheres function separately when not connected by the corpus callosum.
There are a number of reasons for why the cat brain is a goal of computer simulations. Cats are familiar and easily kept animals, so the physiology of cats has been particularly well studied. The physical structures of human brains and cat brains are very similar.[14] Cats, like humans, have binocular vision that gives them depth perception.[97] Moreover, trying to build artificial mammal brains advances the research of both neuroscience and artificial intelligence.[98]
Dawkins opens by talking how organisms “grow up” to understand the universe around them, which requires certain apparatus, such as a brain. But before brains can become large enough to model the universe they must develop from intermediate forms. Dawkins then discusses the digger wasp and the set of experiments conducted by Nikolaas Tinbergen of how the digger wasp models the local geography around its nest. He then talks about the limitations of the digger wasps’ brain and concludes that only the human brain is sufficiently developed to model large-scale phenomena about the world. He then shows a MRI scan of a human brain (later revealed to be his own brain) and describes how an image develops from the eye onto the visual cortex.
Cognitive dysfunction syndrome in companion animals is commonly paralleled to Alzheimer’s Disease in humans due to several brain pathologies observed in both senior humans and senior pets. Necropsies and histological studies performed on the brains of humans with Alzheimer’s Disease and those performed on the brains of cats exhibiting signs of CDS both report hyperphosphorylated tau proteins, β-Amyloid aggregates deposited on the cerebral cortex, ‘knotted’ nerve fibers known as neurofibrillary tangles, and neuron loss in several different zones of the brain. The challenges of evaluating and tracking cognitive function in cats has led to very few trials investigating the effect of nutritional intervention on feline cognition, so as a result, many of the nutrients recommended to support cat cognition have been interpreted from human and canine cognitive support supplements.
A disputing view of the cat's hunting technique and ability is presented by C. K. Brain in "The Hunters or the Hunted?" in which he attributes the cat's prey-killing abilities to its large neck muscles rather than its jaws. Large cats use both the upper and lower jaw to bite down and bring down the prey. The strong bite of the jaw is accredited to the strong temporalis muscle that attach from the skull to the coronoid process of the jaw. The larger the coronoid process, the larger the muscle that attaches there, so the stronger the bite. As C.K. Brain points out, the saber-toothed cats had a greatly reduced coronoid process and therefore a disadvantageously weak bite. The cat did, however, have an enlarged mastoid process, a muscle attachment at the base of the skull, which attaches to neck muscles. According to C.K. Brain, the saber-tooth would use a "downward thrust of the head, powered by the neck muscles" to drive the large upper canines into the prey. This technique was "more efficient than those of true cats".
Functional integration is the study of how brain regions work together to process information and effect responses. Though functional integration frequently relies on anatomic knowledge of the connections between brain areas, the emphasis is on how large clusters of neurons – numbering in the thousands or millions – fire together under various stimuli. The large datasets required for such a whole-scale picture of brain function have motivated the development of several novel and general methods for the statistical analysis of interdependence, such as dynamic causal modelling and statistical linear parametric mapping. These datasets are typically gathered in human subjects by non-invasive methods such as EEG/MEG, fMRI, or PET. The results can be of clinical value by helping to identify the regions responsible for psychiatric disorders, as well as to assess how different activities or lifestyles affect the functioning of the brain.
Although parts of the brain have broadly understood functions, many mysteries remain about how brain cells (i.e., neurons and glia) work together to produce complex behaviors and disorders. Perhaps the broadest, most mysterious question is how diverse regions of the brain collaborate to form conscious experiences. So far, there is no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort. Therefore, as with James's idea that humans have untapped cognitive potential, it may be that a large number of questions about the brain have not been fully answered.
D.M.Fankhauser Removal and study of the cat brain and Cranial nerves of the cat [Retrieved 2011-12-22] (images and instruction) for an anatomy and physiology class for the dissecting of the brain of a cat
During a storm, Tom is trying to find a place to stay after being thrown out of a horse-drawn carriage. In the meantime, Jerry is assisting a mad scientist in a stereotypical old castle. In their experiment, they switch the brains of an orange cat and blue dog. The scientist gives the cat-with-a-dog-brain to Jerry as a companion. While they are sleeping, Tom approaches the castle, capturing Jerry. The cat growls and takes Jerry back, threatening Tom. Tom tries to convince the cat that he is a cat, but fails.
Radulovacki reasoned that if the blocking of adenosine receptors produces excitation, then perhaps stimulation of the same receptors could induce sleep. He knew that experiments by John Phillis and his group (Can. J. Physiol. Pharmacol. 57:1289-1312, 1979), which utilized an iontophoretic application of adenosine in the brain, had demonstrated adenosine's depressant effect on the responses of neurons in several brain regions and that the general neurophysiological effects of adenosine were shown to be inhibitory. In addition, the preliminary experiments in dogs by Haulica "et al." (J. Neurochem. 21:,1019–20, 1973) and the administration of adenosine into the brains of rats, cats and fowl suggested that adenosine was able to produce behavioral sleep. The explanation of adenosine's hypnotic effect was through its interaction with serotonin, widely believed to be a sleep inducing agent. However, since there was no suggestion how this adenosine-serotonin link was achieved, experiments highlighting the potential role of adenosine in sleep had largely been forgotten.
Bungle first appears in "The Patchwork Girl of Oz", the seventh of Baum's fourteen Oz books. The magician Dr. Pipt tests his Powder of Life by animating an ornamental glass cat figurine, for the specific purpose of catching mice for his wife Margolotte. But the Glass Cat turns out to be exceptionally vain, and unwilling to do any work. Margolotte names it Bungle. The Glass Cat is transparent, except for her hard blood-red ruby heart, two large emeralds for eyes, and her bright pink brains, which look rather like a collection of marbles and can be seen working in the cat's head. She has a tail of spun-glass.
Different neuroimaging techniques have been developed to investigate the activity of neural circuits and networks. The use of "brain scanners" or functional neuroimaging to investigate the structure or function of the brain is common, either as simply a way of better assessing brain injury with high resolution pictures, or by examining the relative activations of different brain areas. Such technologies may include functional magnetic resonance imaging (fMRI), brain positron emission tomography (brain PET), and computed axial tomography (CAT) scans. Functional neuroimaging uses specific brain imaging technologies to take scans from the brain, usually when a person is doing a particular task, in an attempt to understand how the activation of particular brain areas is related to the task. In functional neuroimaging, especially fMRI, which measures hemodynamic activity (using BOLD-contrast imaging) which is closely linked to neural activity, PET, and electroencephalography (EEG) is used.
The brain is large relative to the body; at 1:67, its brain-to-body mass ratio is higher than that of cats and dogs.
The cerebral hemispheres of the brain are extensively convoluted.
The brain has well-developed olfactory bulbs and its cerebellum is the most ornamented and complex of any member of its subfamily.
McDaniel described its corpus callosum and white matter as "exceptionally thick."
Hanover is home to an unusually large cat population (including one, Pickle) and was featured in the BBC programme Cat Watch 2014: The 21st Century house cat a three-part series that looked at how cats are adapting to a domestic life by the side of people. This led rise to the very active community group Cats of Hanover.
It had the general appearance of a cat, but some of its physical characteristics are rather unusual for a large cat. The limb proportions of "Homotherium" gave it a hyena-like appearance. The forelegs were elongated, while the hind quarters were rather squat with feet perhaps partially plantigrade, causing the back to slope towards the short tail. Features of the hind limbs indicate that this cat was moderately capable of leaping. The pelvic region, including the sacral vertebrae, was bear-like, as was the short tail composed of 13 vertebrae—about half the number of long-tailed cats'.
The unusually large, square nasal opening, like that of the cheetah ("Acinonyx jubatus"), presumably allowed quicker oxygen intake, which aided in rapid running and in cooling the brain. As in the cheetah, too, the brain's visual cortex was large and complex, emphasizing the scimitar cat's ability to see well and function in the day, rather than the night as do most other cats.
Another possible conceptual approach is to use quantum mechanics as an analogy to understand a different field of study like consciousness, without expecting that the laws of quantum physics will apply. An example of this approach is the idea of Schrödinger's cat. Erwin Schrödinger described how one could, in principle, create entanglement of a large-scale system by making it dependent on an elementary particle in a superposition. He proposed a scenario with a cat in a locked steel chamber, wherein the cat's life or death depended on the state of a radioactive atom, whether it had decayed and emitted radiation or not. According to Schrödinger, the Copenhagen interpretation implies that "the cat remains both alive and dead" until the state has been observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics. However, since Schrödinger's time, other interpretations of the mathematics of quantum mechanics have been advanced by physicists, some of which regard the "alive and dead" cat superposition as quite real. Schrödinger's famous thought experiment poses the question, ""when" does a quantum system stop existing as a superposition of states and become one or the other?" In the same way, it is possible to ask whether the brain's act of making a decision is analogous to having a superposition of states of two decision outcomes, so that making a decision means "opening the box" to reduce the brain from a combination of states to one state. But even Schrödinger didn't think this really happened to the cat; he didn't think the cat was literally alive and dead at the same time. This analogy about making a decision uses a formalism that is derived from quantum mechanics, but it doesn't indicate the actual mechanism by which the decision is made. In this way, the idea is similar to quantum cognition. This field clearly distinguishes itself from the quantum mind as it is not reliant on the hypothesis that there is something micro-physical quantum mechanical about the brain. Quantum cognition is based on the quantum-like paradigm, generalized quantum paradigm, or quantum structure paradigm that information processing by complex systems such as the brain can be mathematically described in the framework of quantum information and quantum probability theory. This model uses quantum mechanics only as an analogy, but doesn't propose that quantum mechanics is the physical mechanism by which it operates. For example, quantum cognition proposes that some decisions can be analyzed as if there are interference between two alternatives, but it is not a physical quantum interference effect.
A well-developed olfactory system may be used to detect mates and prey. A highly sensitive optic nerve has been shown to have visual discrimination and spatial memory comparable to those of a rat. The brain and central nervous system have been extensively studied for evolutionary comparison with placental mammals, particularly with its fellow monotreme, the platypus. The average brain volume is 25 ml, similar to a cat of approximately the same size; while the platypus has a largely smooth brain, the echidna has a heavily folded and fissured, gyrencephalic brain similar to humans, which is seen as a sign of a highly neurologically advanced animal. The cerebral cortex is thinner, and the brain cells are larger and more densely packed and organised in the echidna than the platypus, suggesting evolutionary divergence must have occurred long ago. Almost half of the sensory area in the brain is devoted to the snout and tongue, and the part devoted to smell is relatively large compared to other animals.
Dr. Gazzaniga has led pioneering studies in learning and understanding split brained patients and how their brains work. He has performed numerous studies and done large amounts of research on split brain patients to provide a higher quality understanding into the lives of those affected by this rare phenomenon. He has studied how people who have the two halves of the brain separated function in comparison to those who do not. Dr. Gazzaniga has looked into what bodily functions are controlled by each half of the brain. He has looked at what split brained patients are able to do as a result of their condition such as the ability to draw two different objects with each hand, an ability that a person with a non split brain is unable to do. They study how those with split brain act emotionally and physically in comparison to those who do not have a split brain. Through Gazzaniga’s studies a much greater understanding of the split brain phenomenon has been brought to other physiologists as well as the general population of the world.