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What is the relationship between synaptic changes and behavioral changes? We are far from being able to answer to this question, but, as in other fields of neuroscience, we are getting closer and closer to it. This was considered a great finding. Why was this discovery so important? The basic unit cell of our nervous system is the neuron. Neurons can have many different shapes, some of them really spectacular see the cerebellar Purkinge cell in the above figure. Although we can think of our nervous system as a road network, where electric impulses or information travels, it has one particular property that makes it radically different from most networks we are used to thinking of.

Instead, they would stand next to each other, with gaps between them. The way this is done is through synapses see figure. When the nervous signal reaches one end of a neuron the end of an axon , it causes some substances neurotransmitters to be released into the gap. These neurotransmitters induce some chemical reaction on the end of the adjacent neuron a dendrite.

This chemical reaction triggers the transmission of the nervous signal in the second neuron, so the signal continues to travel through our brain. Different factors like drug or alcohol consumption can modify these biochemical reactions, but the repetition of the transmission also modifies their properties. In this context, plastic refers to its ability to change its functioning as a consequence of past experiences. Now we have a hint about why the discovery of LTP in the mammalian brain was so important. As has just been said, one current view of learning at a molecular level is that it has to do with molecular changes occurring at the synapses.

One of the best candidates for this molecular change has been named Long-Term Potentiation. Long-Term Potentiation LTP is operationally defined as a long-lasting increase in synaptic efficacy which follows high-frequency stimulation of afferent fibers: this form of synaptic plasticity may participate in information storage in several brain regions.

We are far from understanding all the complex mechanisms involved in these processes. It is clear, even from personal experiences, that our brain operates better when our basic needs are satisfied sleep, hunger, thirst. Fear has strong consequences at a molecular level in the way learning occurs.

It has the consequence of modifying the biochemical properties of the neurotransmitters, making some experiences particularly salient this is the basis of traumatic experiences that individuals are unable to forget throughout their entire lives. Up to now we have been talking about learning as if there were just one type of it. But this is not the case. Indeed, it would be inaccurate to assume that our brain is a homogeneous structure, and that all of its parts have equivalent roles in learning.

True, learning happens throughout our brain, but it would be erroneous to assume that there are no differences in learning how to play tennis, how to get around in a new building and how to speak a new language. Is learning more than changes in synaptic strength? Learning and brain systems. If learning is broadly defined as gathering knowledge, it bears a strong relationship with memory, as it refers to our capacity to store knowledge. We can have an initial understanding of the diversity of memory types and learning and storing mechanisms by considering the case of amnesic patients. Amnesic patients usually have trouble remembering their names, where they live, work, where they went on vacation last summer, etc.

Usually they forget information about their personal life. Neuroscientists have proposed a fundamental division between two memory types: declarative memory and procedural memory. Many amnesic patients can be taught some skills, but they fail to explicitly state the sequence by which they managed to do so. At an anatomical level, declarative explicit memory involves the hippocampus and several surrounding cortical areas and also other different cortical areas. If declarative memory corresponds to explicit learning, procedural memory corresponds to implicit learning.

Implicit knowledge is involved in many different aspects of our lives. Implicit learning is also involved in slight changes in motor skills that accompany, for instance, our improvements when learning a new sport. From the point of view of brain structures being involved in this type of learning, there are two subsystems: the neostriatal subsystem belonging to the basal ganglia and the cerebellar subsystem. Although both subsystems subserve different functions, they share the property of being essential in the processes of learning without conscious recollection.

The following table illustrates the relationship between brain areas and memory systems from Squire et al. In this diagram, a third memory system has been added: emotional memory. Emotional memory is the learning and recollection of knowledge about our emotional state in a specific circumstance.

Brain Facts

The scene described by Shakespeare in the first words of Macbeth causes us to contact different fearful experiences that left very strong memories in our brain. The consequences of emotional states in learning have been well documented in the past years. One central structure in emotions is the amygdala. It is a small structure, located in the inner part of the brain, which resembles an almond this is where the name comes from.

The amygdala, as can be seen in the diagram, receives inputs from many sensory and secondary centers and is responsible for increasing our heart rate, blood pressure and, together with the hypothalamus, controlling a wide variety of hormones. As mentioned in the preceding section, changes in the neurotransmitters may have important consequences in the learning processes. These effects can involve increasing the efficiency of storage, as in the case of the increase of arousal induced by emotional changes McGaugh In general, it should be considered that the strength of a memory learning should correlate with its importance for the organism.

The consequences of emotions can be viewed as a successful evolutionary mechanism for learning and remembering the important things of our lives for a review of these topics, see Helmuth, Research in cognitive neuroscience has shown that individuals suffering post-traumatic stress disorder a highly disabling condition, associated with intrusive recollections of a traumatic event, avoidance of situations associated with the trauma, and psychological numbing show abnormal functioning of the amygdala, hypothalamus and the medial frontal cortex.

Although all human beings may suffer a traumatic experience that will not be forgotten in their entire lives, it is undeniable that infancy and childhood are particularly sensitive periods for learning. Up to this point we have been presenting evidence about learning considering that the brain is a relatively mature, stable structure. In this context, the changes occurring at the molecular level would not represent major transformations in its structure and overall functioning. However, as living entities in general, and as humans in particular, we are characterized by a very long period of growth.

The internal carotid arteries supply oxygenated blood to the front of the brain and the vertebral arteries supply blood to the back of the brain. The internal carotid arteries are branches of the common carotid arteries. They enter the cranium through the carotid canal , travel through the cavernous sinus and enter the subarachnoid space.

These branches travel forward and then upward along the longitudinal fissure , and supply the front and midline parts of the brain. They travel sideways along the sphenoid bone of the eye socket , then upwards through the insula cortex , where final branches arise. The middle cerebral arteries send branches along their length. The vertebral arteries emerge as branches of the left and right subclavian arteries. They travel upward through transverse foramina — spaces in the cervical vertebrae and then emerge as two vessels, one on the left and one on the right of the medulla. The vertebral arteries join in front of the middle part of the medulla to form the larger basilar artery , which sends multiple branches to supply the medulla and pons, and the two other anterior and superior cerebellar branches.

These travel outwards, around the superior cerebellar peduncles, and along the top of the cerebellar tentorium, where it sends branches to supply the temporal and occipital lobes. Cerebral veins drain deoxygenated blood from the brain. The brain has two main networks of veins : an exterior or superficial network , on the surface of the cerebrum that has three branches, and an interior network. These two networks communicate via anastomosing joining veins. Blood from the medulla and pons of the brainstem have a variable pattern of drainage, either into the spinal veins or into adjacent cerebral veins.

The blood in the deep part of the brain drains, through a venous plexus into the cavernous sinus at the front, and the superior and inferior petrosal sinuses at the sides, and the inferior sagittal sinus at the back. Blood from here joins with blood from the straight sinus at the confluence of sinuses. Blood from here drains into the left and right transverse sinuses.

The sigmoid drains into the large internal jugular veins. The larger arteries throughout the brain supply blood to smaller capillaries. These smallest of blood vessels in the brain, are lined with cells joined by tight junctions and so fluids do not seep in or leak out to the same degree as they do in other capillaries, thereby creating the blood—brain barrier. At the beginning of the third week of development , the embryonic ectoderm forms a thickened strip called the neural plate. These swellings are known as the primary brain vesicles and represent the beginnings of the forebrain , midbrain and hindbrain.

Neural crest cells derived from the ectoderm populate the lateral edges of the plate at the neural folds. In the fourth week in the neurulation stage the neural folds close to form the neural tube , bringing together the neural crest cells at the neural crest. Cells detach from the crest and migrate in a craniocaudal head to tail wave inside the tube. The tube flexes as it grows, forming the crescent-shaped cerebral hemispheres at the head. The cerebral hemispheres first appear on day These areas are formed as swellings known as the three primitive vesicles.

In the fifth week of development five brain vesicles have formed. The telencephalon gives rise to the cerebral cortex, basal ganglia, and related structures. The diencephalon gives rise to the thalamus and hypothalamus. The hindbrain also splits into two areas — the metencephalon and the myelencephalon. The metencephalon gives rise to the cerebellum and pons.

The myelencephalon gives rise to the medulla oblongata. A characteristic of the brain is the cortical folding known as gyrification. During fetal development , the cortex starts off smooth.

Brain Facts - a Primer on the Brain and Nervous System

By the gestational age of 24 weeks, the wrinkled morphology showing the fissures that begin to mark out the lobes of the brain is evident. The first cleft to appear in the fourth month is the lateral cerebral fossa. This covers the fossa and turns it into a much deeper ridge known as the lateral sulcus and this marks out the temporal lobe. The frontal lobe is involved in reasoning, motor control, emotion, and language. The corticospinal tract carries movements from the brain, through the spinal cord , to the torso and limbs.

Gross movement — such as locomotion and the movement of arms and legs — is generated in the motor cortex , divided into three parts: the primary motor cortex , found in the prefrontal gyrus and has sections dedicated to the movement of different body parts. These movements are supported and regulated by two other areas, lying anterior to the primary motor cortex: the premotor area and the supplementary motor area. These then travel down the spinal cord , with most connecting to interneurons , in turn connecting to lower motor neurons within the grey matter that then transmit the impulse to move to muscles themselves.

The sensory nervous system is involved with the reception and processing of sensory information. This information is received through the cranial nerves, through tracts in the spinal cord, and directly at centres of the brain exposed to the blood. Mixed motor and sensory signals are also integrated. From the skin, the brain receives information about fine touch , pressure , pain , vibration and temperature. From the joints, the brain receives information about joint position.

Sensation collected by a sensory receptor on the skin is changed to a nerve signal, that is passed up a series of neurons through tracts in the spinal cord.

The dorsal column—medial lemniscus pathway contains information about fine touch, vibration and position of joints. Neurons travel up the back part of the spinal cord to the back part of the medulla, where they connect with second-order neurons that immediately swap sides. These neurons then travel upwards into the ventrobasal complex in the thalamus where they connect with third-order neurons and travel up to the sensory cortex.

Neurons travel up the spinal cord and connect with second-order neurons in the reticular formation of the brainstem for pain and temperature, and also at the ventrobasal complex of the medulla for gross touch. Vision is generated by light that hits the retina of the eye. Photoreceptors in the retina transduce the sensory stimulus of light into an electrical nerve signal that is sent to the visual cortex in the occipital lobe. Vision from the left visual field is received on the right side of each retina and vice versa and passes through the optic nerve until some information changes sides , so that all information about one side of the visual field passes through tracts in the opposite side of the brain.

The nerves reach the brain at the lateral geniculate nucleus , and travel through the optic radiation to reach the visual cortex. Hearing and balance are both generated in the inner ear. The movement of liquids within the inner ear is generated by motion for balance and transmitted vibrations generated by the ossicles for sound. This creates a nerve signal that passes through the vestibulocochlear nerve. From here, it passes through to the cochlear nuclei , the superior olivary nucleus , the medial geniculate nucleus , and finally the auditory radiation to the auditory cortex.

The sense of smell is generated by receptor cells in the epithelium of the olfactory mucosa in the nasal cavity. This information passes through a relatively permeable part of the skull to the olfactory nerve. This nerve transmits to the neural circuitry of the olfactory bulb from where information is passed to the olfactory cortex.

Some taste information is also passed from the pharynx into this area via the vagus nerve. Information is then passed from here through the thalamus into the gustatory cortex. Autonomic functions of the brain include the regulation, or rhythmic control of the heart rate and rate of breathing , and maintaining homeostasis.

Blood pressure and heart rate are influenced by the vasomotor centre of the medulla, which causes arteries and veins to be somewhat constricted at rest. It does this by influencing the sympathetic and parasympathetic nervous systems via the vagus nerve. Information about the pressure changes in the carotid sinus comes from carotid bodies located near the carotid artery and this is passed via a nerve joining with the glossopharyngeal nerve.

This information travels up to the solitary nucleus in the medulla. Signals from here influence the vasomotor centre to adjust vein and artery constriction accordingly. The brain controls the rate of breathing , mainly by respiratory centres in the medulla and pons. This is a mixed nerve that carries sensory information back to the centres. There are four respiratory centres, three with a more clearly defined function, and an apneustic centre with a less clear function. In the medulla a dorsal respiratory group causes the desire to breathe in and receives sensory information directly from the body.

Also in the medulla, the ventral respiratory group influences breathing out during exertion. In the pons the pneumotaxic centre influences the duration of each breath, [97] and the apneustic centre seems to have an influence on inhalation. The respiratory centres directly senses blood carbon dioxide and pH.

Information about blood oxygen , carbon dioxide and pH levels are also sensed on the walls of arteries in the peripheral chemoreceptors of the aortic and carotid bodies. This information is passed via the vagus and glossopharyngeal nerves to the respiratory centres.

High carbon dioxide, an acidic pH, or low oxygen stimulate the respiratory centres. The hypothalamus in the diencephalon , is involved in regulating many functions of the body. Functions include neuroendocrine regulation, regulation of the circadian rhythm , control of the autonomic nervous system , and the regulation of fluid, and food intake. The circadian rhythm is controlled by two main cell groups in the hypothalamus. The anterior hypothalamus includes the suprachiasmatic nucleus and the ventrolateral preoptic nucleus which through gene expression cycles, generates a roughly 24 hour circadian clock.

In the circadian day an ultradian rhythm takes control of the sleeping pattern. Sleep is an essential requirement for the body and brain and allows the closing down and resting of the body's systems. There are also findings that suggest that the daily build-up of toxins in the brain are removed during sleep. Sleep necessarily reduces this use and gives time for the restoration of energy-giving ATP. The effects of sleep deprivation show the absolute need for sleep.

The lateral hypothalamus contains orexinergic neurons that control appetite and arousal through their projections to the ascending reticular activating system. Through the autonomic projections, the hypothalamus is involved in regulating functions such as blood pressure, heart rate, breathing, sweating, and other homeostatic mechanisms. The hypothalamus is influenced by the kidneys — when blood pressure falls, the renin released by the kidneys stimulates a need to drink.

The hypothalamus also regulates food intake through autonomic signals, and hormone release by the digestive system. While language functions were traditionally thought to be localized to Wernicke's area and Broca's area , [] it is now mostly accepted that a wider network of cortical regions contributes to language functions. The study on how language is represented, processed, and acquired by the brain is called neurolinguistics , which is a large multidisciplinary field drawing from cognitive neuroscience , cognitive linguistics , and psycholinguistics.

The cerebrum has a contralateral organisation with each hemisphere of the brain interacting primarily with one half of the body: the left side of the brain interacts with the right side of the body, and vice versa. The developmental cause for this is uncertain. Visual input follows a more complex rule: the optic nerves from the two eyes come together at a point called the optic chiasm , and half of the fibres from each nerve split off to join the other. The left and right sides of the brain appear symmetrical, but they function asymmetrically.

There are, however, several important exceptions, involving language and spatial cognition. The left frontal lobe is dominant for language. If a key language area in the left hemisphere is damaged, it can leave the victim unable to speak or understand, [] whereas equivalent damage to the right hemisphere would cause only minor impairment to language skills. A substantial part of current understanding of the interactions between the two hemispheres has come from the study of " split-brain patients"—people who underwent surgical transection of the corpus callosum in an attempt to reduce the severity of epileptic seizures.

Emotions are generally defined as two-step multicomponent processes involving elicitation , followed by psychological feelings, appraisal, expression, autonomic responses, and action tendencies. The amygdala , orbitofrontal cortex , mid and anterior insula cortex and lateral prefrontal cortex , appeared to be involved in generating the emotions, while weaker evidence was found for the ventral tegmental area , ventral pallidum and nucleus accumbens in incentive salience.

The brain is responsible for cognition , [] [] which functions through numerous processes and executive functions. The prefrontal cortex plays a significant role in mediating executive functions. Brain activity is made possible by the interconnections of neurons that are linked together to reach their targets. Dendrites are often extensive branches that receive information in the form of signals from the axon terminals of other neurons.

The signals received may cause the neuron to initiate an action potential an electrochemical signal or nerve impulse which is sent along its axon to the axon terminal, to connect with the dendrites or with the cell body of another neuron. An action potential is initiated at the initial segment of an axon, which contains a complex of proteins.

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The brain can also utilize lactate during exercise. However, short-chain fatty acids e. The function of sleep is not fully understood; however, there is evidence that sleep enhances the clearance of metabolic waste products, some of which are potentially neurotoxic , from the brain and may also permit repair. The brain is not fully understood, and research is ongoing. The boundaries between the specialties of neuroscience , neurology and other disciplines such as psychiatry have faded as they are all influenced by basic research in neuroscience.

Neuroscience research has expanded considerably in recent decades. The " Decade of the Brain ", an initiative of the United States Government in the s, is considered to have marked much of this increase in research, [] and was followed in by the BRAIN Initiative. Information about the structure and function of the human brain comes from a variety of experimental methods, including animals and humans. Information about brain trauma and stroke has provided information about the function of parts of the brain and the effects of brain damage. Neuroimaging is used to visualise the brain and record brain activity.

Electrophysiology is used to measure, record and monitor the electrical activity of the cortex. Measurements may be of local field potentials of cortical areas, or of the activity of a single neuron. An electroencephalogram can record the electrical activity of the cortex using electrodes placed non-invasively on the scalp.

Invasive measures include electrocorticography , which uses electrodes placed directly on the exposed surface of the brain. This method is used in cortical stimulation mapping , used in the study of the relationship between cortical areas and their systemic function. This has enabled the linking of brain activity to behaviour, and the creation of neuronal maps. The development of cerebral organoids has opened ways for studying the growth of the brain, and of the cortex, and for understanding disease development, offering further implications for therapeutic applications.

Functional neuroimaging techniques show changes in brain activity that relate to the function of specific brain areas. One technique is functional magnetic resonance imaging fMRI which has the advantages over earlier methods of SPECT and PET of not needing the use of radioactive materials and of offering a higher resolution. These methods rely on the haemodynamic response that shows changes in brain activity in relation to changes in blood flow , useful in mapping functions to brain areas. Any electrical current generates a magnetic field; neural oscillations induce weak magnetic fields, and in functional magnetoencephalography the current produced can show localised brain function in high resolution.

Connectograms give a graphical representation of the neural connections of the brain. Differences in brain structure can be measured in some disorders, notably schizophrenia and dementia. Different biological approaches using imaging have given more insight for example into the disorders of depression and obsessive-compulsive disorder.

A key source of information about the function of brain regions is the effects of damage to them. Advances in neuroimaging have enabled objective insights into mental disorders, leading to faster diagnosis, more accurate prognosis, and better monitoring. Bioinformatics is a field of study that includes the creation and advancement of databases, and computational and statistical techniques, that can be used in studies of the human brain, particularly in the areas of gene and protein expression.

Bioinformatics and studies in genomics , and functional genomics , generated the need for DNA annotation , a transcriptome technology , identifying genes , and their and location and function. As of , just under 20, protein-coding genes are seen to be expressed in the human, [] and some of these genes are brain-specific.

The long term use of alcohol for example, has shown altered gene expression in the brain, and cell-type specific changes that may relate to alcohol use disorder. Other related studies have also shown evidence of synaptic alterations and their loss, in the ageing brain. Changes in gene expression alter the levels of proteins in various pathways and this has been shown to be evident in synaptic contact dysfunction or loss. This dysfunction has been seen to affect many structures of the brain and has a marked effect on inhibitory neurons resulting in a decreased level of neurotransmission, and subsequent cognitive decline and disease.

Injury to the brain can manifest in many ways. Traumatic brain injury , for example received in contact sport , after a fall , or a traffic or work accident , can be associated with both immediate and longer-term problems. Immediate problems may include bleeding within the brain , this may compress the brain tissue or damage its blood supply. Bruising to the brain may occur. Bruising may cause widespread damage to the nerve tracts that can lead to a condition of diffuse axonal injury.

In addition to the site of injury, the opposite side of the brain may be affected, termed a contrecoup injury. Longer-term issues that may develop include posttraumatic stress disorder , and hydrocephalus. Chronic traumatic encephalopathy can develop following multiple head injuries. Neurodegenerative diseases result in progressive damage to different parts of the brain's function, and worsen with age. Common examples include dementia such as Alzheimer's disease , alcoholic dementia or vascular dementia ; Parkinson's disease ; and other rarer infectious, genetic, or metabolic causes such as Huntington's disease , motor neuron diseases , HIV dementia , syphilis-related dementia and Wilson's disease.

Neurodegenerative diseases can affect different parts of the brain, and can affect movement, memory , and cognition. The brain, although protected by the blood—brain barrier, can be affected by infections including viruses , bacteria and fungi. Infection may be of the meninges meningitis , the brain matter encephalitis , or within the brain matter such as a cerebral abscess.

Brain tumours can be either benign or cancerous. Most malignant tumours arise from another part of the body , most commonly from the lung , breast and skin. Meningioma , cancer of the meninges around the brain, is more common than cancers of brain tissue. A variety of other tests including blood tests and lumbar puncture may be used to investigate for the cause of the cancer and evaluate the type and stage of the cancer. Surgery may be considered, however given the complex nature of many tumours or based on tumour stage or type, radiotherapy or chemotherapy may be considered more suitable.

Mental disorders , such as depression , schizophrenia , bipolar disorder , posttraumatic stress disorder , attention deficit hyperactivity disorder , obsessive-compulsive disorder , Tourette syndrome , and addiction , are known to relate to the functioning of the brain.

Epileptic seizures are thought to relate to abnormal electrical activity. In a person with epilepsy , risk factors for further seizures may include sleeplessness, drug and alcohol intake, and stress. Seizures may be assessed using blood tests , EEG and various medical imaging techniques based on the medical history and exam findings. Some brain disorders such as Tay—Sachs disease [] are congenital , [] and linked to genetic and chromosomal mutations.

A stroke is a decrease in blood supply to an area of the brain causing cell death and brain injury. This can lead to a wide range of symptoms , including the " FAST " symptoms of facial droop, arm weakness, and speech difficulties including with speaking and finding words or forming sentences. Difficulties with movement, speech, or sight usually relate to the cerebrum, whereas imbalance , double vision , vertigo and symptoms affecting more than one side of the body usually relate to the brainstem or cerebellum.

Most strokes result from loss of blood supply, typically because of an embolus , rupture of a fatty plaque or narrowing of small arteries. Strokes can also result from bleeding within the brain. Some treatments for stroke are time-critical. These include clot dissolution or surgical removal of a clot for ischaemic strokes , and decompression for haemorrhagic strokes.

Having experienced a stroke, a person may be admitted to a stroke unit , and treatments may be directed as preventing future strokes, including ongoing anticoagulation such as aspirin or clopidogrel , antihypertensives , and lipid-lowering drugs. Brain death refers to an irreversible total loss of brain function. When brain death is suspected, reversible differential diagnoses such as, electrolyte, neurological and drug-related cognitive suppression need to be excluded.

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Neuroanthropology is the study of the relationship between culture and the brain. It explores how the brain gives rise to culture, and how culture influences brain development.

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  • The philosophy of the mind studies such issues as the problem of understanding consciousness and the mind—body problem. The relationship between the brain and the mind is a significant challenge both philosophically and scientifically. This is because of the difficulty in explaining how mental activities, such as thoughts and emotions, can be implemented by physical structures such as neurons and synapses , or by any other type of physical mechanism. This difficulty was expressed by Gottfried Leibniz in the analogy known as Leibniz's Mill :.

    One is obliged to admit that perception and what depends upon it is inexplicable on mechanical principles, that is, by figures and motions. In imagining that there is a machine whose construction would enable it to think, to sense, and to have perception, one could conceive it enlarged while retaining the same proportions, so that one could enter into it, just like into a windmill.

    Supposing this, one should, when visiting within it, find only parts pushing one another, and never anything by which to explain a perception. There is clear empirical evidence that physical manipulations of, or injuries to, the brain for example by drugs or by lesions, respectively can affect the mind in potent and intimate ways. The size of the brain and a person's intelligence are not strongly related.

    Other animals, including whales and elephants have larger brains than humans. However, when the brain-to-body mass ratio is taken into account, the human brain is almost twice as large as that of a bottlenose dolphin , and three times as large as that of a chimpanzee. However, a high ratio does not of itself demonstrate intelligence: very small animals have high ratios and the treeshrew has the largest quotient of any mammal. Research has disproved some common misconceptions about the brain. These include both ancient and modern myths.

    It is not true that neurons are not replaced after the age of two; nor that only ten per cent of the brain is used. Akio Mori coined the term game brain for the unreliably supported theory that spending long periods playing video games harmed the brain's pre-frontal region and the expression of emotion and creativity. Historically, the brain featured in popular culture through phrenology , a pseudoscience that assigned personality attributes to different regions of the cortex.

    The cortex remains important in popular culture as covered in books and satire. The Edwin Smith Papyrus , an ancient Egyptian medical treatise written in the 17th century BC, contains the earliest recorded reference to the brain. The hieroglyph for brain, occurring eight times in this papyrus, describes the symptoms, diagnosis, and prognosis of two traumatic injuries to the head. The papyrus mentions the external surface of the brain, the effects of injury including seizures and aphasia , the meninges, and cerebrospinal fluid.

    Aristotle , in his biology initially believed the heart to be the seat of intelligence , and saw the brain as a cooling mechanism for the blood. He reasoned that humans are more rational than the beasts because, among other reasons, they have a larger brain to cool their hot-bloodedness. Their works are now mostly lost, and we know about their achievements due mostly to secondary sources.

    Some of their discoveries had to be re-discovered a millennium after their deaths. He concluded that, as the cerebellum was denser than the brain, it must control the muscles , while as the cerebrum was soft, it must be where the senses were processed. Galen further theorized that the brain functioned by movement of animal spirits through the ventricles. In , Mondino de Luzzi 's Anathomia began the modern study of brain anatomy.

    He suggested that the pineal gland was where the mind interacted with the body after recording the brain mechanisms responsible for circulating cerebrospinal fluid. Thomas Willis is considered a second pioneer in the study of neurology and brain science. In these he described the structure of the cerebellum, the ventricles, the cerebral hemispheres, the brainstem, and the cranial nerves, studied its blood supply; and proposed functions associated with different areas of the brain.

    Studies of the brain became more sophisticated with the use of the microscope and the development of a silver staining method by Camillo Golgi during the s. This was able to show the intricate structures of single neurons. He used microscopy to uncover many cell types, and proposed functions for the cells he saw. Charles Sherrington published his influential work The Integrative Action of the Nervous System examining the function of reflexes, evolutionary development of the nervous system, functional specialisation of the brain, and layout and cellular function of the central nervous system.

    Schmitt , and Stephen Kuffler playing critical roles in establishing the field. The word neuroscience itself arises from this program. Paul Broca associated regions of the brain with specific functions, in particular language in Broca's area , following work on brain-damaged patients.

    Carl Wernicke described a region associated with language comprehension and production. Korbinian Brodmann divided regions of the brain based on the appearance of cells. Harvey Cushing — is recognised as the first proficient brain surgeon in the world. The human brain has many properties that are common to all vertebrate brains. As a primate brain, the human brain has a much larger cerebral cortex, in proportion to body size, than most mammals, [] and a highly developed visual system.

    As a hominid brain, the human brain is substantially enlarged even in comparison to the brain of a typical monkey. The sequence of human evolution from Australopithecus four million years ago to Homo sapiens modern humans was marked by a steady increase in brain size. From Wikipedia, the free encyclopedia. This is the latest accepted revision , reviewed on 20 September This article is about the human brain. For information about brains in general, see Brain. Main organ of the human nervous system.

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    Cerebral lobes: the frontal lobe pink , parietal lobe green and occipital lobe blue. See also: List of regions in the human brain and Outline of the human brain. Further information: Neuroscience of sex differences. Structural and functional areas of the human brain.

    Human brain bisected in the sagittal plane , showing the white matter of the corpus callosum. Functional areas of the human brain. Dashed areas shown are commonly left hemisphere dominant. Main articles: Cerebrum and Cerebral cortex. Main article: Cerebellum.

    Main article: Brainstem. Main article: Cerebrospinal fluid. Main article: Cerebral circulation. Main article: Development of the nervous system in humans. Further information: Development of the human brain. Main article: Language processing in the brain. Main article: Lateralization of brain function. Further information: Functional specialization brain.

    Main article: Emotion. Further information: Affective neuroscience. Main article: Cognition.

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    Main article: Neurotransmission. Further information: Summation neurophysiology. Further information: Magnetic resonance imaging of the brain. Main article: Bioinformatics. See also: List of neuroscience databases. Main article: Stroke. Main article: Brain death. Main articles: Cognition and Mind. Main article: Brain size. Main article: History of neuroscience. Drawing of the base of the brain, from Andreas Vesalius 's work De humani corporis fabrica. Subscribe to view the full document. I cannot even describe how much Course Hero helped me this summer.

    In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero. University of Michigan. Brain Facts book - A Companion Publication to