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One particularly fascinating area in the frontal lobe is called the primary motor cortex. This strip running along side the brain is in charge of voluntary movements like waving goodbye, wiggling your eyebrows, and kissing. It is an excellent example of the way that various regions of the brain are highly specialized. Interestingly, each of our various body parts has a unique portion of primary motor cortex devoted to it. Each individual finger has about as much dedicated brain space as your entire leg. Your lips, in turn, require about as much dedicated brain processing as all of your fingers and your hand combine! Because the cerebral cortex in general, and frontal lobe in particular, are associated with such sophisticated functions as planning and being self - aware, they are often thought of as a higher, less primal portion of the brain. Indeed, other animals such as rats and kangaroos, while do have frontal regions of their brain, do not have the same level of development in cerebral cortices. Closer animals to humans on evolutionary treethink chimpanzees and gorillas, more developed this portion of their brain. The brain's parietal lobe is located immediately behind the frontal lobe, and is involved in processing information from body senses. It contains a somatosensory cortex, which is essential for processing sensory information from across the body, such as touch, temperature, and pain. The Somatosensory cortex is organized topographically, which means that spatial relationships that exist in the body are maintained on the surface of the somatosensory cortex. For example, portion of the cortex that processes sensory information from the hand is adjacent to the portion that processes information from the wrist. The temporal lobe is located on the side of the head, and is associated with hearing, memory, emotion, and some aspects of language. The auditory cortex, main area responsible for processing auditory information, is located within the temporal lobe. The Wernickes area, important for speech comprehension, is also located here. Whereas individuals with damage to Brocas area have difficulty producing language, those with damage to Wernickes area can produce sensible language, but they are unable to understand it. The occipital lobe is located at the very back of the brain, and contains the primary visual cortex, which is responsible for interpreting incoming visual information. The occipital cortex is organized retinotopically, which means there is a close relationship between the position of an object in person's visual field and the position of that object's representation in the cortex. You will learn much more about how visual information is processed in occipital lobe when you study sensation and perception.
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Site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape close them as well. Tab will move on to the next part of the site rather than go through menu items. The brain serves many important functions. It gives meaning to things that happen in the world surrounding us. Through five senses of sight, smell, hearing, touch and taste, brain receives messages, often many at the same time. The brain controls thoughts, memory and speech, arm and leg movements and function of many organs within the body. It also determines how people respond to stressful situations by regulating heart and breathing rates. The brain is an organized structure, divided into many components that serve specific and important functions. The weight of the brain changes from birth through adulthood. At birth, average brain weighs about one pound, and grows to about two pounds during childhood. The average weight of an adult female brain is about 2. 7 pounds, while the brain of an adult male weighs about three pounds. The nervous system is commonly divided into a central nervous system and a peripheral nervous system. The central nervous system is made up of the brain, its cranial nerves and spinal cord. The Peripheral nervous system is composed of spinal nerves that branch from the spinal cord and an autonomous nervous system. The brain is made up of two types of cells: neurons and glial cells, also know as neuroglia or glia. Neuron is responsible for sending and receiving nerve impulses or signals. Glial cells are non - neuronal cells that provide support and nutrition, maintain homeostasis, form myelin and facilitate signal transmission in the nervous system. In the human brain, glial cells outnumber neurons by about 50 to one. Glial cells are the most common cells found in primary brain tumors. When a person is diagnosed with a brain tumor, biopsy may be done in which tissue is removed from the tumor for identification purposes by pathologist. Pathologists identify the type of cells that are present in this brain tissue, and brain tumors are named based on this association. The type of brain tumor and cells involved impact patient prognosis and treatment. The brain is housed inside a bony covering called a cranium. Cranium protects the brain from injury. Together, cranium and bones that protect the face are called the skull. Between the skull and brain are meninges, which consist of three layers of tissue that cover and protect the brain and spinal cord. From the outermost layer inward they are: dura Mater, arachnoid and pia Mater. Dura Mater: in the brain, dura Mater is made up of two layers of whitish, nonelastic film or membrane. The outer layer is called periosteum.
The biggest part of the brain is the cerebrum. Cerebrum is the thinking part of the brain and it controls your voluntary muscles, ones that move when you want them to. So you need your cerebrum to dance or kick a soccer ball. You need your cerebrum to solve math problems, figure out video game, and draw picture. Your memory lives in cerebrum both short - term memory and long - term memory. Cerebrum also helps you reason, like when you figure out that you d better do your homework now because your mom is taking you to a movie later. Cerebrum has two halves, with one on either side of the head. Scientists think that the right hand helps you think about abstract things like music, colors, and shapes. The left half is said to be more analytical, helping you with math, logic, and speech. Scientists do know for sure that the right half of the cerebrum controls the left side of your body, and the left half controls the right side.
|Content on this page requires a newer version of Adobe Flash Player.||Figure 5.2 (A) Cerebellar deep nuclei and cerebellar cortex in an idealized brain section. (B) External morphology of the cerebellum.|
|Content on this page requires a newer version of Adobe Flash Player.||Figure 5.3 Midsagittal cross-section of cerebellum showing the three primary lobes of the cerebellum.|
Cerebellum appear to play several roles. It stores learn sequences of movements, it participates in fine tuning and co - ordination of movements produced elsewhere in the brain, and it integrates all of these things to produce movements so fluid and harmonious that we are not even aware of them. Pathologies of cerebellum have long revealed that this part of the brain is involved in motor co - ordination. The cerebellum is divided into three regions, each of which is connected to a specific structure in the brain and involved in specific function. Archicerebellum first appeared in fish. It is connected to the vestibule of inner ear and is involved in balance. The Palaeocerebellum consists mainly of vermis, axial structure and is superimposed on archicerebellum by amphibians, reptiles and birds. The Palaeocerebellum is connected to the spinal cord and controls postural muscle activity by influencing muscle tonus. To play its role in maintaining body posture, muscles must be tense. The Cerebellum therefore controls muscle tension at all times while releasing those muscles required to execute movements. In mammals, neocerebellum is superimposed on these two other parts. It is more voluminous in primates and especially so in humans. It consists of cerebellar hemispheres, is connected to the cortex and contributes to co - ordination of voluntary movements. Among other functions, it ensure that when one set of muscles initiates movement, opposing set acts as a brake so that the body part in question arrives at its target precisely. Grey matter of the cerebellum is also organized somewhat like grey matter of cerebral hemispheres: cortex that forms grey matter on the surface and deep nuclei that serve as relays for efferent pathways leaving this cortex. There are four of these cerebellar nuclei on either side of the median line: fastigial nuclei, also know as roof, serve as relays for the archicerebellum; emboliform and globose nuclei do so for the palaeocerebellum; and dentate nuclei, located in the middle of each cerebellar hemisphere, do so for the neocerebellum. For the body to make any give gesture, sequence and duration of each of the basic movements of each body segment involved must be controlled in a very precise manner. One of the cerebellum's jobs is to provide this control over the timing of the body's movements. It does so by means of a loop circuit that connects it to the motor cortex and modulates signals that the motor cortex sends to motor neurons. In humans, cerebellum also plays a role in analyzing visual signals associated with movement. These signals may come either from movement of objects within the field of vision or from the sight of moving body segments themselves. Cerebellum appears to calculate the speed of these movements and adjust motor commands accordingly. Errors in such calculations largely account for poor motor control observed in patients who have suffered injuries to the cerebellum.
Active Clarity Technique is a rapid and efficient whole - brain clearing Technique. Workflow for clearing tissue with ACT. The brain was isolated from cardiac - perfuse animal and post - fixed in 4% paraformaldehyde overnight to induce DNA - protein crosslinking. The brain was immersed in 4% acrylamide and thermal initiator - containing solution for 18 - 24 hours. The whole brain was incubated at 37 C for 2 hours. After polymerization, lipid membranes were removed by ACT for 4 - 6 hours. Diagram of the ACT - ECT system. Brains before and after ACT processing; C57BL / 6 mouse brains after polymerization, ACT and refractive index matching. Scale bar, 1 cm. Injection of trypan blue into ventricle of cleared brain. Square unit; x: 5 mm, y: 5 mm. Active Clarity Technique for three - dimensional imaging of protein and RNA distribution in adult brain samples. Unsectioned mouse brain tissue Image showing part of midbrain stained with tyrosine - hydroxylase. Scale bar, 100 M. Neurons labelled with adeno - associate virus - green fluorescent protein and immunolabeling of dendritic arbors with anti - GFP antibodies. Scale bar, 100 M. In situ hybridization of ACT - process midbrain slice with 1. 1 Kb DIG - label tyrosine hydroxylase probes. Scale bar, 100 M. Comparison of procedures and processing times between ACT and other clearing methods. Images of the brain are blocked after processing. Dot green lines indicate original sizes of blocks and red lines mark size after clearing. Square unit; x: 5 mm, y: 5 mm. The Rat brain hemisphere processes with 15 hours of ACT. Scale bar, 1 cm. Magnify fluorescent image of boxed region in middle. Nuclear - staining of rat cerebellum acquired with LSM 700 microscope. Scale bar, 1 mm. Size comparison of adult mouse brain and adult rabbit brain. The rabbit's brain was clear after 36 hours of ACT. Human spinal cord block cleared with ACT and immunolabeled. Before and after ACT. Scale bar, 1 cm. The human spinal cord block was clear and stained with SMI32. Syto16 was used for nuclear staining. Spinal cord block was immunostained for PGP 9. 5 and collagen type IV. All three - dimensional reconstructed images were obtained with a Zeiss 780 or 700 confocal microscope with Plan - apochromat 10 / 0. 45 M27 lens. Scale bar, 50 M. Clear organ samples were treated with CUBIC - mount for 5 days to adjust refractive indices of tissue and reagent. Square units; x: 5 mm, y: 5 mm. Transmission images of cleared whole organs by ACT. Images were taken after electrophoretic tissue clearing in PBS. Details of tissue architecture were visualized with a standard dissection microscope. Images were acquired on Olympus BX53 digital microscope DP73 camera. Scale bar, 1 mm. Act - PRESTO for rapid immunolabeling of dense tissues. Comparison of diffusion rate using ACT - processed organs. Schematic diagram for dense tissue immunohistochemistry. Tissues for C entrifugal PRESTO were centrifuge at 600 g for 3 hours using standard Table - top centrifuge to expedite penetration of primary and secondary antibodies. The syringe pump was used for antibody reaction during s yringe PRESTO. Kidneys were labelled with collagen type IV using various protocols.
We selected 101 T 1 - weight brain MR images that are: publicly accessible with non - restrictive license, from healthy participants, of high quality to ensure good surface reconstruction, and as part of Multi - Modal acquisition, five subjects were scanned specifically for this dataset. Scanner acquisition and demographic information are included as Supplementary Material and are also available on http: / Mindboggle. Info / data website. Table 1 lists data sets that comprise Mindboggle - 101 data set. These include 20 Test - Retest subjects from Open Access Series of Imaging Studies data, 21 Test - Retest subjects from Multi - Modal Reproducibility Resource, with two additional subjects run under the same protocol in 3T and 7T scanners, 20 subjects from Nathan Kline Institute Test - Retest set, 22 subjects from Nathan Kline Institute / Rockland Sample, 12 Human Language Network subjects, Colin Holmes 27 template, two identical Twins, and one brain Imaging colleague. We preprocessed and segment T 1 - weight MRI volumes and constructed cortical surfaces using FreeSurfers standard recon - all image processing pipeline 4. Since it has been demonstrated recently that FreeSurfer results can vary depending on software version, operating system, and hardware, every group of subjects was processed by FreeSurfer with the same computer setup. All images were run on Apple OSX 10. 6 machines, except for two, and all were run using FreeSurfer version 5. 10, except for OASIS - TRT - 20, which was run using 5. 00. Following initial pass, JT inspects segmentation and surface reconstructions for errors. Freesurfer then automatically labels the cortical surface using its DK cortical parcellation atlas. Vertices along the cortical surface are assigned to give label based on local surface curvature and average convexity, prior label probabilities, and neighboring vertex labels. Region definitions of labeling protocol represented by the DK atlas are described in Desikan et al.
Volume Imaging with single - cell resolution should allow molecular and structural analyses of biological systems 1 2 3 and enable more accurate medical diagnosis 4 5. Conventional volume Imaging requires tissue sectioning, labeling of serially sectioned tissues with probes for specific targets, such as macromolecules and reconstructing individual two - dimensional images into three - dimensional structures 6 7 8 9 10 11 12. Such processes are not only labor - intensive and time - consuming, but also prone to errors, such as mechanical distortion of tissues caused by sectioning and inaccurate 3D reconstruction due to the complexity of mapping reference points. Development of methods to transform tissues and organs into optically transparent samples and image cellular structures in unsectioned, intact organs has attracted attention 1 2 3 7 13 14 15 16 17 18 19. One way to achieve transparency is immersing samples into selective media with a suitable refractive index to minimize light scattering 20 21. Several hydrophobic reagents have been developed to render tissues nearly transparent, but many of these reagents cause rapid quenching of fluorescent signals during dehydration step 19 22. Hydrophilic reagents have been introduced to maintain fluorescent signals 1 13 15, but optical clearing is generally slow, particularly for large tissues. Substantial progress has been made in tissue clearing and promoting penetration of labeling reagents with the advent of hydrogen - base clearing methods 2 3 23. These methods include protein and acrylamide crosslinking step that selectively immobilizes proteins and other macromolecules, resulting in tissue - embed hydrogel 24 25. Lipid components are selectively removed either by passive diffusion or actively by electrophoresis. Removing lipid components markedly increases optical transparency and the porous nature of hydrogel allows penetration of labeling reagents deep inside thick tissues 2 3. However, hydrogel - embed tissue clearing methods retain dense extracellular matrix, which hinder penetration of macromolecules into thick organs. Although recent advances in tissue clearing and labeling techniques have greatly improved methods to visualize molecules deep inside organs, entire process is slow and requires complex procedures. For example, clearing the entire mouse brain with CLARITY takes at least 1 - 2 weeks and requires a specialized device. Other methods, such as CUBIC and iDISCO, do not require specific equipment and are scalable, but these methods rely on free diffusion of buffers, which delays processing time and makes complete clearing difficult 1 3 16. Pact takes advantage of tissue hydrogel in the porous clearing system. Although systemic perfusion of clearing solution substantially reduces clearing time, passive diffusion clearing is still slow, preventing its application for large volume tissues or whole - organism clearing 2. Therefore, significant challenge in this field is to develop improved methodology to deliver reagents deep inside of thick tissues to achieve whole - tissue and body Imaging with single - cell resolution in reasonable time. In this study, we report rapid, efficient and scalable ACT method, which renders large tissue samples optically transparent and enables labeling of deep structures.
Compatibility of LABOR with histological examination prompted us to analyze cellular distribution of sialoglycans by using confocal fluorescence microscopy with higher spatial resolution. Tissue sections from caudal diencephalon were prepared and immunostained with synaptic marker synaptophysin and marker for astrocytes glial fibrillary acidic protein, followed by reaction with DBCO - Cy5 and staining with DAPI. We focus confocal imaging experiments on the dentate gyrus area of the hippocampus within caudal diencephalon, given that sialylation has been implicated in regulating hippocampal function. In particular, sialoglycans have been shown to play an important role in synaptic plasticity and neurotransmission. To better resolve spatial distribution of 9AzSia, we zoom in to the granule cell layer of the dentate gyrus of the hippocampus. 9azsia labeling exhibits fluorescence pattern that is exclusive to the nucleus, indicating labeling of cell surface sialoglycans. Punctate staining of synapses appear to localize over region with dense 9AzSia labeling, suggesting that many of nascent sialoglycans are distributed in synapses. In addition, 9AzSia fluorescence, although at a relatively lower level, was also observed at locations of astrocytes, suggesting cell surface sialoglycans on astrocytes were metabolically label. As expect, confocal fluorescence imaging on the hippocampus of control mice exhibit minimal Cy5 fluorescence. These results suggest that turnover and biosynthesis of sialic acids are active in the brain, resulting in incorporation of 9AzSia into newly synthesize sialoglycans located on cell surfaces, including synaptic sites.
The limbic system combines higher mental functions and primitive emotions into one system. The limbic system is a complex set of structures found on the central underside of the cerebrum, comprising inner sections of temporal lobes and the bottom of the frontal lobe. It combines higher mental functions and primitive emotions into a single system often referred to as emotional nervous system. It is not only responsible for our emotional lives but also our higher mental functions, such as learning and formation of memories. The limbic system is the reason that some physical things such as eating seem so pleasurable to us, and the reason why some medical conditions, such as high blood pressure, are caused by mental stress. There are several important structures within the limbic system: amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus. The amygdala is a small almond - shaped structure; there is one located in each of the left and right temporal lobes. Know as the emotional center of the brain, amygdala is involved in evaluating emotional valence of situations. It helps the brain recognize potential threats and helps prepare the body for fight - or - flight reactions by increasing the heart and breathing rate. The amygdala is also responsible for learning on the basis of reward or punishment. Due to its close proximity to the hippocampus, amygdala is involved in modulation of memory consolidation, particularly emotionally - laden memories. Emotional arousal following learning event influences strength of subsequent memory of that event, so that greater emotional arousal following learning event enhances persons retention of that memory. In fact, experiments have shown that administering stress hormones to individuals immediately after they learn something enhances their retention when they are tested two weeks later. The Hippocampus is found deep in the temporal lobe, and is shaped like a seahorse. It consists of two horns curving back from the amygdala. Psychologists and neuroscientists dispute the precise role of the hippocampus, but generally agree that it plays an essential role in the formation of new memories about past experiences. Some researchers consider the hippocampus to be responsible for general declarative memory. Damage to the hippocampus usually results in profound difficulties in forming new memories, and may also affect access to memories that form prior to damage. Although the retrograde effect normally extends some years prior to brain damage, in some cases older memories remain intact; this leads to the idea that over time hippocampus becomes less important in storage of memory. Both the thalamus and hypothalamus are associated with changes in emotional reactivity. Thalamus, which is a sensory way - station for the rest of the brain, is primarily important due to its connections with other limbic - system structures. The hypothalamus is a small part of the brain located just below the thalamus on both sides of the third ventricle. Lesions of hypothalamus interfere with several unconscious functions and some so - called motivated behaviors like sexuality, combativeness, and hunger.
Four lobes of the brain are frontal, parietal, temporal, and occipital lobes. The frontal lobe is located in the forward part of the brain, extending back to a fissure known as central sulcus. The frontal lobe is involved in reasoning, motor control, emotion, and language. It contains the motor cortex, which is involved in planning and coordinating movement; prefrontal cortex, which is responsible for higher - level cognitive functioning; and the Brocas area, which is essential for language production. People who suffer damage to Brocas area have great difficulty producing language of any form. For example, Padma was an electrical engineer who was socially active and caring, involved mother. About twenty years ago, she was in a car accident and suffered damage to her Brocas area. She completely lost the ability to speak and form any kind of meaningful language. There is nothing wrong with her mouth or her vocal cords, but she is unable to produce words. She can follow directions but cant respond verbally, and she can read but no longer write. She can do routine tasks like running to the market to buy milk, but she could not communicate verbally if the situation called for it. Probably the most famous case of frontal lobe damage is that of a man by name of Phineas Gage. On September 13 1848, Gage was working as a railroad foreman in Vermont. He and his crew were using an iron rod to tamp explosives down into blasting hole to remove rock along railway path. Unfortunately, iron rod created a spark and caused the rod to explode out of the blasting hole, into Gage's face, and through his skull. Although lying in a pool of his own blood with brain matter emerging from his head, Gage was conscious and able to get up, walk, and speak. But in the months following his accident, people noticed that his personality had change. Many of his friends describe him as no longer being himself. Before the accident, it was said that Gage was a well - mannered, soft - spoken man, but he began to behave in odd and inappropriate ways after the accident. Such changes in personality would be consistent with loss of impulse controla frontal lobe function. Beyond damage to the frontal lobe itself, subsequent investigations into rods path also identified probable damage to pathways between frontal lobe and other brain structures, including the limbic system. With connections between planning functions of the frontal lobe and emotional processes of the limbic system sever, Gage had difficulty controlling his emotional impulses. However, there is some evidence suggesting that dramatic changes in Gage's personality were exaggerated and embellish. The Gage case occurred in the midst of a 19th century debate over localizationregarding whether certain areas of the brain are associated with particular functions.
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