Remodel Connection Essay

The central nervous system (CNS) comprises grey matter, which contains neuron cell bodies and white matter, which contains the nerve axons. Most of the nerve axons are concentrically wrapped around by lipid-rich biological membrane, known as the myelin sheath. In the CNS, myelin is produced by oligodendrocyte. a type of glial cell. (Pfeiffer et al., 1993). These electrical insulating, multilamellar membranes significantly increase the electrical resistance, in which to prevent leakage of electrical currents from the axons, as well as decrease electrical capacitance to reduce the ability of the axons to store electrical energy (Shivane &

Han et al., 2013 hypothesised that “human astrocytes might enhance synaptic plasticity and learning relative to their munic counterparts” so they grafted OPCs and astrocytes into

The discovery of glial cells in the mid-19th century opened numerous doors in neuroscience research; nevertheless, many scientists have sustained a highly neuron-specific perspective all along. Neurons do play the major role in regulating brain function, but glial cells were always thought to only serve and protect their omnipotent counterparts. “Glia number equally or even more than neurons in the brain, so how could we forget such a big population of cells?” Guoping Feng asked.

Human brain consists of billions of cells interconnected together, with each performing its separate functions. It consists of two explicit categories of nerves: neurons and glia cells. Neuron is a single nerve cell in the entire nervous system; which is electrically excitable cell that carries information after being processed via chemical or electrical signals. One of its key characteristics is that it does not undergo cell division. In addition, it maintains a voltage gradient for all the neurons across its membranes. Glia cells, on the other hand, its functionality is to maintain homeostasis.

Using electron microscopy, Bailey and Chen studied the morphological changes seen at the synapse when long-term learning takes place. By assessing habituation and sensitization in Aplysia, they were surprised to find that in animals not exposed to learning situations, only 41% of the varicosities (synaptic knobs) had an active zone, an area with a thicker membrane. Regarding short-term learning, they found no change in these active zones; however, they did fine that only 12% of the vesicles were releasable, as opposed to the normal 30%. When studying the animals with greater sensitization, researchers found that 65% of the varicosities had an active zone, coming from 20 vesicles with an active zone. From this, Bailey and Chen showed that long-term leaning led to morphological differences, occurring just

suggested to be critical for neuron growth(Turner et al. 2003, Vasto et al. 2008, Priller et

hormones, neurotropic factors, environmental demands) are essential for typical differentiation. Especially at this age range, strong region-specific maturational changes occur in the rolandic gray matter, which present an increased susceptibility to deviations from the normal developmental trajectory by improper signaling (Andersen, 2003; Lenroot and Giedd, 2006). Moreover, during development, preadolescent influences are incorporated into the (further) maturation of anatomy and function as they determine set points for adult function, with possibly lasting effects (Andersen, 2003). The phase of preadolescent cortical thinning is preceded by a tremendous overshoot of neurons and connections, during which the brain is established as an over-complete network (Andersen, 2003; Lenroot and Giedd, 2006). The subsequent pruning process removes redundant neurons and connections to optimize the network for environmental needs, the level of redundancy determining the degree of adaptation (Muftuler et al.,

The concept of ‘multi-partite synapses’ (illustrated schematically in Fig. 5), which evolved over a decade ago, states that complex multi-directional relationship exists among the distinct components of synapses in the CNS. The ECM, present in the synaptic cleft and also, extending extra-synaptically, features prominently alongside the presynaptic terminal, the postsynaptic cell, and the perisynaptic process of astrocyte and that of neighboring microglia cells which periodically makes contact with the synaptic structure (Verkhratsky and Nedergaard,

In the Summer of 2015 I had the opportunity of accomplishing my own research project. With the help of my graduate student, I led us to better understand the neural pathway

Brain alterations can be triggered not only by environmental factors, but also by injury or disease. Such alterations usually take the form of changes in the manner in which nerve cells (neurons) connect to one another. “Axonal sprouting” is the mechanism that underpins these processes and involves the development of new nerve endings on undamaged axons which help to re-establish disrupted connections between neurons. Furthermore, the new nerve endings forming on undamaged axons can also facilitate connection with other undamaged neurons, creating new neural pathways that replace the impaired function. For instance, the two brain hemispheres each fulfil clearly defined functions, but if one of them incurs damage, its functions can be transferred

“Today’s science is riveted on our body’s most amazing parts- the brain, its component neural systems, and their genetic instructions.” Neuroanatomy is the study of the anatomy and function of the brain and nervous system. The basic building block of the nervous system and brain is the neuron, or a nerve cell. The neuron is made up of different structures, all playing a vital role in the function of the cell. The first being the dendrites, the bushy, branch extensions that receive the impulse and conduct it towards the rest of the cell. From here the message passes through the axon, a single nerve fiber that carries the impulse away from the cell body. Many axons are covered with a fatty, lipid covering called the myelin sheath. The function

Scientists originally believed that the human brain ceases to produce new neural cells after the first few years of human life. According to Dr. Mercola, the old model, which suggests a finite number of neural cells in the brain and no new cell being generated in place of a dead cell, is no longer relevant. The recent studies

According to Myers, neuroplasticity is currently defined as the ability for the brain to “modify itself after some types of damage” (82). This statement is in stark contrast with past-assumptions concerning how the brain is structured. To elaborate, scientists once believed that the “brain stopped developing after only the first few years of life”, thus supporting the ill-fated claim that that only “young brains would be ‘plastic’” (Liou). In other words, the brain structure a person was initially born with will remain the same for the rest of his/her life—it is unchangeable. It was also widely believed that severed nerve cells after the first few years of life could neither regenerate nor form new connections, implying that the functions

The embryonic brain development process commences after the neural tube is closed at neurulation. Progenitor cells in the brain start to proliferate in the progenitor zone, where they transform into postmitotic cells and migrate to different brain regions. Once they reach their final destination, they start to grow their axons to make connections with other cells (synaptogenesis). When the axons reach their correct targets, these connections are strengthened by myelination [255]. In rodents, myelination continues until the first two postnatal months [255].

Neurogenesis is defined as the creation of new brain cells. Before studies proved that neural cells do have the capacity to proliferate and repair themselves, it was often believed that species are born with a distinct amount of neural cells and as time passes, these cells would die without the ability to be healed or replaced. It was thought that the cells were mainly formed during the embryonic and perinatal stages in the mammals (Ming and Song, 2005). The first piece of evidence that proved that neural cells can be formed throughout the life of a mammal was found by Altman. He found that there were newly formed granule cells in a postnatal rat hippocampus (Altman and Das, 1965). In humans, there are two main regions that were found to have an active amount of neurogenesis. One is the subgranular zone (SGZ) which is located in the dentate gyrus of the hippocampus. It is here that new dentate granule cells are generated. The other is the subventricular zone (SVZ) of the lateral ventricles. Neurons are generated in this area and are migrated through the rostral migratory system (RMS) to the olfactory bulbs where they become interneurons (Gage, 2000). A question scientists continuously investigate is whether or not there is a decrease in an organism’s ability to regenerate and repair neural cells as they age, and if this there is a limit on their ability to regenerate these cells, are there genes or proteins that