Grow Little Cell Grow! Investigating Neurogenesis
Neurogenesis, the production of new nerve cells, has been a revolutionary finding as nerve formation has always been thought to end with adulthood. It has not been until recently that such dogma has been contradicted as research findings report that neurogenesis continues in the hippocampus throughout most of the adult life of mammals and primates (1). Recent correlations have been further made between neurogenesis and depression as the latter depletes neuron cells in the brain while antidepressive drugs have demonstrated to increase neuronal growth
(2).
Neurons are the building blocks of the nervous system as they are responsible for the input, processing and transmission of information. Neurons are derived from stem cells as the latter differentiate into specialized cells and make progenitor cells which are responsible for the formation of neuron and glial cells. Although the majority of neurons are formed during the pre-natal and perinatal stage of development, neuron formation continues in the dentate gyrus of the hippocampus (2). The hippocampus, which lies beneath the cortex is a major factor of learning and memory formation and can indirectly influence emotion. Progenitor cells which are present in the sub ventricular zone of the hippocampus are responsible for such growth as they produce daughter neuron cells through division (2).
In the 1960s, Joseph Altman from MIT reported that new neurons were being produced in the dentate gyrus of the hippocampus of adult rat brains. Although such findings were groundbreaking, they failed to create the stir that Elizabeth Gould's 1998 study caused . The Princeton University neurobiologist demonstrated that the marmoset b...
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...is is a complex issue with an array of possibilities for the future. Further investigations will have to answer some of the questions and issued raised.
Sources
(1)The Scientist Magazine , Human neurogenesis. Group demonstrates that adult human brains grow new cells after all. http://www.the-scientist.com/
(2)American Scientist Magazine, Depression and the Birth and Death of Brain Cells. http://www.sigmaxi.org/amsci/articles/00articles/Jacobs.html
(3)National Depressive and Manic Depressive Association, Antidepressants and Brain Cell Growth. http://ndma.com/web05/web9152.htm
(4) Neuroscience for Kids, New Neurons in Neocortex? New Study Says NO! http://faculty.washington.edu/chudler/newneu.html
(5)National Institute of Mental Health, Learning From Songbirds About Adult Brain Generation.
(6) The Scientist Magazine. http://www.the-scientist.com/
Hippocampus is a small, curved region, which exists in both hemispheres of the brain and plays a vital role in emotions, learning and acquisition of new information. It also contributes majorly to long term memory, which is permanent information stored in the brain. Although long term memory is the last information that can be forgotten, its impairment has become very common nowadays. The dysfunction is exemplified by many neurological disorders such as amnesia. There are two types of amnesia, anterograde and retrograde. Anterograde amnesia is inability in forming new information, while retrograde refers to the loss of the past memory. As suggested by Cipolotti and Bird (2006), hippocampus’s lesions are responsible for both types of amnesia. According to multiple trace theory, the author suggests that hippocampal region plays a major role in effective retrieving of episodic memory (Cipolotti and Bird, 2006). For example, patients with hippocampal damage show extensively ungraded retrograde amnesia (Cipolotti and Bird, 2006). They have a difficult time in retrieving information from their non-personal episodic events and autobiographical memory. However, this theory conflicts with standard model of consolidation. The difference between these theories suggests that researchers need to do more work to solve this controversy. Besides retrieving information, hippocampus is also important in obtaining new semantic information, as well as familiarity and recollection (Cipolotti and Bird, 2006). For instance, hippocampal amnesic patient V.C shows in ability to acquire new semantic knowledge such as vocabularies and factual concepts (Cipolotti and Bird, 2006). He is also unable to recognize and recall even...
The neurons or brain cells are shaped like trees. Young brain cells, called soma, resemble an acorn or small seed of a tree. The seed sprouts limbs when stimulated, called dendrites. Further on in development, the cell will grow a trunk like structure called an axon. The axon has an outer shell, like the bark of a tree, called the myelin sheath. Finally, at the base of the cell, there are root-like structures called axon terminal bulbs. Through these bulbs and the dendrite of another cell, cells communicate with each other through electrochemical impulses. These impulses cause the dendrites to
Reinis, Stanislaw and Jerome M. Goldman. The Development of the Brain. Springfield, IL: Charles C Thomas Publishers, 1980.
Reinis, Stanislaw and Jerome M. Goldman. The Development of the Brain. Springfield, IL: Charles C Thomas Publishers, 1980.
During early childhood, there is a huge proliferation of connections between neurons, usually peaking around the age of two. The adolescent brain then cuts down the amount of connections, deciding which ones are important to keep and which can be let go. While there are various theories as to the molecular mechanisms by which pruning actually occurs, most agree that pruning is primarily carried out by a very motile form of glial cell, called microglia [1], and pre-programmed cell death (apoptosis). These microglia are thought to remove cellular debris and perform surveillance during the healing process of an injured brain, but in the healthy, developing brain they have a possibly more important function. If a synapse receives little activity, it is weakened and eventually deleted by microglia and other glial cells through a process called long-term depotentiation (LTD). After the synapse has been removed, the space and resources that it once used are taken by other synapses. These synapses are strengthened by long-term potentiation (LTP). These processes and various others take place throughout development, peaking at adolescence and reaching their base around the age of 21, and transform the brain to create more complex and efficient neuronal configurations.
Approximately 17% of people are having depression in their lifetime (Gibbons, et al., 2012). It was found that “more than 350 million people of all ages suffer from depression” (World Health Organization [WHO], 2012). It is the fourth in the rating of major public problems, and it is predicted to be illness number one in developed countries by year 2030 (Hollon and Sexton, 2012). In Scotland, the number of patients in ten years has been reduced by half, but the number of antidepressants prescribed has doubled (Stirling, 2013). According the Scottish NHS there are 420 thousand patients who are receiving depression treatment (Stirling, 2013). However this statistics might not reflect the size of the problem. According to...
The only theory of creation that teachers are allowed to teach in public schools is the theory of evolution. No other idea is considered and this is not acceptable. Many people think it is closed minded to only teach one religion, but that is a two way street. It is also closed minded to only teach evolution. Someone may argue the reason why they only teach evolution is because if they teach any religion based theory then it forces religion on people. Teaching evolution forces a different belief on religious people. We need to find a way to teach multiple theories.
Acquired immune deficiency syndrome (AIDS) is a syndrome caused by the human immunodeficiency virus, characterized by a depressed immune system and the presence of one or more opportunistic diseases. AIDS is the final stage of HIV. You cannot be born with AIDS; AIDS is a disease that must be gained. When HIV is turned into AIDS, the immune system has been increasingly damaged by the virus which puts the immune system at risk for opportunistic infections. When you have AIDS, you are still HIV positive. So if one was to engage in coitus with a person with AIDS, the HIV infection can still be transmitted (Greenberg, Bruess, and Conklin, 2011). “On average, the survival time for African-Americans with AIDS is lower than for other racial or ethnic groups.” (Johnson, K. MD, 2012)
The Human Immunodeficiency Virus (HIV) targets the immune system and weakens people 's defense systems against infections and some types of cancer. As the virus destroys and impairs the function of immune cells, infected individuals gradually become immunodeficient. Immune function is typically measured by CD4 cell count. Immunodeficiency results in increased susceptibility to a wide range of infections and diseases that people with healthy immune systems can fight off. The most advanced stage of HIV infection is Acquired Immunodeficiency Syndrome (AIDS), which can take from 2 to 15 years to develop depending on the individual. AIDS is defined by the development of certain cancers, infections, or other severe clinical manifestations.
To begin with, creationism is a great example of an ongoing religious conflict which has caused a lot of discussion. It is a lesson that all students should learn, whether in public school or private. The main concern is how teachers can teach creationism without crossing religious boundaries. Anderson addresses the importance of teaching creationism:
R. L. Paul, M. M. (1972). The Species of the Brain Research, 1-19. pp. 113-117. S. A. Clark, T. A.
As the human body goes through different experiences, the brain grows, develops, and changes according to the environmental situations it has been exposed to. Some of these factors include drugs, stress, hormones, diets, and sensory stimuli. [1] Neuroplasticity can be defined as the ability of the nervous system to respond to natural and abnormal stimuli experienced by the human body. The nervous system then reorganizes the brain’s structure and changes some of its function to theoretically repair itself by forming new neurons. [2] Neuroplasticity can occur during and in response to many different situations that occur throughout life. Some examples of these situations are learning, diseases, and going through therapy after an injury.
The place of evolution in public schools is embedded in the cultural conflicts of American politics. This debate has been the center of the "culture wars" since the Scopes trial in the 1920s and remains to be a point of contention today. A 2005 poll reports that 38% of Americans would prefer teaching creationism instead of evolution, so divide is clearly significant (Berkman 485). The issue continues to spark questions of what "common" means in the context of separation of church and state. To the extent that evolution is similar to other "morality policies," the battle has symbolic meaning for the mass public as well as strong implications for the power of science as a "social institution" (486). The trouble with the battle between secularists and creationists today is that it is often seen as a divide between religion and science. Failing to acknowledge any validity in the creationist argument reveals ignorance and further polarizes the nation. At the surface level, separation of church and state is simple enough: remove creationism entirely from public schools to avoid conflict. However, the moral implications are far deeper.
Depression is a serious and common problem that affects people of all social class and racial group throughout the world. They are good and affordable treatment for depression. Most people who have depression do not receive adequate treatment. We must do more and do better to take care of ourselves. It is not easy for any of us to tackle a problem of this magnitude, but by being responsible and taking care of our own health and mental well-being needs, we can also reach out to help others who are dealing with depression or other mental issues by sharing with them information’s and pointing them in the right direction to find the help they need.
Harvard Dictionary of Music [Book] / auth. Apel Willi. - Cambridge : Harvard University Press, 1969.