Cognitive Variances In The Aging Brain

As a human get older, many of the organs will deteriorate and lost the functions. Out of all of the organs, our brains are extremely vulnerable to the process of aging. In the article of “Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice”, the researchers leaded by Saul Villeda in University of California, San Francisco, focus on the study of physical and functional property of the hippocampus in mice. Hippocampus manages the learning and memory process. However, it is extremely sensitive to aging and shows many down regulations as the brain ages. The study had also revealed the important role of Creb, which maintain hippocampus properly functional and healthy. Two different assays were used to study the role of Creb in the cognitive function and synaptic plasticity which includes testing hippocampus-related memorizing and learning processes and measuring the dendritic spine number and synaptic plasticity.

The prefrontal cortex, which is the anterior part of the frontal lobes, controls understanding consequences, impulse control, abstract thinking, long range planning, and mental flexibility (Ortiz 93-94). Researchers at UCLA, Harvard Medical School, and the National Institute of Health have been working together to understand brain development. Their research has shown that at a young age the brain overproduces gray matter, which is the overall thinking part of the brain. After this comes the pruning process in which gray matter is removed. Paul Thompson from UCLA describes this time as a "massive loss of brain tissue" (as quoted in Ortiz 94). The average amount of tissue lost per year is one to two percent (Ortiz 94). While this pruning process is taking place the myelination is occurring simultaneously. Myelination is when white matter, what insulates the brain, makes brain process more efficient. This process is also thought to shape brains neural connections for adulthood (Ortiz 95). With age, the brain becomes denser and more organized which makes it better at processing and understanding information. Changes in the brain also can happen late into the twenty's (Beckman 3). A member of the UCLA research team reported that "[The] frontal lobe undergoes the most change during adolescence-by far. It is also the last part of the brain development" (as quoted in Ortiz 94). For most, full brain development is reached during the ages

As we age, our brain and nervous system go through natural changes. An aging adult may experience memory loss, decreased touch sensation, change in the perception of pain, change in sleep pattern, decreased coordination and increased risk for infection (Ignatavicius, 2013, p. 912) .

Alzheimer’s disease is the progressive loss of memory and mental functions. The disease affects memory, thought control, language, and other cognitive functions. The disease typically appears with old age and is often found age 60. Alzheimer’s causes the brain to develop clumps and tangles fibers in the brain tissue along with the loss of neuron connections. Throughout the brain, proteins are abnormally distributed and they form tangled bundles of fibers and amyloid plaques. Some neurons fail to function properly and lose their connections, which are necessary for the transmission of messages to the body. The hippocampus is the key brain structure in the formation of memories and often experiences the first signs of damage.

There are people who think that older adults are not capable of learning new information because of the number of neurons in their brain decline as they age. In the PBS video “Stealing Time”, the old cage potato rats were given a change of scene with an enriched environment and the results were that their dendrites grew and made new synaptic connections where there were none before. These rats were better on future tasks than the old rats that were not given a change of scene. When older adults are doing a task in a laboratory setting they are less efficient at processing the information presented to them and their reaction time is slower. “Older adults show more brain activity between the prefrontal cortex and the medial temporal lobe than

The brain is made up of neurons. The features that make up the neurons are dendrites which receive signals from other neurons. Another part of the neuron is the axon which holds microfibers that carry information inside the neuron from the detricals to the endpoints of the neurons called terminal branches. The neurons in the brain communicate with one another through neurotransmitters that release chemicals.

What are people willing to do to maintain a healthy mind and body? A former emperor of china, Qin Shi Huang, killed himself trying to live forever by consuming age-stopping mercury pills. In the 1400's Pope Innocent VIII believed by transfusing three young boys blood into himself he would absorb their youth, he died in the process. In the 1800's Leonard Jones ran for president with the promise to achieve immortality, he believed this would be accomplished through prayer and fasting, later that year pneumonia led to his death.

Age-related declines are not constant across brain regions. Moreover, patterns of brain aging differs among individuals. Post mortem (PM) studies cannot help in assessment of brain tissue and its components. Moreover, PM cannot provide information on dynamic process of adult brain development, and its connection with brain structure and function. MRI helps in in-vivo measurements of the brain. It was realized that there is cortical thinning as age progresses. . Some studies of cortical thickness failed to replicate stability of the primary sensory regions (e.g., calcarine cortex) (Fjell et al., 2009; Salat et al., 2004) while others found that cortical thinning in frontal and parietal lobes exceed that of the temporal and occipital regions (Thambisetty et al., 2010). It is suggested that myelin is related to shrinkage in cerebral cortex or responsible for loss of cortical volume. MRI has helped evaluate leukoaraiosis which is a change in white matter integrity that is displayed on a T2-weighted MR image as a high signal intensity area. This area is defined as white matter hyperintensities (WMH) which depicts pathological processes such as ischemic lesions, gliosis, axonal degeneration, loss of myelin, microinfarcts, and expansion of perivascular spaces (de Leeuw et al., 2001; Pantoni, 1998). WHM is observed around the borders of the ventricles and deep in the subcortical WM regions. WHM is not present in health adults until the age of 50-55 (Hopkins et al., 2006). Further,

It is full of comprehensive and engaging style; well reference and scientifically proven, summarizes the current revolution in neuroscience and neuroplasticity, and closes the gap that the old age or matured brain, which is unchangeable is changeable and malleable (plastic); extending it functions from one region to the other. Doidge engaging style of writing, scientific proves, and academic tone help to make the book persuasive.

Alzheimer's disease (AD) is the most common type of dementia, and accounts for more than half of the dementia cases. The disease was named after German psychiatrist and neuropathologist Alois Alzheimer in 1906. Increased levels of protein inside and outside the brain’s nervous cells make it hard to stay healthy, causing them to deteriorate and eventually die. The brain region called the hippocampus is the center of learning and memory in the brain, and the cells in this region are often the first to be damaged. Eventually, the size of the hippocampus will become smaller from lack of cell growth. An MRI

There are also cognitive changes during middle adulthood. There is a mixed pattern of positive and negative changes in cognitive abilities. Processing speed starts to decrease during this time period however crystallized thought does not decline until older age (pg. 456). Working memory begins to decline however semantic memory continues to increase as we learning throughout our older years (ph 456). Usually most memory decline is during older age and can be attributed to Alzheimer’s disease of dementia.

Cognitive aging is commonly labeled strictly as memory and only found in “some people”. However, this is not true. The knowledge of cognitive aging has grown immensely, but there is still much to be learned. The surface has only been scratched with many more questions to be answered. Cognitive aging is worthy of study and effects everyone, but there is also much more is still to be learned.

Craft, J Gordon, C 2011, ‘Alterations in neurological function across the life span’, in J Craft, C Gordon, A Tiziani (eds), Understanding pathophysiology, Elsevier Mosby, Chatswood, NSW, pp. 188-226.

Why does the human brain age? Brain aging is a part of human life and a big part of society as the awareness for brain aging increases. Over time memory tends to become less efficient as we age and the neurons in the brain decreases (Bendheim, P.E. (2009). By 2050 in the US, 20 percent of the population will be 65 years or older. And as the elderly population increases, so will the incidence of age-related neurological disorders (Perlmutter, David. (2004). Therefor it is important to understand the aging brain, and how to keep the brain functioning as one ages.

It is clear to neurobiologists that aging results in a decrease in brain size as well as a decrease in the efficiency of brain functions. It has been a widely held belief that aging causes neurons to die and for the overall number of neurons to decrease as one reaches old age. Studies