Tuesday 10 February 2009

Plasticity in the Adulthood and the Elderly

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Plasticity in the Adulthood and the Elderly

Contrary to the once-popular assertion that the brain loses 100 000 neurons every day (or more if accompanied by smoking and drinking), new technologies have shown that there is no age dependence if one counts the total number of neurons in each area of the cerebral cortex (Terry, DeTeresa and Hansen, 1987). Age-dependence only applies to the number of “large” neurons in the cerebral cortex. These large neurons decline with the consequence of increasing the number of small neurons, so that the aggregate number remains the same.

There is some decrease in neuronal circuitry as neurons get smaller, however, and the numbers of synapses are reduced. While reduced connectivity corresponds with reduced plasticity, it does not imply reduced cognitive ability. On the contrary, skill acquisition results from pruning some connections while reinforcing others. So, people continue learning throughout life.

Do older adults learn in the same way as the young? There is considerable evidence showing that older adults show less specificity or differentiation in brain recruitment while performing an array of cognitive tasks (Park et al., 2001).

A Positron Emission Tomography (PET) activation study was carried out during the word-fluency tasks. Among the young subjects, the left anterior temporal lobe and frontal lobe were activated during the retrieval of proper names. During the retrieval of animate and inanimate names, and syllable fluency, the left infero-posterior temporal lobe and left inferior frontal lobe (i.e., Broca’s area, see Figure 2.3) were activated. By contrast, the activated areas among the elderly subjects were found to be generally smaller or sometimes inactive, though certain areas which were not active among the young subjects were active among the elderly (Tatsumi, 2001).

It is premature to base conclusions on these findings which need further investigation. One interpretation of these activation patterns is that other brain areas are brought into play among the older adults in an effort to compensate for deficient word retrieval. Alternatively and in favour of the vitality of the ageing brain, fluency or experience with a task necessarily reduces activity levels so that with higher processing efficiency, these tasks can also be shuttled to different areas of the brain for processing.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 49

2 comments:

  1. I am presently researching different models for establishing an ELDER COLLEGE at my college...i want it set up so that they are learning NEW and DIFFERENT things than they learned before...in order to keep the brain plastic...any advice???

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  2. Sorry for the date of the answer. I was really hectic.

    I am not a teacher, but I think teaching is an art.

    First one important concept: the brain has a highly robust and well-developed capacity to change in response to environmental demands, a process called plasticity.

    So if you teach something you increase or keep the plasticity. The message is “use it or lose it”.

    If you want it set up so that they are learning NEW and DIFFERENT thing, you have take exams, previous a posterior to the course.

    Remember one exam is a photo, that is mean you evaluate the performance in determinate moment. Another important idea is: if you take the same exam very far to the course, the performance will change (Normally)

    Finally you have to remember that much remains to be understood, however, about the interaction between increasing knowledge and declining executive function and memory across the lifespan so that further research is needed in this area.

    Be good, and if you can't be good, be careful.

    Hegel

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