Different Brain Areas and Memory Function
closely tied to Intelligence, since information encoding and
be one of the key features of Intelligence. Changes
in the way the brain processes information
have been noticed by
researchers. One of the areas of
interest is the prefrontal cortex.
in brain activity have been observed in many MRI studies involving
age groups. The areas with the most
notable differences are all within the prefrontal cortex.
A study conducted by Rypma et al. (2001) used
the functional magnetic resonance imaging technique to observe brain
when participants were given a variety of tasks designed to tax working
at different levels.
aspects of the memory system seems to be affected differentially by
aging. The phonological loop seems not to
affected by the process of aging. This
is evidenced by the fact that digit span is constant across all age
groups. Elderly adults do not lose much
capacity in verbal memory. The central
executive is impaired at a greater level than the two slave systems in
changes in brain activity observed by Rypma et al.
(2001) are believed to be compensatory
mechanisms by the brains of the elderly fashioned to counteract the
reduced activity in other regions.
the problems with research of this type is that age-related changes in
activation of brain regions do not always equate to different levels of
performance between young and old participants. This
is why researchers such as Cabeza et al (1997)
have put forth the
idea that increased activation in prefrontal cortical regions during
retrieval may be a result of functional compensation.
et al (2001) study examined the ventrolateral prefrontal cortex, the
dorsolateral prefrontal cortex, and the rostrolateral prefrontal cortex
prime potential prefrontal cortical regions for differential activation. When the high cognitive load of this study
was imposed, a shift in brain region activity was observed. The older adults showed an increased
activation of their rostrolateral prefrontal cortex when compared to
younger adults. The younger adults,
had more activation in the dorsolateral prefrontal cortex.
Parts of the
prefrontal cortex are
thought to be crucial parts of the phonological loop.
Specifically, BA 44, 45, and 47 are thought
to be involved. These three regions were
found to be activated at identical levels in young and old participants.
thought to be involved with
the maintenance and manipulation of stored semantic information. It is significantly more active in younger
participants. It is believed to therefore
be involved especially with the maintenance and manipulation of
information. The fact that older
participants performed as well as younger ones hints at the idea that
older participants employ more mnemonic processes (a central executive
to compensate for the reduction in more automatic supracapacity
This area, BA
found to be more active in
the older participants. The precise
function of this brain region is as yet unclear. It
could be that it represents a compensatory
Working Memory process. It could also be
that it is involved in the storage of emotional states during semantic
encoding. Activation of this BA has been
found during the viewing of emotional stimuli (Lane et al. 1997, and
et al. 1997)
change observed in older adults with normal memory capability is
thought to be
related to a redistribution of task load. "Cognitive
Load" is the
amount of mental processes active at a time. A
high cognitive load signifies that too many mental
processes are going
on at once. Too much "cognitive
load" on a person will inhibit their abilities at various concentration
and memory tasks, and generally impede any sort of mental process. Older adults may be using slightly different
mechanisms for encoding of memory than younger adults.