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A critical evaluation
of the use of fMRI in the advancement of our understanding of the structure of
memory.

 

           

INTRO

Memory has been a principal
concern of the field of cognitive psychology since its inception, it is often
thought of as a library from which one can retrieve information as taking out a
book, however the nature of memory is much more elusive, it is often describe
as a memory trace, a mental representation of a previous experience, neuroscientists
presume that this memory trace would correspond to a physical change in the
brain, involving synapses. In order to understand how memories are formed,
stored and retrieved, several models have been theorised. Cognitive
psychologists have used many tools and techniques in their endeavor to
investigate the structure of memory. Since its invention in the early1990s, functional
magnetic resonance imaging (fMRI) has become a very popular tool of
neuroscience research (Poldrack, 2008), including in the investigation of the
cognitive processes of memory. This essay will endeavor to critically evaluate
the various theories of memory structure through the findings of fMRI. The
essay will investigate the multi-store model, the unitary store model, and the
working memory model, the use of fMRI and its limits. BLABLABLA

 

FMRI

Before exploring the
advancement of the understanding of memory structure enabled by the use of
fMRI, let’s briefly address what is an fMRI, what information it can provide
and what are its limits. Functional magnetic resonance imaging produces a
dynamic three-dimensional image of the brain, and infers brain activity by
measuring the amount of blood, and the levels of its constituents: glucose,
iron, and oxygen that flow to the different regions of the brain as they become
active. It has several advantages in that it is very precise, the dense
blood-vessel supply to the cerebral cortex allow for a spatial resolution of 1 millimeters,
however because changes in the blood flow takes about one third of a second to
become visible, fMRI’s temporal precision is not as precise as that of other
neuroscience techniques (Glover, 2011). FMRI

 

What we know thanks to fMRI
about the link between regions of the brain and memory

 

A distinction was made early
on in psychology between short-term memory (STM) and long-term memory (LTM),
since William James in 1980 in fact (Derek Evan Nee, Marc G. Berman, Katherine
Sledge Moore, & John Jonides, 2008). The first one is of short
duration, a few seconds, and of limited capacity, a few items, whereas the
second one has a duration of up to several decades, and surprisingly an unlimited
retention capacity.  This distinction was
central in the development of the multi-store model of memory structure which
was pioneered by Atkinson and Shriffin (1968), who described it as composed of
three stores, the sensory store which is modality specific and holds
information briefly, a short-term store that is of limited capacity, and a
long-term store that has an unlimited capacity.  This approach has  (Atkinson & Shiffrin, 1968)  Abundant behavioral research has gathered evidence
in favour of the distinction between STM store and a LTM store,  and the serial effect is one of strongest
evidence for the multistore model.  It
showed that items recalled from a list, were remembered differently depending
on their placement in the list, items low on the list were retrieved from STM and
subjected to rapid decay and phonological interferences, whereas item recalled
from high on the list were retrieved from LTM and subject to semantic
interferences. In a 2005 neuroimaging study on the serial position curve , used
fMRI to investigate the difference in retrieval from STM and LTM in healthy
adults it posited that if different items are indeed retrieved from different
stores depending on their placement on the list then different regions should
be activated for retrieval of early and late items. The study focused on the
region of the brain most commonly associated with LTM, the hippocampal memory
system in the medial temporal lobe (MLL), which should be activated from
retrieving early probles.  The findings
confirmed the dual-store theory, as the fMRI revealed that the MLL was
activated during the retrieval of late probes, and regions associated with STM,
including the frontal and parietal cortices, were activated during the
retrieval of both late and early probes (Deborah Talmi, Cheryl L. Grady,
Yonatan Goshen-Gottstein, & Morris Moscovitch, 2005). CRITIC

 

WORKING MEMORY

 

 

The limits of fMRI and
neuroscience and the continued use of other techniques for the investigation of
memory.

 

 

CONCLUSION

 

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