Transcript Making Memories: Brain Activity that Predicts How Well

M AKING M EMORIES : B RAIN
A CTIVITY THAT P REDICTS H OW
W ELL V ISUAL E XPERIENCE W ILL
B E R EMEMBERED
James B. Brewer, Zuo Zhao, John E. Desmond,
Gary H. Glover, John D. E. Gabrieli
Presented by: David Wu
B ACKGROUND I NFORMATION

Most important regions for declarative memory:
parahippocampal cortex and some regions of frontal
cortex
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Traditionally fMRI studies used block designs with novel
versus repeated scenes to determine which brain areas
encode declarative memory
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Confounds: could be a response to novelty and not
encoding, or could reflect habituation, reduced
attention or strategic differences because activation is
averaged over long predictable blocks
This study attempts to resolve these confound by using a
event-related design, where separate activations are
recorded for each stimulus
D ESIGN

6 right-handed subjects (3F, 3M, aged 22-32)
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4 fMRI scans consisting of 24 pictures of
indoor and outdoor scenes
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30 minutes later, given an unexpected
memory test which consisted of all the
previously seen pictures and 32 new pictures
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Judge whether each picture was clearly
remembered, familiar, or forgotten
R ESULTS

7 regions where activity level predicted
whether pictures would be remembered,
familiar or forgotten
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1 was in the right inferior frontal sulcal
region of the dorsolateral prefrontal cortex
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6 were in bilateral parahippocampal cortex
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Activations greater for remembered
compared with familiar (t(5)=3.55, P<0.05)

And for familiar than forgotten (t(5)=4.56,
P<0.01)
R ESULTS
Displays voxels
with significant
positive
Right dorsolateral
prefrontal cortex
(upper right slice 1)
correlations
between eventrelated activations
to pictures and
subsequent
memory for those
pictures.
Bilateral
parahippocampal
cortex (all other
regions)
R ESULTS
Examples of average
signal intensity in each
region
Graph D shows mean
voxel response in
parahippocampal areas
showing significant
correlation with
subsequent memory in
each subject
D ISCUSSION

The activated prefrontal area is related to
spatial working memory tasks

Memory for scenes determined by spatial
working memory processes in the right
prefrontal area, and long-term memory
processes in the bilateral parahippocampal
areas

Has been proposed two regions constitute a
neural circuit that mediates the formation of
spatial long-term memories
M Y O PINION


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Strengths:

Simple and effective design that produced
unambiguous results
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Concise paper that was very easy to read
Limitations

Did not image the entire brain, there could
be other activation areas that were not
found

Small sample size
Future Direction: Do different areas predict how
well you will remember words, objects or faces?
B IBLIOGRAPHY

Brewer J. B., Zhao Z., Desmond J. E., Glover G. H.,
Gabrieli J. D. E. (1998). Making Memories: Brain
Activity that Predicts How Well Visual Experience Will
Be Remembered. Science, 281(5380): 1185-1187