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#P184
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
Speaking of Smells: The Relationship Between Describing
Odors and Memory Recognition
Nicole K Beers, Amy E Callahan, David E Hornung
Biology Dept. St. Lawrence University Canton, NY, USA
Since the phenomenon of “verbal overshadowing” suggested
verbalizing a perceptual experience may interfere with the ability to
accurately recall a memory, the present study examined the effect
describing an odor at the time of encoding had on olfactory
memory. To examine the relationship between odorant description
and memory, during the training phrase, 39 subjects were placed
into one of three groups and exposed to 8 target odorants from a 20
odorant “Sniffin Sticks” set. In Group 1 subjects verbalized a self-
generated description of each odor, in Group 2 subjects circled a
description of each odor from 4 alternatives appropriate for that
particular odorant, and in Group 3 subjects smelled each odor
without providing any verbal description. After participating in an
unrelated task for 15 minutes, subjects were presented the entire
20 odorants (12 distracters), one at a time, and asked if they
remembered smelling that particular odorant during the training
phase. After the completion of this phase of the experiment,
subjects were again presented the 20 odorants and asked to name
each one. Finally, the odorants were presented a third time and
subjects were asked to choose the correct name from an odorant
list. Subjects in Group 2 had significantly less recognition ability
as compared to Groups 1 and 3 (75% versus 88% correct).
However subjects in Group 2 also had many fewer (17% versus
34%) false positives - incorrectly identifying that a distracter was in
the target set. Apparently having subjects pick an odorant
description made it more difficult to remember target odorants but
also produced fewer false memories whereas self-generating a
verbal description of an odorant or simply trying to remember the
odorant odors produced a “better” olfactory memory but also
produced more false positives. Acknowledgements: The
St. Lawrence University Fellows Program and the Biology
Department provided some of the funding for this work.
#P185
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
Differences in olfactory event-related potentials (OERPs)
among apolipoprotein ε4 positive and negative individuals
in an odor memory retrieval task
Melissa R Cervantez
1
, Lisa V Graves
1
, Amanda J Green
2
,
Charlie D Morgan
1
, Claire Murphy
1,2
1
San Diego State University San Diego, CA, USA,
2
University of California, San Diego La Jolla, CA, USA
The current study investigated olfactory event-related potentials
(OERPs) among healthy and individuals at risk for Alzheimer’s
disease (AD) as they completed an odor memory task. At risk
individuals were determined by genotyping, using the strongest
genetic risk factor associated with AD, the ε4 allele of
apolipoprotein E (ApoE ε4). OERPs were recorded from the FZ, PZ,
and CZ midline scalp electrode sites in 60 participants among
3 different age groups: young (10 F, 10 M, mean= 21.35 years),
middle (10 F, 10 M, mean= 50.35 years), and old (10 F, 10 M,
mean= 68.95 years). Each age group contained an equal number of
ApoE ε4+ and ApoE ε4- subjects. The odors were presented for 200
msec with an inter stimulus interval of 30 secs by a computer-
controlled olfactometer. Subjects were instructed that they were
performing a memory task and completed three sessions: session 1
was an exposure trial for encoding, session 2 was a retrieval trial
using odors, and session 3 was a retrieval trial using odor labels. We
focused here on the retrieval trial using odors for recognition. The
odor retrieval trial produced OERPs for the following response
types: hits, misses, correct rejections, and false positives. The results
indicated a significant interaction between response type, electrode
site, and ApoE status in N2 latency (p<.05). The N2 latencies were
significantly longer in ApoE ε4+ subjects for hits, misses, and false
positives than ApoE ε4- subjects, across all electrode sites. There
was also a significant N1 amplitude effect with response type
(p<.05). Correct rejections and false positives both had significantly
higher amplitudes than misses. The results indicate that OERPs
during memory retrieval with odors have the potential to
differentiate between ApoE ε4 positive and negative individuals.
Acknowledgements: Supported by NIH grant # DC00262-14 from
the National Institute on Deafness and Other Communication
Disorders. We thank Paul Gilbert for his statistical expertise and
Jessica Bartholow, Roberto Zamora, Ariana Stickel, Derek Snyder,
Kyle Sigel, Jean-Loup Bitterlin, Kristina Constant, and Sanae
Okuzawa for helping with data collection, entry and analysis.
#P186
POSTER SESSION V:
TRIGEMINAL SYSTEM; BEHAVIOR
AND PSYCHOPHYSICS; ODORANT
RECEPTORS & OLFACTION PERIPHERY
Relationships between Confidence Accuracy and Odor
Familiarity: The Effect of Apolipoprotein-E Status
Jacquelyn F. Szajer, Claire Murphy
San Diego State University San Diego, CA, USA
Metamemory, or the ability to monitor, judge, and control our
memories, is an important aspect of cognition because it helps to
determine cognitive and behavioral self-regulation involved in
overall judgment and decision-making (Marquie & Huet, 2000).
Deficits in metamemory abilities have been found to accompany
both healthy aging and Alzheimer’s disease (AD), and various
models link related phenomena, such as high-confidence false
recognition, to declines in executive functioning associated with
normal aging and AD (Cosentino, 2007). Many studies have linked
the accuracy of metamemory judgments to levels of familiarity
(Chua et al., 2009), however, few studies have examined this
relationship in aging populations. Accordingly, the main goal of the
current study was to examine the relationship between familiarity
and confidence accuracy in healthy aging individuals compared to
those with AD. Data were included from 158 patients diagnosed
with possible or probable AD, and were compared with data from
138 non-demented elderly controls (
n
= 296). Since prior research
suggests that memory-based olfactory tests are equally, if not more
sensitive than more semantic, visual tasks when examining
cognitive decline in normally aging individuals and those with AD,
in particular (Murphy et al., 1999), recognition memory was
assessed using a signal-detection based olfactory recognition
memory task. Univariate analyses revealed a significant interaction
between Apo-E status and familiarity levels for those in the AD
group,
F
(5,158) = 2.8, p <.05, but not for the control group. This
interaction accounted for approximately 15% of the variance in
confidence accuracy for those diagnosed with AD. Applications and
implications are discussed. Acknowledgements: Supported by NIH
grant # AG04085 from the National Institute of Aging to CM.
Abstracts | 89
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