Transcript Recognition Memory amongst Individuals

Recognition memory amongst individuals varying in the
personality dimensions of Reward Seeking and Impulsivity
Chase Kluemper1, Chelsea Black1, Yang Jiang1, Jane E. Joseph2, & Thomas H. Kelly1, 3
Departments of Behavioral Science1, Anatomy & Neurobiology2, and Psychology3
University of Kentucky, Lexington, KY
TIME (ms)
Introduction
-100
3
0
100
200
300
500
600
700
800
900
Reward Seeking x
Electrode interaction,
greatest at FPZ
(P<0.001)
2
-100
10
Electrode FPZ
New Stimuli
8
1
ACTIVATION (uV)
Sensation Seeking is a personality trait that is associated with the
initiation, escalation and development of problems associated with drug
use. The efficacy of prevention interventions targeting high sensation
seekers are enhanced by presenting persuasive messages in unfamiliar
and unexpected high sensation value contexts. Previous research by our
group has established sensation seeking group differences at the N200
component of the ERP waveform during Old/New recognition memory
task performance, reflecting individual differences in automatic stimulus
novelty and orienting processes. The purpose of this study was to
examine the role of impulsivity and reward seeking dimensions of
sensation seeking in response to novelty.
400
Results
TIME (ms)
0
100
200
300
400
500
600
700
800
900
Impulsivity x
Electrode
interaction,
greatest at PZ
(P=0.06)
Electrode PZ
New Stimuli
6
0
Low RS /
Low Imp
4
Impulsive
Reward
Seeking x
Impulsivity
x Stimulus
interaction
(P=0.002)
greatest for
New items
2
-3
High RS /
High Imp
-4
-5
0
Reward
Seeking
High RS /
High Imp
N200
Peak
FN400
Peak
LPC Latency
P100
Latency
N200
Latency
LPC Latency
Participants:
Study Phase:
High RS / Low Imp,
N=21, 10 Males
High RS / High Imp,
N=21, 10 Males
-100
3
Low RS / High Imp,
N=20, 10 Males
200
300
400
500
1
0
600
700
800
-100
10
900
Electrode FPZ
Old Stimuli
8
6
Low RS /
Low Imp
-1
0
100
200
300
400
500
600
700
800
900
Electrode PZ
Old Stimuli
Reward Seeking x
Impulsivity x
Electrode
interaction,
greatest at PZ
(P=0.05)
Low RS /
Low Imp
Impulsive
4
Impulsive
Reward
Seeking
-2
Reward
Seeking
Reward Seeking
x Impulsivity
interaction,
greatest at FPZ
(P=0.07)
-4
-5
Low
100
Reward
Seeking x
Impulsivity x
Electrode
interaction,
greatest at
FPZ
(P<0.001)
-3
Low RS / Low Imp,
N=19, 8 Males
0
2
ACTIVATION (uV)
Reward Seeking (RS)
Low
High
-81 healthy 18-30 yr-olds
-Right-handed, English-speaking, and not regular drug users
-Each subject was categorized on Reward Seeking and Impulsivity using
uncorrelated impulsivity and sensation-seeking items from the impulsive
sensation-seeking scale of the Zuckerman-Kuhlman Personality
Questionnaire (median split into 4 groups):
High RS /
High Imp
2
High RS /
High Imp
0
-2
Task Design:
Each subject studied a randomized set of 100 computer-displayed black
and white line drawings for five seconds per drawing. The same study
stimuli were then displayed for a second time, at random, also for five
seconds apiece. Subjects were told to remember each drawing by relating
it to themselves or a personal memory. Retention of old stimuli was tested
by a 20-stimulus practice task, and all subjects achieved a retention rate
of >90% before beginning the task.
STUDY PHASE (100 OBJECTS):
Electrode Location:

FPZ
TEST PHASE (140 OBJECTS):
Test phase:
Subjects were presented with studied (70) and unstudied (70) stimuli, old
and new respectively, presented in random order and were instructed to
discriminate between the two by pressing one of two buttons as quickly
as possible upon stimulus presentation.
Recordings:
- 64 channel EEG (Neuroscan Synamp 2, event-related potentials, 0.05 –
40 Hz band pass)
Axial
PZ
OLD
NEW
OLD
OLD
NEW
NEW
OLD
OLD
93%
92%
High RS / Low Imp
669 + 2.44
95%
High RS / High Imp
669 + 2.43
93%
NEW
UNIVERSITY
OF KENTUCKY
* Mean + SE
-P100 Latency: Impulsivity x Electrode interaction (P=0.06). Impulsivity
group differences were greatest at posterior sites, with maximum effect at
Electrode PZ.
-N200 Peak Value: Reward Seeking x Impulsivity x Electrode interaction
(P=0.07). Differences were significant at electrode FPZ only.
-N200 Latency: Reward Seeking x Impulsivity x Electrode interaction
(P=0.05). Latency differences were observed at posterior electrodes, and
maximum effect was seen at PZ.
-FN400 Peak Value: Reward Seeking x Electrode interaction (P=0.001).
Group differences in Reward Seeking occurred only at the FPZ site.
-Late Positive Component (LPC) Peak Value: A Main effect of stimulus was
shown by all four groups, a hallmark of the Old/New task ERP waveform.
-Late Positive Component (LPC) Latency: Reward Seeking x Impulsivity x
Stimulus interaction (P=0.002). Greatest differences were observed for New
stimuli. This analysis also uncovered a Reward Seeking x Impulsivity x
Electrode interaction (P<0.0001). This interaction was most prevalent
among frontal electrodes, and maximum effect was seen at FPZ.
Conclusions
High
Impulsivity (Imp)
Low RS / High Imp
664 + 2.45
673 + 2.44
EEG Data:
-2
Methods
Accuracy
Impulsive
-2
Reward
Seeking
Reaction Time (ms)*
Low RS / Low Imp
Low RS /
Low Imp
-1
Behavioral Data:
NEW
Saggital
The personality dimensions of reward seeking and impulsivity are
associated with individual differences in automatic stimulus novelty and
orienting processing. Task performance (reaction time, accuracy) was
comparable across groups. The Impulsivity x Electrode interaction
observed at the P100 component may represent visual attention
differences across groups, since the maximum effect was observed at
electrodes in proximity to ocular processing. The N200 component, which
has been implicated in novelty processing, is influenced by Reward
Seeking and Impulsivity. FN400, associated with familiarity, was influenced
by Reward Seeking status, only. These results suggest that the influence of
the sensation-seeking sub-dimensions of Reward Seeking and Impulsivity
may vary as a function of novelty- and familiarity-processing. The expected
old/new task stimulus effect, observed in the LPC component associated
with memory and contextual processing, was influenced by both Reward
Seeking and Impulsivity. An understanding of the neurophysiologic basis
of information processing in individuals at risk for drug abuse may help
target appropriate prevention strategies.
This project is supported by NIDA grant P50 05312-15 to the Center for Drug and
Alcohol Research Translation at the University of Kentucky