European Psychiatry - Volume 33 - March 2016

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S152 24th European Congress of Psychiatry / European Psychiatry 33S (2016) S116–S348
4 Hackensack University Medical Center, Psychiatry and Behavioral
Medicine, Hackensack, NJ, USA
∗ Corresponding author.
Introduction Previous transcranial magnetic stimulation (TMS)
studies indicate that exposing the subjects to an emotionally valent
stimulus results in larger motor evoked potentials (MEP). Up to
date, no TMS studies have been conducted in order to investigate
the effect of personal memories with emotional value on corti-
cospinal excitability.
Objects To investigate changes in corticospinal excitability and
sensorimotor integration induced by retrieval of negative or neutral
autobiographical memories (AM).
Aims To contribute to a further characterization of neural circuits
involved during the evocation of negative AM.
Methods In 12 healthy volunteers, we recorded motor evoked
potentials (MEPs) elicited by TMS pulses during the retrieval of
negative AM or neutral AM. Furthermore, we also tested Short-
interval Intracortical Inhibition (SICI), Intracortical facilitation (ICF),
Short and Long afferent Inhibition (SAI and LAI) in the two different
experimental conditions.
Results Retrieval of negative AM induced a larger increase in
MEP amplitude (35.01%) compared to neutral AM (F(1,22) = 7.04,
P = 0.013). Furthermore we showed that retrieval of Negative AM
increasedn ICF (F(1,22) = 5, P = 0.03) and decrease SAI (F(1,22) = 7.04,
P = 0.039). The other TMS parameters were different between con-
ditions.
Conclusions Our results indicate that evocation of negative AM
induce a complex modulation of excitatory and inhibitory sensor-
imotor networks. Further studies are needed to explore the link of
these electrophysiological biomarkers with the strength, valence
and specificity of negative AM.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW106
Differential effects of APOE genotypes
on intrinsic functional connectivity of
the entorhinal cortex associated with
episodic memory in amnestic mild
cognitive impairment
J. Chen ∗, H. Shu , Z. Wang , D. Liu , Z. Zhang
Southeast University, Department of Neurology, Affiliated ZhongDa
Hospital, School of Medicine, Nanjing, China
∗ Corresponding author.
Background The apolipoprotein E (APOE) gene is a well-
established genetic susceptibility factor for the conversion from
amnestic mild cognitive impairment (aMCI) to Alzheimer’s disease
(AD). Moreover, entorhinal cortex (ERC) is one of the earliest brain
regions of AD pathology that disrupts the formation of episodic
memory. The present study was the first to investigate whether
there are differential effects of APOE polymorphism on functional
connectivity (FC) of ERC and cognition in aMCI.
Methods The FC analyses of ERC in whole-brain were performed
in 83 aMCI and 88 healthy controls (HC).
Results In the ERC network, aMCI with APOE epsilon 4 ( 4)-
carriers showed decreased FC with the bilateral middle temporal
gyrus (MTG) and the right precuneus (PCUN), and the right pre-
central gyrus (PreCG), while APOE 2-carriers showed increased
FC (except decreased FC with the right PreCG) compared to HC.
The altered FC between ERC and right MTG correlated with the
impairment of episodic memory in aMCI carried APOE 4 and 2
allele.
Conclusions These results provide novel evidence that APOE
4 and 2 alleles affect multiple physiopathologic pathways in
the ERC network, which aMCI with 4-carriers can accelerate
the pathological progression of network-based mechanisms while
2-carriers may play a protective role in contributing to a com-
pensatory mechanism. It further suggests that APOE can appear to
indirectly mediate the ERC-MTG neural pathway associated with
the impairment of episodic memory in aMCI.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW107
Computational modeling of
reinforcement learning using
probabilistic selection task and
instructional probabilistic selection
task
D. Frydecka ∗, J. Drapala , E. Kłosi ´nska , M. Krefft , B. Misiak
1 Wrocław, Poland
2 Wroclaw University of Technology, Institute of Computer Science,
Wrocław, Poland
3 Wroclaw Medical University, Department of Psychiatry, Wrocław,
Poland
4 Wroclaw Medical University, Department of Genetics, Wrocław,
Poland
∗ Corresponding author.
Introduction Humans learn how to behave both through rules
and instructions as well as through environmental experiences. It
has been shown that instructions can powerfully control people’s
choices, often leading to a confirmation bias.
Aim To compare learning parameters in reinforcement learning
task with and without instructions.
Methods We recruited 52 healthy adult control subjects
(21 males, 31 females, age 30 ± 6.5 years). Participants com-
pleted Repeatable Battery of Neuropsychological Status (RBANSS).
Twenty-seven participants completed additionally Probabilistic
Selection Task (PST) while twenty-five participants completed
Instructional Probabilistic Selection Task (IPST). To analyze learning
parameters, we used Q-learning model with 3 parameters: learn-
ing rate due to positive and negative reinforcements as well as
exploration-exploitation parameter.
Results Both groups did not differ with respect to cognitive func-
tioning measured with RBANSS (immediate and delayed memory,
visuospatial abilities, language and attention); however, partic-
ipants who completed PST had trend-level statistically faster
learning rates due to positive (P = 0.099) and negative reinforce-
ments (0.057) in comparison to participants who completed IPST.
Both groups did not differ with respect to exploration-exploitation
parameter (0.409).
Conclusion In healthy adults, interference of confirmation bias
can influence learning speed independent of cognitive functioning
(immediate and delayed memory, visuospatial abilities, language
and attention).
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
EW108
Risk associated to subtypes of seizure
disorders in dementia patients
M. Habeych ∗, R.C. Castilla-Puentes
1 Center for Clinical Neurophysiology, Neurological Surgery,
Pittsburgh, USA
2 Johnson and Johnson, Global Medical Safety, West Chester, PA, USA
∗ Corresponding author.
Introduction Seizure disorders have been identified in patients
suffering from different types of dementia. However, the risks