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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.

http://dx.doi.org/10.1016/j.eurpsy.2016.01.223

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.

http://dx.doi.org/10.1016/j.eurpsy.2016.01.224

EW107

Computational modeling of

reinforcement learning using

probabilistic selection task and

instructional probabilistic selection

task

D. Frydecka

1 ,

, J. Drapala

2

, E. Kłosi ´nska

3

, M. Krefft

3

, B. Misiak

4

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.

http://dx.doi.org/10.1016/j.eurpsy.2016.01.225

EW108

Risk associated to subtypes of seizure

disorders in dementia patients

M. Habeych

1 ,

, R.C. Castilla-Puentes

2

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