Freeze-Fight-Flight mechanisms in violent offenders

The most comon reaction that animals and human show when being exposed to a
threatening situation is the freeze-fight-flight (FFF) response (Blanchard et
al., 2011). In different vorms of psychopathology, including psychopathy, a
disbalance in this FFF system is suspected (Roelofs, et al., 2009; Heuer et
al., 2007, von Borries et al., under revision). A literature study on violent
attacks by lone wolfs (assignment by the WODC) has shown that a difference
between reactive and instrumental aggression is crucial. For these two types of
aggression, specific hypotheses were formed on the basis of literature, with
respect to the different components of the FFF system. However, these
hypothesis are based on analogue evidence and theoretical models. It is of
importance to test these hypothesis experimentally, in order to objectively
quantify the FFF sequence in violent offenders. Furthermore, it is important to
understand the roles of two hormones related to FFF, cortisol and testosterone.
It is know that these hormones influence fight and flight behavior in healthy
people (Volman et al., 2011) and that they are related to aggresion (van Honk
et al., 2007)

Based on the literature study (encompassing literature on FFFFF, case
descriptions of lone wolfs, and literature regarding different forms of
aggression) specific hypotheses with regard to the role of freeze-fight-flight
and focus (FFFF) in violent offender types (instrumental versus reactive
aggressive) have been formed. Objective of the proposed study is to
experimentally test these hypothesis by means of an innovative experimental
setup that allows us to measure these FFFF responses in humans and relate them
to different forms of aggression.

Balance board
A balance board consists of a set of finely calibrated scales, measuring
mechanical forces. The pattern of forces can be used to derive body position
with at a high spatial (1M with a sub-millimeter) and temporal resolution 100
Hz. The platform records reliably over four vertical forces. The pressure
sensors derive directly from the wii balance board. Each sensor has a maximum
pressure of 120Kg. In-house electronics is build to get a clean amplification
from the sensors. A National instruments card, USB-6221, takes care of the A/D
conversion and connects with usb to a pc.

Task 1
Affective approach-avoidance learning task
The goal of this learning task is to investigate the emotional influence on
instrumental approach avoidance. To disentangle the emotional responses from
the instrumental responses, these two are separated in time and space. The
learning task consists of one approach and one avoidance block. The task is
framed in terms of a gems collecting and sorting task. At the beginning of each
trial, an emotional face (angry or happy) is shown on the screen preceding the
instrumental stimulus. Instrumental stimuli (gems) are colored shapes. In each
block, there are 6 instrumental stimuli types. In the approach block,
instrumental stimuli (gems 1-6) are presented to one side of the screen
surrounded by a white frame. Good gems (gems 1-3) are to be collected, whereas
bad gems (gems 4-6) are not to be collected. Participants are instructed to
indicate that they want to collect the gem by making a step from the middle of
the balance board to the side where the gem is presented (approach-go). They
could also decide not to collect the gem by remaining in the middle of the
balance board for 2.5 seconds (approach-nogo). At the end of each trial (after
the choice), the instrumental stimulus (gem) disappeared and the outcome is
shown in the middle of the screen. In the avoidance blocks, instrumental
stimuli (gems 7-12) are presented. Bad gems (gems 7-9) are to be avoided,
whereas good gems (gems 10-12) are not to be avoided. Participants choose
whether to escape from the gem (avoid-go; by taking a step to the side where a
white frame is presented, the other side of where the gem is presented) or
remaining in the middle (avoid-nogo). Participants are not told which gems are
good or bad. Participants have to learn the correct choice by trial and error.
Making the correct choice (approach block: approach-go for good gems,
approach-nogo for bad gems; avoidance block: avoid-go for bad gems, avoid-nogo
for good gems) will be reinforced probabilistically (either +10 cents for
reward, or -10 cents for punishment; chance of a reward given the correct
choice is 0.80). In total, the task consists of 240 trials, with 120 trials per
block, and with 20 trials per instrumental stimuli, of which 10 were preceded
by an angry facial stimulus and 10 were preceded by a happy facial stimulus.

Visual stimuli and timing for task 1
The visual stimuli that are presented for each participant, consist of faces
from 20 models (10 male) taken from several databases (Ekman and Friesen 1976;
Matsumoto and Ekman 1988; Martinez and Benavente 1998; Lundqvist et al. 1998).
Each model shows 2 emotions (angry and happy), matched for brightness and
contrast values, displayed against a black background. To exclude influence
from hair and nonfacial contours, the faces are trimmed (Van Peer et al. 2007;
Roelofs, Minelli, et al. 2009). On each trial, a face is presented centrally
for 3000 ms. After 500 ms black screen, participants are required to make
either a Go or a NoGo response as fast as possible within 2500 ms upon
presentation of the instrumental stimuli. No response being made within 2500ms
is recorded as a nogo response. After a stimulus-outcome delay of maximally
3000 ms, the outcome is presented for 1000 ms, (+20 cents for reward, -20 cents
for punishment). The intertrial interval is jittered (3000 ± 1000 ms). Stimuli
presentation and response acquisition are controlled by a PC running
Presentation software 14.8 12.30.10.

Duration: 50 minutes

Outcomes in terms of FFFF
Approach/avoidance will be operationalized as time to approach/avoidance on
correct trials (milliseconds).
This will be analyzed separately in two emotional contexts (happy or angry face)

Task 2
Step task
This task will be done on the stabilometric platform. This is a Wii
balanceboard adjusted to measures sponaneous and nonspontaneous adjustments in
bodyposture. Changes in pressure (through changes in body posture) can be
measures in anterior-posterior as well as medio-lateral directions (Fig. 2).
During the tasks, subjects will be asked to stand on the platform and watch
pictures presented on a monitor (eye height to subject). Stimuli will be
presented in blocks, and each block will be preceded by new instructions. The
instructions create congruent conditions (step away from angry faces (avoid)
and step towards happy faces (approach)) and incongruent conditions (step away
from happy faces (avoid) and step towards angry faces (approach)).
Stimuli:
40 actors, per actor 3 emotios (angry, happy, neutral)
Blocked design; 6 blocks consisting of 3 congruent and 3 incongruent conditions
For task 2 and 3 same stimuli will be used consisting of pictures of human
actors portraying either facial emotions of anger, happiness or neutral
expression (version 1 of task 2 and 3) or whole body expressions of anger,
happiness and neutral (version 2 of task 2 and 3).

Trial details
each stimuli will be presented for 3 seconds, followed by a black screen for
4-6 seconds. On average a trial then lasts 8 seconds.
the task will first performed with pictures of faces only (version 1) followed
by pictures of whole body expressions (versie 2).
the total duration of the experiment is 16 minutes

Outcomes in terms of FFFF
Approach/avoidance will be operationalized as time to approach/avoidance on
correct trials (milliseconds).



Task 3
Freeze task
In this task the same platform will be used as well as the same stimuli (see
below). During this task however, subjects only have to passively view the
pictures while standing quietly on the platform. The outcome measure are small
variations in body sway during viewing of these stimuli (changes of amount
pressure and standarddeviations in changes of location of pressure)

Stimuli:
20 actors, per actor 3 emotios (angry, happy and neutral)
Blocked design; 3 blocks with one emotion per block, total 20 stimuli
For task 2 and 3 same stimuli will be used consisting of pictures of human
actors portraying either facial emotions of anger, happiness or neutral
expression (version 1 of task 2 and 3) or whole body expressions of anger,
happiness and neutral (version 2 of task 2 and 3).

Trial details:
each stimuli is presented for 3 seconds
each block is followed by a 5 second black screen before a new block starts
again two versions will be done, one with only faces, and one with whole body
expressions

Duration: 4 minutes


Outcomes in terms of FFFF
Freeze will be operationlized as the standarddeviation in bodysway.



Hormonal measures
Before and after the three experimental tasks, subjects will be asked to
provide saliva. They will spit through a straw into a little plastic tube
(50µl). Analysis will reveal levels of corticol and testonsterone. Supplies
will be used from Salicap colletion devices (IBL International, Hamburg,
Germany). All tubes will be stored at -20 °C. Biochemical analysis of free
cortisol will be done by *competitive electrochemiluminescence immunoassay
(ECLIA, Elecsys 2010, Roche Diagnostics). Testosterone concentrations will be
determined using competitive chemiluminescence immunoassay (LIA) with a
sensitivity of 0,0025 ng/ml (IBL, Hamburg, Germany).

Subjects have to act according to the following rules in order to get valid and
reliable smaples:
- No koffie, tea, chocolate, cola or alcohol on the day of testing
- no extensive physical exercise on the day of testing
- no more then 5 cigarettes on the day of testing before the session begins
- Minimal one hour before the start of the measurement no eating, smoking or
drinking (with the exception of water) is allowed. After the session everything
may be eaten again.

Duration: 5 minutes

Picture rating
After the experimental tasks, subjects will rate each stimuli on a 9-point
likert scale on both arousal (not at all - absolutely) and valence (very happy
- very angry).


Heat rate measures
To have an autonomic measure of reactivity to stimuli we will measure heart
rate during the experimental task using 5 lead setup to ensure accuracy.

Questionnaires
MINI and SCID as DSM interviews; NLV for IQ level; Stai, staxi, Lsas for fear,
anxiety and anger; RPQ and IPAS for aggression, LEQ (stressful life events)

non risk involved