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Associations between aversive learning processes and transdiagnostic psychiatric symptoms revealed by large-scale phenotyping

Toby Wise, +1 more
- 15 Nov 2019 - 
- pp 843045
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TLDR
The findings implicate aversive learning processes under uncertainty to the expression of psychiatric symptoms that cut across traditional diagnostic boundaries, and are more complex than previously conceptualised.
Abstract
Background: Aversive learning processes are a candidate source of dysfunction in psychiatric disorders. Here symptom expression in a range of conditions is linked to altered threat perception, manifesting particularly in uncertain environments. How precise computational mechanisms that support aversive learning, and uncertainty estimation, relate to the presence of specific psychiatric symptoms remains undetermined. Methods: 400 subjects completed a novel online game-based aversive learning task, requiring avoidance of negative outcomes, in conjunction with completing measures of common psychiatric symptoms. We used a probabilistic computational model to measure distinct processes involved in learning, in addition to inferred estimates of safety likelihood and uncertainty. We tested for associations between learning processes and traditional psychiatric constructs alongside transdiagnostic factors using linear models. We used partial least squares regression to identify components of psychopathology grounded in both aversive learning behaviour and symptom self-report. Results: State anxiety and a transdiagnostic compulsivity-related factor were associated with enhanced learning from safety. However, data-driven analysis using partial least squares regression indicated the presence of two separable components across our behavioural and questionnaire data: one linked enhanced safety learning and lower estimated uncertainty to physiological anxiety, compulsivity, and impulsivity; the other linked enhanced threat learning and heightened uncertainty estimation to symptoms of depression and social anxiety. Conclusions: Our findings implicate aversive learning processes under uncertainty to the expression of psychiatric symptoms that cut across traditional diagnostic boundaries. These relationships are more complex than previously conceptualised. Future research should focus on understanding the neural mechanisms underlying alterations in aversive learning and how these lead to the development of symptoms and disorder.

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ARTICLE
Associations between aversive learning processes
and transdiagnostic psychiatric symptoms in a
general population sample
Toby Wise
1,2,3
& Raymond J. Dolan
1,2
Symptom expression in psychiatric conditions is often linked to altered threat perception,
however how computational mechanisms that support aversive learning relate to specic
psychiatric symptoms remains undetermined. We answer this question using an online
game-based aversive learning task together with measures of common psychiatric symptoms
in 400 subjects. We show that physiological symptoms of anxiety and a transdiagnostic
compulsivity-related factor are associated with enhanced safety learning, as measured using
a probabilistic computational model, while trait cognitive anxiety symptoms are associated
with enhanced learning from danger. We use data-driven partial least squares regression to
identify two separable components across behavioural and questionnaire data: one linking
enhanced safety learning and lower estimated uncertainty to physiological anxiety, com-
pulsivity, and impulsivity; the other linking enhanced threat learning and heightened uncer-
tainty estimation to symptoms of depression and social anxiety. Our ndings implicate
aversive learning processes in the expression of psychiatric symptoms that transcend diag-
nostic boundaries.
https://doi.org/10.1038/s41467-020-17977-w
OPEN
1
Wellcome Centre for Human Neuroimaging, University College London, London, UK.
2
Max Planck UCL Centre for Computational Psychiatry and Ageing
Research, University College London, London, UK.
3
Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA.
email: t.wise@ucl.ac.uk
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1234567890():,;

M
any core symptoms of mental illness are linked to
learning about unpleasant events in our environment.
In particular, symptoms of mood and anxiety disorders,
such as apprehension, worry, and low mood, can intuitively be
related to altered perception of the likelihood of aversive out-
comes. Indeed, the importance of altered threat perception is a
feature of many diagnoses that extend beyond disorders of mood
to encompass conditions such as psychosis
1
and eating dis-
orders
2
. As a result, research into how individuals learn about
aversive events holds great promise for enhancing our under-
standing across a diverse range of mental health problems.
Computational approaches are a powerful means to char-
acterise the precise mechanisms underpinning learning, as well as
uncovering how these relate to psychiatric symptom
expression
3,4
. Recent studies have leveraged computational
modelling to capture associations between learning processes and
psychiatrically relevant dimensions in non-clinical samples
58
,as
well as in clinical conditions ranging from anxiety and depression
to psychosis
912
. A common nding across studies is that of
altered learning rates, where psychopathology is linked to inap-
propriate weighting of evidence when updating value
estimates
7,13,14
. Notably, there is evidence suggesting that people
with clinically signicant symptoms of anxiety and depression
show biased learning as a function of the valence of information,
updating faster in response to negative than positive outcomes
presented as monetary losses and gains
12
, a bias that might
engender a negative view of the environment. However, we pre-
viously found an opposite pattern in a non-clinical study using
mild electric shocks as aversive stimuli, whereby more anxious
individuals learned faster from safety than from punishment, and
underestimated the likelihood of aversive outcomes
15
. This latter
nding highlights a need for a more extensive investigation using
larger samples.
In addition to aberrant learning, another process implicated in
the genesis of psychiatric disorder relates to the estimation of
uncertainty
16
. While there are multiple types of uncertainty, here
we use the term to refer to estimation uncertainty, describing the
precision of a learned association. Estimation uncertainty is
highest when there is a lack of experience, or the association to be
learned is unstable. For example, having seen two coin ips and
observing one head and one tail, one might believe the likelihood
of observing a head is 50%, though they are highly uncertain
about this estimate due to a lack of evidence. This kind of
uncertainty plays a fundamental role in learning, and computa-
tional formulations optimise learning in the face of non-
stationary probabilistic outcomes based on uncertainty
11,1720
.
While psychiatric symptoms, including anxiety, have been linked
to an inability to adapt learning in response to environmental
statistics such as volatility
5,9
, little research has investigated how
individuals estimate, or respond to, uncertainty in aversive
environments and its potential association with psychiatric
symptoms. This is a crucial question given that core features of
anxiety revolve around the concept of uncertainty. For example,
individuals with anxiety disorders report feeling more uncertain
about threat and being less comfortable in situations involving
uncertainty
2124
. In an earlier lab-based study we observed a
surprising relationship, nding that more anxious individuals
were more certain about stimulusoutcome relationships
15
.
However, this was in a relatively small sample and therefore
warrants further investigation.
Existing work on aversive learning has had a particular focus
on symptoms of anxiety and depression
7,12
. However, these
approaches have not been designed optimally for identifying
mechanisms that span traditional diagnostic boundaries. This
assumes importance in light of recent studies, using large sam-
ples, showing several aspects of learning and decision-making
relate more strongly to transdiagnostic factors (symptom
dimensions that are not unique to any one disorder) than to any
specic categorical conception of psychiatric disorder
6,8,2527
.
Applying such an approach to aversive learning may yield better
insights into the role of learning in psychiatric disorders. In
addition, computationally dened measures of learning and
decision-making can facilitate identi cation of novel transdiag-
nostic factors, going beyond those identied based solely on
correlated symptom clusters in self-report and clinical interview
measures
6,2830
.
Here, we aim to clarify the nature of the relationship between
aversive learning processes and traditional measures of anxiety, as
well as transdiagnostic psychiatric factors identied in prior
work
6
in a large, preregistered study conducted online. This
allows us to measure effects with high precision, potentially
helping to resolve mixed ndings from previous studies
12,15
,in
addition to identifying small but meaningful effects that cross
traditional diagnostic boundaries
6
. As in similar prior
studies
6,8,25,26,31
, we do not purposefully recruit subjects diag-
nosed with mental health problems, instead focusing on exploring
relationships with the variation in symptoms present in the
general population. While this does not allow concrete conclu-
sions about clinical disorders per se, we note ndings using
similar approaches have replicated those seen in clinical
samples
8,32
, providing reassurance these methods can generate
insights into psychiatrically relevant phenomena. Thus, we use a
computational approach to test whether anxiety and transdiag-
nostic symptoms are associated with biased learning from safety
and threat, whether these factors relate to altered estimates of
threat likelihood, and whether they are associated with different
levels of uncertainty during threat learning. We then use partial
least squares (PLS) regression, a data-driven multivariate method,
to derive transdiagnostic latent components of psychopathology
grounded in both self-report and computational measures. In
contrast to our primary analyses, this analysis is exploratory and
data-driven, enabling us to generate hypotheses for future
research. Given difculties in using traditional aversive stimuli in
an online setting, we develop a game-based avoidance task
designed to engage threat and avoidance processes without the
need for administration of painful or noxious stimuli. Both the
task and modelling are, in principle, similar to our previous lab-
based task
15
, but their implementation here allows straightfor-
ward administration in large samples recruited online. Our results
demonstrate that learning from safety and danger are associated
with distinct symptom dimensions that cut across diagnostic
boundaries, implicating aversive learning processes in a range of
psychiatric symptoms.
Results
Task performance. Four hundred subjects recruited online
through Prolic
33
performed a game-based aversive learning task,
where the aim was to y a spaceship through asteroid belts
without being hit (Fig. 1). Getting hit by the asteroids reduced the
integrity of the spaceship, and after sufcient hits the game ter-
minated. Crucially, there were two zones at the top and bottom of
the screen where subjects could encounter a hole in the asteroid
belt, each associated with a changing probability of being safe. In
order to perform well at the task subjects needed to learn which
zone was safest and behave accordingly.
Subjects were engaged and performed well at the task, with a
median number of spaceship destructions of 1 (Interquartile
range = 2) over the course of the task. They also reported high
motivation to perform the task, providing a mean rating of 85.70
(SD = 18.44) when asked to rate how motivated they were to
avoid asteroids on a scale from 0100. Reassuringly, no subjects
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met our exclusion criteria designed to remove those not engaging
in the task.
Computational modelling of behaviour. To quantitatively
describe behaviour, we t a series of computational models to
subjects position data during the task (see Methods and Sup-
plementary Methods for a full description of tested models). The
winning model was a probabilistic model incorporating different
updates parameters for safety and danger, as well as a stickiness
parameter representing a tendency for subjects to stick with their
previous position. This model represents an extension of one we
have previously used successfully as a lab-based aversive learning
task
15
, and is described fully in the Methods section. Briey, this
winning model assumes that subjects in the task represent the
safety probability of each zone using a beta distribution, which is
updated on each trial based on encounters with danger or safety.
Simulating responses using the model, using each subjectsesti-
mated parameter values, produced behavioural proles that
demonstrated a high concordance with the true data, reproducing
broad behavioural patterns seen in the true data (Supplementary
Fig. 1). We note that we do not wish to make strong claims
regarding the strategy employed by subjects in performing this
task; our central focus was on exploring relationships with symp-
toms, and we focused on probabilistic models as they provide a
natural measure of uncertainty that can be associated with symp-
toms. It is possible that more complex reinforcement learning
models for example could produce equally good ts to the data.
Task and model validation. It was important to rst ensure that
the task has content validity, and that it produces behaviour
reminiscent of more traditional tasks. Likewise, the computa-
tional models used should provide measures and parameter
estimates that reect the behaviour they aim to describe. We
therefore conducted extensive validation exercises. These are
reported fully in Supplementary Methods, but we summarise
them here.
First, we ensured the task did induce states of subjective anxiety
in the majority of subjects (Fig. 2a), and this level of anxiety was
correlated with self-report state and trait anxiety (Fig. 2c, d).
Importantly, subjects adjusted their position to a greater extent
following danger than following safety (Fig. 2e), indicating that
they were adapting their behaviour in response to outcomes in
the task, rather than behaving randomly. With respect to our
computational model, we veried that the models update
parameters were robustly correlated with subjects tendency to
move, or stay, following danger and safety, respectively (Fig. 3d).
We also assessed whether safety and uncertainty values, produced
by simulating data from our model with best tting parameters,
related to subjects model-free behaviour. We found that subjects
changed their position more when model-derived uncertainty was
high, and when the difference between the safety value of the two
zones was small. This pattern (Fig. 3c) indicates that value and
uncertainty measures do reect meaningful quantities for
behaviour. Finally, we veried that our models update para-
meters showed greater updating from danger relative to safety, as
we found in a previous lab-based study
15
, nding this was indeed
the case (Fig. 3e).
Parameter recovery analyses are also reported in Supplemen-
tary Fig. 2 and indicated good recoverability (lowest r between
true and recovered parameter value = 0.61). It should be noted
that we did nd a moderate negative correlation between the two
update parameters (r = 0.49), which may be an artefact of the
fact that safety and danger outcomes in the task were partially
anticorrelated (i.e., when one zone was likely to be safe, the other
was likely to be dangerous). However, despite this, parameter
recovery tests indicated good recoverability of these parameters.
Relationships with anxiety. First, we asked whether our four
behavioural variables of interest (threat update parameter, danger
update parameter, mean estimated safety probability, and mean
estimated uncertainty) were associated with anxiety (both state
and trait) and intolerance of uncertainty. The strongest rela-
tionships, with highest posterior density (HPD) intervals that did
not include zero, were positive effects of state anxiety on safety
update rates and mean estimated safety probability (Fig. 4,
Table 1), although effects for trait anxiety were in the same
direction and of a similar magnitude for some measures, indi-
cating more anxious individuals learned faster about safety and
perceived safety as more likely overall.
However, it is possible that our state and trait anxiety sum scores
may obscure more nuanced effects relating to different symptom
dimensions. To test this, we performed exploratory analyses on the
two subscales of our trait anxiety measure, which represent
cognitive symptoms, such as worry, and physical symptoms, which
reect aspects of physiological arousal. This analysis revealed a
dissociation between cognitive and somatic trait anxiety, whereby
cognitive symptoms were associated with heightened learning from
danger, heightened uncertainty, reduced learning from safety, and
lower safety probability, while somatic anxiety showed an opposite
pattern (Table 1 and Fig. 5). The same was true for state anxiety to
a lesser extent; while effects for somatic anxiety remained strong,
those for cognitive anxiety were weaker and had 95% HDPIs that
ab
Asteroid belt
Safety
zone B
Safety
zone A
Shields:
Score:
9260
Spaceship
Fig. 1 Task design overview. a Subjects were tasked with playing a game that had a cover story involving ying a spaceship through asteroid belts. Each
asteroid belt featured two locations that could potentially contain escape holes (safety zones), and subjects were instructed to aim to y their spaceship
through these to gain the highest number of points. Subjects were only able to move the spaceship in the Y-dimension, while asteroid belts moved towards
the spaceship. The probability of each zone being safe varied over the course of the task but this could be learned, and learning this probability facilitated
performance. b Screenshot of the task, showing the spaceship, an asteroid belt with a hole in the lower safety zone (safety zone B), a representation of the
spaceships integrity (shown by the coloured bar in the top left corner) and the current score.
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NATURE COMMUNICATIONS | (2020) 11:4179 | https://doi.org/10.1038/s41467-020-17977-w | www.nature.com/naturecommunications 3

included zero (Table 1 and Fig. 5). Together, these results indicate
that different components of trait anxiety have distinct relation-
ships with aversive learning processes.
Associations between aversive learning and transdiagnostic
factors. Following this, we examined the extent to which task
behaviour was associated with three transdiagnostic factors of
psychopathology identied through self-report assessments in
previous research
6
. Here, we observed effects of a factor labelled
compulsivity and intrusive thought (Fig. 4, Table 2), reecting the
fact that subjects scoring higher on this factor learned faster about
safety and had higher safety probability estimates. There was also
a weak effect of this factor on uncertainty, although the HPDI for
this included zero. Other effects were weak, and including
reported task motivation as a covariate had a negligible effect on
the results (see Supplementary Figs. 5 and 6). Importantly, all of
these analyses were determined a priori and are included in our
preregistration. We also examined effects of age and sex, and their
interactions with our primary variables. These results are
described in Supplementary Fig. 4.
Psychiatric constructs derived from behaviour and self-report.
Numerous studies have used dimensionality reduction procedures
such as factor analysis on questionnaire-based data to identify
factors of psychopathology that cut across diagnostic
boundaries
6,2830
. This, in turn, has revealed that many beha-
viourally dened phenotypes are more strongly associated with
transdiagnostic factors than any single disorder
6,8,26
. We built
upon this work by incorporating computationally derived indexes
of behaviour into this dimensionality reduction procedure, where
the aim was to identify latent constructs grounded in both self-
report and behaviour. We used PLS regression, a method that
identies latent components linking multivariate data from mul-
tiple domains based on their shared covariance. This general
a
60
How anxious did the game
make you feel?
How much did you want to
avoid the asteroids?
40
Count
20
0
0
100
80
60
Task-induced anxiety
rating
40
20
Density
0
20
0.0 0.2 0.4
Magnitude
0.6 0.8
Danger
200
150
100
Number of subjects
50
0
Safety
1.0
0510
Number of crashes
15 20
40
STICSA state anxiety score STICSA trait anxiety score
60 20 40 60
25 50
Rating
State anxiety
R = 0.25, p = 4e–07
Trait anxiety
R = 0.21, p = 2.09e–05
Rating
75 100 0 25 50 75 100
150
100
50
0
b
cd
ef
Fig. 2 Subjective and behavioural responses during the task. a Distribution of task-induced anxiety ratings recorded after the task. b Distribution of task
motivation ratings. c, d Relationships between task-induced anxiety ratings and state and trait anxiety scores. Correlations represent Pearson r statistics,
and p values are two sided without correction for multiple comparisons. e Degree of location switching after encountering danger and safety across
subjects. The switch magnitude is the average absolute change in position between trial n and trial n + 1. As expected, subjects showed more switching
behaviour after encountering danger and were more likely to stay in the same position following a safe outcome. f Distribution of crash number
(representing the number of subjects hitting enough asteroids to end the game) across subjects.
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method has been employed successfully in prior studies to provide
insight into how panels of cognitive and behavioural measures
relate to multivariate neuroimaging-derived phenotypes
3436
.
PLS-like analyses can be problematic if not properly validated (for
example producing spurious results due to overtting), and so we
adopted best-practice methods for validating these results
3739
,
selecting the optimal number of components using cross-
validation and training the model on 75% of the data, before
testing its performance on the remaining 25% of the data.
Importantly, in contrast to other analyses, this was an exploratory
analysis where our aim was to provide indicative results that can
be validated in future research.
We rst identied the number of components that best
describe our data by evaluating the performance of a predictive
a
b
de
c
Responses
Uncertainty
Safety value
Tr ia l
1.0
0.5
Subject
position
0.0
1.0
0.5
Value
0.0
0
–10,000
–20,000
WAIC
–30,000
ALB
Learning from danger Learning from safety
1.0
0.7
0.6
0.5
0.4
Parameter
0.3
0.2
0.1
0.0
0.8
0.6
+
n
(danger)
p
(safety)
0.4
0.2
0.0
0.0 0.2 0.4
Response shift
0.6 0.0 0.2 0.4
Response shift
0.6
0.0 0.2 0.4
Estimated value
0.6 0.8 1.0
Danger (R = 0.25))
Safety (R = –0.24))
Danger (R = –0.31))
Safety (R = 0.12))
ALB
softmax
ALB
sticky
ALB
UCB
Model
ALB
variance
Dual
learning
rate RW
Rescorla
wagner
0.1
Uncertainty
0.0
0 50 100 150 200 250
Tr ia l
0 50 100 150 200 250
Tr ia l
0 50 100 150
Value
difference
–0.05
Uncertainty
0.00 0.05
Regression coefficient
(± 95% HPD)
0.10
0.15
Predictor
200 250
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Frequently Asked Questions (15)
Q1. What contributions have the authors mentioned in the paper "Associations between aversive learning processes and transdiagnostic psychiatric symptoms in a general population sample" ?

The authors show that physiological symptoms of anxiety and a transdiagnostic compulsivity-related factor are associated with enhanced safety learning, as measured using a probabilistic computational model, while trait cognitive anxiety symptoms are associated with enhanced learning from danger. 

A common finding across studies is that of altered learning rates, where psychopathology is linked to inappropriate weighting of evidence when updating value estimates7,13,14. 

Their dependent variables were parameters and quantities derived from their model, which represented the way in which an individual learns about safety probability and how they estimate uncertainty. 

Safety probability was designed to fluctuate relatively rapidly to ensure that uncertainty fluctuated continuously over the course of the task. 

Another important aspect of learning uncertainty that the authors did not investigate is volatility, namely the tendency of stimulus–outcome relationships to change over time. 

these models have been used successfully in previous studies to capture value-based learning61, where they explain behaviour in aversive learning tasks better than commonly used reinforcement learning models15,62, a pertinent characteristic in the current task. 

In particular, symptoms of mood and anxiety disorders, such as apprehension, worry, and low mood, can intuitively be related to altered perception of the likelihood of aversive outcomes. 

One speculative possibility is that a persistent underestimation of threat likelihood would lead to an abundance of aversive prediction errors, causing a state of subjective physiological anxiety. 

PLS-like analyses can be problematic if not properly validated (for example producing spurious results due to overfitting), and so the authors adopted best-practice methods for validating these results37–39, selecting the optimal number of components using crossvalidation and training the model on 75% of the data, before testing its performance on the remaining 25% of the data. 

This approach is naturally suited to probability estimation tasks, as the beta distribution is bounded between zero and one, and provides a measure of uncertainty through the variance of the distribution. 

Associations between aversive learning processes and transdiagnostic psychiatric symptoms in a general population sample Toby Wise 1,2,3✉ & Raymond J. Dolan 1,2Symptom expression in psychiatric conditions is often linked to altered threat perception,however how computational mechanisms that support aversive learning relate to specificpsychiatric symptoms remains undetermined. 

Subjects were engaged and performed well at the task, with a median number of spaceship destructions of 1 (Interquartile range= 2) over the course of the task. 

This procedure provides a null distribution, from which the authors can then determine the likelihood of observing predictive accuracy at least as high as that found in the true data under the null hypothesis. 

This was important, because if outcomes were entirely symmetric (i.e. safety in one zone indicated danger in the other), the authors would be unable to determine the extent to which value updating was driven by safety versus danger. 

One explanation for the discrepancy between their results and those found by Aylward et al.12 is that this previous study included subjects with a mix of anxiety and depressive disorders, and a negative bias in learning may be more characteristic of depressive symptoms.