Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
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Biologically Inspired Cognitive Architectures
journal homepage: www.elsevier.com/locate/bica
Research article
Emotional simulations and depression diagnostics
Max Talanov b,⇑, Jordi Vallverdú a, Bin Hu c, Philip Moore c, Alexander Toschev b, Diana Shatunova b,
Anzhela Maganova b, Denis Sedlenko b, Alexey Leukhin b
a
Universitat Autònoma de Barcelona, Catalonia, Spain
Kazan Federal University, Russia
c
Lanzhou University, China
b
a r t i c l e
i n f o
Article history:
Received 10 June 2016
Revised 22 September 2016
Accepted 25 September 2016
Available online xxxx
Keywords:
Dopamine
Serotonin
Fear
Artificial intelligence
Simulation
Rat brain
Affective computing
Emotion modelling
Neuromodulation
a b s t r a c t
In this work we propose the following hypothesis: the neuromodulatory mechanisms that control the
emotional states of mammals can be translated and re-implemented in a computer by controlling the
computational performance of a hosted computational system. In our specific implementation, we represent the simulation of the ‘fear-like’ state based on the three dimensional neuromodulatory model of
affects, in this paper ‘affects’ refer to the basic emotional inborn states, inherited from works of Hugo
Lövheim. Whilst dopamine controls attention, serotonin is the key for inhibition, and fear is a elicitator
for inhibitory and protective processes. This inhibition can promote [in a cognitive system] to blocking
behaviour which can be labelled as ’depression’. Therefore, our interest is how to reimplement biomimetically both action-regulators without the computational system to resulting in a ‘failed’ scenario. We have
simulated 1000 ms of the dopamine system using NEST Neural Simulation Tool with the rat brain as the
model. The results of the simulation experiments are reported with an evaluation to demonstrate the correctness of our hypothesis.
Ó 2016 Elsevier B.V. All rights reserved.
1. Introduction
The current rapid developments in neurocognitive sciences and
new discoveries related to the core mechanisms of natural intelligence have triggered new insights and opportunities in the field of
biologically inspired cognitive systems. There are new and reliable
data related to a key aspect [previously undervalued or hidden]
which builds the entire cognitive processes architecture: emotions
(Minsky, 2007).
Research has shown that emotions play a significant role in natural intelligence and adaptive behaviour (Damasio, 1999; Picard,
Vyzas, & Healey, 2001). Additionally, the intrinsic value of emotions in cognitive processes remains undervalued by researchers
who take a behaviourist approach to artificial emotions based on
basic observable actions; we term this: the ‘skinnerian’ approach
to emotions. This approach basically considers the emotional performance as epiphenomenalist without considering the deep mech-
⇑ Corresponding author.
E-mail addresses:
[email protected] (M. Talanov),
[email protected]
(J. Vallverdú),
[email protected] (B. Hu),
[email protected] (P. Moore),
[email protected] (A. Toschev),
[email protected] (D. Shatunova),
[email protected] (A. Maganova),
[email protected] (D. Sedlenko), alexey.
[email protected] (A. Leukhin).
anisms that are hidden under this black box. This view can be
somehow useful for ‘real-time’ emotional detection during
Human-Robot Interactions or Human-Computer Interactions.
Attempts to design computer emotional architectures have
been proposed, consider for example CogAff (Sloman, 1994) or LIDA
(Franklin, Madl, D’Mello, & Snaider, 2014) which are architectonically modulatory and whilst they simulate the homeostatic role
of emotional mechanisms, they fail to provide an integrative way
to implement emotional design into all areas of computational
activity.
As a departure point of our model, we consider a simple ‘‘fear”,
which is necessary to evaluate ‘‘fly-or-fight” actions (Stevenson &
Rillich, 2012). Our study focuses on two opposing and complimentary neuromodulators: dopamine and serotonin (Daw, Kakade, &
Dayan, 2002). Dopamine is related to brain reward processes,
whilst serotonin is implied into aversive or inhibitory processes;
used in combination we may design a system that manages ‘flyor-fight’ actions in which several learning procedures could be
easily implemented.
We argue that our proposal represents a milestone in the creation of a new generation AI intelligence incorporating the capability to create neuromodulatory architectures which can run over
several conceptual models, languages and systems. The posited
http://dx.doi.org/10.1016/j.bica.2016.09.002
2212-683X/Ó 2016 Elsevier B.V. All rights reserved.
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
http://dx.doi.org/10.1016/j.bica.2016.09.002
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M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
approach is designed to model human cognitive processes such as:
creating unique and plastic cognitive identities. This is a basic, but
solid, first step towards grounded cognitive systems that share
across the whole cognitive multi-heuristic architecture the same
controlling mechanisms: synthetic neuromodulators.
2. The problem
Dating from the seminal work of Rosalind Picard in the mid
1990s (Picard, 1997), interest in emotion(s) has gained significant
traction; this is particulary evident where the understanding of
the connection between cognition and thinking is concerned
(Ahn & Picard, 2006; Damasio, 1999; Picard, 2003). We have indicated the cognitive perspectives which seem to offer the most promise in the context of the reimplementation of emotions in a
computised machine (Bridges et al., 2015). Based on these cognitive perspectives, we propose an approach for a neurobiologically
plausible model to represent the influence of emotions over neurobiological processes of thinking mapped to the emotional influence
over computational processes using neuromodulation.
Research, for exmple see: Arbib and Fellous (2004), Picard
(1997), Kort, Reilly, and Picard (2001), Ahn and Picard (2006),
and Damasio (1994, 1998), has identified that emotions form a
fundamental part of human cognition and are important in cognitive processes which include: attention, motivation, strategy selection, mood disposal, and reaction, invention. In this paper we have
paid special attention to mental disorders (see Section 3.1 for a
detailed discussion). It is clear that emotions and neuromodulators
play a crucial role in the diagnosis and management of depression,
schizophrenia and addictive personalities which includes drug
addition. Once explained, the crucial role of grounded and emotional aspects in cognitive architectures, we have adopted the
Lövheim model as a reference for our own architecture.
Lövheim (2012) has developed a three-dimensional model of
emotions based on monoamine neurotransmitters: serotonin, dopamine, and noradrenaline. The vertexes of the model are affects as
defined in the Tomkins ‘‘Theory of affects” (Kelly, 2009). Tomkins
(1962, 1963, 1991) referres to basic emotions as ‘‘innate affects”,
where affect in his theory, stands for the ‘‘strictly biological portion
of emotion”. Basic affects are: enjoyment/joy, interest/excitement,
surprise, anger/rage, disgust, distress/anguish, fear/terror, and
shame/humiliation. There are basic affects which are managed soley
by the internal cognitive processes of an individual, other basic
affects are intrinsically related to social interactions; however in
all cases ‘‘fly-or-fight” or even neutral states are hormonally
controlled.
In our previous publications we have demonstrated the attention regulation of dopamine (Vallverdú et al., 2015); in the studu
presented in this paper we have extend our implementation with
a second monoamine neuromodulator: serotonin (Meltzer, 1998).
The serotonin (5-HT) neurotransmitter is main actor in how a body
prepares to deal with some perceived danger. Additionally the
serotonin neurotransmitter acts as a bridge channel for an action
regulation: it controls sexual satiation (Arnone et al., 1995). There
is a final aspect related to the serotonin: loss is also related to ageing and several neuropsychiatric diseases (Pfaff, 2002); for this reason we explore the possible outcomes of an implemented
bioinspired architecture which uses serotonin.
There is extensive evidence which implicates a deficit in serotonergic neurotransmission in the development of stress or major
depression; this is related to the combination of disturbances in
cholinergic and serotonergic functions. We use a naturalistically
inspired model of cognition where the management of a selec
tion/suppression/reinforcement actions are neuromodulatory
managed following a complex flow of hormonal interactions.
3. Illustrative scenario
The aim of intelligent systems is to realise set goals in dynamic
environments such as the healthcare domain. The concept of self
has been identified along with the internalised and externalised concepts in respect of self forms an important component in cognitive
modelling and emotive response; this has synergies with the two
types of stimuli which are: (1) internal stimuli (events triggered
by an individual with a response from their external environment)
and (2) external stimuli (events triggered in their external environment which prompt an emotional response.
In this paper we are addressing emotive response to events
(stimuli) with a particular focus on the healthcare domain and
mental disorders. In the following illustrative scenarios we discuss
two specific areas in relation to mental disorders: (1) depressive
states and (2) Schizophrenia; the concept of self forms an important element in such mental disorders in terms of the diagnosis
and management in terms of short, medium, and long term time
scales. We argue that emotive responses are central to this process.
3.1. Depression and depressive states
Depression is a prototypical mental disorder and we argue that
cognitive factors, taken with physical symptoms, forms a pivotal
feature is the diagnosis and treatment of the condition. Depression
is a feature of a number of mental disorders (American Psychiatric
Association, 2013) we may however view depression on a spectrum as, whilst it may be clinical depression, it may also be a normal reaction to life events or side effects as a result of drugs and
medical treatments. Recent evidence has suggested that recurrent
episodes of severe depression are associated with changes in brain
function that further heighten vulnerability and functional impairment. It is argued in Thase (1999) that an: ‘‘integrated approach” to
diagnosis and management imbues profound beneficial effects for
all stakeholders in the treatment of depression.
There is a very large (and growing) body of of documented
research in the literature addressing depression and depressive
states, for example see: Dyrbye, Thomas, and Shanafelt (2006),
Lawlor and Hopker (2001), Blatt (2004), Joiner, Coyne, and
Blalock (1999), Blanchard, Waterreus, and Mann (1994), Thase
(1999), Greenberg and Watson (2006), Spitzer, Md, and Williams
(1980), and Sandra (1997). Depression is a highly variable condition that impacts individuals across demographics and gender
(Blanchard et al., 1994; Thase, 1999) and Greenberg in Greenberg
and Watson (2006) introduces the emotional component into the
treatment of depression.
Depression is a highly variable condition that impacts individuals across demographics and gender (Blanchard et al., 1994; Thase,
1999); Greenberg in Greenberg and Watson (2006) introduces the
emotional component into the treatment of depression. We have
considered the concept of self self in both internalised and externalised forms and this forms an important element in such mental
disorders in terms of the diagnosis and management (both short
and long term) of the conditions and we argue that emotive
responses are central to this process.
Depression and depressive states reflect an individuals low
mood and aversion to activity such that there can be significant
affects in terms of an individuals thoughts, behaviour, feelings
and sense of well-being (American Psychiatric Association, 2013;
Sandra, 1997; Spitzer et al., 1980). Depression may trigger mood
swings including feeling: sad, anxious, empty, hopeless, helpless,
worthless, guilty, irritable, ashamed or restless. Additionally, interest
in activities (that were previously enjoyed) along with eating disorders, problems in concentration, remembering details or making
decisions. In extreme cases, individuals suffering from depression
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
http://dx.doi.org/10.1016/j.bica.2016.09.002
M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
[along a spectrum of depressive states] may contemplate, attempt
or commit suicide. Insomnia, excessive sleeping, fatigue, aches,
pains, digestive problems or reduced energy may also be present
(NIMH, 2015a). There is a clear synergy between these observations and the emotive responses identified by behavioural biologists such as Plutchik in Plutchik (1980) (see Section 4) where
similar negative and positive reactions are discussed.
In this paper we are interested in the cognitive aspects of
depression and it’s treatment. Whilst an ‘‘integrated approach”
Thase (1999) may include: (1) cognitive behavioural therapies
(CBT) Beck (2011) using both face-to-face and remote (possibly
on-line) consultations and (2) drug treatments, our aim is to provide an effective basis upon which the cognitive and physiological
factors that relate to depressive states are captured and processed
to improve the diagnosis and treatment of depression. Moreover,
our aim is to include emotional response (based on objective data
(much of the cognitive response data is subjective) using cognitive
modelling) to stimuli in the diagnosis and treatment of patients in
the depressive spectrum as this aspect of the condition is, we
argue, central to understanding depression.
In considering depression we may also identify Alzhieimers’
disease and dementia as a primary cause [of depression] (Walker
et al., 2012). In this research the Cornell Scale for Depression in
Dementia (CSDD) which is a scale specifically developed to assess
signs and symptoms of major depression in patients with dementia
(Alexopoulos, Abrams, Young, & Shamoian, 1988). The mood
related factors identified in the Cornell Scale do, in fact, bear a similarity to the Behavioural and Psychological Symptoms of Dementia
(BPSD) as discussed in Qassem, Tadros, Moore, and Xhafa (2014)
and Moore, Thomas, Tadros, Xhafa, and Barolli (2013). Clearly,
the impact of dementia may be reflected in depression but also it
may be interesting to note that the research we present in this
paper may be useful in the management of dementia.
Recent evidence has suggested that recurrent episodes of severe
depression are associated with changes in brain function that further heighten vulnerability and functional impairment. Thase in
Thase (1999) argues that: ‘‘integrated approach to preventative
therapy saves lives and has profoundly beneficial effects for our
patients, their loved ones, and society”.
3.2. Schizophrenia
As with depression there is a very large (and growing) body of
of documented research in the literature addressing Schizophrenia,
for example see: Saha, Chant, Welham, and McGrath (2005),
McGorry (2000), Wolf and Berle (1976), Bleuler (1968), Wynne
(1978), and NIMH (2015b). Schizophrenia is a mental disorder
often characterised by abnormal social behaviour and failure to
recognise ‘what is real’. Common symptoms include: false beliefs,
unclear or confused thinking, auditory hallucinations, reduced social
engagement and emotional expression, and inactivity. Diagnosis is
based on observed behaviour and the person’s reported experiences. Precursors to Schizophrenia include: genetic, environmental, and factors psychological and social processes; such
precursors appear to be important contributory factors (Singh,
Burns, Amin, Jones, & Harrison (2004) and Large, Ryan, Singh,
Paton, & Nielssen (2011)) and importantly, there are recognised
issues with recreational and prescription drugs appear to cause
or exacerbate symptoms.
The derivation of the term Schizophrenia is Greek (skhizein - ‘‘to
split”, and phren - ‘‘mind”). Notwithstanding the genesis of the
term, Schizophrenia does not imply a ‘‘split personality”, or a ‘‘multiple personality disorder” (a condition with which it is often confused in public perception of the condition). Rather, the term
means a ”splitting of mental functions”, reflecting the presentation
of the illness (Baucum, 2006).
3
The mainstay of treatment is antipsychotic medication, which
primarily (and importantly for the discussion presented in this
paper) suppresses dopamine receptor activity. Counseling, job
training and social rehabilitation are also important in treatment.
In more serious cases (where there are risks asociated with self
harm or harm to others) patients may be subject to involuntary
hospitalisation (Becker & Kilian, 2006). It has been argued that
symptoms may begin in young adulthood with around 0.3–0.7%
of people being affected during their lifetime (van Os & Kapur,
2009). The disorder is thought to mainly affect the ability to think;
however it also usually contributes to chronic problems with behaviour and emotion. People with schizophrenia are likely to have
additional conditions, including major depression and anxiety disorders; the lifetime occurrence of substance use disorder is almost
50% (Buckley, Miller, Lehrer, & Castle, 2009). The average life
expectancy of people with the disorder is ten to twenty-five years
less than the average life expectancy (Laursen, Munk-Olsen, &
Vestergaard, 2012) and this may be the result of increased physical
health problems and a higher suicide rate (about 5%) (Hor & Taylor,
2010; van Os & Kapur, 2009). It has been estimated that in 2013
16,000 people died from behaviour related-to or caused by
schizophrenia (Naghavi et al., 2015).
In considering treatment options (see Section 3.3) Swaran Singh
has argued in Singh (2010) that:
‘‘Early intervention in psychosis services produce better clinical
outcomes than generic teams and are also cost-effective. Clinical
gains made within such services are robust as long as the interventions are actively provided. Longer-term data show that some of
these gains are lost when care is transferred back to generic teams.
This paper argues that sustaining these early gains requires both a
reappraisal of generic services and an understanding of the active
ingredients of early intervention, which can be tailored for longer
input in cases with poorer outcome trajectories.”
As evidence accumulates, implementation of evidence-based
practice in real work settings is a major challenge as it is throughout the mental health service system. The momentum of preventively orientated treatment must be maintained through the 2nd
National Mental Health Strategy and in the face of recent misleading polemic regarding the treatability of psychotic disorders, especially
schizophrenia.
The
evidence
demonstrates
that
schizophrenia and related disorders have never been more treatable (McGorry, 2000). Furthermore, aspects of the minimal self
that involve senses of ownership and agency in the context of both
motor action and cognition can be clarified by neurocognitive
models of schizophrenia that suggest the involvement of specific
brain systems (including prefrontal cortex, supplementary motor
area, and cerebellum) in the manifestation of neurological symptoms in this disorder (Gallagher, 2000).
Primary prevention requires a sophisticated knowledge of key
causal risk factors relevant to the expression of a disorder. The causal risk factors most useful from an intervention standpoint may
turn out to be somewhat removed from the neurobiology of the
disorder and may even be relatively non-specific, so that tackling
them could reduce the risks for a range of mental disorders. The
frontier for more specific prevention in schizophrenia and related
psychosis is currently represented by indicated preventive interventions for subthreshold symptoms. Again, these may be relatively broad spectrum early in the prepsychotic phase but more
proximal to onset, greater treatment specificity can be explored.
However, this can be viewed more as preventively orientated
treatment rather than primary prevention per se. Early detection
of first episode psychosis and optimal intensive treatment of first
episodes and the critical early years after diagnosis also represent
increasingly attractive preventive foci in psychotic disorders.
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
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M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
In relation to a neurocognitive model of schizophrenia that
requires us to make a distinction between two aspects of the minimal sense of self: the sense of self-ownership and the sense of selfagency (Gallagher, 2000). Schizophrenic patients who suffer from
thought insertion and delusions of control also have problems with
this forward, pre-action monitoring of movement, but not with
motor control based on a comparison of intended movement and
sensory feedback. The control based on sensory feedback is
thought to involve the cerebellum. By contrast, problems with forward monitoring are consistent with studies of schizophrenia that
show abnormal pre-movement brain potentials associated with
elements of a neural network involving supplementary motor, premotor and prefrontal cortex. Problems with these mechanisms
might therefore result in the lack of a sense of agency that is characteristic of these kinds of schizophrenic experience.
3.3. Non-drug related treatment strategies
The treatment options for the management of depression and
schzophrenia will include both drug and non-drug related therapies
(Roshanaei-Moghaddam et al., 2011) and must include cognitive
and emotional factors (Schupp, Junghöfer, Weike, & Hamm, 2003)
including affective factors (Lang, Greenwald, Bradley, & Hamm,
1993). In a meta-analysis of 56 studies related to the relationship
between psychotherapy and drug therapy in the treatment of
unipolar depression in adults (Roshanaei-Moghaddam et al.,
2011), the research findings suggest that psychotherapy was superior to drug therapies (Roshanaei-Moghaddam et al., 2011). An
interesting novel technology is Transcranial Magnetic Stimulation
(TMS) therapy which has been widely used and investigated in
depression (Lopez-Ibor, López-Ibor, & Pastrana, 2008). In 2007
TMS was approved for treatment-resistant depression in Canada,
Australia, New Zealand, the European Union and Israel; in other
countries it is undergoing trials and remains largely experimental.
A multi-modal [integrated] approach to the management of
depression will generally include both psychotherapy and drug
therapy with consultations conducted on both a F2F and remote
basis which will include the monitoring of patients emotional
and physical current prevailing state which will include the monitoring of medication and its effect.
4. Our idea
To reimplemet emotional psychoneurobiological phenomena in
the machine we used neurobiologically plausible simulation
approach, this was needed to keep the connection with biological
nature of emotions. We have created the simulation of the brain
pathways or subsystems that plays important role in the neurobiological emotional processes reimplementing emotion-like processes on a cellular level.
Based on roles of the neuromodulators we have created a mapping from one neuropsychological model of affects in order to
implement it into computing system parameters. Fig. 1 shows
the dimensional model of mapping in which levels of neuromodulators are mapped to simulate ‘‘innate emotional states” or affects.
For a detailed exposition see our previous articles: Bridges et al.
(2015), Talanov, Vallverdú, Distefano, Mazzara, and Delhibabu
(2015), and Vallverdú et al. (2015). In summary and more specifically, the parameters of a computational system taken into account
are as follows:
Computing utilisation is a metric able to quantify how busy
the processing resources of the system are. It can be expressed
by the average value of all the single processing resources’
utilisation.
Fig. 1. The correlation of emotional states with monoamines levels and computational system parameters, based on Lövheim Cube of emotion (Lövheim, 2012).
Computing distribution aims at quantifying the load balancing
amongst processing resources. It can be expressed as the variance of single resources’ utilisation.
Memory distribution is associated with the amount of memory
allocated to the processing resources. It can be quantified by the
variance of the amount of memory per single resource.
Storage volume is an index related to the the amount of data
and information used by the system.
Storage bandwidth quantifies the number of connections
between resources, i.e. processing and data nodes.
Human depressive states are associated with low serotonin
levels which promote inhibitory states which are understood as
depressive states. In computational systems, the depressive state
of all computing parameters along to serotonin axis is close to
the lowest operational state. A depressive state can be triggered
by a long running computational process which is not completed
and should be [normally] terminated, the reason being that it will
run infinitely without any realistic probability of a successful conclusion. Alternatively, any successful process can trigger off
depression state.
We recognise that the nature of the depression is more complex
than the present serotonin modelling may realise. However, it is
also true that in considering the fundamentamechanistic processes, direct correlations to levels of neuromodulators can be indicated and employed to control basic excitatory/inhibitory
processes management. Thus, we are not claiming to emulate computationally depressive states; we suggest a biomimetic computational mechanism to implement neuromodulatory-like strategies
which include inhibitory processes.
5. Details on modelling dopamine and serotonin pathways
Four practical purposes, our model is predicated on the dopamine and serotonin systems of a rat brain based on works of:
Sprague-Dawley and Long-Evans (Nair-Roberts et al., 2008;
Sadowski, Wise, Park, Schantz, & Juraska, 2014; Wang & Morales,
2009). We have modelled two main sub-systems involved in the
‘‘cube of emotions” described in Section 4. The sub-systems are:
Dopamine pathways:
– Nigrostriatal pathway including thalamus, striatum and
substantia nigra.
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
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– Mesolimbic and mesocortical pathways from VTA to prefrontal cortex.
Serotonin pathways:
– Middle pathway from raphe neurons to cerebral cortex,
cerebellum, basal ganglia.
– Rostral pathway from raphe nuclei to 5 areas: uses 5HT1
‘‘slow inhibition” and 5HT2 ‘‘slow excitation”.
Pathways or sub-systems were selected based on their role in
the emotional processing of a mammalian brain. As indicated
above (see Section 4), dopamine and serotonin are key players in
an emotional picture of mammalian neurobiology and selected
pathways play important role in a mammalian thinking that we
reference as being analogous to computational processes of modern computers.
5.1. The dopamine pathway
In previous research we have have based our studies on the
dopamine sub-system because it: (1) allows the simplest implementation in a realistic neural network and (2) controls basic features fundamental for the regulation of learning processes. The
approximate principal schema of the dopaminergic nigrostriatal,
mesolimbic and mesocortical pathways is presented on Fig. 2.
The majority of the neurons in a striatum are GABA inhibitory
cells and have dopamine receptors. The dopamine has a dual influence on striatum neurons as it: (1) inhibits the (D2-type) in the
indirect pathway and (2) excites (D1-type) in the direct pathway.
When dopamine is low [in the striatum] the indirect pathway
becomes overactive and the direct pathway becomes underactive,
thus balancing the distribution of neuronal activities between two
parts of the nigrostriatal pathway.
The implementation of the dopamine pathways is depicted on
Fig. 3 where the pathways are indicated by text on arrows:
1. ‘‘Direct”: Cerebral cortex (stimulate) ? Striatum (inhibit) ?
complex SNr-GPi (Thalamus is less inhibited) ? Thalamus (stimulate) ? Cerebral cortex (stimulate) ? muscles and etc.
2. ‘‘Indirect”: Cerebral cortex (stimulate) ? Striatum (inhibit) ?
GPe (STN is less inhibited) ? STN (stimulate) ? complex SNrGPi (inhibit) ? Thalamus (is less stimulated) ? Cerebral cortex
(is less stimulated) ? muscles and etc.
5
5.2. The serotonin pathways
The diagram presented in Fig. 4 depicts the overall modelled
structure of the serotonin pathways. Efferent projections from
the rostral group to raphe nucleus, cerebral cortex, thalamus, basal
forebrain (includes septum), hypothalamus, locus coeruleus, ventral tegmental area, limbic system (includes hippocampus, amygdala), basal ganglia, such as neostriatum, substanta nigra and
nucleus accumbens, also to other nucleus, e.g. trigeminal nucleus,
facial nucleus, laterodoral tegmental nucleus (Müller & Jacobs,
2010).
Afferent projections to the raphe nucleus are from ventral
tegmental area, limbic system, basal ganglia, cerebral cortex, basal
forebrain, hypothalamus, other nucleus, periaqueductal grey and
reticular formation (Müller & Jacobs, 2010).
Neurons of the serotonin pathways project to different parts of
a brain and interact with other neurotransmitter pathways. The
serotonergic projection from the dorsal raphe nucleus (DR) to the
locus coeruleus (LC) which plays an inhibitory role.
Serotonin transmission affects the dopamine pathways. The
Activation of serotonin receptors in the prefrontal cortex (PFC)
and in the nucleus accumbens stimulates the dopamine release.
The activity of dopaminergic neurons of the ventral tegmental area
(VTA) is under the excitatory control of 5-HT receptors located in
the PFC. The effect on the dopamine system in the VTA is dependent on the type of activated serotonin receptor. The 5 HT1A,
5 HT3 receptor agonists increasing dopamine release in the
VTA and PFC and the 5 HT2C receptor agonists decreasing dopamine release [in the VTA and PFC. In the substantia nigra, nucleus
accumbens and in the striatum serotonin antagonizes the dopamine function (Daw et al., 2002; Müller & Jacobs, 2010).
5.3. The noradrenaline pathways
The diagram 5 depicts a simplified structure of the schema of
the simulation of noradrenaline pathways as discussed in following sections where we consider: (1) the motor cortex, (2) the bed
nucleus of the stria terminal, (3) the raphe nuclei, (4) the perirhinal
cortex and Nucleus paragigantocellularis lateral, (5) the lateral dorsal tegmental nucleus, (6) the nucleus tractus solitarii, and (7) the
locus coeruleus.
Fig. 2. The dopamine system of a rat brain (Kourrich et al., 2015). SNc - substantia nigra pars compacta, SNr - substantia nigra pars reticulata, STN - subthalamic nucleus,
GPe - globus pallidus external, GPi - globus pallidus internal, Acb - nucleus accumbens, VTA - ventral tegmental area, PPTg - pedunculopontine tegmental nucleus,
Amy - amygdala.
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M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
Fig. 3. The simplified schema of the simulated dopamine sub-system including: nigrostriatal and mesolimbic and mesocortical pathways.
5.3.1. Motor cortex
The motor cortex projects to noradrenaline receptors of locus
coeruleus (LC in the diagram) (Ferrucci, Giorgi, Bartalucci,
Busceti, & Fornai, 2013), via glutamate.
5.3.2. Bed nucleus of the stria terminal
Cholinergic innervation to the bed nucleus of the stria terminal
(BNST) is provided by the latero-dorsal tegmental nucleus, and the
BNST in its turn projects to the amygdala. Glutamatergic inputs to
the BNST originate from neurons located in the prefrontal cortex
(Crestani et al., 2013) and regulate the activity of GABA inhibition.
The activity of BNST neurons is regulated by GABAergic inputs
from both intrinsic sources.
5.3.3. Raphe nuclei
Both a1 - and a2 -adrenergic receptors play a role in mediating
noradrenergic regulation of serotonin release in the raphe as well
as in raphe projection areas (Ordway, Schwartz, & Frazer, 2007).
5.3.4. Perirhinal cortex and Nucleus paragigantocellularis lateral
Prominent afferents to the LC include the nucleus paragigantocellularis (PGi) and the ventromedial aspect of the prepositus
hypoglossi (PrH) in the rostroventrolateral and dorsomedial
medulla, respectively. These nuclei provide strong excitatory and
inhibitory influences on LC neurons (Ordway et al., 2007), respectively, and are also sources of several neurotransmitter inputs to
the LC nucleus. The stimulation of the PGi strongly excites the LC
neurons. In contrast, strong inhibition is produced by PrH stimulation (Berridge & Waterhouse, 2003). That inhibitory input also
arises from the PGi is revealed when the strong glutamate input
is antagonized pharmacologically.
5.3.5. Lateral dorsal tegmental nucleus
The inbound axons project to the lateral dorsal tegmental
nucleus (LDT) on a1 and a2 adrenergic receptors from the LC. In
its turn the LDT cholinergic neurons project to the LC where noradrenaline neurons are activated.
5.3.6. Nucleus tractus solitarii
There are strong ascending projections of these nucleus tractus
solitarii (NTS) NE cells to forebrain areas such as the BNST (into
GLUT receptor of BNST), nucleus accumbens (into GABA receptor)
(Aston-Jones, 2002). Amygdala also plays important role in affective and cognitive processes.
5.3.7. Locus coeruleus [LC]
The striatum receives a small amount of NE projections only via
scattered fibres from the LC, nonetheless these striatal afferents
seem to possess a high turnover rate. Stimulation DA neurons of
VTA increases the activity of the LC (Ferrucci et al., 2013) receiving
signals from the D1/D2 receptors and generating further exposure
on them.
The main afferents to the LC include projections from the
prefrontal cortex (activates noradrenergic LC neurons via a
glutamate), lateral hypothalamus, raphe nuclei, and amygdala
(Aston-Jones, 2002). Furthermore, the LC receives NE afferents
from lower medullary A1 and A2 regions. Additionally, LC receives
DA afferents from VTA. The a1 - adrenergic receptor, receives
signals from the LC and has an intensive influence over most DA
neurons activity of the VTA. The PFC activates noradrenergic LC
neurons via a glutamate. Inside the PFS there is an underlying
inhibitory effect of prefrontal activation when the more potent
glutamate-mediated excitation is antagonized (Ordway et al.,
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
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M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
7
N
Fig. 4. The simplified schema of the serotonin sub-system including: middle and rostral pathways.
Fig. 5. The simplified schema of the noradrenaline sub-system.
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M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
Fig. 6. Experimental results: the computational power used per each 5 ms of the simulation.
2007). Gamma-aminobutyric acid (GABA) has a tonic inhibitory
effect on the LC and regulates levels of norepinephrine in the
cortex.
6. Results
To evaluate and validate the posited approach the simulation is
implmemted using the NEST the Neural Simulation tool (Gewaltig
& Diesmann, 2007) (NEST) with the current validation being
restricted to the dopamine pathways. We trigger the dopamine
production in SNc, PPTG, amygdala programmatically on 400 ms
of the simulation a shown in Fig. 3.
The ‘spike generator’ of the motor cortex is triggered every
20 ms to initiate the neuronal activity. The overall duration of
the simulation is 1000 ms during which we determine the reaction
of simulated thalamus and motor cortex on the neuromodulation
related to dopamine levels as a rise in spiking activity and the following slow decay. Spike detectors are installed in: the motor cortex ‘‘Glu[1]”, the prefrontal cortex, VTA, SNc, the thalamus. Spike
generators of PPtg and the amygdala remain active until 600th
ms of our simulation.
We have registered every 0.1 ms the simulated neuronal activity and computational power consumed to compute every 10 ms of
the simulation. The orange or topmost graph on Fig. 6 is the computational power used for the simulation of the rat brain with
dopamine neuromodulation. The histogram indicates the frequency of spikes for: green – Motor cortex [Glu1], blue –
Thalamus.
The computational power shown in Fig. 6 is represented in
number of seconds used by the CPU on 100% of utilisation of the
machine with running simulation. According to the graph shown
in Fig. 6 we indicate the rise of the computational power consumed
at 410 ms of the simulation that we correlate with the dopamine
neuromodulation that matches our hypothesis of the correlation
of fear of a mammalian brain with the computational power consumed of a computational system.
7. Conclusions and future work
In this, and previous works Talanov and Toschev (2014) and
Vallverdú et al. (2015), we propose that mechanisms similar to bio-
logical affects and emotions can be translated and implemented in
computerised system parameters in artificial systems. Following
the model of H. Lövheim we have considered the creation of
dopaminergic, serotonergic and norepinephrinergic neuromodulation systems of mammalian brains in order to design our computational model. Thus, we introduce an ‘emotional-like’ mechanistic
approach to artificial reasoning. Our intention is not only emulate
the human cognitive architecture for human understanding to: (1)
test if such evolutionary approach can be instantiated into computational frameworks and (2) evaluate the potential of this implementation to improve the quality and complexity of their
computational/cognitive processes.
We have implemented a model of dopamine system of a rat
brain using NEST Neural Simulation Tool to evaluate and validate
our posited approach in a simulation of 1000 ms of dopamine neuromodulation inside the model, the results identify the increase of
computational power exactly during neuromodulation. This can be
understood as partial proof of our hypothesis regarding dopamine
axis. We have also created a model for the inhibitory role of neurotransmitters, as exemplified by serotonin. As a consequence of
both models, dopamine and serotonin, we have demonstrated that
both neuromodulators can be successfully implemented into computational environments along with the power of the combination
of both synthetic hormones. This approach allows the management
of increasingly complex cognitive behaviours into computational
decision-taking AI.
Whilst our study has identified and addressed a number of challenges we have identified a number of open remaining open
research questions. In considering these questions we plan further
experimental validation and enhancement of proposed model,
modelling and validation of serotonin and norepinephrine systems,
their integration, validation of integrated system, development of
appraisal models, with implementation in a working cognitive
architecture.
Acknowledgments
Part of the work was performed according to the Russian
Government Program of Competitive Growth of Kazan Federal
University. Prof. Vallverdu’s research is supported by DGICYT:
Innovacion en la prctica cientfica: enfoques cognitivos y sus consecuencias filosficas, (FFI 2011-23238).
Please cite this article in press as: Talanov, M., et al. Emotional simulations and depression diagnostics. Biologically Inspired Cognitive Architectures (2016),
http://dx.doi.org/10.1016/j.bica.2016.09.002
M. Talanov et al. / Biologically Inspired Cognitive Architectures xxx (2016) xxx–xxx
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