Measuring Fear, Anxiety And Depression Flashcards
What is Boissy et al’s 2007 definition of Emotions?
Emotions = a short-lived affective response to an event that is associated with specific bodily changes
What are the 3 components of emotions?
1) Subjective experience
2) Behavioural expressive component
3) Neurophysiological expressive component
What is Nettle and Bateson’s 2012 definition of moods?
Moods = relatively enduring affective states that arise when negative or positive experience in one context or time period alters the individuals threshold for responding to potentially negative or positive events in subsequent contexts or time periods
True or false
Moods are the background emotional state against which responses to emotions occur
True
How are moods triggered?
Moods are triggered by the accumulation of experience
How are emotions triggered?
Emotions have an immediate triggering event
True or false
In human contexts it’s possible to experience extreme interactions which can then result in an emotional state which spills over over time
True
What happens when an emotional state is sustained?
When an emotional state is sustained it can turn into a mood
What happens if a mood state is prolonged for a long period of time?
If the mood states are prolonged for very long periods of time then they can become pathological
By pathological I mean clinical states will begin to show
Define fear
Fear = A complex negative short-lived affective state functioning to preserve life from threat/pain
What is Sylvers et al 2011’s definition of fear?
An aversive emotional state during which an organism is motivated to escape a specific and imminent threat
What is Dias et al 2013’s definition of fear?
Fear = Stimulated by specific stimuli and resulting in defensive responses that gradually subside when these are no longer present
How is fear characterised?
Fear is characterized by short-lived high arousal that quickly dissipates after the threat is avoided
What triggers fear?
Fear is only seen in the presence of specific triggers
Is fear a mood or emotion?
Emotion
Is anxiety a mood or emotion?
Mood
Anxiety is a complex negative sustained affective state or mood
True or false
When anxiety is very enduring we can get clinical anxiety which is pathological
True
What is Dias et al 2013’s definition of anxiety?
A state of apprehensive mood accompanied by increased arousal and vigilance that arises from general and non-specific stimuli perceived as being potentially threatening (in the future)
What is Sylvers et al 2011’s definition of anxiety?
Anxiety = An emotion that motivates hypervigilance, with heightened sensitivity to external stimuli that represent an ambiguous or uncertain threat
What is anxiety associated with?
Anxiety behaviour is fear-like but may occur in absence of external triggers and is associated with a sustained elevated, but lower arousal state than fear
True or false
Anxiety has specific triggers in the environment
False
Anxiety has no specific trigger in the environment
What is the emotional valence of fear and anxiety?
They’re both negative valence
What’s the temporal focus of anxiety and fear?
Fear is present focussed
Anxiety is future focussed
What is the duration of arousal for fear and anxiety?
Fear is phasic (brief)
Anxiety is tonic (sustained)
What is the defensive direction of fear and anxiety?
Fear has avoidance (escape)
Anxiety has approach
What is the specificity of threat for fear and anxiety?
Fear is specific
Anxiety is diffuse/uncertain
What is the pain perception of fear and anxiety?
Fear has blunted pain perception
Anxiety has enhanced pain perception
True or false
There are a range of responses to fear eliciting situations not just avoidance
True
True or false
Anxiety has different responses not just approach
True
Why is pain perception blunted in fear eliciting situations?
With fear pain perception is blunted because if there’s an imminent threat that can threaten your survival you want to be able to still be functional to escape that threat
If you have pain in that situation it may mean you can’t escape that threat
Why does anxiety cause enhanced pain perception?
With anxiety you have enhanced pain perception in anticipation of the actual harm
What are the 4 categories of factors that can elicit fear responses?
1) Innate threats
2) Novel stimuli
3) Learned fear
4) Social/emotional contagion
True or false
Innate threats are genetically encoded
True
True or false
Innate threats are not species specific
False
Innate threats are species specific
What modifies fear eliciting properties of the potential triggers?
Fear eliciting properties of the potential triggers are modified by the characteristics of both the stimulus and the opportunity to manage exposure to that stimulus
How is a stress response triggered in the brain?
First the sensory cortex will detect and interpret sensory cues
Then the hippocampus will retrieve stored conscious memories and process the information from the sensory cortex to see if the threat is real based on previous memories
The hippocampus will then determine the context of the situation
The amygdala then decides the emotions and determines the threat
The amygdala will then store fear memories
The amygdala will then trigger the fear responses towards specific contexts and cues
What happens after the amygdala triggers the fear responses?
The central amygdala sends messages to other areas of the brain to trigger differential fear responses according to the threat
The Sympathetic branch of the Autonomic Nervous System will then trigger the adrenal medulla to:
- kick off catecholamine
- adrenaline production
- release glucocorticoids
This then readies the body for action
This leads to a whole range of responses such as:
- increased heart rate
- increased respiration rate
- dilation of pupils
- increased vigilance
- increased blood pressure
- tension of the muscle
- eliminate behaviourWhat happens in an animal if it freezes or hides?
Some animals will freeze or hide in a fear eliciting situation
This is mediated by the vagus nerve stimulation which will result in:
- bradycardia
- shallower breathing
- reduced consumption of oxygen
Give examples of anxiety inducing situations
Sustained social isolation
Novel environment
Light
Internal cues
How are anxiety responses triggered in the brain?
The amygdala is triggered in the same way as the fear response
The amygdala then triggers the bed nucleus of stria terminalis to mediate which behaviours and autonomic responses arise
With anxiety this triggers hypervigilance and hyperarousal
What are innate fears?
Genetically encoded fear responses are known as innate fears
Innate fears are cues that even if never experienced previously will result in unconditional arousal of brain systems and trigger the fear responses
True or false
Innate fears are stimuli which consistently threatened survival through evolutionary history
Innate fears have adaptive value
True
True or false
It appears possible to select for/against propensity to show fearfulness and anxiety traits
True
Why must we be careful when interpreting studies that select for/against propensity to show fearfulness?
This is because they’re selecting for particular trait expression of fear but there are many different strategies to fear responses
So what might be occuring is that they selected for a predisposition to a particular response in relation to the same fear eliciting stimulus rather than selecting for a difference in internal experience
Why must we be careful when interpreting studies that select for/against propensity to show fearfulness?
This is because they’re selecting for particular trait expression of fear but there are many different strategies to fear responses
So what might be occuring is that they selected for a predisposition to a particular response in relation to the same fear eliciting stimulus rather than selecting for a difference in internal experience
What 3 situations can experiential aspects affect expression of fear and anxiety?
1) During gestation
2) During early life
3) Conditioning of cues paired with aversive stimuli or events
What happens during gestation that can affect expression of fear and anxiety?
When a mother experiences a frightening or anxiety inducing situation during pregnancy then the offspring can respond to those situations in a more reactive way
This is because the environmental effects on the mother are preparing the offspring to be better adapted to a threatening environment in which they’re going to be born into
How do we know that early life experiences can affect expression of fear and anxiety?
Cross fostering experiments indicate rat pups nursed by anxious mothers are more likely to be more emotionally reactive later in life
These are modifications to the offspring that help the animal adapt to that environment
Explain how conditioning of cues with stimuli or events can affect the expression of fear and anxiety?
Animals can learn to pair certain cues to events or aversive stimuli and retrieve those memories to react fearfully to those cues at a later date
This reduces the likelihood of that harmful experience happening again if they’re pre-emptively taking action
Animals can also learn things that reduce fearfulness
The animals can learn if they’ve had repeated exposure to the fear eliciting stimulus but nothing bad actually happens
This allows the animal to learn not to respond to the stimulus
There can be counter conditioning where we can retain the learning of animals to associate something positive with a situation which may have frightened them before
What is the human definition of depression?
Human depression = a mental state or chronic mental disorder characterized by feelings of sadness, loneliness, despair, low self-esteem, and self-reproach; accompanying signs include psychomotor retardation (or less frequently agitation), withdrawal from social contact, and vegetative states such as loss of appetite and insomnia
What is the human definition of depression?
Human depression = a mental state or chronic mental disorder characterized by feelings of sadness, loneliness, despair, low self-esteem, and self-reproach; accompanying signs include psychomotor retardation (or less frequently agitation), withdrawal from social contact, and vegetative states such as loss of appetite and insomnia
Is depression a mood or an emotion?
Mood
What is depression?
Depression is a low arousal negative mood state associated with reduced responsiveness to stimuli
True or false
If depression is prolonged it can become pathological
True
Animals show depression like behaviour
These animals have also been used to model human depression
What does this mean in terms of indicator validity?
This means that there is some homology to human depression which can be used as an indicator
How is mild depression adaptive?
Some argue that mild depression and this lack of responsiveness to stimuli could be adaptive
Mild depression may indicate something is wrong to the individual and that that situation needs to be avoided
Mild depression can also indicate problems to others
In social species mild depression can elicit help and care from others in the group
It can also indicate problems to potential caregivers
Mild depression causes minimal movement and despair postures which may minimise attacks from conspecifics and predators
How is severe depression maladaptive?
Severe depression is considered to be maladaptive
Severe depression can be seen as pathological development of adaptive behaviour that’s not actually working in that environment
The reason severe depression is Maladaptive is because the subject doesn’t respond to danger and shows increased susceptibility to disease
Due to this severe depression is a challenge to survival
True or false
The true cause of depression is unclear
However it’s likely that a combination of factors and stress that cause depression
True
True or false
Depression seems to be associated with multiple genes acting together in interactions with the environment
True
True or false
In humans there is lots of evidence supporting heritability of susceptibility to major depression
There’s a genetic predisposition
In humans major depression is heritable and more likely in females
True
True or false
In humans the biochemical environment effects susceptibility to depression
Alcohol and drug dependency can increase risk of depression
True
True or false
In humans personal experience and psychological factors can increase susceptibility of depression
In particular traumatic experiences does this such as bereavement
True
True or false
In humans illnesses are associated with depression
However we don’t know if depression came first and predisposed some of these conditions or whether the condition came first and predisposed the person to experience depression
True
True or false
In humans and animals prolonged inescapable stress is one of the most common triggers of depression and depression like states
We know that predictability and controllability have a major impact on being able to cope with stress
True
Give 5 examples of situations where animals show depression like behaviour
Acute sickness Social defeat Loss of offspring Loss of social bonds When an active strategy fails
Why does the brain of a depressed person look different to a non-depressed person?
Depressed brains have reduced brain activity
What we see as a result of this reduced activity is atrophy and reduction of neurogenesis associated with stress
Due to this brain areas important for memory formation, management of emotion and attention are interupted
Brain areas including the hippocampi (problems with memory) and frontal lobes (managing emotional and attention) are less active and atrophy
True or false
Evidence suggests that neurotransmitters are balanced in a depressed brain
False
Evidence suggests that neurotransmitters are out of balance in depressed brains
Because of depression what happens to brain areas dealing with thinking (ability to process information), sleep, mood appetite, and behaviour?
Brain areas dealing with thinking (ability to process information), sleep, mood appetite, and behaviour don’t seem to function normally
What we’re seeing in these brain areas is a shrinkage of cells that are present and a reduction in the number of cells that are present
We know that brain cells need to stay active to maintain connections so without the activity they shrink and eventually atrophy
How can some of the brain outcomes be potentially used as an indicator?
By looking at the brain and the neurotransmitters
By looking at the outcomes of abnormal responses in some of these behavioural systems
Which brain systems are thought to be causes of depression?
Disturbances in the Limbic Hypothalamic-Pituitary-Adrenal (LHPA) axis
Disturbances in the serotonin (5HT) system mostly consistently associated with mood altering illness
Interactions between the LHPA axis and the serotonin (5HT) system
What does the Limbic Hypothalamic-Pituitary-Adrenal axis regulate?
Arousal Sleep Appetite Experience of pleasure Mood
What causes Limbic Hypothalamic-Pituitary-Adrenal axis disturbances and does this result in?
Disturbances in the Limbic Hypothalamic-Pituitary-Adrenal axis are associated with increased in circulating cortisol
These disturbances result in:
- excessive secretion of Corticotropic Releasing Factor in the hypothalamus
- reduced glucocorticoid receptor in the limbic region
- this increases circulating cortisol
How does chronic stress affect the serotonin (5HT) system?
In chronic stress the glucocorticoids interact with serotonin (5HT) receptors in the brain
This leads to aberrant serotonin function
Aberrant serotonin function is implicated in the aetiology of major depression and anxiety disorders
We know that serotonin is really important in allowing individuals to cope with stress
We also know that the levels of serotonin in the synapses are associated with increased in Brain Derived Neurotropic Factor (BDNF) in the cell neurone through a series of chemical messages to the cell
Brain Derived Neurotropic Factor is involved in nourishing the cell neurone allowing the cell to become more active and make other connections with other cells
This has some implications for the shrinking of active cells in those areas of the brain that become less active and atrophy
There are commonalities in the way that animals respond to fear
Give examples of this
There are commonalities in the way that animals respond to fear in terms of changes in:
- postural expressions that are species specific
- alarm calls
- odours
- species specific facial expressions
True or false
Species specific facial/postural expressions, alarm calls and odours serve as alerting indicators to conspecifics of danger
True
True or false
For animals with less of a tendency to be demonstrative in terms of changing posture or have fixed facial features it can be difficult to assess their fear
True
How is the startle response augmented when fearful?
We see animals in fear eliciting situations being:
- more likely to startle
- more severe startles
What does fear do to other behavioural systems and why?
Fear is always prioritised and inhibits other behavioural systems
This is because fear is designed to protect against imminent danger
Interruption of these other behaviours can be used as indicators of fear
True or false
Fear can be assessed using a range of behavioural and physiological indicators
However we need to be mindful that not all of the potential indicators that measure fear do not measure valence
True
True or false
Responses to fear can not be used as an indicator
False
Responses to fear can be used as an indicator
Responses to fear vary according to the threat
Give 3 examples of responses to fear
1) Active defence
The animal may attack the threat
2) Active avoidance
This is where the animal tried to escape or hides if escape isn’t possible
3) Passive avoidance
This is where the animal freezes or becomes immobile
Bradycardia and shallow breathing occur here as driven by the amygdala
Which fear response strategy is used can be modified by the context and the environment
Give examples of this
If the danger is close but can be avoided then the animal will flee
If the danger is distant or inescapable then the animal may hide or freeze
If the predator detects motion the animal will freeze
If the danger is inescapable but hiding is ineffective the animal will fight
True or false
There are likely to be differences between individuals in their thresholds between the different strategies and which strategy they are more or less likely to adopt
Some research links personality, temperament and genetic aspects to whether or not an animal, or a subpopulation of animals, uses active coping styles or passive coping styles
True
True or false
Usually within a population there’s a normal distribution of fear coping styles
However there are some species that seem to have distinct binary subpopulations for either one or the other coping style
True
True or false
There’s often common indicators used for both anxiety and fear making it hard to distinguish
What the indicator is measuring tends to be dependent on the situational context
True
Give examples of what the expression of anxiety can involve
Increased activity
Cautious investigation/approach type response
Enhanced pain perception
In some species there are specific species behavioural patterns that have been validated as indicators of anxiety
True or false
In humans chronic anxiety and fear are usually referred to as a pathological disorder
True
True or false
In humans chronic anxiety and fear are well distinguished
False
In humans chronic anxiety and fear are not well distinguished but tend to be distinguished based on the drugs given to treat the symptoms and behavioural signs
There are a range of different symptoms which we may potentially see in other animals if there is homology with humans
Give examples of these symptoms
In humans we see:
- gastrointestinal problems
- hypertension
- asthma
- alopecia
Fatigue and insomnia can be seen in humans and other animals
These are psychosomatic disorders
Clinical anxiety in humans is associated with long term alterations in what 2 areas and what can it lead to?
1) Psychology
This is about how the threat is processed
This can lead to:
- uncontrollable apprehensive expectations
- jumpiness
- excessive vigilance
- fidgeting
2) Physiology
This can lead to:
- gastrointestinal upset
- diarrhoea
- frequent urination
- tachycardia
- chronic dryness of the mouth
- increased shallow breathing
Extreme fear and anxiety in humans can lead to abnormal behaviour
This is seen to some extent in other animals
Give examples of the abnormal behaviour
Hyperexcitability and restlessness
This seems to be more associated with clinical anxiety
Withdrawal and depression
This is associated with clinical depression where there becomes a lack of responsiveness to stimuli
Give examples of behavioural tests for fear and anxiety
Open field test Failure to feed Novel objects test Predatory odours Plus maze Social interactions Human interaction/approach test Avoidance Defensive burying Hole board test Emergence test Startle reflex Tonic immobility/Restraint test Motivational conflict test
What happens in an open field test?
An individual is placed in an open arena and activity and defecation is observed
Elimination or defication is not always consistently a good measure across species
The activity of the animal in the arena can be associated with fear and anxiety and modified by anxiolytics
What happens in a plus maze?
Plus mazes take advantage of rodents innate fear of open light spaces
You get a maze in the form of a cross that’s elevated with 2 of the arms of the cross open to the light with no walls, while the other 2 arms are dark and have walls
Naturally the rodents show aversion to the open arms
If anxiety is decreased by an anxiolytic they will spend more time in the open spaces than when they’re anxious
The plus maze test let’s us see whether or not an anxiolytic works
We can also potentially adopt the maze to look at other factors in the environment that affect the animals
Give an example of an avoidance test?
Mirror test
What happens in a defensive burying test?
In rodents when confined with a threatening object they try to bury it
You can see if this behaviour is depressed with an anxiolytic
What happens in a hole board test?
You get a board with a series of holes and you look at the number of times a head is dipped through these holes
The board is on a table or high up
The more anxious the animal the less likely it is to look through the holes to see the drop beneath it
What happens in an emergence test?
You take advantage of aversion of light environments in species that are naturally nocturnal
You look at how long it takes for the animal to leave a dark box and enter a bright room
The more anxious the animal the longer it will take to leave the box
What happens in a startle reflex test?
The startle response is experimentally induced
The amplitude or latency to startle is what you measure
Amplitude = degree of startle in terms of the height of the jump
What happens in a tonic immobility/restraint test?
Tonic immobility is a state in which you see profound motor inhibition (lack of movement)
This is thought of as a predator response and so is only seen in stressful experiences
Tonic immobility is experimentally restraint
You will then record the number of times it’s required to enduce tonic immobility and how long until the animal rights itself
The number of inductions required to induce tonic immobility and duration of tonic immobility before righting is positively related to fear
Tonic immobility varies between individuals so it pays to be mindful of individual variation in response
What happens in a motivational conflict test?
This is a learned test
This is where you put conflict between what the animal wants to do
The more risk averse the animal is the more anxious it tends to be
Give an example of a motivational conflict test and explain what happens in it?
Vogel conflict test
Vogel conflict tests are where you send shocks to the animals foot everytime it goes to drink
This creates conflict to decide how thirsty the animal needs to be to risk a shock
The more risk averse the animal is the more anxious it tends to be
Give examples of learnt behaviour tests
Motivational conflict test Transgenic knockouts Stimulation of the brain Developmental tests Conditioned emotional responses
What happens in a stimulation of the brain test?
These are used as models of panic disorder
This is where you directly stimulate the brain centres known to be associated with controlling the experience of fear, panic and anxiety in humans
Give examples of developmental tests?
Maternal separation
Isolation
What happens in a conditioned emotional responses test?
This is where you see repeated pairing of a particular cue with a fear eliciting stimulus so that the animal associates those 2 things together
Then when you present the particular cue alone you get the response
You can then look to see if the response is modified by an anxiolytic
What are the 8 issues and factors affecting measures of fear and anxiety?
1) There’s a lack of clarity between measures of emotion and pathological mood states
2) Tests are often not standardised
3) Many tests of fear and anxiety can be affected by various environmental factors
4) Many tests actually involve a titration between fearful/anxious behaviour vs exploration
5) Repeatability and validity are not always checked for species, and different tests/indicators do not always correlate with the species
6) For tests depending on learned associations memory can be affected by stress
7) Individual and strain variation may affect results
8) Effects of apparent anti-anxiety agents can sometimes be explained by factors other than reduced anxiety
Give examples of potential indicators of depression in humans
Increases in circulating glucocorticoids Anhedonia Appetite and sleep disturbance Weight change Decreased energy Difficulty in concentrating Emptiness Boredom Irritability Self directed aggression
Give examples of potential indicators of depression in non-human animals
Anhedonia Minimal movement Apathy Reduced maintenance behaviour Changes in cognitive bias REM sleep abnormalities Alterations in peripheral immune system leading to over activation of pro-inflammatory cytokines
Name some models of depression
Anhedonia electrodes Chronic mild model of stress Learned helplessness Behaviour despair test Social separation model Drug models
What happens in the anhedonia electrodes test?
First the rat is implanted with electrodes
Then it’s trained that when they see a light cue that there is an opportunity to access a pleasurable reward which should stimulate the electrodes
The rats are then injected with cytokine interleukin-2
This lowers the self-stimulation of the brain which is thought to mimic anhedonia and depression, due to the disturbance of dopamine release
Injection of cytokine interleukin-2 results in failure to self stimulate the lateral hypothalamus (the rewards center)
What happens in the anhedonia electrodes test?
First the rat is implanted with electrodes
Then it’s trained that when they see a light cue that there is an opportunity to access a pleasurable reward which should stimulate the electrodes
The rats are then injected with cytokine interleukin-2
This lowers the self-stimulation of the brain which is thought to mimic anhedonia and depression, due to the disturbance of dopamine release
Injection of cytokine interleukin-2 results in failure to self stimulate the lateral hypothalamus (the rewards center)
What happens in the chronic mild model of stress?
The chronic mild model of stress is where cumulative mild unpredictable stressors suppresses motivation to work for palatable sucrose solutions and decreases ability to associate the environment with reward
Motivation to work for the palatable sucrose solution is a potential indicator of depression
The chronic mild model of stress seems to be impacting on the ability of the rats to experience pleasurable sensations and rewards
The cumulative mild unpredictable stressors cause depression
Examples of cumulative mild unpredictable stressors are:
Photoperiod changing
Suddenly having wet bedding
Suddenly having an unfamiliar animal in the next cage
Give examples of behaviour despair tests and explain what happens in them
Tail suspension test
In the tail suspension test the rat is suspended by its tail
You would then measure the duration of immobility
Swim force test
In this test the animal is placed in water with no chance of escape and they need to keep swimming without rest
At some point the animal will give up on escaping and just focus on keeping its head above water
The animals give up sooner on subsequent tests
However if the animal is pretreated with an antidepressant then the animal is less likely to give up and so takes longer to give up
What happens in the social separation model?
In social separation models there is a separation of animals that would have a bond
It is usually separation of mother and infant
This is especially done in primates
This results in anaclitic depression in infants which impairs physical development, social development and intellectual development
What happens in drug models of depression?
This is where you induce depression like states with drugs
Reserpine can induce depression pharmacologically
What happens in the learned helplessness model of depression?
Learned helplessness is based on loss of control
In the learned helplessness model there’s an inescapable punishment paired with a cue
Then when you give the cue again without the inescapable punishment it produces passivity or failure of escape responses
The animals also fail to relearn the escape responses when it’s possible to avoid the punishment
They also show deficits in other situations where escape behaviour (active responses) would be normal
Give examples of deficits in other behaviours due to learned helplessness
Loose weight
Reduced appetite
Groom and play less
What is the learned helplessness type of depression associated with?
The learned helplessness type of depression is associated with increased noradrenaline in the nerve endings of the forebrain and decreased serotonin release in the forebrain
Learned helplessness is also seen in invertebrates, what kinds of questions does this raise?
This raises interesting questions about the emotional experience of these so called lower order animals
What are the 7 issues/factors affecting measures of depression?
1) We still don’t fully understand the mechanisms of depression
2) There are some differences in animal models seen with gender
3) You need to be careful in generalising rodent models to other species
4) Inactivity could occur for a range of reasons not just depression
As a result you need multiple indicators
5) In humans a combination of clinical signs are currently used for diagnosis, but not every individual may have the same profile
As a result you need multiple indicators
6) It’s unclear whether some measures can discriminate from other long term low arousal mood states yet
7) Ways of measuring cognitive bias without substantial training are limited
