Lecture 1 Flashcards
Consequences of stres
Mobilization of energy (e.g. gluconeogenesis)
Cardiovascular activity increases
Improved attention, better memory
Suppression gastro-intestinal activity
Suppression growth
Suppression reproduction
Suppression immune system
Increased risks due to chronic stress
Diabetes, myopathy, exhaustion
High blood pressure
Neuropsychiatric disorders: PTSS, major
depression
Reduced growth
Amenorrhea
Infectious diseases
what were the begginings of neurobiological research of emotional behavior?
Phinease Cage –> studied by John Harlow
3D reconstruction showed damage to PFC (inhibition in behavior)
What is the relationship between stress and emotion
What is the definition of emotion?
An emotion is a particular subjective state or feeling, a quality of conscious
awareness and a way of responding accompanied by physiological
arousal.
What type of affect/hedonic valence do emotions have (examples)
Emotions may have positive or negative affect/hedonic valence.
– Examples:
* fear/anxiety
* sadness/grief
* anger/aggression
* hate
* frustration
* love/devotion
* hope
* joy/happiness
Emotional behavior/emotional response
Emotional behavior (e.g. observable motor patterns)
Emotional response (e.g. measurable physiological indices)
What is Charles Darwin’s work on expression of emotions
- The Expression of Emotions in
Man and Animals (1872)
points out the relevance of studying emotion in animal models (presence/changes throughout evolution) - Emotional expression essential for communication - autonomic aspects of emotions
What is the adaptive fight-flight response to a predator?
- Hypothalamus activates sympathetic division of nervous system
- Heart rate, blood pressure, and respiration increase
- Adrenal medulla secretes epinephrine and norepinephrine
- Blood flow to skeletal muscles increases
- Stomach contractions are inhibited
What are relevant contributions of Walter B. Cannon (1871-1945)
› Homeostasis concept
› Fundamental role of the
Sympathetic Nervous and
Adrenomedullary System
(Adrenaline)
› Fight/Flight response
› Selfregulation (the wisdom of
the body)
What are relevant contributions of Philip Bard (1898-1977)
› Bard, a student of Cannon’s,
made serial transections,
essentially disconnecting the
cerebral cortex from outflow
pathways in cats. When
transection just included the
forebrain (a), a range of
behaviors constitutive of rage
was observed when a cat was
presented with innocuous
stimuli.
› These behaviors included:
* Arching of the back
* Extension of claws
* Hissing
* Spitting
* Pupil dilation
* Increased blood pressure, heart
rate and adrenal secretion
- Inhibitory role of PFC
- Hypothalamus
What are relevant contributions of Hans Selye (1907-1982)
- Introduced the term stress
- Stress is the non-specific
response of the body to any
noxious stimulus or demand. - General Adaptation Syndrome
(GAS) - HPA-system as the main
hormonal mediator of stress
HPA axis
What are the two main physiological emotional response pathways?
What is James-Lange’s theory of emotion - (Somatic theory of emotional response)
Physiological responses induce feeling (see scheme lecture slides)
Theories of emotion
- common-sense view: Perception -> Feeling -> physiological response
- james-lange view: Perception -> Physiological response -> Feeling
- cannon-bard view: Perception -> Feeling/Physiological response
- modern biopsychological view: Perception/Physiological response/Feeling <-> Perception/physiological response/Feeling
What are the target organs of stress hormones
› Brain
* Neuroendocrine receptor mechanisms
* Neurotransmitter systems
* Serotonin
* Noradrenaline
* Dopamine
› Periphery
* Cardiovascular system
* Immune system
Steroid hormones talk back to the brain: negative/positive feedback regulation
Release of cortisol -> negative feedback loop, system shuts down
Limbic system (Papez, 1937)
proposed that the part of the cortex dedicated to processing emotion is the limbic lobe, as defined by Broca. The limbic lobe comprises a ring of “primitive” cortex around the brainstem, including the cingulate cortex, the parahippocampal gyrus, and the hippocampal formation.
Limbic system:
Amygdala - stria terminalis/ ventral amygdalofugal pathway
– information of past (emotional) experience
Hypothalamus
– preparation of peripheral physiology
Hippocampus - fornix - mammilary bodies
– information of where and how
Limbic cortex
Role of amygdala in emotional behavior
- Key coordinator of emotional behavior
- Experience and expression of emotion
- Important for fear and aggression
complex of nuclei: receives information from all sensory systems
Amygdala complex
sensory input mainly Lateral nucleus (sensory cortex/sensory thalamus to lateral nucleus) –> Basal nucleus/Central nucleus/Accessory basal nucleus
Basal nucleus –> central nucleus –> Hypothalamus, midbrain, pons, and medulla
Accessory basal nucleus –> central nucleus –> Hypothalamus, midbrain, pons, and medulla
Main and accessory olfactory bulb –> Medial nucleus –> Medial basal forebrain and hypothalamus
Fear conditioning in rodents
sound /shock conditioning –> freezing fear response –> physiological response measure
What role does the amygdala play in Fear Conditioning
*The amygdala receives input
from all sensory systems
- Appears to be responsible
for adding emotional
significance to another
stimulus - Amygdala projects to
brainstem regions that
control emotional behavior
output
Amygdala stimulation produces emotional behaviors through subcortical pathways
(Neuro)biological research of aggressive behavior
(end 19th century)
- Friederich Golz
(1890) : Serenic effects of surgical
ablation temporal lobe in
extreme aggressive dogs. - Gottlieb Burkhardt
(1892): Serenic effects of surgical
ablation temporal and
frontal cortex in 4 out of 6
agitated and neurotic
schizophrenic patients.
The amygdala and Kluver-Bucy syndrome
Dramatic anti-aggressive effects after surgical removal of
(parts of) the temporal lobe in cats and monkeys.
Kluver-Bucy syndrome:
1. Social isolation
2. Sensory depression
3. Loss of initiative
4. Hypersexual
5. Enhanced food-intake
What is the role of the amygdala in aggression
Various types: ranging from defense to attack
Different forms of aggression are regulated differently by the brain.
Androgens are important
Predatory aggression: efficient, weak ANS
Affective aggression: for show, strong ANS
Amygdala is essentially involved: lesion studies (Pribram),
electrical stimulation has opposite effect
Provoking or taming aggression and attack by electrical stimulation of discrete areas of the brain
From lesion studies it has
become clear that the posterior
hypothalamus is important
for expression of anger.
Electrical stimulation of the
hypothalamus produced region-
dependent effects:
Stimulation of the medial
hypothalamus causes affective
aggression (threat attack).
Stimulation of the lateral
hypothalamus causes predatory
aggression.
What is the stress response?
› The stress response is by definition the behavioral physiological response to an uncontrollable and/or unpredictable stimulus.
› Is the stress response an indicator of a stressor?
› What is the difference between a stress response and an emotional response?
What is the current (mis)use of the stress concept
› Stress is currently defined as any actual or potential threat to
homeostasis (adversity)
› The term stress is used for both life-threatening situations and
everyday minor challenges
› The term stress became almost exclusively interpreted in terms of
its negative consequences, i.e. maladaptation and disease
vulnerability
› Stress models are often ecologically irrelevant (mice do not get shock in nature in the way they do in a laboratory setting)
› Circular reasoning: The presence of a physiological stress response is often used as an indicator of stress
What are the main autonomic nervous and neuroendocrine pathways in the bodily response to stressors?
Rat exppetiment corticosterone response
social defeat stronger corticosterone response than footshock/swimming? Is the corticosterone response an accurate measure of stress?
corticosterone during social conflict
higher corticosterone in social defeat than social victory
Sexual behavior: HPA response
highest corticosterone response
Circadian and ultradian rhythms
- peak in the morning
- Consider negative feedback (when high stress cort. level depends on activation of HPA axis)
social conflict physiological impact of winning/loosing; Sympathetic response sex, aggression
Important! summary
› There is no difference in the magnitude of the ‘stress’ response between positive, rewarding situations (sexual behavior, aggressive behavior) and negative, aversive situations (restraint, social defeat).
› Hedonic emotional valence of stimuli perhaps expressed in the termination of the ‘stress’ response.
› Neuroendocrine ‘stress’ response signals novelty or saliency?
Conclusion
› Stressor ≠ HPA axis activation
› Stressor ≠ Sympathetic activation
› The HPA axis and the sympathetic nervous system should be considered as systems involved in the physiological support of any behavior induced by any
kind of intrinsic or extrinsic stimulus.
› When is a stimulus a stressor?
* controllability/predictability (Seligman & Weiss 1972)
Glucocorticoids - metabolic hormones rather than stress hormone
What are the main factors moderating the response to stressors
Importance of control over situation (ability to impact/end stressor)
Conclusion
› Stress responsivity is not due to the physical characteristics of the stressor.
› Stress responsivity is related to the psychological appraisal of the stressor in terms of its controllability and predictability.
- stressdepends on degree of controllability and of how life threatening something is
