Amy Romijn Flashcards
What are emotions?
Motivated state consisting of:
- Physical arousal
- Expressive behaviours
- Cognitive/conscious experience
What are the two major divisions of the nervous system?
CNS - includes brain and spinal cord, processes information
PNS - includes the nerves connecting the CNS to muscles and organs
What is the peripheral nervous system?
- Contains the sensory (afferent) branch and the motor (efferent) branch
- Sensory info comes into our brains
- Motor branch Info that comes from the brain and to the body
- Motor branch contains the somatic nervous system and the autonomic nervous system
- Somatic does conscious control
- Autonomic does unconscious control
What is the autonomic nervous system?
- Controls unconscious movement (heartbeats)
- Contains the parasympathetic and sympathetic systems
- Parasympathetic and sympathetic innervate same visceral structures
- Sympathetic is mostly in the thoracic and lumbar system
What does the sympathetic and parasympathetic systems do
- Sympathetic mobilises the body during extreme situations (fight or flight)
- Parasympathetic controls routine maintenance functions (rest and digest)
- Both act in balance to keep the body’s systems stable and balanced despite outside conditions –> homeostasis
- PNS has an inhibitory effect on the SNS
What neurotransmitter is used by the sympathetic division?
- Norepinephrine (aka noradrenaline)
- Uses acetylcholine at some synapses but norepinephrine is released onto the target organ
- Has a second pathway, via the adrenal gland which norepinephrine and epinephrine into the blood stream (slower acting - sympathomedullary)
What neurotransmitter is used by the parasympathetic division
- Acetylcholine
- Uses it as every synapse and is released onto the target organ
What is the adrenal medulla?
- Major organ of the sympathetic nervous system (inside part of the adrenal gland)
- Releases adrenaline (aka epinephrine) and noradrenaline (aka norepinephrine) into the blood stream
- These hormones are then picked up by receptors in the organs
- Both adrenaline and noradrenaline have similar effects on the body, though act on slightly different receptors
What controls the autonomic nervous system?
- Hypothalamus is the key brain site for integration of multiple biological systems to maintain homeostasis
- Hypothalamus projects to the medulla oblongata where the cells that drive the autonomic systems are located
- Medulla is located in the lower half of the brain stem and contains the cardiac, respiratory, vomiting and vasomotor centres
- Deals with the autonomic functions of breathing, heart rate, and blood pressure.
What are somatic reflexes
Responses involving skeletal muscle e.g. knee jerk/blinking
What are visceral reflexes
Unconscious, automatic, stereotyped responses to stimulation involving visceral receptors and effectors
Visceral reflex arc (pathway)
- Receptors transmit via
- afferent neurons to the
- interneurons in the CNS
- efferent neurons transmit away from the CNS to the
- effectors which make adjustments
Visceral reflex arc: Blood pressure
- high blood pressure detected by arterial stretch receptors
- afferent neuron carries signal to CNS
- efferent signal travel to the heart
- Heart slows reducing bloody pressure
Homeostatic negative feedback loop
What does the enteric nervous system contain
- Glial cells
- 500 million neurons
- 40 neurotransmitters identified
- Produces 50% of all dopamine
- Produces 95% of all serotonin
- Barrier restricts blood flow to second brain
What is the enteric nervous system
- Third branch of the autonomic nervous system
- In the gut
- ‘Second brain’
- Very new
- Only just beginning to understand the interactions between the two brains
- Promising area - plaques or tangles found in brains of people with Alzheimer’s are present in neurons in their guts too
- Potential to use gut biopsies to make early diagnoses, as well as to monitor response to treatments
How do we measure emotion?
Psychological aspects of emotion allows researchers to objectively measure emotion
Emotion according to Darwin: Anger
- Frowning
- Protect eyes in anticipation of attack
Emotion according to Darwin: Surprise
- Eyebrows raised
- Mouth open
- Open the eyes wide to facilitate sight
- Draw in air quickly to put the body in a state of readiness
Emotion according to Darwin: Disgust
- Raised upper lip
- Expelling offensive matter from the mouth
- Accompanying nose and eye wrinkles (by products)
Emotion according to Darwin: Fear
- Eyebrows raised
- Mouth open
- More problematic for Darwin
- Movements similar to surprise but more tense
- Potential conflict between readiness and protection
Cross-cultural emotion studies: Paul Ekman
- Psychologist
- Pioneer in the study of emotions and their relation to facial expressions
- Inspired by Darwin
- Conducted several universality studies which provided the first methodologically sound evidence for Darwin’s arguments on emotion
Cross-cultural emotion studies: Ekman et al. (1972)
- Isolated South Fore tribe in New Guinea
- Preliterate
- Told stories to provoke an emotional response (e.g. your friend has come to see you, your child has died, you are angry and about to fight)
- Showed 3 faces of Westeners
- Asked to choose the most relevant expression
Results:
- Happy: 90% correct
- Sad, angry, disgust: 68-89% correct
- Fear and surprise were not discriminated at levels exceeding chance
Six basic emotions (Ekman, 1984)
- 6 primary emotions
- These evolved through their survival benefits (each unique in its cause and expression)
- Emotions occur automatically and rapidly
- Short in duration (different from moods)
Methodological issues with Ekman’s research
- Forced choice paradigms can inflate accuracy
- Sorenson (1976) conducted a similar study that allowed for open ended responses
- Anger, fear and happiness showed a high degree of accuracy
- Sad face was often called angry
- Inconsistent results for disgust and surprise
Two system emotional approach
- Two types of facial expression with different control systems
Spontaneous expression:
- Sub-cortical system
- Bottom-up ‘reflexive’ expression
- Universal and biologically determined
Those under voluntary control:
- Cortical system
- Mediates voluntary system (display rules)
- Top-down ‘contrived’ expression
- Shaped by environmental conditions
Theories of emotion: James-Lange theory (1884-1885)
- A stimulus leads to bodily arousal first, which is then interpreted as an emotion
- No body = no emotion
- Critique = sometimes there is no distinct physiological effect that maps onto each emotion we have
Theories of emotion: Cannon-Bard theory
- A stimulus leads to activity in the brain which then sends signals to arouse the body and interpret the emotion at the same time
What is interoception
- Ability to perceive and integrate physiological signals from within the body
- Key component in the generation of affective states
What is alexithymia?
- Difficulty in experiencing, expressing and describing emotional responses
- Difficulty in describing feelings to others
- High prevalence in autism
- Tend to have poor interoception
What is the amygdala?
- Major focus of emotion research in recent years
- Connections to thalamus, hypothalamus and other structures
- Major role in emotions especially fear
- Structure responsible for the rapid processing of sensory information that may be dangerous
- Because it does not require cortical input (conscious processing) the response is fast but not always that accurate
- Unconscious automatic response
Neurobiology of fear conditioning: Joseph LeDoux
Work has focused on brain mechanisms mediating fear conditioning. Key findings include :
- Legions to amygdala prevent fear conditioning
- Legions to thalamus (sensory relay) prevent conditioning
- Emotional processing can be preconscious and precognitive
Two routes of fear processing: Short route
- Immediate
- Less accurate
- Unconscious
- What’s that???
emotional stimulus –> sensory thalamus –> amygdala –> emotional response
Two routes of fear processing: Long route
- Slower
- More accurate response
- Conscious
- Draws on contextual information
emotional stimulus –> sensory thalamus –> sensory cortex –> amygdala –> emotional response