Lecture 3 - Physiological Perspective of Emotion

autonomic nervous system

a set of neurons communicating between CNS and visceral organs, it maintains homeostasis, it consists of the SNS and PNS

sympathetic nervous system (SNS)

responsible for the flight or fight response, it activates energy reserves, it prepares you for vigourous activity like escaping a predator, HR and breathing go up, it causes increased sweating and decreased digestion, it releases glucose for extra energy and goosebumps, the sympathetic nerves from your brian that innervates vestigial organs signalling to your heart that you need to breath faster

peripheral nervous system (PNS)

decreases HR and slows down your breathing, increases digestion, insulin is released to store energy in the liver and fatty tissue, it facilitates sexual arousal to prepare the body for reproduction

nausea

the SNS will produce retching to prepare for vomiting and the PNS stimulates the intestines to cause cramping and discomfort

sexual activity

the PNS promotes arousal and the SNS promotes orgasm and ejaculation

predator fear

the PNS will slow HR and the SNS activates to promote escape when seen

endocrine system

cortisol is released by the adrenal gland enhancing metabolism and increases the availability of bodily fuels

what are commonly used measures of emotion?

heart rate, blood pressure, respiration rate, electrodermal activity, cardiac pre-ejection period, respiratory sinus arrhythmia, interbeat interval, QRS complex and electrocardiogram

electrocardiogram (ECG)

it is used to measure changes in electrical activity generates by heart muscle contraction

QRS complex

indicates contraction, relaxation of ventricles

heart rate

number of beats per minute

cardiac inter beat interval

mean ms between beats over some time window, finer grained measure of change

systolic blood pressure

pressure of blood on arteries while ventricles are contracting

diastolic blood pressure

pressure while ventricles are relaxed

mean arterial pressure

average pressure across systole, diastole

electrodermal activity

sweat glands keep the skin hydrated and regulate temperature, SNS activation can increase sweat gland activity, this is what allows increase of speed of electrical conductivity by the skin due to increased sweat

parasympathetic influence

usually slows HR from the pacemaker’s natural rhythm of around 90 BPM, breathing in/inhalation blocks PNS influence on the heart

respiratory sinus arrythmia (RSA)

this refers to normal slowing down of HR during expiration so breathing out and speeding up of heart rate during inspiration, if its bigger that means that PNS is dominating, it influences vagal nerve activity

low RSA

this is associated with anxiety and depression

measurement challenges

individual differences in physiology are large, effects of emotion must always be defined as change from an immediately preceding baseline, the ANS responds to many events other than emotion, including physical movement, cognitive activity, sneezing, coughing and speech, ANS responses take 1 to 2 seconds to be detected and for hormones in saliva its 15-20 mins

william james

proposed that emotional feelings are caused by interoception, the perception of bodily changes, he also proposed that different emotional feelings may be associated with different profiles of activity in the body

pure autonomic failure

a condition in which the ANS ceases to influence the body, ppl report feeling emotions but less intensely

locked in syndrome

all output from the brain to muscles, ANS is lost due to brainstem damage, many patients seem tranquil but some do describe feeling emotions

autonomic specificity hypothesis

each emotion has a distinct, recognizable pattern of ANS response

autonomic specificity study

they had participants pose facial expressions of fear, anger, sadness, disgust, surprise and happiness then they had to relive strong memory for each emotion, they the measures HR, finger temperature and skin conductance

autonomic specificity study results

they found that heart rate increased during fear, anger, sadness but it slowed in disgust, they also found that finger temperature increased during anger and happiness but decreased in fear and disgust

emotion effect meta analysis

found that happiness produced less arousal than negative emotions, heart rate accelerates more anger, fear and sadness than disgust, anger however produced higher blood pressure, greater finger temperature and finger pulse amplitude compared to fear

emotion effect meta analysis limitations

they examined one physiological measure at a time rather than patters, the emotions elicited in the studies were weak, there was a limited range of physiological variables included and measures may have averaged over periods lasting much longer than the emotional responses

positive emotion physiology study

participants had to watch a set of slide evoking target emotions, for enthusiasm it was lottery with growing number of matches, for attachment love it was childhood fictional characters, for nurturant love it was baby animals, for amusement it was far side cartoons and for awe it was panoramic nature views, they measures cardiac inter beat interval, cardiac PEP, electrodermal activity, RSA and mean arterial pressure

positive emotion physiology study results

they found that emotions differed significantly in profile of physiological changes across measures, for instance for enthusiasm only the electrodermal response increased because this corresponds to SNS activity, MAP is activated because BP is high when SNS is active

status of autonomic specificity

the data is not adequate to offer a strong test of autonomic specificity, still a significant gap in the literature regarding this

culture and emotion physiology study

participants had to describe, relive personal experiences of happiness, pride, love, anger, disgust and sadness then they measured skin conductance/electrodermal activity and found that there was slight increases in skin conductance during emotion in both european americans and hmong americans

stress and its health consequences

they studied causes of cancer in lab rats and found that both experimental and control groups had extremely high rates, the reason for this was poor injection techniques cause seyle would drop them, chase them around and traumatize them causing stress from the manipulation itself to cause the disease

alarm (general adaptation syndrome)

a brief period of high arousal, readying the body for vigorous activity, it is mediated by sympathetic nervous system, hormones adrenaline and cortisol, in the immune system it prepares the body to fight infection

resistance (general adaptation syndrome)

a period of prolonged but moderate arousal in response to some stressor, it is mediated primarily by the endocrine system, in the immune system when activity is extended the body acts sick causing sleepiness, lack of appetite, fever and low sex drive

exhaustion (general adaptation syndrome)

the final stage of reaction to a prolonged stressor, characterized by weakness, fatigue, loss of appetite and lack of interest, in the immune system the body runs out of proteins to support immune function and illness increasingly likely as immune system is unable to fight disease

HPA axis

mediates resistance in the endocrine system, the adrenal gland is what releases cortisol which is a stress hormone, it is important for handling stress responses and managing cortisol levels, it regulates immune function and energy, you can measure cortisol levels in the saliva, hair, urine and blood

hypothalamus (HPA axis)

it releases the corticotropin releasing hormone (CRH)

pituitary gland (HPA axis)

uses CRH to release adrenal corticotropic hormone (ACTH)

adrenal gland (HPA axis)

use ACTH to release cortisol, it is located at the top of the kidneys

vagus nerve/vagal tone)

has parasympathetic influence on the heart, those with higher levels are better at regulating emotion and less vulnerable to depression, it can increased through surgery to stimulate it, slowed breathing can help activate it 

short term effects of stress

increase in HR and BP causes delivery of more oxygen, glucose to the brain and muscles, increased stomach acid secretion causes you to digest food quickly for use, converting protein to glucose causes more energy available for your muscles to use and postponed reproduction causes resources to be redirected to escape and coping

long term effects of stress

if increased HR and BP goes on for too long it causes hypertension and atherosclerosis, if increased stomach acid secretion goes on for too long it causes ulcers and other damages, if you convert too much protein to glucose it causes fatigue, muscle, hair and skin breakdown and if you postpone reproduction for too long it causes reduced sex drive and infertility 

limbic system

a set of neural structures that act as the emotion network of the brain, participates in sensation, emotion, reasoning and communicates extensively with each other

lesion

a form of damage to the part of the brain resulting from injury or surgery, observation of its effects is a method of study to determine roles of brain areas, ex; the vmPFC is often damaged in head trauma and leads to risk taking behavior, it is limited because injury related lesions are rarely limited to one structure, you cant draw causal conclusions from these studies and surgical lesions are rarely possible in humans

electroencephalography (EEG)

this is a technique that uses electrodes on the scalp to measure electrical potentials generated by neurons when firing, you can measure brain activity on a fine grained time scale so it has great temporal resolution, it is limited because the tasks have to be simple, head and eye movement create noise and it has low spatial resolution so you can rarely tell where activity is being generated

event related potentials (ERPs)

these are rapid changes in the EEG signal, in response to particular stimuli and associated with distinct psychological processes

error related negativity

a type of ERP that occurs 100ms after a participant commits an error in a simple task, this is stronger in anxious individuals

functional magnetic resonance imaging (fMRI)

when neurons are active they use oxygen, replenished by the blood, it detects differences in oxygenated and deoxygenated hemoglobin, indicating where neurons have recently been active, it has really good spatial resolution, it is limited because the scanner is small, noisy, it can be claustrophobia inducing and it has lower temporal resolution than EEG

neurotransmitters

these are chemical neurons that are used to communicate with one another, a drug can increase or decrease its release by activating or blocking receptors which extends or shortens the time it spends in the synaptic gap, this technique is limited because each neurotransmitter has many effects so its hard to isolate to one structure, psychological process

amygdala

a small almond shaped structure in each temporal lobe, it receives output from hearing, vision, pain and other senses, it sends output to many regions of brainstem as well as the cortex

kluver-bucy syndrome

this is a pattern of emotional changes accompanying removal of both anterior temporal lobes, including the amygdalae, in animals it causes reduced behavioral response to dangerous/unpleasant stimuli such as snakes, fire and feces, other symptoms include lack of normal caution in approaching strangers and diminished learning to avoid shock, pain

urbach-wiethe disease

in humans it is caused by calcium damage to the amygdala, and fearless behavior through panic can be induced by suffocation

fear conditioning

this is a procedure where one learns that a new stimulus like a tone or color predicts electrical shock or other aversive events, for instance a lab rat hear distinctive sound tone, immediately followed by electrical shock, the tone and shock are paired repeatedly until the rat shows a fear response to the tone, including freezing and increase in BP

fear conditioning study

rates received either surgery after lesioning the left amygdala or a sham surgery not causing a lesion, when healed, fear conditioning procedure, after hearing the tone they measured change in mean arterial blood pressure and seconds behavioral freezing

fear conditioning study results

amygdala lesioned rats showed weaker fear conditioning responses, smaller increases in blood pressure, and less time freezing after hearing the shock-predicting tone, humans with amygdala damage report understanding the tone predicts the shock, but show no physiological signal of fear

fMRI studies of the amygdala

photographs of fearful facial expressions elicit the strongest response, even when presented briefly, amygdala reactivity to unpleasant images strongest individuals who experience stronger/more frequent negative emotion in real life, amygdala activity is diminished when cognitive reappraisal is used to reduce distress, some amygdala cells respond to pleasant stimuli like smiles

homeostasis

the body’s regulation of temperature, blood chemistry, hydration, and other variables, keeping them within a healthy range

hypothalamus

located above the brain stem, below the thalamus, it acts as the body’s thermostat, regulating physiological variables and behavior to maintain homeostasis

the reward circuit

the nucleus accumbens and ventral tegmental area respond strongly to many rewarding stimuli, including sugar, gambling, and sex, dopamine is primary neurotransmitter, multiple microcircuits supporting different functions, including learning and prediction as well as approach toward rewards

the insular cortex

a region of the cortex tucked inside the fold between the temporal and parietal lobes

interoception

perception of the body, especially visceral organs such as the heart, digestive system, bladder, muscles and the skin

the prefrontal cortex

active in cognitive functions such as planning, working memory and the inhibition of impulses, it is activated when participants are using cognitive reappraisal to reduce emotional intensity and inhibits activation of the amygdala

results of PFC damage

despite normal memory, intelligence and ability to process info logically, tend toward poor, impulsive decisions, tendency to perseverate on previously learned behavior rather than updating to change in environment and it also causes deficits in empathy, ability to read others’ emotions

frontotemporal lobar dementia (FTLD)

deterioration of the frontal and temporal lobes of the cortex, effects on empathy similar to those in PFC damage

B endorphins and opioid peptides

the body’s natural painkillers, regulating pain sensations from the body, activity inhibits experience of social/emotional as well as physical pain

b endorphin

activity increased by exercise, sex and many drugs of abuse (especially heroin, prescription painkillers)

naloxone

a drug that blocks endorphin access to receptors, used to treat heroin and painkiller overdoses

serotonin

involved in wide range of functions, including sleep, memory, appetite control, nausea, low levels fo it is linked to aggressive behavior though the effect is small

selective serotonin reuptake inhibitors (SSRIs)

drugs commonly used to treat depression, inhibit removal of serotonin from the synaptic gap, they work within hours but significant effects don’t emerge for 2-3 weeks

oxytocin

as a hormone in body, causes uterine contractions, milk expression in nursing, in humans and some other mammals, levels increase in brain during sexual arousal, orgasm, promotes pair-bonding after mating, oxytocin nasal spray elicits willingness to trust but effects are inconsistent and it caused men to rate attractiveness of their partner but not other women

iowa gambling task

it is like a card game used to study decision making, especially how ppl balance short term rewards vs long term consequences, you want to win as much money as possible so start with some play money and make choices from four decks of cards, for deck A and B each car has a big reward but there are big penalties that make you lose more than you win over time, decks C and D have smaller rewards but only small penalties so you can slowly build profit

what is the point of the Iowa Gambling Task?

early on, people don’t know which decks are good or bad but overtime healthy ppl learn to switch to the good decks (C and D), ppl with amygdala or vmPFC damage will keep choosing form the bad decks even when they keep losing, it tests real life decision making and also measures emotional signals that are meant to warn ppl about risky choices before making them