emotion and the brain - Tom Johnstone Flashcards
define emotion
subjective experience accompanied by visceral motor and sterotypical somatic motor changes in response
- strong link with visceral motor system therefore strong assoc with preganglianic autonomic neurons in brain stem and spinal cord
define visceral motor
supplies and recieves stimulation from smooth and cardiac muscle and glands amking up the autonomic NS
define stereotypical somatic motor
supplies and recieves stimulation from skin, skeletal muscle, joints and tendons
describe cannon and bard study into emotion in cats
removed cortex, underlying white matter and basal ganglia in cats
found led to ‘sham rage’ - no obvious target but hissed, arched back, increase in bp, dilated pupils
sham rage not elicited when remove hypothallamus
findings of cannon and bard emotion in cats
cortex acts as an emotional inhibitor, regulating instinctual emotions of the thallamus - to experience the emotion not dependent on cortex but regulation of the response does
thallamus thought to be core emotional expression in the brain
problem with cannon and bard
cats have smaller cortex to humans - regulation may differ as many areas assoc with other process and complex range of emotions
what is cannons overall view of emotion
percieve stimulus - in environment which activates receptors and sends excitatory/inhibitory stimulus to cortex
LEADS TO
thallamic arousal - emotion neurons close to relay neurons in sensory pathway leading to
EMOTIONAL FEELING
AUTONOMIC RESPONSE/BODY CHANGE (ie GSR)
BEHAVIOUR CHANGE ie body language, face expression
CHANGE IN VOCAL EXPRESSION
Why are emotions useful (nico frida)
“action tendency” - prepare us for a rapid action to a stimulus
ie sad because fall so cry and this makes others empathise and help
describe Hess study into cats
electrical stimulation of hypothallamus in cats lead to rage response - bodily changes ie increased heart rate etc
hyp also link to homeostatic regulation of the body ie temp, hunger, emotion, cardiac rhythm
describe the papez loop (1937)
emotion occurs because of activity in circuit of basic structures - cortex and subcortical areas thallamus sensory cortex BG hypothallamus
what is the process of the papez loop
1- incoming sensory info relayed to thall
GOES TO
- stream of thought - thall to sensory cortex to provide awareness of environment,
- stream of movement - thall to basal ganglia involved in motor coord and planning etc
- stream of feeling - thall to hyp which regulated emotion- hyp to hipp and thall
sensory cortex, hipp and thall to cingulate cortex before feeling
describe papez stream of feeling
downstream
1- downstream (bodily response)
info from hyp to brainstem and spinal cord
lead to rapid and direct change in behaviour
decribe MaClean Truine advances of Papez loop
1- reptilian brian ‘r complex’
stereotypical rigid behaviours in brain stem and cerebellum for survival
oldest and most primitive - behaviours are ritualistic, consisten and repetitive - dont learn from mistakes as no relay to the hippocampus
describe the limbic system
group of interconnecting structures in the brain between the cortex and hypothasllamus
ie cc, cingulate gyrus (attention and reward), fornix, parahippocampal gyrus
AS WELL AS
amyg (emotion/fear reg - not in papez), hipp (memory and learning), hyp (output to viscera),
disagreement about what defines the limbic system
describe Kluver and Bucy study (1939)
remove medial temporal lovbes of rhesus monkeys
lesions affected sig amount of limbic system - including cortical areas ie amyg and hipp
kluver and bucy syndrome
visual agnosia - dont recog objects or appreciate significance
hypermetamorphosis - compulsion to approach all stimuli encountered
oral tendencies - place everything in mouth
change in emotion - tame, dull, no fear
change in sexual behaviour - hyperactive and hypersexual
describe marlowe et al 1975 kluver and bucy syndrome
human kluver bucy patient
meningoencephalitis
cant recog ibjects, flat, restless, indifferent, ingest everything see and sexual advances to males and females (pyriform cortex)
reduced social stress - less fearful of social situations
describe Le Doux fear conditioning in rats
pair tone with shock leading to freezing behaviour
lesion to medial geniculate nucleas (all auditory info through MGN of thall) - still respond to stimulus even when sever all MGN connection with auditory pathway - only connect to amyg
destroy MGN and amyg - no fear response - thereofre AMYG critical in fear learning and expression of fear
describe LeDoux ‘low road’
imprecise rough response directly to stimulus recieved in amygdala - to thall straight to amyg
generates a rapid response even though may not completely have preocessed the stimuli
Describe LeDoux ‘‘high road’
More precise and slower processing of information allowing identification of stimuli and adjusting of response
thall to cortex to amyg
LeDoux - hippocampus influence of fear conditioning
involved in context conditioning
when remove in rats, no fear when placed in cage would usually expect to recieve a stimulus even though conditioning to stimulus in in tact
describe Patient SM (Adolphs et al 1994)
bilateral amygdala destruction due to urbach luiethe disease which calcifies the amygdala and cause atrophy in anterior medial temporal lobes
cant recog fear emotion in facial expressions and rating of emotional content lower than average
little expression of fear but no problem with overall concept
describe Bechora et al 1995 patient SM study
sm fear conditioning - no fear response but did have GSR to stimuliand accurately describe relationship between stimuli and expectation of response
+ patient with selective hipp damage present fear conditioning but not procedural recall
double dissociation: amyg in fear conditioning and response but hipp in declarative learning of fear stimuli
emotional faces as stimuli in experiments
when look at facial expressions they do not immediately evoke a response - however, through evolution have learnt to associate the presentation of certain expressions with expectations of what may occur ie fear face predicts dangerous stimuli
describe johnstone et al 1995 amyg and fear faces
fmri when expose to fearful facial expressions in blocks of neutral, happy or fear
bilateral amygsala activation (greater in left) o fear faces
describe whalen et al 1998 backwards masking
fmri of amyg activation in absence of explicit expose to fearful stimuli
present stimuli for very short period that dont realise seen followed by neutral face
pps report only seeing neutral but increased activity in amyg to fear face - amyg respond rapidly to emotionally valent stimuli (HOW?)
Whalen et al 2004 - amygdala indicators of fear faces
white sclera as indicator of facial expression in LeDoux low road
masking paradigm of white sclera against black and inversed control
sig increase in amyg activation for white sclera>black sclera