Lecture 3 - Faces Flashcards
What is an agnosia?
Inability to recognise
typically, other cognitive functions are intact
What is prosopagnosia caused by
- damage to bilateral occipitotemporal lobe
- right hemisphere lesion - fusiform face area - NEEDS TO BE INVOLVED
Describe prosopagnosia
- inability to recognise familiar faces
- can recognise when triggered by other cues
- can be both acquired and congenital
What are the two types of prosopagnosia
- apperceptive - can’t perceive or encode the face properly.
- associative - accurately encode and perceive face, but cannot link it to semantic information about the person - failure to match the face to info due to loss of information or disconnection with memory stores
Describe apperceptive prosopagnosia
- reflects a breakdown at the STRUCTURAL ENCODING stage
- they aren’t really perceiving a face, and can’t intergrate the facial features into a whole.
Describe associative prosopagnosia
- reflects a breakdown of Personal Identity nodes, Facial Recognition Units, or the links between them
- also happens in Capgras and fregoli delusion
What is the fregoli delusion
Patient believes that two people are actualyl one person in disguise, and they don’t have to be physically similar….
related to psychoticism
- faulty links between structural encoding and FRUs AND PINS
Describe Capgras Syndrome
- aka Capgras Delusion
- delusion that certain people have been replaced by imposters
- typically does not mourn the person they think is gone
- does recognise that it’s a difficult thing to believe but holds onto it
What do Ellis and Young hypothesise causes Capgras Syndrome
- opposite of prosopagnosia
- recognition is OK but autonomic responses to familiar faces are lost - the arousal associated with seeing the person you love is gone..leading to a strange sensation
- this is supported by another study which found that these people treated their person normally over the phone
- in prosopagnosia, the overt recognition is gone, but arousal still works
What is emotion?
Physiologically-based state involving perception, experience, physiological arousal, goal-directed activity and expression
- cross-cultural consistency
- ## evident in congenitally blind
What is emotional language?
- eg. swearing
- right hemisphere produces this
- ## not affected by aphasic, and includes overlearned things such as happy bday song, days of the week etc
What does the sneering defiance show us?
- it’s usually on the left side of the face
- face is innervated contralaterally, so the right side of the brain controls left side
- left side of face appears to be more emotinoal
What is the right hemisphere hypothesis?
- RHS involved in control of emotion - irrespective of affective valence
- people with RHS insult demonstrate greater difficulty interpreting emotion in speech and recognising emotional laden words, and identifying emotion in faces than those with LHS damage.
even difficulty with the words love and hate
- less emotionally expressive
- smile and laugh less
- less accurate facial expressions
What is the valence hypothesis?
- left hemisphere is for positive valence emotions
- right hemisphere is for negative emotions
What is evidence of the valence hypothesis?
- Left hemisphere injury promotes ‘CATASTROPHIC-DYSPHORIC’ reaction - hopelessness, despair, anger, depression
- right hemisphere injury can lead to ‘indifferent-euphoric’ reaction - euphoria, joy, plasticity, minimisation of symptoms - anosagnosia
idea is that damage to left hemisphere leads to overinput from the right hemisphere - leads to dysphoria, from the right side.
- pathological crying is seen more in left HS lesion, and pathological laughing seen in right HS lesion
