brain asymmetries Flashcards
Humans have what type of symmetry?
bilateral symmetry
or clear left-right symmetry
What does lateralisation mean?
where cognitive processes are specialised to one side of the brain
What are the 2 hemispheres connected by?
corpus callosum
(bundle of fibres)
What is the left hemisphere dominate in?
producing speech
speech comprehension
What is the right hemisphere dominate in?
spatial perception
word comprehension
What is an advantage of hemispheric specialisation?
it avoids duplication
duplication (e.g symmetry) is a waste of neural space
Evidence for brain asymmetry: Broca’s patient “Tan”
post mortem evaluation found lesion located at inferior posterior frontal lobe in left hemisphere
became Broca’s area
Evidence for brain asymmetry: Wernicke
his patient’e speech was devoid of any meaningful content
found lesion in temporal lobe
became Wernicke’s area
Evidence for brain asymmetry: Sperry split brain
corpus callous is severed or disrupted by surgery, normally used for epilepsy
found right visual filed is processed by left hemisphere
left visual field is processed by right hemisphere
(Sperry and Gazzaniga)
What is another term for split brain?
callosal syndrome
What is Corpus Callosotomy?
operation of cutting bundle of fibres (the corpus callosum)
What is our brain reaction to symmetry?
our brains are ‘fined tuned’ to symmetry
but also to some assymmetry
What do aesthetic judgements activate?
the prefrontal cortex and the temporopareital
What do symmetry judgements activate?
the parietal and premotor areas
What is the fusiform gyrus?
a large region in the inferior temporal cortex
argued to be evolved specially for face perception
What is prosopagnosia?
the inability to recognise familiar faces and facial expressions
What is the “averageness hypothesis”?
Langlois and Roggman, 1990
idea that average shaped faces are more attractive e.g symmetrical faces
indicates good health
What is the “right hemisphere hypothesis”?
idea that right hemisphere mainly processes all emotions regardless of affective valence (how can object affects observer)
What is the “valence-specific hypothesis”?
idea that left hemisphere processes positive affective responses
right hemisphere processes negative affective responses
Are facial expression symmetrical or asymmetrical?
asymmetrical
What does handedness mean?
refers to the tendency to use one hand more than the other
What hand is dominate in most cultures?
right-handedness is dominate in all cultures
also referred to as dextral
What does pseudo neglect mean?
the natural tendency to shift spatial attention to the left
Planton et al: the graphemic frontal area
GMFA is said to be involved in writing specific lateralisation
it’s a subpart of the superior premotor cortex, close to Exner’s area
What is visual neglect?
an attention disorder
results from strokes and brain injuries
What brain region is associated with visual neglect?
the angular gyrus of the parietal lobe
Left neglect
result of damage to right hemisphere causing person to have difficulty attending to stimuli on left side
Right sided spatial neglect
more rare than left neglect
