Affective Blindsight Flashcards
What is the visual pathway?
Optic Nerve - Optic Chasm - Lateral geniculate nucleus - optic radiation - striate cortex - superior corticulus - pretectum - hypothalamus - optic tract
What doe the retina see?
dots
What does the Lateral geniculate nucleus LGN see?
dots
What does the Striate Cortex (V1) see?
-
What does the Superior Coriculus (V2) see?
0-0
What does the Pretectum (V4) see?
shapes eg triangle and squares
At which point do contralateral field vision change?
optic chasm
What is responsible for detecting moving objects in fields of vision?
Superior Corticulus
What fissure differentiates inversion vision?
Calcarine Fissure
What are clinical signs of hemianopia cases with cortical blindness? (6)
- No blink response to threat
- Opto-kinetic reflex may be absent
- No alpha rythmn or posterior region (no response to opening and closing of eyes)
- Photic reflex often persists (pupils still constrict)
- Anton’s syndrome - denial of blindness or anosognisia
- Possible amnesia - due to hippocampi damage
What is Photic reflex?
Pupils still restrict
What is Anton’s syndrome?
Denial of blindness or anosognisia
What are signs of recovery from hemianopia? (4)
- Presence/absence of light (without form)
- Primitive movement
- Contours
- Colours
Who did Gordon Holmes (1918) study?
WW1 soldiers with loss of vision
Who did Poppel , Held et Frost (1973) study?
War veterans that could orient direction of gaze but did not report seeing stimuli
Who did Humphrey (1974) study?
Monkeys with V1 damage that could still point and navigate
What could Weiskrantz, Warrington, Sanders and Marshall (1974) patient DB still do? (5)
- Able to orient gaze towards stimuli
- Point to stimuli
- Above chance for horizontal and vertical stimuli
- Above chance guessing X and O’s/ squares and rectangles
- Above chance at guessing movement
Where do 10% of fibres from retina project to?
Superior Colliculus
What is TN able to identify above chance?
Facial emotions (58-69%)
At chance for shapes and face/nonface (45%)
Describe Ledoux Model?
Low road for sensory thalamus straight to amydala bypassing sensory cortex for fight/flight threats and must be rapid and crude
Descrbe Weiskrantz’s Model?
Retina sends messages to LGN - VI - V2 - Temporal/pariental regions OR Superior Colliculus - Pulvinar - Amygdala
What did Morris et al study determine?
Right amygdala stimulation occurred to conditioned angry faces even when subliminal and amygdala activity correlates with activity in superior colliculus and pulvinar
What did Del Zotto et al study determine?
Brain responses faster to changes in emotional faces than neutral faces when measured with EEG ie transfer of information is fast
What did Burra et al study determine?
For fear faces amygdala response is greater for broadband and low spacial frequency faces than neurtral ie transfer of information is crude
What happens when TN observes starring faces?
Able to detect starring at 67% and amygdala detected
