Perception and neuropsychology Flashcards
What is the structure of the eye?
- Outer layer (cornea)
- Middle layer (choroid)
- Inner layer (Pupil, Iris, Lens, Vitreous Humor)
What is the function of the retina?
Involved in transduction, they take the energy and convert it into a neural signal.
What is the function of sensation?
Registering of sensory information by the brain
What is the function of perception?
Assigning a meaning to that sensory information
What is the function of cones?
Used for colour vision, day time photo receptors, high resolution
What is the function of rods?
Do not process colour, used at night time, low resolution
Are cones or rods more numerous?
Rods are more numerous
Where are cones found?
In the fovea
Do rods get gradually larger or smaller as you get further from the fovea?
Rods get gradually larger as you get further from the fovea
What is retinotopic mapping?
Point-to-point mapping of the external world onto our retina, lateral geniculate nucleus and V1
What is the function of the eyes receptive fields?
The receptive field is the area of the retina when stimulated by light causes a change in the neural activity
What is lateral inhibition?
Enhances contrast (makes things appear better)
What performs lateral inhibition?
The retinal ganglion cell.
What do rods and cones like to look at in the visual field?
Diffused light
What does the retinal ganglion like to look at in the visual field?
Spots
What does the Lateral geniculate nucleus like to look at in the visual field?
Spots
What does V1 like to look at in the visual field?
lines of difference
What is double dissociation?
Once info arrives at the primary visual cortex it splits into 2 pathways:
-Dorsal stream for spatial vision/ location (parietal lobe)
-Ventral stream for pattern perception (temporal lobe)
What happens when you damage your parietal lobe?
Unable to perform a landmark task
What is the Herman Grid illusion?
The dot in the intersection disappears because we are foviating.
What is the correct order for the waste station pathway?
- Eyes (optic nerve)
- Subcortex
- Cortex
What study did Mishkin and Ungerleider conduct?
Monkey object and landmark discrimination tasks, study suggested that when you damage your temporal lobe you are unable to perform an object task but able to perform a landmark task
What is apperceptive agnosia?
Damage of the ventral stream, failure of object recognition due to a failure of visual perception, poor matching and copying
What is Dorsal simultagnosia?
Damage to dorsal pathway, failure of object recognition due to a spatial perceptual impairment, can recognise objects but not more than one and cant tell you what is happening in an image but can name what is in it
What is ventral simultagnosia?
Damage to ventral stream, failure of object recognition due to a complex perceptual impairment, can recognise objects but not more than one
What is associative agnosia?
Failure of object recognition due to a higher-order complex perceptual impairment, can describe object but doesn’t know what it is
What are perceptual constancies?
Perception of an object stays constant even when the objects retinal image changes
What is a bottom-up theory?
Looking at an object and breaking it down into constituent parts then building it back up with all the elements and recognising what the object is
What is a top-down theory?
Speed of recognition and reading, “how would we read so fast if we had to break all the letters in words down to form a sentence?”
What are the visual cues in depth perception?
-Binocular cues
-Retinal disparity
-Convergence and divergence
-Monocular cues
What are the monocular cues?
-Relative size
-Texture gradients
-Interposition
-Perspective
-Relative height
-Motion parallax (requires movement)
What did the Young-Helmholtz trichromatic theory suggest?
That there are 3 cones in interpreting colour for colour perception
What happens when you damage the optic nerve?
You develop right monocular blindness
What visual field would be impaired if you damaged the right side of the brain?
the LVF
What happens when you damage the optic chiasm?
You develop bitemporal hemianopia
What happens if you put multiple LGN cells together?
You form a line
What is the function of area V5?
visual motion area
What is blindsight?
Patched areas in the blindness of the eye is called ‘islands of residual vision’, cant see things stationary but can sense something
What is achromatopsia?
Absence of colour vision from damage to V4
What is akinetopsia?
Absence of motion vision from damage to V5
What did Rene Descartes research?
Recognised that the brain was symmetrical and every structure on the left side was on the right side as well, Pineal gland was a pea-sized structure between the two hemispheres
What did Gall & Spurzheim believe in?
Phenology. pseudoscience bumps on brain meant over or underdevelopment
What did Paul Broca discover?
Broca localises language to the left frontal lobe by research of patient Tan. Discovered Brocas aphasia.
What is Brocas aphasia?
Difficulty in language output
What did Karl Wernicke discover?
Patients output is normal but comprehension seemed impaired
What is Wernickes aphasia?
A difficulty in comprehension of language, output is fine
What does damage to the occipital lobe cause?
Blindness, blindsight and apperceptive agnosia
What is the function of the superior temporal gyrus?
Auditory processing
What is on the lateral surface of the temporal lobe?
Superior, middle and inferior temporal gyrus
What is on the medial surface of the temporal lobe?
Medial temporal lobe
Where is the medial temporal gyrus found?
Near the hippocampus
What happens when you damage the right temporal lobe?
Visual memory impairments
What happens when you damage the left temporal lobe?
Verbal memory impairments
What happens when you damage the middle temporal gyrus?
Achromatopsia, akinetopsia, ventral simultagnosia, associative agnosia
What happens when you damage the superior temporal gyrus?
Deafness, Wernicke’s aphasia, auditory aphasia
What happens when you damage the parietal lobe?
Impairments in processing spatial information (control of movement)
What happens when you damage the left parietal lobe?
-Agraphia (difficulty spatially organising your writing)
-Acalculia (difficulty in calculating math problems)
-Right/ left confusion
-Dyslexia
-Difficulty in drawing
What happens when you damage the right parietal lobe?
Difficulty in recognising unfamiliar views of objects, contralateral neglect
What is ego-based neglect?
Neglect of the left determined by your body parts
What is object-based neglact?
Neglect the left side of objects
What happens if you damage the frontal lobe?
Impairments in motor function, Brocas aphasia, Impairments in divergent thinking, response inhibition
What are the four areas of the frontal lobe?
-Motor cortex
-Premotor Cortex
-Prefrontal cortex
-Orbitofrontal cortex
What is contralateral neglect?
Things in LVF do not exist/ occur to patient, no conception of objects in LVF, cannot look/ turn left
