Brain disorders Flashcards
Hemi-spatial neglect
Disorder of ATTENTION, not VISION where person has no perception of one side of the world. Damage to temporal and parietal area on ones side of face (often damage to right side as VAN is right hemisphere system)
Pareidolia
Seeing faces everywhere
Prosopagnosia
Face blindness - Can see eyes, nose, face etc but do not meld them into the entire face
Blindsight
Damage to V1 produces retinotopic deficits in the corresponding location in the visual field. But a few individuals with V1 damage can process visual stimuli in the “blind” field although they claim they cannot see anything (due to low road)
Achromatopsia
loss of the ability to see colour due to damage to V4
AKINETOPSIA
MOTION BLINDNESS (damage to V5/MT)
- Version 1 - see things as a series of snapshots
- Version 2 - things that are moving disappear completely, only when things are stationary do they have enough coherence to become visible
Dorsal stream damage
Good at what (distinguishing between shapes, identifying angles) bad at where (visually guided movement, using locational cues)
Ventral stream damage
Good at where (can post card into slow, can identify shape based off its location) poor at what (identifying angles, distinguishing shapes)
optic ataxia
(difficulty making eyes move to right part of space
Apperceptive Agnosia
People cannot TAKE visual input (patterns of light, colours, motion etc) and CONVERGE this into a meaningful object. Cannot copy a drawing, but can draw shapes pretty well from memory. Normal perception of elementary attributes but impaired visual perception of WHOLE objects
Associative agnosia
Intact visual perception, but loss of knowledge of WHAT objects are. Can copy but not identify objects. Cannot draw from memory
Amblyopia
- Visual defects in the brain as a result of poor visual input during critical periods
Strabismus
(“lazy eye”, one eye does not move or track as well as another does, brain stops trusting it to rely visual input, relies on good eye, and we can have same effect as in the kittens as grain will not grow projections to be able to see from this eye.
Astigmatism
Eyeball is not perfectly spherical, has an odd angle that light may be coming in at one plane
If not corrected early in life, will be problematic forever (you cant correct brain)
Congenital Cataracts
Cloudy film in cornea which blocks light getting in. Need to correct as EARLY in development as possible so brain can organise itself appropriately
Synaesthesia
Cross-modal correspondences in which peoples brains create experiences that don’t match sensory input
Schizophrenia
Excess of dopamine release
Parkinsons
degradation of basal ganglia (results in failure to learn implicit sequences - even though episodic memory is intact) - loss of dopamine
Major depressive disorder
- Lack of serotonin
- Increased risk in cases of maternal infection
- Causes deficits in working memory capacity
- Less synaptic connections, loss of dendritic spines
Korsakoff Syndrome
Amnesia caused by lack of vitamin B1, degeneration in PFC and some areas in thalamus - present with anterograde amnesia. Due to PFC not working, they engage in confabulation (if they cant remember something, they just make it up)
Seen in patients with long history of severe alcohol abuse (due to nurtitional benefits in people who source most of their calories from alcohol
Alzheimer’s Disease
Widespread brain disorders, cause “tangles” in the brain. See a gradual breakdown of function with deficits in all sorts of memory. Episodic goes first, then deficits in semantic memory.
