Module 4: Brain Disorders Flashcards
do humans have a dominant hemisphere in their brain?
no. There is no overall dominant hemisphere, but some functions are more dominant in one hemisphere than in the other.
what is the most strongly lateralized function in humans? and in which hemisphere is it lateralized?
language and speech.
Mostly dominant in the left hemisphere for most of the population.
what are the main functions of the right hemisphere?
face perception -> areas of the visual cortex.
voice tone / prosody
perceptual grouping
what is prosody?
the rhythm of speech
what are contralateral functions?
the hemispheres will control opposite sides of the body.
R hemisphere controls left movement, vision, and sensation.
The l hemisphere controls right movement, vision, and sensation.
what was the relation found between hand dominance and laguage?
95% of right-handed people had language in their left hemisphere,
whereas 70% of left-handed people had language in the left hemisphere.
what proportion of the population is left-handed?
10%
what sides of vision go to which hemisphere?
the right side of vision goes to the left hemisphere, and the left side of vision goes to the right hemisphere.
what do we call the overlap of vision between our left and right eye? and what does it do?
binocular disparity.
it helps with sense of depth
what are the language abilities found in the right hemisphere?
comprehension and reading
what are the language abilities NOT found in the right hemisphere?
Verbal reports
True or False
True or False
the frontal lobe and the parietal lobe constitute the biggest proportion of the brain volume and are highly evolved in humans.
True
what does the parietal lobe do?
it mediates attention
what are the 2 processes of attention?
bottom up and top down processes
what is the top down process of attention?
-it is our conscious control over our behaviours.
-the top down process is driven by conscious thoughts and those are regulated by thoughts and experiences.
give and example where of the top down process is at work.
-the conscious controlled behaviour of not eating cake in the context of being on a diet.
-seeing a messed up picture but still seeing it as normal due to our experience and our expectation of how it should be.
what is the bottom up process?
it is the unconscious control over our behaviours: biological urges and desire will control our behaviours and thoughts.
-it is driven by salient external stimuli
what results from damage to the parietal lobe?
a syndrome called “Spatial Neglect”
how is the parietal lobe responsible for attention?
-it helps direct our attention to things through our eye movements; what i’m looking at = where my attention is directed to.
what is spatial neglect?
loss of awareness to one entire side of space.
what is the problem of attention in psychology?
it is very common. according to William James, everyone knows what attention is. The problem is that everyone has a different idea of what attention is.
what is attention all about?
attention is about selectivity
what is attention selectivity?
it’s the taking possession of the mind in a clear form of ONE thought among many many others.
what does selectivity rely on?
Location and Specificity of features.
what can we identify our attention as?
attention acts like a filter: it prioritizes and selects the features we will focus on for our limited capacity processing resources in the brain
talk about location selectivity.
it’s when we shift our attention through eye movements to specific locations.
our attention is directed to the place we are looking at.
what happens when we shift our eyes/vision to look at something or somewhere else?
what do we call this?
our attention shifts with our vision and the new field of vision is our new focus.
we call this location selectivity.
talk about selectivity attending to specific features.
what are those features?
our attention will be directed toward the things that stand out from the background based on shape, color, sound, and voice.
example: a green square in a full white background will grab our attention.
TRUE OR FALSE
Our brain has unlimited capacity processing resources.
FALSE
The brain processing resources are capacity limited. This is why selectivity is important. We will attend to the most relevant stimuli first
is multi-tasking a thing?
NO!!
It is physically and mentally impossible to attend to all of the stimuli that are constantly received from all our senses, we can switch between tasks very quickly, but multi-tasking is impossible.
TRUE OR FALSE
the bottom-up process is conscious controlled.
FALSE!!
the bottom-up process is automatic
what captures the attention in the bottom-up process?
-involuntarily captures the attention
-highly salient stimuli
-stimuli that stand out from the back ground (pop-out)
what are the three things that the top-down process does?
-selects + prioritizes stimuli to which to attend based on task/goal.
-a voluntary shift of attention.
-selects features on which to focus attention on
what happens once a stimulus involuntarily captures our attention?
It becomes impossible to NOT see that stimulus
Do bottom-up and top-down processes involve the same brain regions/networks?
if not, which network controls which process?
NO!
the controlled directed attention (top-down) is controlled by the dorsal network.
the stimulus-driven attention (bottom-up) is controlled by the ventral network.
how did Corbetta and Schuman navigate through the different areas of the brain and which process did they control?
and when?
based on MRI
studies on patients with brain lesions
in 2002
what is spatial neglect most commonly caused by?
strokes: blockage of blood supply to the brain
explain spatial neglect.
which side of the body/hemisphere does it affect?
spatial neglect is due to damage in the parietal lobe.
it results in the loss of awareness of one entire side of space.
if the left parietal lobe is damaged, the right side of space will be neglected. IT IS CONTRALATERAL.
Do patients of spatial neglect have visual impairments?
no.
spatial neglect patients have perfect vision.
which side of the cortex is most commonly damaged prior to spatial neglect?
the right parietal cortex.
however, it can happen on the left side.
what is another important symptom of spatial neglect?
simultagnosia
what is simultagnosia?
it is the inability to perceive multiple stimuli at once
how is simultagnosia expressed in patients of spatial neglect?
patients with spatial neglect will ignore everything happening on one side of space.
however, even if both stimuli (folding finger) are happening on the favored/intact side of space SIMULTANEOUSLY, the person will only identify the stimuli closest to the intact side of vision.
what does spatial neglect highlight in respect to the parietal lobe?
it highlights the importance of the parietal lobe in directing one’s attention to the opposite side of space.
what does spatial neglect highlight with respect to the parietal lobe?
it highlights the importance of the parietal lobe in directing one’s attention to the opposite side of space.
are people suffering from spatial neglect aware of their disorder?
no.
They only become aware of it when people point it out repeatedly.
do people with spatial neglect have an imagination of what might be happening on the contralateral side of space?
no.
their imagination of that side of space is gone.
they are unaware of anything happening on that other side.
does spatial neglect ever go away?
it happens after a stroke.
for some people, it gets better in a few weeks, for others it stays long term
what does the frontal lobe mediate?
the frontal lobe mediates executive functions.
what results from damages to the frontal lobe?
DEMENTIA
What is the frontal lobe responsible for?
behavioral control
choosing appropriate behavior: inhibition/suppression of inappropriate behavior
give an example of conflict between bottom-up and top-down processes where the frontal lobe had an essential role.
when we’re on a diet, we will have the urge to eat a cake (bottom-up: biological urges), but our frontal lobe will inhibit this behavior due to the context, which we are on a diet. (top-down)
name 3 neuropsychiatric disorders linked to deficits in inhibitory control.
1- OCD (obsessive compulsive disorder)
2- ADHD(attention deficit hyperactivity disorder)
3- reward addictions (gambling, shopping, gaming, etc…) feelings of instant reward
what is ADHD characterized by?
inability to prevent distraction, impulsive behaviors
what is OCD characterized by?
repetitive compulsive disorder (cleaning, washing hands, doing things a certain number of time)
who introduced frontal leucotomies/lobotomies?
Egas Moniz
what is the purpose of frontal leucotomies? and what is the process?
Frontal leucotomies is the process of deliberately causing lesions in the frontal lobe because I seemed to cause relief in patients suffering from psychosis (schizophrenia most often)
this was first observed in chimpanzees
when were frontal lobotomeis stopped?
when anti-psychotic medications became available in the 1950s
when was the first frontal lobotomy done? and where?
it was a performed in a surgical theater, in 1935
were frontal lobotomies only done in surgical theaters?
no.
by 1951, Walter Freeman, from the USA, had performed this surgery on almost 18,000 patients by the bedside (no need for surgical theater)
what are the 2 most common dementias?
most common: Alzheimer’s disease
2nd most common: Frontotemporal Dementia
what is frontotemporal dementia due to?
loss of neurons in the frontal and temporal lobes.
what happens to the lobes, physiologically, as they lose neurons?
the shrivel and shrink
what are the symptoms of FTD?
1) Loss of empathy
unaware of the emotions of others
do things without caring about others’ feelings
2) Apathy
lack of motivation, socially and emotionally distant and withdrawn
similar to depression
3) Disinhibition
increase of inappropriate behaviors
lack of self care and hygiene
lack of social tact
4) Deficits in executive functions
hardships in planning and organizing
since the frontal lobe is damaged, speech, language and motor deficits visible too
