Module 36 - Attention and Perception Flashcards
What is cognition dependent upon?
Cognition is dependent on these heteromodal association cortices
Temporal association cortex
Frontal association cortex
Parietal association cortex
Green area = Information from more than one sensory modality is coming together = more than just vision or more than just sensation
What key role does the temporal association cortex have in cognition?
Key role in vision
What is typical when patients have a frontal lobe lesion?
- Frontal lobes are one of the most difficult areas to study of the brain
- Patients with frontal lobe lesions often have no deficits that show up on routine testing, but they are unable to function in the real world
- “More than another other part of the brain, the frontal lobes enable us to function as effective and socially appropriate human beings.”
What happened to Phineas Gage?!?!
Phineas Gage = he could no longer cope with normal social conversations, and unable to plan for his future in order to be a contributing member of society.
What are the three main functions of the frontal cortex?
- Restraint
- Inhibition of inappropriate behavior
- Initiatives
- Motivation to pursue positive or productive activities
- Order
- Capacity to correctly perform sequencing tasks & other cognitive operations
What do we mean by → restraint is one of the main functions of the frontal cortex?
Inhibition of inappropriate behavior
What do we mean by → initiatives is one of the main functions of the frontal cortex?
Motivation to pursue positive or productive activities
Motivation to pursue positive or productive activities
What do we mean by → the order is one of the main functions of the frontal cortex?
Capacity to correctly perform sequencing tasks & other cognitive operations
What would we expect after frontal cortex lesions (in terms of function)?
- Lack of restraint
- Lack of initiation → socially inappropriate responses
- Lack of order → disorganized thoughts + lack of ability to plan
What are the different subdivisions of function within the frontal lobes?
- Dorsolateral
- Ventromedial
- Left frontal
- Right frontal
What types of deficits do we expect when a patient has a dorsolateral lesion?
Apathetic
Lifeless
Abulic
What types of deficits do we expect when a patient has a ventromedial lesion?
Impulsive disinhibited, poor judgment
What types of deficits do we expect when a patient has a left frontal lesion?
Associated more with depression-like symptoms
What types of deficits do we expect when a patient has a right frontal lesion?
Mania
True or false: bilateral lesions in the frontal lobes produce more obvious deficits, but not that exceptions ALWAYS exist!!!
TRUE
What type of symptoms do patients present when the frontal lobe is variably depressed in function?
- Akinetic mutism
- Akinetic mutism is a medical term describing patients tending neither to move (akinesia) nor speak (mutism). Akinetic mutism was first described in 1941 as a mental state where patients lack the ability to move or speak. However, their eyes may follow their observer or be diverted by sound.
- Not due in a disruption in language function → but more of an inability for your mouth to make a motor movement to produce speech
- Abulia
- An absence of willpower or an inability to act decisively, as a symptom of mental illness
- Catatonia
- Akinetic catatonia. This is the most common. Someone with akinetic catatonia often stares blankly and won’t respond when you speak to them. If they do respond, it may only be to repeat what you said. Sometimes they sit or lie in an unusual position and won’t move.
- Excited catatonia. With this type, the person may move around, but their movement seems pointless and impulsive. They may seem agitated, combative, or delirious, or they may mimic the movements of someone who’s trying to help them.
- Catatonia is a group of symptoms that usually involve a lack of movement and communication, and also can include agitation, confusion, and restlessness.
What is akinetic mutism?
- Akinetic mutism is a medical term describing patients tending neither to move (akinesia) nor speak (mutism). Akinetic mutism was first described in 1941 as a mental state where patients lack the ability to move or speak. However, their eyes may follow their observer or be diverted by sound.
- Not due in a disruption in language function → but more of an inability for your mouth to make a motor movement to produce speech
What is abulia?
An absence of willpower or an inability to act decisively, as a symptom of mental illness
What is catatonia?
- Akinetic catatonia. This is the most common. Someone with akinetic catatonia often stares blankly and won’t respond when you speak to them. If they do respond, it may only be to repeat what you said. Sometimes they sit or lie in an unusual position and won’t move.
- Excited catatonia. With this type, the person may move around, but their movement seems pointless and impulsive. They may seem agitated, combative, or delirious, or they may mimic the movements of someone who’s trying to help them.
- Catatonia is a group of symptoms that usually involve a lack of movement and communication, and also can include agitation, confusion, and restlessness.
If there was a lesion on the right frontal lobe, what type of catatonia would the patient most likely present?
Excited catatonia → more manic presentation
If there was a lesion on the left frontal lobe, what type of catatonia would the patient most likely present?
Dulled presentation of catatonia → akinetic catatonia
What are the steps to do when you are evaluating a patient’s frontal lobe function?
- Part 1 = the history and behavioral observations
- The best test is real-world; history from family or other contacts may be more revealing than patient exam
- Behavioral observations, looking especially for:
- Abulia
- Inappropriate jocularity (witzelsucht)
- Other abnormalities of comportment or insight
- Confabulation
- Utilization behavior and environmental dependency
- Perseveration, impersistence, and spontaneous frontal release signs
- Incontinence
- Behavioral observations, looking especially for:
- Part 2 = mental status exam → attention, memory, etc.
- Part 3 = other exam findings
Explain the circumstances of what happens when you’re reading THE COLORS in the image. If we look at something like this and just ask someone to read out the COLORS… but the color of the word and the word itself are contrasting… you need two things to be able to accomplish this task.
You need initiation = ability to start because this can be very overwhelming
You also need a little bit of restraint = for example for the first word, we are so conditioned to language that the first thing we will probably want to do is say purple, but we need to be able to say red, then green… then orange… Instead of purple, yellow, green
What is formal testing to test the ability of a patient to suppress inappropriate responses?
Stroop test → color test, for example, → does the patient have the ability to restraint
What is the difference between history and behavioral observations?
- Behavioral observations are what we look for as a clinician = how is the patient is acting in the here and now.
- History = is the information we get from the patients family
- When we put the two information together = can be very useful
Is it common for a patient with a frontal lobe lesion to present with primitive reflexes, or “frontal release signs” (grasp, suck, snout, root)?
- Yes, these primitive reflexes come back
- For example, the grasp reflex in children is typically extinguished between 6 and 12 months of age → this is when you give a baby something and then to grasp onto it. You often see people with a traumatic brain injury have family come in and put their hand in their hand, and the patient will grasp their hand, but not let go when they are asked to let go → this is often the grasp reflex = clinician needs to be able to tell the difference between the command of squeeze my hand and the grasp reflex
IMPORTANT QUESTION: What are the 3 main functions of the frontal cortex? Give some examples of each function.
IMAGE
What is an example of an objective measure of cognition?
The MoCA
What are the different things we test with the MoCA?
- Attention and working memory
- Digit span (forward and backward)
- Vigilance
- Listen to a series of letters. Tap finger when you hear letter A.
- Visuospatial/executive
- Naming → animals to identify
- Language → repeat a sentence back
- Abstraction → what is similar between a clock and a watch
- Delayed recall → same words as memory
- Orientation→ date, month, year, place, city
What is the role of selective attention?
- We will sense something, then we will pay attention to it and then we will analyse the information at a higher level
- For example, you will sense that you have hit your hand with a hammer, then you will attend to it, so you will look at your finger, and then your perception of it → omg I just hit my finger with a hammer
- ***Neuron’s response to an object can be greatly altered by attention
What happens with damage to the right posterior parietal cortex?
- Contralateral neglect syndrome
- It is the inability to attend to the left side of the world
What is the contralateral neglect syndrome?
- Contralateral neglect involves a deficit in attention paid to one side of the visual field, usually the side that is contralateral to the damage. It can result in the individual not attending to stimuli in that area to the extent that he does not seem to be aware of such stimuli.
- Look at image = patient very bias to the right side
Does the contralateral neglect have any damages to the primary visual system (optic tract, eyeball, optic chiasm)
No, the damage is higher processing areas = parietal cortex
Explain the findings of the Bisiach & Luzzatti (1978)
- Researcher in 1978, research on two different patients –> they ask patients in their hospital bed to visualize the square in Milan (square that everyone in Italy is very familiar with)
- Patients could describe everything on the right side, but could not describe the left
- Then they switched the orientation of where the patient would be standing when visualizing = the other side of the square
- The patients could again describe everything on the right
- But when asked to describe more, the patient says that it is all that they could see
- You can appreciate that the patient actually had described the whole square, therefore the visual information storage is all there in their head, but the patient is simply unable to describe both sides of the square at the same time.
- The patient is only at one time able to attend to the right.
- The study was able to separate the contralateral neglect syndrome from other higher cognitive systems like memory
- The visual memory of the square was still there, but at any given time, they were only able to attend to the right side of the world.
Why does this attentional deficit often happen on the left side of the brain with a contralateral neglect syndrome?
- In a typical patient, the right parietal lobe attends to both the right and the left side of the world. Whereas our left parietal lobe only attends to our right side of the world.
- So you can see that if there is damage to the right side of our brain, we are no longer able to see these dark purple lines. We can’t attend to this information. But because the left hemisphere is still intact, that right information is still there = four light purple lines.
Ture or false: The right parietal lobe does most/all of the attending on the left.
True.
In a typical patient, the right parietal lobe attends to ____________________ of the world. Whereas our left parietal lobe ________________of the world.
In a typical patient, the right parietal lobe attends to both the right and the left side of the world. Whereas our left parietal lobe only attends to our right side of the world.
What happens when you have a right hemisphere lesion?
Now, you are no longer able to attend to the left
Left hemisphere is still intact and able to attend to the right
It is easier to talk about different concepts related to attention than it is to pinpoint a specific brain region responsible for each of these concepts/abilities, but … there is a type of anatomy of attention. What are the four main areas of attention?
- Widespread projection systems
- Frontal association cortex
- Parietal association cortex
- Anterior cingulate cortex and limbic pathways.
- *** this is in a hierarchy way→ starting from widespread projection systems
What is the hierarchy of the anatomy of attention?
- Widespread projection systems → (we need this before we our frontal association cortex can act upon for our attention) → BRAINSTEM
- Frontal association cortex
- Parietal association cortex
- Anterior cingulate cortex and limbic pathways.
