03-10-23 - Language and cognition Flashcards
Learning outcomes
- Recall the primary features of the cerebral cortex
- Explain the organization of language processing
- Summarize the concept of dominant and non-dominant hemispheres
What is meant by cognition?
What 6 concepts does cognition encompass?
- Cognition is the The acquisition, retention and use of information that allows successful behaviour in our complex and changing environment
- 6 concepts cognition encompasses:
1) Perception (not the same as sensation)
2) Attention
3) Memory and learning
4) Emotion and social cognition
5) Symbolic representations (language etc.)
6) Reasoning and problem solving
Cognition within a sensory modality (hearing, vision or touch etc.)
What do primary areas received to determine the perceptual qualities of the modality?
What are Modal qualities (e.g. pitch, volume, timbre, harmonics for audition) from the higher-order cortex integrated with?
What 3 things does this integration allow for?
What can we recall for recognition of objects, faces & spaces?
- Cognition within a sensory modality (hearing, vision or touch etc.)
- Primary areas receive unprocessed modality data, association areas (also called higher-order areas) along with sub-cortical components function to determine the perceptual qualities of the modality e.g if one note is higher than another, if the same notes sound better on another instrument etc
- Modal qualities (e.g. pitch, volume, timbre, harmonics for audition) from the higher-order cortex are integrated with both themselves and information from other sensory modalities (e.g. sound & vision)
- 3 things does this integration allow for:
1) Appreciation of music
2) Detection of danger
3) Integration of other people’s behaviour - Recall the secondary visual processing cortex for recognition of objects, faces & spaces (later lecture)
Multi-sensory integration. What is a combination of processed sensory perceptions used to determine?
How do we go about interpreting these signals?
- Multi-sensory integration
- Combination of processed sensory perceptions (vision, temperature, sound) are used to determine what is happening, and where it’s happening i.e If it looks like fire, sounds like fire and burns you, it probably is fire.
- Interpreting these signals:
- These three sensory modalities arrive in the cortex mantel at 3 primary locations
- Sub-cortical structures & association fibres move the information through the association cortices for processing and integration to become either a reflex or a cognitive state
Describe the 3 stages of multi-sensory integration – for motor output.
What is an example of this process?
- 3 stages of multi-sensory integration – for motor output:
1) Sensory information about the environs and body project to the primary cortical areas (visual, somatosensory, auditory)
2) Information is then passed to the sensory association areas in the parietal lobe and the temporal lobe for integration.
3) From there integrated information is shared with the supplementary motor cortex (which is processing information about intent in association with other frontal lobe areas) & then to the pre- & motor cortex to allow incorporation of sensory input into planned integrated motor events
- An example of this process would be taking a penalty kick, where we think about where the wind, ball, and goal are, and how we need to position ourself in space
What is an example of where senses can be fooled?
- The McGurk effect is an example of when senses can be fooled - Visual sensory information is interpreted and is dominant over auditory processed information
What is the next level of complexity in cognition?
What is an example of this?
- The next level of complexity in cognition is the integration of sensory with non-sensory information
- Example:
- Vision: Imagine you are alone in a dark forest late at night with dark shadows and strangely shaped trees
- Auditory: Imagine the sharp crack of a twig breaking in the undergrowth near where you are standing
- Emotion/memory: Remember that on the news an escaped homicidal inmate has been reported as escaping from prison less than half a mile from where you are
- In this example, we are integrating what we are seeing and hearing with what we know
What is synaesthesia?
What are examples of this?
What is the most commonly studied for of Synaesthesia?
How can it be diagnosed?
- Synaesthesia is the conflation of sensory experiences from one sensory domain with those from another, or the mixing of two modalities of the same sensory domain
- Synaesthesia is a fancy name for when you experience one of your senses through another.
- Hearing music and seeing colors in your mind is an example of synaesthesia
- Most commonly studied is called colour-graphemic synaesthesia where specific black and white shapes are perceived in colour
- Synaesthesia can be diagnosed with a Colour-graphemic Synaesthesia test (in picture)
- During the test, as we increase the size of displays/complexity, those without synaesthesia take longer and longer to figure out what is wrong
What are the areas of the brain responsible for speaking and hearing words?
Where are they located?
Which hemisphere is dominant for speech in most people?
How is this confirmed?
- Broca’s area is responsible for speaking words – it is located anterior to the primary motor cortex
- Wernicke’s area is responsible for hearing words – it is located posterior to the auditory cortex
- The left hemisphere is dominant for speech in most people (confirmed by Wada test) – we don’t generate speech on the right side if the left side is dominant
Broca’s and Wernicke’s area diagram
What does the Wernicke – Geschwind Model describe?
What are the 2 parts of the Wernicke – Geschwind Model?
When can a form of aphasia occur that affects this mode?
- The Wernicke – Geschwind Model describes what happens when you say words you read (see it, understand it, organise it
- 2 parts of the Wernicke – Geschwind Model:
1) Visual information is passed to Wernicke’s area via the angular gyrus, and so on to Broca’s area etc.
2) The visual cortex can pass information directly to Broca’s area but the path remains elusive
- A form of aphasia (conduction) occurs that affects this model when the link between the two areas (the arcuate faciculus) is damaged, and is typified by a reduced ability to repeat spoken words.
- Aphasia is a disorder that affects how you communicate.
- It can impact your speech, as well as the way you write and understand both spoken and written language.
Describe the 4 stages of what happens when you hear, understand and repeat spoken words.
What areas also light up during this process?
- 4 stages of what happens when you hear, understand and repeat spoken words:
1) Afferent information arrives at the auditory cortex and Wernicke’s area (left temporal lobe).
2) Wernicke’s area comprehends the words and passes the information to Broca’s area for sentence construction and syntax.
3) Broca’s area stimulates the motor cortex to control the lips & tongue etc (Broca’s area also has some comprehension)
4) The spoken word is repeated.
- Note that other association areas are also lit up and so the process is not clear cut
What is aphasia?
What causes Wernicke’s aphasia?
Describe Wernicke’s aphasia.
What can explain certain deficits associated with Wernicke’s aphasia?
- Aphasia - the partial or complete loss of language abilities following brain damage
- Wernicke’s Aphasia is caused by damage to Wernicke’s area
- Wernicke’s Aphasia - Speech flows but is often nonsensical because the patient has reduced comprehension of speech (their own and sometimes others) consequently sentence meaning is very poor
- Associated with a “hearing/understanding words” malfunction, sufferers do not understand their own speech, and seem unconcerned that they do not make sense.
- However, this is complicated by an inability of Wernicke’s aphasics to also understand written information
- The visual understanding parts of the temporal lobe, specifically the ‘what’ pathway can also be affected which helps explain this deficit.
Wernicke’s aphasia patient transcript (in picture)
What causes Broca’s aphasia?
Describe the presentation of Broca’s aphasia
- Broca’s aphasia is caused by damage to Broca’s area
- Broca’s aphasia description:
- Also known as motor or non-fluent aphasia, patients have difficulty speaking- often stuttering to find the right word.
- Patients are aware they are making little sense. They have largely no problem responding to the spoken or written word.
What does Broca’s area contain?
What is Wernicke’s area responsible for?
How are the 2 areas linked?
What certain phrases can Broca’s aphasics struggle to say?
What is there a reduced comprehension in for Broca’s aphasics?
- Broca’s area has the motor programs for generation of language and sentence syntax
- Wernicke’s area is predominantly responsible for language comprehension the two areas are linked by the arcuate fasciculus
- Interestingly Broca’s aphasics might be able to say “oar” but not “or” or “Bee” but not “be”
- Reduced comprehension of written or verbally presented functional words like “put on top” etc.
Broca’s aphasia patient interview transcript (in picture)
Describe the comparison of Broca’s and Wernicke’s aphasia (in picture)
Are all cortical functions bilateral?
What is an example?
Which hemisphere is dominant in right and left handed people?
What is comprehended by the dominant side of the brain?
What are Wada tests used for?
Describe Wada’s tests.
What is used in place of Wadas tests now?
- Not all cortical functions are bilateral e.g. language processing.
- Most right-handed people (95%) have a dominant left hemisphere
- Left-handed people are more likely to have a dominant right hemisphere
- Language is produced and speech comprehended by the dominant side of the brain (mostly the left)
- Wadas tests are used to determine hemispheric dominance
- In Wadas tests, one side of the brain is anaesthetized via the appropriate internal carotid and the subject tested for speech.
- If the dominant side remains awake, speech is unaffected
- An fMRI will normally be used in place of Wadas tests now
What does the term ‘split-brain refer to?
What is the role of the corpus callosum?
Describe 3 limitations/abilities of split-brain patients
- The term “split-brain” refers to patients in whom the corpus callosum has been cut for the alleviation of medically intractable epilepsy
- The main role of the corpus callosum is to serve as a conduit allowing information to transmit from one side of the brain to the other (e.g., from the left to right frontal lobes).
- It is also hypothesized to play a major role in movement control, cognitive functions (such as memory and learning), and vision.
- 3 Limitations/abilities of split-brain patients:
1) Split brain patients cannot verbally identify objects felt behind the screen with the left hand as it is controlled by the right brain (no language), however objects in the right hand can be identified verbally
2) Split brain patients cannot verbally identify objects seen with only the left visual field as it cannot communicate with the right brain (no language), however objects seen in the right visual field can be identified verbally
3) In both cases however, the right brain can communicate what it knows independently by drawing (visual task) or holding up fingers (if the hidden task was counting
* If you ask the patient to draw with the left hand, cross-over will still occur, as there has only been a cut at the level of the corpus callosum
* We will end up with a left-handed drawing of what is seen by the right side of the brain
Split brain screen test diagram (in picture)
