9.1 Higher Brain Functions Flashcards
What is the function of Broca’s area and where is it located?
Formulation of language components and sends information to motor cortex (motor function)
Located in the frontal lobe
What is the function of Wernicke’s area and where is it located?
Responsible for interpretation of written and spoken words (language comprehension)
Located in the temporal lobe
Define cognition
Ability to attend to an external stimuli or internal motivation, identify its significance and make a meaningful response
Give 3 functions of cortical association areas
1) Responsible for the complex processing
2) Arrival of input -> generation of behaviour
3) Cognition
Give 4 functions of the prefrontal cortex
1) Learning, memory & planning
2) Personality: appreciation of self in the world that allows actions to be planned andexecuted
3) Procedural memory: problem solving and planning
4) Working memory: Telephone number, directions (held in the mind for immediate need)
What is the function of the parietal lobe?
Involved in attention and perceptual awareness
Is attention right or left hemispehere dominant?
Right
What may be seen in a person with a right hemishphere problem?
Include the specific syndrome
Inattention or neglect of other half of body ‘contralateral neglect syndrome’. Patient will be inable to attend to objects, or their own body in a portion of space, despite intact visual acuity.
Eg. Difficulty performing tasks relating to left hand side such as dressing
What is a right hemisphere problem specifically associated with?
Damage to right parietal cortex- unequal distribution of cognitive function between hemispheres
What is the function of the Temporal lobe?
Recognition and identification of complex stimuli
List 2 things that may be seen in a patient with damage to the Temporal lobe?
1) Difficulty recognising, identifying and naming objects = agnosias
2) Acknowledge the stimulus but cannot say what it is
Compare damage to the RIGHT vs LEFT inferior temporal cortex
Inferior RIGHT ➞ patient can describe a familiar face but not recognise the person, prosopagnosia (acknowledge the stimulus but cannot say what it is)
Inferior LEFT ➞ patient has poor recall of verbal and visual content e.g music recognition
If a patient has impaired long term memory what structure is most likley damaged?
hippocampus
What are the main functions of the LEFT hemisphere?
1) Processes logical tasks/analytical
2) Language: spoken/heard, written/read, gestured/seen
3) Maths
4) Motor skills (handedness)
Hence, the left hemisphere processes information in sequence e.g. language
What are the main functions of the RIGHT hemisphere?
1) Processes non-verbal tasks/ spatial relationships mental imagery
2) Emotion of language
3) Music/art
4) Visuospatial
5) Body awareness
Hence, the right hemisphere looks at the whole picture. e.g., spatial awareness
Give some generalised features of a person who is right vs left sided brain dominant
Define Lateralization
Tendency for some neural functions/cognitive processes to be specialised to one side of the brain
Give 3 key examples of laterlization
1) Parietal lobes – attention
2) Temporal lobes – recognition
3) Language centres
Describe laterlization of function in terms of the image below
1) On the image, stare at the noses of the two faces.
2) Decide which face seems to you to be happier
3) From your vision lectures we know that the left side of the image is transferred (first) to the right side of you brain and vice versa
4) The right side of most peoples brain is specialised for face processing and emotions
5) Hence, most people say that B is the happier, since the upturned mouth on that side seems more cheerful and it is this side of the image which is first presented to the right hemisphere
What are the 2 main language centres in the brain and what connects these?
Broca’s area and Wernickies area connected by subcortical white matter tracts known as the arcuate faciculus
State what damage would be associated with damage to:
1) Broca’s area
2) Wernickies area
3) Arcuate Faciculus
Language is localized and lateralized, in which hemisphere and lobe is it typically dominant?
Left frontal and temporal cortices
Define dysphasia (aphasia)
A disruption in the comprehension and/or generation of language
What are the two important areas for language and how are these connected?
Wernicke’s and Broca’s area connected by subcortical white matter tracts known as the arcuate fasciculus
What is Wernicke’s aphasia?
List 4 examples of what may be seen
Loss of receptive/sensory processing, patient is usually unaware and hence unaffected
Examples:
- Language expression is normal but comprehension and repetition impaired
- Language produced but it lacks meaning and contains paraphrasic errors and neologisms
- Written language similarly incoherent
- Unable to follow spoken or written commands
What is Broca’s aphasia?
List 2 examples of what may be seen
Patient will have expressive, non-fluent speech, they are typically aware and frustrated by it
Examples
- Paucity of spontaneous speech, telegraphic and minimal
- Can follow instructions as long as no need to verbalise ‘close your eyes’
What structure is damaged in conductive aphasia?
What functions are affected in the patient?
Damage to Arcuate fasciculus
Patients repetition impaired but comprehension and expression intact
What is global aphasia?
Combines features of Broca’s and Wernicke’s
A Speech disorder is known as what?
What is the exact problem?
Dysarthria: inability to correctly use muscles to verbalise
Tricky to distinguish but spares written and verbal comprehension and written expression
What features does the right hemisphere ‘add’ to speech?
Adds ‘colour’ to speech Eg. tone, stress, rhythm
What is the limbic system?
A complex set of deep-cortical structures that deal with emotions, memory and arousal
Involved in high levels of processing sensory information and output to homeostasis planning of behaviours and motor responses
‘attaches a behavioural significance and response to a stimulus’
What 3 main structures make up the limbic system and describe each
List 2 additional structures
1) Hypothalamus: homeostasis, ANS, endocrine, hunger
2) Hippocampus: short term memory, emotion, spatial navigation
3) Amygdala: emotions, fear and aggression
Extra:
Cingulate gyrus: wraps around the corpus callosum
Parahippocampal gyrus: medial temporal lobe
What is the location of the limbic system?
Found either side of the thalamus, underneath the cerebrum
Define Learning
The way new information is acquired by the CNS and is observable through changes in behaviour
Define memory
Ability to register (encode), store and retrieve information
What type of injury may impair our memory?
Impaired by diffuse cerebral injury or temporal lobe disease
Give 6 types of memory with examples?
1) Motor and non-motor
2) Declarative and non declarative
3) Working– current, problemsolving
4) Explicit– events and factual knowledge
5) Working memory–material maintained in consciousness
6) Long-term memory–stored unconsciously
Compare Declarative and non-declarative memory
Declarative: available to conciousness (history, words and their meaning)
Non-declarative: generally not available to conciousness (motor skills, puzzle solving, associations)
What are the timelines for:
- Immediate memory
- Working memory
- Long-term memory
Immediate memory: fraction of a second- seconds
Working memory: seconds to minutes
Long-term memory: days to years
Define working memory and in which part of the brain is it controlled
Ability to hold something in the mind for seconds to minutes
Limited capacity to store items/chunks of information in conscious memory before it rapidly disappears when attention diverted E.g. digit span
Controlled in the Pre-frontal cortex and temporal cortex
Can working memory vary amoung individuals and why?
Yes, it depends on the context, personal experiences and higher executive functions
E.g. chess players, card players, jnr doctors on ward rounds
Define long term memory and in which part of the brain is it controlled?
Storage of potentially unlimited capacity
Controlled by the hippocampus, amygdala, mammillary bodies, thalamus and prefrontal cortex
How can long term memory be divided and brifely describe each
1) Explicit–memories that are accessible to consciousness
- Episodic: autobiographical content
- Semantic: facts
2) Implicit– memories not consciously accessible–typically motor memory
- Motor skills – riding a bike
- Conditioning – Pavlovian responses
- Priming – name a city
Give 2 conditions ECT may be used to treat and explain the idea behind this type of treatment
Korsakoff syndrome and dementias
Sends an electrical current through temporal or frontal lobe. This aims to induce a massive seizure, to create an amnesia. Overall, the goal of this is to wipe out memories to reset brain.
Why is ‘forgetting’ essential?
‘buffers’ useless information from our brains to avoid overcrowding/ distractions
Define Amnesia?
Give 3 instances where this may occur
Inability to learn new information or to retrieve information already acquired
Head trauma, toxins, dementia may all result in Amnesia
What are the two types of amnesia?
1) Anterograde amnesia
- Laying down of new memories
- Temporal lobe dependent
2) Retrograde amnesia
- Retrieval of preformed, established memories
- More diverse throughout cerebral cortex
Memory is stored where?
Hippocampus which then transfers information to overlying cortex
What is Transient global amnesia?
Temporary and reversible disruption of short term memory accompanied by repetitive questioning. Patient’s usually wake and don’t recall the preceding 24-48hrs
No neurological deficit other than anterograde amnesia
What would investigations about transient global amnesia show?
How would you treat?
All investigations are normal
Treatment is supportive only
Is Transient global amnesia more common in males or females?
Give 4 possible causes
Usually aged >50 years & M > F
Causes: Idiopathic, minor head trauma, sexual intercourse, heavy exercise, brief shock
