Cerebellum, Cerebrum, Limbic system 2 Flashcards
True false - all tasks are bilaterally arranged in the cortex
- FALSE, some are bilateral but many are unilateral
- ex. lesion the non-fluent aphasia portion of the left hemisphere and have deficit, lesion same location on right hemisphere no deficit!
List two examples of bilateral tasks arrangement
- hearing
- motor function (RLE on left side, LLE on right side)
What happens if bilateral lesion of parahippocampus? unilateral lesion?
- bilateral: can’t make new memories
- unilateral: no problems
when does lateralization of the brain occur?
- early, it is reinforced by growth, development, and experience
symptoms of right parietal lobe lesions
- hemineglect syndrome
- ignore anything in left visual field: draw clock with all numbers on right side
- almost exclusively after right lesions
- loss of recognition of spacial relations
- loss of prosody (ability o understand voice inflection, = monotone voice)
What are the two components of language function
- verbal - use and understanding of spoken, written, or read words (what you say), generally in the left cortex
- nonverbal - affective components such as inflection, intensity, emotion. Also called prosody, generally in teh right cortex
how much of the meaning of language is derived from prosody?
80-90%
What is the dominant language hemisphere for right handed people? left handed people?
- Right handed: 96% left dominant, 4% right
- left handed: 70% left dominant, 15% right, 15% both
- Broca’s is located in dominant language hemisphere
What happens if you lose Broca’s area?
what is this called?
- can’t drive larynx, can’t speak
- can understand written and verbal language
- Broca’s aphasia, motor aphasia, or expressive aphasia
If right handed and have a stroke of the left middle cerebral artery, what is most likely speech related deficit?
- most people will have lost Broca’s area and won’t be able to speak
What happens if a young child damages Broca’s area on the dominant side?
can develop a speech center on the opposite side (plasticity)
Split brain study:
- if cut corpus callosum what happens
- right hemisphere knows what it is seeing
- left brain can’t process what it is seeing
- left hand can write what it sees (bc right brain knows what it is)
- right hand can’t write what it is bc left brain never knew what it saw
- he went over a bunch of other examples of this…
How are Wernicke’s and Broca’s connected?
- Wernicke’s interprets spoken language
- “tells” broca’s what to say in response to interpretation
What happens if Wernicke’s has a lesion
- can hear what is said but can’t produce meaningful language
- answer is completely wrong, words in wrong order
- Wernicke’s aphasia or receptive aphasia
- often do not know what saying is wrong
define; difficulty speaking inability to speak difficulty in reading inability to read
- dysphasia
- aphasia
- dyslexia
- alexia
Define:
- apraxia
- agnosia
- loss of task performance without loss of movement (agraphia)
- loss of the significance of a sense: astereognosia, visual agnosia, auditory agnosia, amusia
Where is memory in the cortex
distributed widely
types of memories (not classification)
- auditory
- visual
- olfactory
- procedural
How are memories generated, how long do they last?
- by experiences and practice
- can be fleeting or long lasting
What structure “moves” memories from ST to LT
hippocampus
re-written memories
add new information to a memory
Two types of memory classification
- declarative (facts and events)
2. non declarative (procedural such as riding a bike, classical conditioning)
What two brain structures can learn via classical conditioning?
- cerebellum: pavlovs salvation
- amygdala: emotional conditioning, fear of a snake
What brain structures are involved in procedural memory?
basal ganglia
What type of memory loss when lesion hippocampus bilaterally
anterograde, can’t make new memories
Four Fs of limbic function
- fighting (aggression)
- flight
- feeding
- fooling around
- emotional/visceral brain
What is the role of the limbic system
- attach emotion to the moment
- determine physiologic response to the moment
What are the components of the limbic system (4)
- olfactory system
- temporal lobe (parahippocampi and hippocampus)
- amygdala
- papez circuit
Overview of olfaction circuitry
- nerves through cribriform plate of the ethmoid bone
- synapse in the olfactory bulb
- project into the brain
Where do projections from the olfactory bulb go? Why is this significant?
- piriform cortex and entorhinl cortex
- also amygdala
- straight to cortex without first synapsing in the thalamus, only sense to do this
What is sensitive about the circuitry of olfactory sensation?
sensitive to hypoxia
- temporal lobe epilepsy will often have an aura of a very unpleasant smell
Why is the hippocampus so sensitive to hypoxia?
- high metabolic rate
= memory is one of the first things to be lost after hypoxic events
Papez circuitry (9)
- cingulate cortex
- cingulum
- parahippocampal gyrus
- hippocampus
- fornix
- mammillary bodies
- mammillothalamic tract
- anterior nucleus of thalamus
- cingulate cortex
Lesion of the temporal lobe likely to cause what condition?
Alzheimer’s
- related to ACh
Bilateral lesion of the amygdala causes what condition?
Kluver-Bucy syndrome
Kluver-Bucy syndrome sx
- flat affect
- loss of learning
- excessive exploratory behavior
- hyperphagia
- abnormal sexual behavior (mount everything)
Temporal lobe epilepsy sx
- aura of odor (orbital, frontal, entorhinal)
- deja vu (hippocampus)
- anxiety (amygdala)
- rage (amygdala)
- autonomic response
Dementia
- related to loss of what part of the brain
typically associated with lesions of the hippocampus
Four types of memory that can be lost
- anterograde: can’t make new memories
- retrograde: past memories
- declarative: events that can be recalled, peoples names, faces
- non-declarative: riding a bike, music, language
Wernicke’s encephalopathy
- dysfunction/degeneration of mammillary bodies
- assoc. with ethos abuse and lack of thiamine
- confusion, memory loss, AMS, gate abnormality
*thiamine before glucose
Korsakoff’s syndrome
- etoh
- amnestic confabulatory syndrome
- fanciful realities
- may visually hallucinate
