Neuroanatomy of Language Flashcards
What are the three layers of the meninges from superficial to deep?
dura mater
arachnoid membrane
pia mater
Describe the dura mater
outermost meninx, composed of tough fibrous connective tissue
Describe the arachnoid membrane
-middle meninx, delicate membrane with a spider web appearance
Describe the Pia mater
inner most meninx that clings directly to the brain and spinal cord
What is the subarachnoid space?
the space between the Pia mater and the main part of the arachnoid layer
-it contains blood vessels, web like processor of the arachnoid layer and CSF
Describe the ventricular system
a system of four interconnected hollow chambers filled with CSF at the centre of the brain
Where are the 2 lateral ventricles located?
within each cerebral hemisphere (telencephalon)
Where is the third ventricle located?
centrally in the forebrain (diencephalon)
Where is the fourth ventricle located?
in a small chamber in the hindbrain (metencephalon)
3rd and 4th ventricles communicate via the ______________
cerebral aqueduct (a narrow channel running through the midbrain)
The ventricular system is continuous with the ________ of the spinal. cord and is connected to the _________ via the 4th ventricle
central canal
subarachnoid space
CSF is produced where?
in the chord plexuses within the walls/roof of ventricles
The __________ divides the frontal lobe from parietal lobe
central sulcus (Rolando)
The ____________ separates the frontal from temporal lobe
lateral (sylvian) fissure
The ____________ separates occipital lobe from the temporal and parietal lobes
parieto-occipital sulcus
The L and R cerebral hemispheres are separated by the ______________
longitudinal fissure
Classification of areas of cortex based on similar cellular morphology (size, shape) and organization are called what?
Brodmann’s areas
What area corresponds to BA 44?
broca’s area
What area corresponds to BA 22?
Wernicke’s area
What are corresponds to BA 41& 42?
primary auditory cortex (Heschl’s gyrus)
What area corresponds to BA 43?
Primary gustatory cortex
What area corresponds to BA 1,2,3?
primary somatosensory cortex
What area corresponds to BA 4?
primary motor cortex
What major functional systems are found within the FL?
primary motor cortex and primary olfactory cortex
What major functional systems are found within the PL?
primary somatosensory cortex
primary gustatory cortex
What major functional systems are found within the TL?
primary auditory cortex
What major functional systems are found within the OL?
primary visual cortex
In general describe primary sensory areas
most sensory information arrives here first
In general describe primary motor areas
-send commands to muscles
In general describe secondary sensory motor areas
Higher order visual, somatosensory and auditory areas located
near respective primary area & information further processed
In general describe association areas and list the 3 association areas in the brain
- Not exclusive to sensory or motor info & composed of regions that receive inputs from one or more modalities
- Attention, planning and memory
- Association areas: prefrontal, limbic, parieto-temporal-occipital area (language processing)
What area corresponds to BA 6?
premotor cortex
Which is the largest lobe in the brain?
frontal
Describe the primary motor cortex
- located on pre central gyrus
- homunculus
- specific area for speech, hand, finger movements, & eye-hand coordination
- each hemisphere controls contralateral side of body
- damage leads to hemiplegia
Describe the premotor cortex
- located anterior to primary motor strip
- guide voluntary body movements and integrates sensory input
Describe the supplementary motor cortex
- Located dorsal to premotor cortex
- Involved in planning complex motor movement and movements under internal control (sequence of movements from memory)
Describe the function prefrontal association area
Higher aspects of motor control and planning/execution of behaviour and other cognitive functions (control of behaviour; abstract thinking and reasoning)
The prefrontal cortex can be divided into the dorsolateral prefrontal cortex that is responsible for ___________ and the inferior orbital prefrontal cortex that is responsible for __________
- working memory functions
- decision making and affective responses
Where is Broca’s area located and what is its function
- inferior frontal gyrus (typically left hemisphere)
- located in front of area of primary motor cortex that controls jaw, lip, tongue and vocal cord movements
- important for speech production
Lesions to the frontal lobe can lead to what?
- lack of inhibition of behaviours including speech
- May have normal intelligence and memory but personality changed (poor impulse control, quick temper, irritability
- Bilateral lesion: reduced or cessation of behaviour
What are the general functions of the parietal lobe?
- reading, writing, language and calculation
- perceptual synthesis, spatial orientation, cross modality integration, memory and cognition
Analysis and integration of info in inferior parietal lobule contributes to what?
complex perception
describe the location and function of the primary somatosensory cortex
- located in post central gyrus
- all modalities of somatic sensation are received here
- sensory homunculus
What are the 2 association areas in the PL important in language
- angular gyrus
- supramarginal gyrus
What area is represented by BA 39?
angular gyrus
What area is represented by BA 40?
supramarginal gyrus
Describe the location and function of the angular gyrus
- Posterior inferior parietal lobe (just posterior to Wernicke’s area)
- Involved in processing of auditory and visual input & language comprehension
- Processes letters with corresponding sounds
- important for reading, writing, abstract thinking and calculation
Describe the location and function of the supra marginal gyrus
- inferior lateral parietal lobe
- involved in reading (meaning and phonology)
- symbolic integration for writing
Damage to the PL leads to
complex perceptual disorders of constructional skills, spatial orientation, body schema, memory, also often neglect opposite side of body (hemispatial neglect)
A right PL lesion may lead to
- Balint’s syndrome
- 3D spatial disorientation
- dressing apraxia
A left PL lesion may lead to
-Gerstmann’s syndrome (right-left disorientation, acalculia, agraphia, finger agnosia)
What are the important functions of the temporal lobe?
- Involved in speech comprehension (semantic processing)
- Integrates written and oral symbols to make them meaningful
- Houses primary and secondary auditory cortex
- Medial temporal areas most related to memory (hippocampus)
Describe the location and function of Heschl’s gyrus. What is the result of a lesion in this area?
- Dorsal surface of superior temporal gyrus & buried within sylvian fissure (lateral)
- Region represents primary auditory cortex and auditory association cortex
- Lesion to this area causes pure word deafness
Describe the location and function of Wernicke’s area
- left posterior portion of superior temporal gyrus
- Encircles auditory cortex on Sylvian fissure = auditory language association area
- critical to understanding of language
what is the result of a lesion in Wernicke’s area
Wernicke’s aphasia
What is the result of right TL lesions?
-affects appreciation of music and rhythm and nonverbal memory
What are the types of white fibers?
projection fibers
association fibers
commissural fibers
Describe projection fibers
Sensory and motor fibers that travel vertically from cortex to brainstem & spinal cord
Describe association fibers
- Most numerous fiber type
- Confined within one hemisphere (intra hemispheric communication) and connect different regions
Describe commissural fibers
- Fibers run horizontally and connect corresponding areas of both hemispheres
- Most are included in the Corpus callosum; the rest make up the anterior commissure
The ___________ is an association fiber connecting broca’s and wernicke’s areas
arcuate fasiculus
the brain receives ___________ of the body’s blood supply
15-20%
with 5-8 seconds of interrupted blood flow to the brain, what happens?
person is unconscious
with 20 seconds of interrupted blood flow to the brain, what happens?
neuronal activity stops
with 4-6 minutes of interrupted blood flow to the brain, what happens?
irreversible brain damage
T or F: spinal cord can handle lack of oxygen longer than the brain can
true
What two pairs of arteries supply the brain with blood?
- verebtral arteries
- internal carotid arteries
Left and right vertebral arteries come together at the base of the brain to form a single _________
basilar artery
What is the circle of willis? Which blood vessels does it include?
- A ring of arteries in the brain, it provides a safety mechanism, if one artery gets blocked the circle will still provide some blood to the brain
- Includes: internal carotid arteries, ACA, MCA, PCA, anterior communication artery + posterior communicating artery? (not sure about this)
The internal carotid arteries branch off into what?
- anterior cerebral artery (ACA)
- middle cerebral artery (MCA)
- posterior cerebral artery (PCA)
Describe the ACA and what happens if it is damaged?
-Distributed mostly throughout medial surface of cortex
extending posteriorly into parietal lobe
-Interruption results in paralysis of legs, feet
-Prefrontal lobe symptoms (impaired thinking, reasoning, planning)
Describe the MCA
- Branches to most of the lateral cortex, largest of cortical arteries
- Has main vessel within sylvian fissure
- It supplies motor and sensory areas involved in speech, audition and language!
Describe the PCA and what happens if it is damaged?
- covers medial surface of occipital lobe and base of temporal lobe
- supplies primary visual area
- occlusion of basilar artery (which supplies PCAs) results in total blindness and cerebellar symptoms
What are the types of stroke
- blockage/ischemic stroke
- hemorrhagic stroke
Describe ischemic strokes
- most common form of stroke (85%)
- Can be caused by thrombosis or embolism
What is a transient ischemic attack
- temporary interruption of blood circulation to brain
- Sx: weakness, double vision, headache, numbness, dysarthria and dizziness
- puts you at higher risk for having subsequent stroke
describe hemorrhagic stroke
- approx 15% of stroke, but accounts for higher mortality rate than ischemic
- similar focal neurological signs as ischemic but more ill
- can be intracerebral, subdural, or aneurysm
Describe arteriovenous malformation
- a congenital condition involving connections between arteries
- susceptible to hemorrhaging
What two important principles of functioning are central to understanding effects of brain lesions on cognitive processes?
- contralaterality
- hemispheric specialization
LH is responsible for ______________________
speech, reading, writing, math, language related sounds
RH is responsible for ____________
non-verbal aspects of language, prosody, narrative, inference, spatial, perceptional information processing
