Cerebral Hemispheres Flashcards
label the general surface features
label the general features within the cerebral hemisphere?
What is a gyrus?
Elevation in the cerebral cortex surrounded by one or more sulci
Where is the grey and white matter found in the brain?
Grey matter on the surface
White matter inside
What is the basal ganglia?
Collection of neuronal cell bodies buried in the white matter
What should be known about the pattern of sulci and gyri?
Is variable but some constant features must be remembered
what are major anatomical landmarks of cerebrum?
median longitudinal fissure
corpus callosum
why does the right side of this image look shiny?
presence of pia matter - pia matter is vascular
label the different features of this image?
label the feature on this image?
label the different gyrus’?
label the Supero-lateral view after part of frontal and parietal lobe have been cut away?
What is the corpus collosum?
Thick band of nerve fibres that divides the cortex lobes into right and left
Connects the left and right sides of the brain,a llowing for communication between both hemispheres
What is the insula?
Small region of cerebral cortex lcoated deep within the lateral sulcus
What is cortical mapping?
Invasive procedure in which electrical stimulation is applied briefly to cortical surface for the purpose of identifying cortical areas for sensory, motor or language function
What are the different areas of the brain in cortical mapping called?
Brodmann areas
How many Brodmann areas are there?
52
What is the posterior part of the cerebral hemisphere responsible for?
Sensory information
What is the anterior part of the cerebral hemisphere responsible for?
Motor information
What are the medial portions (limbic system) of the cerebral hemisphere responsible for?
Storing and retrieving processed information
How does the ‘strength’ of each hemisphere compare?
We have one dominant and non-dominant hemisphere
There are primary sensory areas and adjacent association areas in the brain, what is an example of this?
Identifying objects in hand by touch
Talking to your friend
What is the purpose of the frontal lobe?
Motor control
What are some important parts of the frontal lobe?
Area 4, precentral gyrus (primary motor cortex)
Area 44, 45 - inferior frontal gyrus
Prefrontal cortex
what is the Primary Motor cortex?
somatotopic representation of contralateral half of body (motor homunculus)
The primary motor cortex, located just in front of the central sulcus, is the area that provides the most important signal for the production of skilled movements
within precentral gyrus
what is Broca’s area of motor speech?
a center for the motor programming of speech articulation movements within inferior frontal gyrus
what is the prefrontal cortex responsible for?
cognitive functions of higher order- intellect,judgement, prediction,planning.
What Brodmann area is the primary motor cortex?
Area 4
What is area 4 of the frontal lobe responsible for?
Somatotopic representation of contralateral half of body (motor homonculus)
What is the motor homonculus?
Map of brian areas dedicated to motor processing for different anatomical divisions of the body
What Brodmann areas of the brain is the inferior frontal gyrus?
44 and 45
What are functions of the prefrontal cortex of the frontal lobe?
Cognitive functions of higher order such as intellect, judgement, predicting and planning
What is the purpose of the parietal lobe?
Somatosensory
What are some important parts of the parietal lobe?
Post central gyrus (areas 3, 1, 2)
Superior parietal lobule
Inferior parietal lobule
What Brodmann areas form the post central gyrys?
Areas 3, 1 and 2
What is the function of the post central gyrus?
Primary senosry area
Receives general sensation from contralateral half of body
What demonstrates the somatotopic representation of the post central gyrus?
Sensory homunculus
What is the function of the superior parietal lobule?
Interpretation of general sensory information (senosry association area) and conscious awareness of contralateral half of body
What is the function of the inferior parietal lobule?
Interface between somatosensory cortex and visual and auditory association areas
In dominant area, contributes to language function
What does a parietal lobe lesion lead to?
Hemisensory neglect (neuropsychological condition)
Right-left agnosia (inability to interpret sensation and hence to recognise things)
Acalculia (loss of ability to perform simple calculations)
Agraphia (loss of ability to communicate through writing)
What is the medical term for inability to interpret sensation and hence to recognise things?
Agnosia
What is the medical term for the loss of the ability to perform simple calculations?
Acalculia
What is the medical term for the loss of the ability fo communicate through writing called?
agraphia
What is the function of the temporal lobe?
Hearing and smelling
What are some important areas of the temporal lobe?
Superior temporal gyrus
Auditory association areas
Inferior surface
what is the function of the superior temporal gyrus?
Primary auditory cortex
What are the Heschl’s convolutions of the superior temporal gyrus (primary auditory cortex)?
41 and 42
Where are the auditory association areas found?
Posterior to areas 41 and 42 (primary auditory cortex)
What is the area of the brain that deals with language development called, and what hemisphere is it found in?
Wernicke’s area, found in dominant hemisphere
What is the function of the inferior surface of the temporal lobe?
Receives fibres from olfactory tract, conscious appreciation of smell
What is the function of the occipital lobe?
For visual
What are important areas of the occipital lobe?
Medial surface
Rest of lobe is the visual association cortex (areas 18 and 19)
What Brodmann area is the primary visual cortex and where is this found?
Area 17, found on either side of the calcarine sulcus (medial surface of occipital lobe)
What Brodmann areas are visual association areas?
Areas 18 and 19
What is the function of visual association cortex?
Concerned with interpretation of visual images
What are the different lobes of the brain?
Frontal
Parietal
Occipital
Temporal
Limbic lobe
Where is the limbic lobe found?
Medial surface of cerebral hemisphere
What is the function of the limbic lobe?
Involved in memory and emotional aspects of behaviour
What are some area that form the limbic lobe?
Cingulate gyrus
Hippocampus (medial aspect of temporal lobe)
Parahippocampal gyrus
Amygdala (subcortical grey matter close to temporal pole)
What are the language areas?
Broca’s area (motor speech area)
Wenicke’s area (auditory association area necessary for recognising spolen words - found in dominant hemisphere only)
features of brocas aphasia?
Understands speech Misses small words Aware of difficulties in speech
Damage to frontal lobe
Weakness/paralysis of one side of body
features of Wernicke’s aphasia?
“You know that smoodle pinkered & that I want to get him round & him like you want before”
Fluent speech, with new meaningless words, can’t understand speech, doesn’t know of mistakes
Damage to temporal lobe
No paralysis
What is the medical term for problems with speech due to damage to one or more speech areas of the brain?
Aphasia
What are the differences between Broca’s aphasia and Wernicke’s aphasia in terms of where the damage is and paralysis?
Broca’s - damage to frontal lobe, paralysis of one side of body
Wernicke’s - damage to temporal lobe, no paralysis
In white matter what are the 3 types of myelinated axon fibres bundled into tracts?
Commisural fibres
Association fibres
Projection fibres
What is the function of commisural fibres?
Connect corresponding areas of two hemispheres (corpus collosum)
What is the function of association fibres?
Connect one part of the cortex with the other
May be long or short
What is the function of projection fibres?
Run between cerebral cortex and various subcortical centres
Pass through corona radiata and the internal capsule
What is 3D cerebral tractography?
3D modelling technique that maps functional white matter tracts using data collected using MRI
Based on symmetry of brain water diffusion
What is the internal capsule?
White matter structure situated in the inferomedial part of each cerebral hemisphere
What kind of fibres is the interal capsule made up of?
Projection fibres to and from the cerebral cortex
Where is the internal capsule found?
Narrow area between the thalamus and caudate nucleus mediallly and lentiform nucleus laterally
What does the internal capsule derive blood supply from?
Middle cerebral artery
label different features of the internal capsule?
label different parts of white matter?
label different features of the basal ganglia?
What is the basal ganglia?
Subcortical nuclei (collection of neuronal cell bodies, grey matter) deep within each hemisphere
What is the basal ganglia made up of?
Caudate nucleus
Putamen
Globus pallidus
Substantia nigra in midbrain (functionally part of them but not anatomically)
what is the basal ganglia with a tail?
Caudate
what is the basal ganglia with a hard shell?
Putamen
what is the pale globe basal ganhglia?
Globus pallidus
The hard shell + the globe form a lens like structure basal ganglia?
Lentiform nucleus
The black substance?
Substantia nigra ( lies in midbrain)
The subthalamic nucleii
label basal ganglia?
Explain the connections of the basal ganglia?
Caudate nucleus and the putamen are the ‘input regions’ receiving inputs from motor cortex, premotor cortex and thalamus
In turn connected to ‘output regions’, the globus pallidus and the substantia nigra
Globus pallidus projects primarility to the thalamus which in turn sends fibres to the motor area of cortex
What is the function of the basal ganglia?
Help regulate initiation and termination of movement
what is lateral to the internal capsule?
lentiform nucleus made up of the putamen laterally and globus pallidus medially.
label the image?
basal ganglia
The major function of the basal ganglia is to help regulate initiation and termination of movements.
Because they play a role in controlling the motor system they are often referred to as the “extrapyramidal system”
Pathology: Parkinson’s, chorea, athetosis etc.
summary
Cerebral hemispheres – outer grey matter, inner white matter, deep in the white matter- basal ganglia (grey matter).
Median longitudinal fissure separates 2 lobes, corpus callosum connects.Central sulcus, lateral sulcus, parieto-occipital sulcus.
Frontal lobe – thinking, motor cortex, Broca’s speech area.
Parietal lobe – sensory
Temporal lobe – Auditory, Wernicke’s area (language), smell.
White matter – association, commisural & projection fibres.
Basal ganglia – control movement by connecting to motor cortex .(Starting and stopping of movements).
