The Cerebral Hemispheres Flashcards
What is a sulcus?
Dip
What is a gyrus?
Elevation
What is a fissure?
Larger dip
Where is grey matter found on the brain?
On surface
Where is white matter found on the brain?
Inside
What is basal ganglia?
Collection of neuronal cell bodies buried in the white matter
Features of corupus callosum
Contain fibres which go from one hemisphere to another
A communicating bridge
Important sulci to remember
Central sulcus
Lateral sulcus
Cingulate sulcus
Parieto-occipital sulcus
Important fissures to remember
Median longitudinal fissure
Transverse fissure
Important gyri to remember
Precentral gyrus
Postcentral gyrus
Cingulate gyrus
Another name for the lateral sulcus
Lateral fissure
What does the parietal lobe separate?
The parietal lobe from the occipital lobe
Lobes of the brain
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Gyri of the frontal lobe
Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus
What is cortical mapping?
Mosiac map of the cortex with 52 areas called Brodmann Areas
Main function of frontal lobe
Motor
What is the precentral gyrus?
Primary motor cortex
What is the inferior frontal gyrus?
Brocas Area of motor speech
What is the function of the prefrontal cortex?
Cognitive functions of higher order intellect
Judgement
Prediction
Planning
Functions of the frontal lobe
Somatotrophic representation of contralateral half of body (motor homunculus) - precentral gyrus
Brocas area of motor speech
Cognitive functions of higher order intellect, judgement, prediction and planning
Rest of musculature
Eyes
What is the post central gyrus?
Primary sensory area
Function of primary sensory area / post central gyrus
Receives general sensations from the contralateral half of the body Somatostopic representation (sensory homunculus)
Parts of the parietal lobe
Post central gyrus
Superior parietal lobe
Inferior parietal lobe
Function of the superior parietal lobe
Interpretation of general sensory information (sensory association area)
Conscious awareness of contralateral half of body
Function of inferior parietal lobe
Interface between somatosensory cortex and visual and auditory association areas
Additional function of the dominant hemisphere of the inferior parietal lobule
Contributes to language functions
What is observed in hemisensory neglect?
One field of vision
What is seen in right left agnosia?
Inability to process sensory information
What is acalculia?
Difficulty in performing simple mathematic tasks
What is agraphia?
Loss of ability to communicate through writing
Overall functions of the temporal lobe
Hearing
Smell
Areas of the temporal lobe
Superior temporal gyrus
Auditory association areas
Inferior surface receives fibres from olfactory tract (conscious appreciation of smell)
What is the superior temporal gyrus?
Primary auditory cortex
What is the auditory association area in the dominant hemisphere called?
Wernickes area
Function of wernickes area
Understanding of the spoken word
Main function of occipital lobe
Vision
What is the calcarine sulcus on the occipital lobe? Where is this found?
Primary visual cortex
Medial surface of the occipital lobe
What is the rest of the occipital lobe?
Visual association cortex
Function of the visual association cortex
Interpretation of the visual images
What is the limbic lobe involved with?
Memory
Emotional aspects of behaviour
What does the limbic lobe consist of?
Cingulate gyrus
Hippocampus
Parahippocampal gyrus
Amygdala
Where is the hippocampus found?
Medial aspect of the temporal lobe
What is the amygdala?
Subcortical grey matter close to the temporal pole
What is the function of the posterior part of the cerebral hemisphere?
Sensory
What is the function of the anterior part of the cerebral hemisphere?
Motor
What is the function of the medial portions of the cerebral hemisphere (limbic system)?
Storage and revival of processed information
Two types of hemispheres
Dominant
Non dominant
Main function of frontal lobe
Motor function i.e. skeletal muscle movement
intellect i.e. thinking
Main function of parietal lobe
Somatosensory i.e. touch/temperature
What part of the temporal lobe is hearing?
Top part
What part of the temporal lobe is smell?
Bottom part
What is Brocas Area?
Motor speech area
What is Wernickes Area?
Auditory association area
Necessary for recognition of the spoken word
Where is Wernickes Area found?
Temporal lobe in the dominant hemisphere
What is aphasia?
Problem with speech due to damage to one or some speech areas in the brain
Two types of aphasia
Broca’s Aphasia
Wernicke’s Aphasia
Features of Broca’s Aphasia
Understands speech
Misses small words
Aware of difficulties in speech
Where would be damaged to result in brocas aphasia?
Frontal lobe
What may also be present with brocas aphasia?
Weakness/paralysis to one side of the body
Features of Wernickes Aphasia
Fluent speech with new meaningless words
Cant understand speech
Doesn’t know of mistakes
Where would there be damage to to result in wernickes aphasia?
Temporal lobe
Would there be assosiated paralysis with wernickes aphasia?
No
What are the 3 types of white matter in the forebrain?
Commissural fibres
Association fibres
Projection fibres
Neumonic to remember the 3 types of white matter in the forebrain
CAP
Function of commissural fibres
Connect corresponding areas of the two hemispheres (corpus callosum)
Function of association fibres
Connect one part of the cortex with the other
May be short or long
Function of projection fibres
Runs between the cerebral cortex and various subcortical centres
Pass through the 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.
What is the internal capsule?
Made up of projection fibres passing to and from the cerebral cortex
Where is the internal capsule found?
Narrow area between the thalamus and caudate nucleus medially and the lentiform nucleus laterally
Blood supply to the internal capsule
Middle cerebral artery
When is the internal capsule frequently affected?
In stroke
What is a main feature of the internal capsule?
It is very densely concentrated
What are basal ganglia?
Subcortical nuclei (collection of neuronal cell bodies - grey matter) deep within each cerebral hemisphere
What makes up basal ganglia?
Caudate nucleus
Putamen
Globus pallidus
What is functionally a part of the basal ganglia but not anatomically?
Substantia nigra
What colour is substantia nigra?
Black
Where does substantia nigra lie?
Midbrain
What does the substantia nigra lie next to?
Red nucleus
What makes up the lentiform nucleus?
Putamen laterally
Globus pallidus medially
What are the input regions receiving input from the motor cortex, premotor cortex and from the thalamus?
Caudate nucleus
Putamen
What are the output regions connected to the input regions?
Globus pallidus
Substantia nigra
What does the globus pallidus primary project to? In turn where does this send fibres to?
Thalamus
Sends fibres to motor area of the cortex
Major function of the basal ganglia
Help regulate initiation and termination of movements
What is the basal ganglia often called?
Extrapyramidal system
White and grey matter of the cerebral hemispheres
Outer grey
Inner white
Deep in white - grey (basal ganglia)
What separated the two cerebral hemispheres?
Median longitudinal fissure
What connects the two cerebral hemispheres?
Corpus callosum