Topography of the Brain Flashcards
What sulcus separates the left and right hemispheres of the cerebral cortex?
the longitudinal fissure
What sulcus separates the frontal and parietal lobes? How does it run?
- the central sulcus
- left to right (looking down superiorly)
What sulcus lies anterior to the central sulcus?
- pre-central sulcus
- lies in the frontal lobe
What sulcus lies posterior to the central sulcus?
- post-central sulcus
- lies in the parietal lobe
What sulcus separates our temporal lobe from our parietal lobe?
- lateral fissure
- lateral aspect of the head
What sulcus separates the cerebellum and the temporal lobe?
the transverse fissure
The cingulate sulcus:
- located where
- separates
- medial view, just above the corpus
callosum, above cingulate gyrus - separates the limbic system and the
cerebral system
What sulcus separates the parietal and occipital lobes?
- parieto-occipital sulcus
- more posterior on the brain, like
where the occipital lobe is located
What sulcus divides our visual cortex?
- calcarine sulcus
- posterior of the brain (in the occipital
lobe) - much lower, closer to the cerebellum
Lobes of Brain:
Major Sulci:
Major Sulci: Medial View:
What gyrus lies between the pre-central sulcus and the central sulcus?
the pre-central gyrus
Pre-central Gyrus: Function:
- Primary Motor Cortex (voluntary)
What gyrus is located between the central sulcus and the post-central sulcus?
the post-central gyrus
Post-central Gyrus: Function:
- Primary Somatosensory Cortex
(most sensory processing)
What gyrus is found on the temporal lobe just below the lateral fissure?
the superior temporal gyrus
Superior Temporal Gyrus: Function:
- reception and processing of sound
What gyrus lies between the corpus callosum and the cingulate sulcus?
the cingulate gyrus
Cingulate Gyrus: Function:
- part of the limbic system
Para-hippocampal Gyri:
- location
- function
- medial temporal lobes, close to
midbrain - part of the limbic systems
Name two gyri that are part of the limbic system.
- cingulate gyrus
- para-hippocampal gyri
Uncus:
- location
- function
- anterior part of parahippocampal
gyri, looks like a hook, close to
midbrain, medial temporal lobes - role in olfaction, emotion and
memory
Major gyri:
Medial View: Gyri:
under the tooth like structure is parahippocampal gyri
tooth like structure is the optic chiasm
Inferior view of the brain: Label the gyri:
insert diagram
look up? check complete anatomy
Organisation of the brain:
Functional Cortical Areas:
Broca’s Area:
- location
- function
- lesion would cause
- unilateral (left hemisphere if right
handed person), anterior brain,
frontal lobe, circular - language production
- expressive dysphasia; cant produce
full language needed, can’t produce
sentence - not fluent
Wernicke’s Area Function:
- location
- function
- lesion would cause
- unilateral (left hemisphere if right
handed person), posterior brain,
parietal/temporal lobes, circular - language comprehension
- receptive dysphasia; can produce
sentence but will not make sense - fluent
Which cortical areas are found on both hemispheres of the brain?
- primary motor cortex
- primary somatosensory cortex
- process info from and send info to
the opposite side eg the info from
the right side of the body crosses
over to the left hemisphere
Somatotopic Organisation Definition:
within the functional areas, different parts of the body are mapped to specific areas of the cortex
Somatotopic Organisation: Homuncules:
little man sitting with feet in the lateral fissure and rest of the body flung around
Somatotopic Organisation:
Our language centre’s are unilateral.
- only located on one side of the brain
(broca and wernicke’s) - generally left hemisphere of brain as
most people are right handed
(crosses over)
Classes of White Matter Tracts in the Brain (3):
- Projection Fibers
- Association Fibers
- Commissural Fibers
Projection Fibers (3):
- connect groups of neurons within
the CNS - travels up the spinal cord, connects
to a nucli in the brain and then
projects to area required
Association Fibers:
- connect different parts of the
cerebral cortex
Commissural Fibers:
- connect EQUIVALENT areas of the
two sides of the brain
General Classes of Tracts in the Brain:
Internal Capsule:
- Label
- Type of Fiber
- Function
- projection fiber
- two-way tract for the transmission of
information to and from the cerebral
cortex. - Long part of axon of neuron
Fornix:
- Label
- Type of Fiber
- Function
- Projection Fiber
- connects the mammillary bodies
with the hippocampi; connecting the frontal and temporal parts of the limbic system
Corpus Callosum:
- Label
- Type of Fiber
- Function
- Commissural Fiber
- connects the right and left
hemispheres and functionally related
structures
What view of the brain is shown below? What is labelled below?
Corpus calluses
Transverse view
What view of the brain is shown below? What is shown below?
Coronal view
Corpus Callosum: Transverse View: Label the Genu and Splenium:
genu is anterior inner curve
splenium is posterior curve
body isn’t visible as it the cut is too low
What are the two types of association fibers?
- long fibers; spanning the entire
length on one side of the brain - short fibers loop between the
cortical areas
Association Fiber Types
What are basal ganglia?
collections of cell bodies (grey matter) deep within each hemisphere involved in movement
Basal Ganglia Functions:
- process information related to
emotions, motivation and cognition - Regulate movement:
- initiation of movement
- switching between motor
programs
- inhibit antagonistic and
unnecessary movements
- regulate force of movement
Neural Components of Basal Ganglia: State:
- caudate nucleus
- putamen
- globus pallidus
Caudate Nucleus:
- neural component of basal ganglia
- c-shaped nuclei located in the frontal
lobe - head region curves and extends to
form elongated body tapering at tail
and ending at the temporal lobe
What is shown below?
Putamen:
- neural component of basal ganglia
- large rounded nuclei in forebrain
- connected to caudate nucleus at
head region of the caudate - quite lateral coronally
- sits within the insular lobe
What is labelled below?
the putamen
Globus Pallidus:
- neural component of basal ganglia
- externus: relays info between other
basal ganglia nuclei and the internal
globus pallidus - internal: sends output to the
thalamus - just medial to putamen
- difference in colour to putamen
What is shown below?
What neural components of the basal ganglia make up the Striatum?
Caudate Nucleus + Putamen
What neural components of the basal ganglia make up the Lentiform Nucleus?
Putamen + Globus Pallidus
What neural components of the basal ganglia make up the Corpus Striatum?
Caudate Nucleus + Lentiform Nucleus
(Caudate Nucleus + Putamen + Globus Pallidus)
The internal capsule is (projection fiber) a white matter structure separating which neural components of the basal ganglia?
Lentiform Nucleus and Caudate Nucleus from the thalamus (carries info past the basal ganglia)
Neural Components of Basal Ganglia:
Blood Supply to the Brain:
- anterior and posterior circulation co-
exist and anastomose via the Circle
of Willis - anterior circulation = two internal
carotid arteries (from the middle
cerebral and anterior cerebral
arteries) - posterior circulation = two vertebral
arteries (from the subclavian
arteries), which form the basilar
artery which branches into the
posterior cerebral arteries
Blood Supply to the Brain:
Posterior View of the Circle of Willis:
Circle of Willis:
When looking at the caudate nucleus in coronal section will always be
lateral to the lateral ventricles
Circle of Willis:
Cerebellar Blood Supply:
Cortical Distribution of the
middle cerebral artery
Cortical distribution of
the posterior cerebral artery and the anterior cerebral artery
The arterial supply to the basal ganglia comes mainly from the
middle cerebral artery; a continuation of the internal carotid artery
the main blood supply is via the lenticulostriate arteries
- The arterial supply to the basal ganglia mainly comes from the 4 lenticulostriate arteries on either side, which arise from the middle cerebral artery which is a continuation of the internal carotid artery which is a bifurcation of the common carotid artery which is a branch of the arch of the aorta on the left and a branch of the brachiocephalic trunk on the right
Blood supply to Basal Ganglia:
Which artery is affected?
Middle Cerebral Artery = more lateral
anterior cerebral would be more midline
Angiogram: Anterior Circulation:
- normal circumstance anterior and
posterior communicating arteries are
closed - classic circle of willis seen in 34.5%
- common variations are:
- one small posterior
communicating and one large
- anterior communicating large
Angiogram: Posterior Circulation:
Posterior circulation
insert diagram
If you lose circulation in the anterior cerebral artery,
because it supplies the internal surface of the brain, you will lose motor and sensory information in your lower limb
If you lose circulation in the middle cerebral artery,
loss of motor and sensory information to upper body
- If you lose circulation in the middle cerebral artery you lose motor and sensory supply in the upper limbs because it supplies the part of the brain hence where the arms of homunculus lie in the lateral fissure
Identify the labelled structure.
Middle Cerebral Artery
running between temporal lobe and rest of the brain.
What type of deficit would a patient experience if there was an injury to the highlighted area?
Receptive dysphasia (Wernicke’s Area)
What type of white matter fibres/tract is the corpus callosum?
- projection fibers
- association fibers
- commissural fibers
commissural fibers
Identify the labelled structure.
Putamen
