Control L8 forebrain Flashcards
Where is the outer brain derived from?
The telencephalon
Where is the inner brain derived from?
Diencephalon
Where did the forebrain derive from?
The prosencephalon
What are the two part of the forebrain?
The telencephalon and diencephalon
What is the primary role of the forebrain?
High level processing e.g. memory, cognition, learning, integration of different sensory modalities
How many swellings of telencephalon are there in development? What are they called? What connects them?
2
Telencephalon vesicles
Connected by lamina terminalis
How does the embryonic telencephalon move to form the shape of the brain?
The telencephalon folds down around the diencephalon
What does the embryonic telencephalon become?
Cerebral hemispheres
What does the embryonic lamina terminalis become?
The corpus callosum and anterior commissure
How does the diencephalon develop?
appears as a swelling of the lateral aspect of the central canal. As it develops, the lumen of the central canal narrows and two pairs of swellings form - the thalamus dorsally and the hypothalamus ventrally. The narrowed central canal forms the 3rd ventricle
What sulcus separates the hypothalamus and the thalamus?
Hypothalamic sulcus
What shape is adopted by the telencephalon in development?
C shape
Where is the inferior horn of the ventricles?
Temporal lobe
In the coronal plane, at what level can the anterior and posterior horns of the ventricles be seen?
At the level of the occipital lobes
What are the 4 divisions of the diencephalon?
Thalamus
Hypothalamus
Subthalamus
Epithalamus
Where does the diencephalon sit?
On top of/superior to the brainstem
What is the role of the thalamus?
Relay information between parts of the CNS, motor and sensory processing
What is the role of the hypothalamus?
Autonomic control (BP, sexual functions),homeostasis and endocrine functions
What is the role of the subthalamus?
Functionally part of the basal nuclei/ganglia and involved in motor control
Can the subthalamus be seen in a midsagittal section?
No
What is the role of the epithalamus? What gland does this?
To secrete melatonin via the pineal gland
What is the shape of the thalami? What matter is it formed of?
Egg shaped grey matter
What ventricle is found between the thalami?
3rd ventricle
What connects the two thalami?
Massa intermedia aka interthalamic adhesion
What nuclei in the thalamus send fibres to the cerebral cortex?
Relay nuclei
In what manner can information be sent to the cerebral hemisphere from the thalamus?
Directly to a defined area of diffusely to multiple areas
What is the only sense which is not processed in the thalamus?
Olfaction aka smell
What are the three nuclear groups in the thalamus?
Anterior nuclear group
Medial nuclear group
Lateral nuclear group
Where does the anterior nuclear group communicate with?
The cingulate cortex
Where does the medial nuclear group communicate with?
Prefrontal cortex
How many subdivisions of the lateral nuclear group are there?
9
What are the subdivisions of the lateral nuclear group?
VA
VL
VPL and VPM
LD and LP
Pulvinar
MG
LG
Where does the VA of the lateral nuclear group communicate with?
Pre motor cortex
Where does the VL of the lateral nuclear group communicate with?
Primary motor cortex
Where does the VPL and VPM of the lateral nuclear group communicate with?
Somatosensory/primary sensory cortex
Where does the MG of the lateral nuclear group communicate with?
Auditory cortex
Where does the LG of the lateral nuclear group communicate with?
Visual cortex
What lateral nuclear group does VPL stand for?
Ventral posterior lateral nuclei
What lateral nuclear group does VPM stand for?
Ventral posterior medial nuclei
What lateral nuclear group does LG stand for?
Lateral geniculate
What lateral nuclear group does MG stand for?
Medial geniculate
What are the borders of the hypothalamus?
Superiorly = thalamus separated by hypothalamic sulcus
Anteriorly = anterior commissure and remnants of lamina terminalis
Anterioventrally = optic chaism and pituitary stalk
Inferiorly/caudally = mamillary bodies
What is the central lobe on the medial surface, that is in the middle of the frontal, parietal, occipital and temporal lobes?
Limbic lobe
What are some fucntions the limbic system/lobe involved in?
Memory and emotions
What part of the brain does CN I develop from?
Telencephalon
What are four main parts of the outer brain?
Cerebral cortex
Corpus striatum
Limbic structures
Subcortical fibres
What is the corpus striatum nicknamed?
Striped body
What are the three structures of grey matter which comprise the corpus striatum?
Globus pallidus (internus and externus)
Putamen
Caudate nucleus
What makes up the lentiform nucleus?
The globus pallidus and putamen
What is the corpus striatum part of? And what is its role?
Basal nuclei/ganglia thus has a role in motor control
What connects the putamen and caudate nucleus?
Cellular bridges of grey matter and white matter fibres
Why is it named the corpus striatum?
As when a section is taken through it, it has a striated appearance
What is the shape of the caudate nucleus?
C - shaped
What parts is the caudate nucleus made up of?
A head, body and tail
Where does the caudate nucleus sit?
Within the c of the lateral ventricles forming a wall between the anterior and inferior horns. The head and body of the caudate nucleus sit laterally to the anterior horn and the tail forms the roof of the inferior horn of the lateral ventricle
Where does the head of the caudate nucleus sit in comparison to the internal capsule as seen in a horizontal section?
Medially to the anterior limb
What fibres separate the corpus straitum from the thalamus?
The white matter fibres of the internal capsule
What are three major parts of the hemispheric limbic system?
Hippocampus
Fornix
Amygdala
How does the hemispheric limbic system sit in comparison to the thalamus?
The hippocampus sits laterally to the thalami and the fimbria of the fornix carries white matter fibres from the hippocampus, arches over the thalami as the crus and body of the fornix to connect to the columns of the fornix forming the mamillary bodies medially to the two thalami
What fibres are found in the fornix?
Efferent fibres of the hippocampus
What boundary of the lateral ventricles is formed by the hippocampus?
The floor of the inferior horn of the lateral ventricles
What are association fibres?
Fibres which interconnect areas within a hemisphere and adjacent gyri e.g. short association fibres between post and pre central gyrus and long association fibres between lobes of the same hemisphere
What are commissural fibres?
Nerve fibres which interconnect areas between hemispheres e.g. great cerebral commissure aka corpus callosum and the anterior/rostral commissure
What are the parts of the corpus collosum?
Rostrum, genu, body and splenium
Where do the corpus collosum and anterior commissure originate from embryologically?
Telencephalon
What are the three types of white matter subcortical fibres of the hemispheres?
Association fibres
Commissural fibres
Projection fibres
What are examples of areas with commissural fibres?
Corpus callosum
Anterior commissure
Hippocampal commissure aka commissure of the fornix
Where are projection fibres found? What is there function?
In the corona radiate and internal capsule
Connect cerebrum with the rest of the CNS
What is the relationship between the corona radiata and the internal capsule?
They are continuous with eachother
Are projection fibres ascending, descending or both?
Both
What is the course of the internal capsule?
Connects to the crus cerebri, anterior part of the pons and the medulla pyramids by travelling from the corona radiata between the head of caudate nucleus and lentiform nuclei.
What are the parts of the internal capsule?
Anterior limb (between head of caudate and putamen)
Genu of internal capsule
Posterior limb (between thalamus and lentiform nucleus)
