Title: DFM3 / Moment 2 / Neurologi / 1-9 / 4. Neuroanatomy

Components of the CNS?

Telencephalon

Cortex cerebri

Cerebellum

Truncus encephali (brainstem)

Sections of the brain? Nomenclature

Q: Gray matter?
A: Cell bodies of neurons

Q: White matter?
A: Nerve tracts

Q: White matter color because of?
A: Myelin

Q: Section, 1 and 2
A: Coronal section
1 - Gray matter
2 - White matter

Q: Name and function
A: Corpus callosum, connecting the hemispheres

Q: Diencephalon?
A: Thalamus + hypothalamus

Thalamus

Hypothalamus

Cells in the layers of the cerebral cortex?

Vä - Gyrus
Hö - Sulcus

1 and 3 - name and function
2 - only name

Cerebral cortex division into functional areas?

Cerebral cortex, division into lobes?

Q: Frontal lobe function?
A: Motivation, Planning, Decision-making, Social skills, ”Personality”

Q: What functions are in the temporal lobe?
A: Recognition of objects, sounds, etc.
Note that the two lobes on either side of the brain have different functions within recognition

Q: What functions are in the parietal lobe?
A: Attention

Q: What is the difference between the functions of the left and right parietal lobe?
A: The left hemisphere only recognize what is going on on the right side of you whereas the right hemisphere can process information from both the left and the right side of you

Q: What functions are in the occipital lobe?
A: Recieves and processes visual information

Q: Language regions of the cerebral cortex?
A: Broca's area in the frontal lobe and Wenicke's are in the temporal lobe

Q: Damage to Wenickes area?
A: Results in a sensory aphasia, your language perception becomes malfunctional

Q: Damage to Broca's area?
A: Results in a motor aphasia, language expression becomes malfunctional

Q: What is the left hemisphere main function in speech?
A: Words and sentences, speech ability

Q: What is the right hemisphere main function in speech?
A: Emotional contenct of speech

Q: Deep brain structures?
A: Subcortical nuclei

Q: Where are the subcortical nuclei?
A: Telencephalon

Q: Subcortical nuclei in telencephalon?
A: The basal ganlias:
Nucleus caudatus
Putamen
Globus pallidus

Q: Where is thalamus?
A: Diencephalon, under telencephalon

Q: Nucleus caudatus and putamen can together be called?
A: Striatum

Q: What is the function of thalamus?
A: Relays sensory signals to cerebral cortex

Q: What are the functions of the basal ganglias in the telencephalon?
A: (emotions)
Initiates movement and controls movement amplitude

Q: Whats the anatomical relation of hypothalamus to thalamus?
A: Rostral and inferior

Section, arrows, structure

section, arrows, structure

Q: What is the function of hypothalamus?
A: Homeostasis and emotions

Q: Parkinson's dissease and the basal ganglia?
A: Dopamine neurons from substantia nigra cause damage to the innervation of striatum (hypokinesia) which causes difficulties to initiate and scale movements

section, arrow, structure

Q: What is the limbic system?
A: Emotional parts of the brain

Q: What is the difference between the old and the new view of the limbic system?
A: The new view divides it into an anterior and an posterior part

Q: What are the function of the anterior part of the limbic system?
A: emotions

Q: What are the function of the posterior part of the limbic system?
A: memory

Q: What parts of the cortex make the anterior limbic system? (7 st)
A: Orbital and medial prefrontal cortex och Cingulate gyrus (syns ej på bilden)

Q: Cingulate gyrus is associated with?
A: negative emotions

Q: Which parts of the brain make the posterior limbic system? (3 st)
A: Hippocampus
Fornix
Corpus mammilare

Q: What is nondeclarative memory?
A: Learning to swim och bike

Q: Brainstem three parts?
A: Mesencephalon
Pons
Medulla oblongata

Q: What is the reticular formation?
A: a diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness.

Q: What is declarative memory?
A: memories that you can use in the future via communication

Q: What is the function of the ascending part in the reticular formation?
A: Consciousness

Q: What is the function of the descending part in the reticular formation?
A: Motor functions

Q: Which are the two main dopamine systems?
A: The nigrostriatal system and the mesolimbic system

Q: What is the function of the nigrostriatal system?
A: Dopamine for motorfunctions

Q: What is the function of the Mesolimbicsystem?
A: Dopamine for motivation and reward

Paths of dopamine?

Q: Which part of the dopamine system is mostly affected in Parkinson?*
A: Nigrostriatal system

Serotonin paths?

Q: What is the most regular function of serotonin?
A: Mood
Aswell as hunger-satiety and motor functions

Q: What are the sources of serotonin?*
A: Raphe nuclei and pons

The cranial nerves relation to the parts of the brain?

Q: Other functions of the brainstem?
A: Breathing, swalloving and cardiovascular regulation aswell as the functions of the Cranial nerves

Q: What does cerebellum do?
A: Corrects movement errors

Q: What are the processes of the cerebellum called?*
A: Folia

Q: Cerebellum functional divisions?
A: Spinocerebellum
Cerebrocerebellum
Vestibulocerebellum

Q: Spinocerebellum functions?
A: Axial muscles, legs and arms

Q: Cerebrocerebellum functions?
A: Complex movements such as speech

Q: Vestibulocerebellum functions?
A: Balance and eye movements

Q: Causes of cerebellar dysfunction?
A: Chronic alcohol abuse
Gluten intolerance
Focal lesions
Genetic disorders

Q: Lesions in the upper part of spinocerebellum is causes?
A: Atactic gait
> Affects axial muscle functions such as walking

Q: Upper part of spinocerebellum controls?
A: The legs

Q: Lower parts of spinocerebrellum controls?
A: The arms

Q: Lesions in the cerebrocerebellum causes
A: Speech problems (dysarthria)
Inability to perform rapid hand movements (dysdiadochokinesis)

Q: Lesions to the vestibulocerebrellum causes?
A: Inability to stand up (nystagmus)

Q: Two types of nerves that connect the spinal cord to the rest of the body?
A: Sensory and motor neves
(They can unite and form a mixed spinal nerve)

Q: Nerves that project to other nerves within the spinal cord?
A: interneurons

Q: White matter in spinal cord contains?
A: Ascending and descending pathways

Q: Grey matter in spinalcord contains?
A: Motor neurons and interneurons

Q: Two differens types of sensory ascending nerve pathways?
A: Receptor endings
Pain and temperature fibers

Q: The ascending sensory nerves when united are called?
A: Mechanosensory afferent fibers

Q: The receptor ending component of the ascending sensory pathway goes to?
A: The dorsal column

Q: The pain and temperature fiber component of the ascending sensory pathway goes to?
A: Spinothalamic tract

Q: What does the dorsal root ganglia contain?
A: The cell bodies of sensory neurons, cranial nerve ganglia is the brains equivalence

Q: The descending motor pathways in the spinal cord two components?
A: Lateral cortico spinal tract
Medial cortico spinal tract

Q: Lateral cortico spinal tract controls?
A: Distal muscles

Q: Medial cortico spinal tract controls?
A: Proximal muscles

Q: The meninges function?
A: Protects the CNS

Q: Arachnoid means?
A: Spiderweb

Q: Three menings?
A: Dura mater
Arachnoidea mater
Pia mater

Q: Where are the three menings located?
A: Right below the skullbone

Q: What is the space between the arachnoidea and pia mater called?
A: Subarachnoidal space

Q: What does the subarachnoidal space contain?
A: Cerebrospinal fluid

Q: Home many ventricles does the ventricular system contain?
A: 4

Q: What is the function of the ventricular system?
A: Cerebrospinal fluid production

Anatomy of the ventricular system?

Explain the circulation of the cerebrospinalfluid?*

Q: What is the total volume of the CBF?
A: 120-150ml

Q: How much CBF is produced everyday?
A: 500ml

Q: What is the CBF other function than protection?
A: "Washing" the CNS

Q: What can diagnostic samples of CBF tell?
A: Infections, bleeding, bacterias etc.

Q: What is the CBF relation to the spinalcord?*
A: Spinal cord ends at L1 but the CBF goes all the way S1

Q: Major arteries bringing blood to the brain?
A: A. carotis interna
A. vertebralis

Q: Merge of the two A.vertebralis?
A: A. basilaris

Q: What connects a. carotis interna dx/sin?
A: A. communicans anterior

Q: What connects a. basiliaris (vertebralis blood) to the A. carotis interna blood?
A: A. communicans posterior

Q: What is the circulatory anastomosis in the brain called?
A: The circle of Willis

Q: Stroke in A. cerebri anterior?
A: Personality changes and weakness in legs

Q: Stroke in A. cerebri media?
A: Aphasia, weakness in face, arm and hand

Q: Stroke in A. cerebri posterior?
A: Visual defects

Q: Arteries distributing blood to the different regions of the brain?
A: A. cerebri anterior, media and posterior

Left arteries names and function?
Right arteries names and function?

The dorsal column-medial lemniscal system; Tactile information from the body
The axons of cutaneous mechanosensory afferents enter the spinal cord through the dorsal roots; the majority ascend ipsilaterally through the dorsal column.
First order neurons;

- In the dorsal columns of the spinal cord fibers conveying information from lower limbs lie most medial and and travel in a circumscribed
bundle known as fasciculus gracilis.
- From the upper limbs, trunk, and neck lie in a more lateral bundle known as the fasciculus cuneatus.
- In turn, the fibers in these two tracts end in different subdivisions of the dorsal column nuclei: a medial subdivision, the nucleus gracilis; and a lateral subdivision, the nucleus cuneatus.

Second order neurons;

- Send their axons (when leaving dorsal column nuclei = internal arcuate fibers) to the somatic sensory portion of the thalamus.
- The internal arcuate fibers subsequently cross the midline and then form a dorsoventrally elongated tract known as the medial lemniscus. This is called decussation of the medial lemniscus. Happens in the caudal medulla.
- The axons of the medial lemniscus synapse
with thalamic neurons located in the ventral posterior lateral
nucleus (VPL).

Third order neurons;

- Send their axons via the internal capsule to terminate in the postcentral gyrus of the cerebral cortex, a region known as the primary somatosensory cortex, or SI.
- Neurons in the VPL also send axons to the secondary somatosensory cortex (SII), a smaller region that lies in the upper bank of the lateral sulcus.

The trigeminothalamic system; Tactile information from the face
- Cutaneous mechanoreceptor information from the face is conveyed centrally by a separate set of first-order neurons that are located in the trigeminal (cranial nerve V) ganglion.
First order neurons;

- Peripheral processes from opthalmic, maxillary and mandibular branches. Each branch innervates a well-defined territory on the face and head, including the teeth and the mucosa of the oral and nasal cavities.
- Enter the brainstem at the level of pons to terminate on neurons in the trigeminal brainstem complex.
- Trigeminal complex; Principal nucleus (most of mechanoreceptors) + Spinal nucleus (Receptors sensitive to pain, temperature and coarse touch).

Second order neurons;
- Neurons cross the midline and ascend to the ventral posterior medial (VPM) nucleus of the thalamus by the way of the trigeminothalamic tract (also called the trigeminal lemniscus). 
Third order neurons;
- Send their axons to cortical areas SI and SII.

Proprioceptive information from the body; Lower Limb
Enter the spinal cord through the dorsal roots and, for much of their course, travel with the axons conveying cutaneous information. 
Important for;

1. Ability to sense limb position.
2. Functions of the cerebellum, a structure that regulates the timing of muscle contractions necessary for the performance of voluntary movements.

First order neurons;

- Bifurcate into ascending and descending branches, some which penetrate the dorsal horn of the spinal cord and synapse on neurons located there, as well as on neurons in the ventral horn. (Important for e.g ''knee-jerk'' reflex).
- Those that enter the spinal cord between L2-T1, synapse on neurons in Clarke's nucleus. Afferents that enter below this level ascend through the dorsal column and then synapse with neurons in Clarke's nucleus.

Second order neurons;

- Second-order neurons in Clarke's nucleus send their axons into the ipsilateral posterior lateral column of the spinal cord, where they travel up to the level of the medulla in the dorsal spinocerebellar tract.
- These axons continue into the cerebellum, but in their course, give off collaterals that synapse with neurons lying just outside the nucleus gracilus.

Third order neurons;
- Decussate and join the medial lemniscus, accompanying the fibers from cutaneous mechanoreceptors in their course to the VPL of the thalamus.
Fourth order neurons;
- From the VPL axons project out to the somatosensory cortex

Q: Proprioceptive information from the body; Upper limb
First order neurons;
[...]
Second order neurons;
[...]
Third order neurons;
[...]
A: - Enter the spinal cord through the dorsal root and travel via the dorsal column (fascilus cuneatus) up to the level of the medulla, where they synapse on proprioceptive neurons in the dorsal column nuclei.
- Bifurcate into ascending and descending branches, some which penetrate the dorsal horn of the spinal cord and synapse on neurons located there, as well as on neurons in the ventral horn. (Important for e.g ''knee-jerk'' reflex).; - Send their axons across the midline, where they join the medial lemniscus and ascend to the VPL of the thalamus.; - From VPL axons project out to the somatosensory cortex

Q: Central pathway conveying proprioceptive information from the face
- Conveyed through the [nerve]
First order neurons;
[...]
Although the exact route is not clear, information from proprioceptive afferents in the mesencephalic trigeminal nucleus also reaches [...]
A: trigeminal nerve; - Instead of residing in the trigeminal ganglia, they are found within the central nervous system, in the mesencephalic trigeminal nucleus (a well defined cluster of neurons lying at the lateral extent of the central gray region of the midbrain).
- These pseudounipolar neurons have peripheral processes that innervate
muscle spindles and Golgi tendon organs associated with facial musculature (especially the jaw muscles) and central processes that include projections to brainstem nuclei responsible for reflex control of facial muscles.; the thalamus and is represented in somatic sensory.

Anterolateral system; Central pain and temperature pathway
First order neurons;

- Enter the spinal cord via the dorsal roots.
- Terminate in the dorsal horn.
- There they branch into ascending and descending collaterals, forming the dorsolateral tract of Lissauer.
- Axons in Lissauer's tract typically run up and down for one or two spinal cord segments before they penetrate the gray matter of the dorsal horn. Once within the dorsal horn, the axons give off branches that contact second-order neurons located in Rexed's laminae 1, 2, and 5.

Laminae;

Rexed laminae = Descriptive divisions of the spinal gray matter in cross section.
Laminae content;
1 and 5 - Projection neurons whose axons travel to brainstem and thalamic targets.
2 - Spinal cord interneurons.
C fibers terminate in - 1 and 2
Aδ fibers terminate in - 1 and 5
Non-nociceptive (Aβ) afferents terminate primarily in - 5.
Some of these neurons receive converging inputs from nociceptive and non-nociceptive afferents. They are called wide-dynamic-range neurons. Some of these receive visceral sensory input as well, making them a likely substrate for referred pain.

Second order neurons;

- In laminae 1 and 5 of the dorsal horn of the spinal cord cross the midline and ascend to the brainstem and thalamus in the anterolateral quadrant of the contralateral half of the spinal cord.
Structures which the neurons project to;
1. Ventral posterior lateral nucleus (VPL) (Sensory-discriminative aspects of pain: the location, intensity and quality of the noxious stimulation)
2. Subdivisions of the reticular formation, the deep layers of the superior colliculus, the central gray, the hypothalamus, and the amygdala.
In addition, a distinct set of thalamic nuclei that lie medial to the ventral posterior nucleus, which group together here as the midline thalamic nuclei. (Affective-motivational aspects of pain)

Third order neurons;

1. From VPL to somatosensory cortex (SI, SII)
2. From midline thalamic nuclei to anterior cingulate cortex and the insula.

Q: Pain and temperature pathways for the face
First order neurons;
[...]
Second order neurons;
[...]
Structures;
[...]
A: - Originates from trigeminal ganglion and from ganglia associated with CN VII, IX and X.
- After entering the pons, these small myelinated and unmyelinated trigeminal fibers descend to the medulla, forming the spinal
trigeminal tract (or spinal tract of cranial nerve V) and terminate in two subdivisions of the spinal trigeminal complex: the pars interpolaris and pars caudalis.; - In the trigeminal nuclei, cross the midline and terminate in a variety of targets in the brainstem and thalamus.; 1. Discriminative aspects - Projections to the contralateral ventral posterior medial nucleus (via the trigeminothalamic tract) and projections from the VPM to primary and secondary somatosensory cortex.
2. Affective/motivational aspects - mediated by connections to various targets in the reticular formation and midbrain, as well as by the midline nuclei of the thalamus, which supply the cingulate and insular regions of cortex.