Neuroanatomy Flashcards
(182 cards)
1
Q
Peri
A
around
e.g., perimeter, periaqueductal gray
2
Q
Para
A
beside
e.g., paramedic, paraventricular
nucleus
3
Q
Hypo
A
below
e.g., hypodermic, hypothalamus
4
Q
Pre
A
in front of
e.g., precentral gyrus
5
Q
Post
A
after/behind
e.g., postcentral gyrus
6
Q
Superior/super/supra
A
above
e.g., superior colliculus,
suprathreshold
7
Q
Inferior/infra
A
below
e.g., inferior colliculus
8
Q
Epi
A
on top of
e.g., epiglottis, epithalamus
9
Q
Ipsi
A
same
e.g., ipsilateral
10
Q
Contra
A
opposite
e.g., contralateral
11
Q
Rostral
A
towards nostril
12
Q
Caudal
A
towards trail
13
Q
Dorsal
A
towards back
14
Q
Ventral
A
towards belly
15
Q
Medial
A
towards midline
16
Q
Lateral
A
away from midline towards side
17
Q
Forebrain
A
Ventricle: Lateral and Third
Subdivision: Telencephalon (lateral) and Diencephalon (third)
Telencephalon principal structures: cerebral cortex, basal ganglia
18
Q
Every major sensory system except for … makes a stop in the thalamus
A
Smell
19
Q
Retino-geniculo-calcarine Pathway just structures
A
Retinal ganglion cells → LGN (where synapse of these axons occur) → Striate Cortex (AKA V1 or Area 17)
20
Q
Retino-geniculo-calcarine Pathway specific
A
Whatever we see is projected onto the retina and the retinal ganglion cells will respond to stimulus. They have axons that extend into a bundle which is called the optic nerve (cranial nerve #2). Bundle of axons coming from retinal ganglion cells will cross here forming an “x”, hence the name optic chiasm but still continue on after the crossing. Crossing over official name: decussate which means crossing the midline to go to the contralateral side. After the chiasm, they are now called the optic tract. Same axons, different names. No synapse yet!
First synapse in the thalamus, specifically the lateral geniculate nucleus (LGN). LGN sends its own axons (projects) to the back of the brain to the caudal end of the occipital lobe, specifically V1=striate cortex= Area 17. Area 17 hugs the calcarine fissure.
21
Q
What happens if V1 is destroyed?
A
If V1 is destroyed, then the person will be blind but they will still walk around objects blocking a straight pathway and will duck when punched. Visual info is still somehow coming across and this process is called “blindsight”
22
Q
What does Tectofungal Visual Pathway allow for?
A
allows for unconscious habitual visual reflexes
23
Q
Tectofungal Visual Pathway just structures
A
Both retinas’ retinal ganglion cells → Superior colliculus (Mesencephalon) → Pulvinar Nuc. Of Thalamus (Diencephalon) → Extrastriate Cortex = V2 & V3 = Areas 18 & 19
24
Q
Tectofungal Visual Pathway long answer
A
Whatever we see is projected onto the retina and the retinal ganglion cells will respond to stimulus. They have axons that extend into a bundle which is called the optic nerve (cranial nerve #2). Bundle of axons coming from retinal ganglion cells will cross here forming an “x”, hence the name optic chiasm but still continue on after the crossing. Crossing over official name: decussate which means crossing the midline to go to the contralateral side. After the chiasm, they are now called the optic tract. Same axons, different names. Superior colliculus (Mesencephalon) → Pulvinar Nuc. Of Thalamus (Diencephalon) → Extrastriate Cortex = V2 & V3 = Areas 18 & 19
25
Superior colliculus (Mesencephalon)
two bumps above the two inferior colliculus. Can only see if you separate the cerebellum from the brain.
26
How does tunnel vision happen?
Tumor can occur at chiasm which will block crossing over. Only ipsilateral things can go through. Interruption on both so you get tunnel vision. You lose extreme peripheral vision
27
Non-Neural Tissue (Meninges)
Dura mater: outermost, thick tough layer which covers the entire brian. Looks white, thick, and plasticy. Actually it consists of 2 layers but we look at it as one.
Cranial Nerves attached here.
Arachnoid: Transparent softer middle layer. Looks like shrink wrap so it allows you to see blood vessels, which look like spider webs, hence the name. Covers everything.
Pia mater: Thin/soft layer which hugs the surface of CNS intimately in every nook and cranny. Can only see with a microscope b/c only a couple cells thick.
28
Meningitis
Meninges = 3 layers which cover the brain/spinal cord
Meningitis: inflammation of these layers which can be with bacterial (dangerous/fatal but antibiotics can fight it) or viral (caused by virus, no treatment, tamer version)
29
Hypothalamus
structure of diencephalon located anterior and inferior to thalamus. Has both neural + endocrine functions. Connects to pituitary gland through infundibulum.
30
Pituitary Gland
Master gland of endocrine system b/c it releases hormones that tell others what to do. Reports to hypothalamus.
31
Anterior Pituitary Gland
What does it release?
Controlled by hypothalamus but there is no neural connection between the two.
Hypothalamus will release GnRH and TRH that are instructions into the bloodstream. Blood vessels will pick these hormones up to take to the anterior. The ring of cells around infundibulum called median eminence will release whichever hormones it tells it too. Two gonadotropin examples: FSH and LH.
32
GnRH, FSH, LH, TRH
GnRH: gonadotropin-releasing hormone
FSH: promotes maturation of the follicle and stimulates production of estrogen + progesterone in females and sperm cells in males
LH: regulates ovulation in females and stimulates production of testosterone in males
TRH: thyrotropin releasing hormone
33
Anterior Pituitary Gland
Regulation
Emotional and exteroceptive influence via afferent nerves to hypothalamus. Neurosecretion of releasing factors and inhibitory factors from hypothalamus into the primary plexus of hypophyseal portal circulation. Hypophyseal portal veins carry neurosecretions to the anterior lobe. Specific secretory cells of anterior pituitary (adenohypophysis) influenced by neurosecretions from the hypothalamus
34
Posterior Lobe Pituitary Gland
Supraoptic and paraventricular nucleus (parts of the hypothalamus) will make and release the hormones: ADH (vasopressin) and oxytocin. They travel through median eminence and infundibulum which connects the hypothalamus to the posterior pituitary gland. From here, ADH (vasopressin) and oxytocin are released.
35
ADH + Oxytocin
ADH (vasopressin) Supraoptic: anti-dieutric hormone which regulates salt and water content in the blood by affecting water retention
Oxytocin (paraventricular): uterine contractions during childbirth and lactation
| posterior pg
36
Cranial Nerve I
Olfactory
Smell-related. Small but won’t see it so just point to olfactory bulb since that is where it projects to.
37
Cranial Nerve II
Optic: Visual-related. Bundle of axons belonging to retinal ganglion cells that transfer visual information from the retina to vision centers in the brain. Form optic chiasm now called the optic tract.
38
Cranial Nerve IV
Trochlear: Allows you to move the eyes to look down and up as well as side to side at the same time, such as towards the nose. Moves the superior oblique muscle.
39
Cranial Nerve III
Oculomotor: Responsible for eyeball and eyelid movement. Thick.
40
Cranial Nerve V
Trigeminal: Thickest. Innervates muscles of the masseter for chewing, such as jaw. Carries info of sensation to the face including oral cavity and teeth and texture for anterior 2/3 tongue.
41
Cranial Nerve VI
Abducens: Move eye from side to side laterally through adducting.
42
Cranial Nerve VII
Facial: Innervates the muscle for facial expression. Carries taste info from anterior ⅔ on tongue.
43
Cranial Nerve VIII
Vestibulocochlear: Responsible for balance + hearing. Transmits sound and equilibrium info from inner ear to brain.
44
Bell's Palsy
Facial nerve inflammation leads to facial weakness or paralysis
45
Cranial Nerve IX
Glossopharyngeal: Innervates muscle of the throat. Sensation and taste info from the posterior ⅓ of the tongue. Sensation to the tonsil, pharynx, and middle ear.
46
Cranial Nerve X
Vagus: Innervates visceral organs. Parasympathetic (rest + digest) outputs on visceral organs.
47
Cranial Nerve XI
Spinal Accessory: Innervates trapezius muscles such as shoulder shrugging. Provides motor function to the sternocleidomastoid muscle.
48
Cranial Nerve XII
Hypoglossal: Innervates muscles of the tongue.
49
Human Brain + Blood Supply
Fresh oxygenated blood comes up the two branches of the vertebral artery. They join to become the basilar artery at the pons. Branch again outward at the base of the circle to become posterior cerebral. Connect to middle cerebral artery via Posterior communicating artery. Two branches of the middle cerebral turn into anterior cerebral arteries as we move up. Anterior cerebral arteries joined via Anterior communicating arteries.
50
Where does anterior cerebral artery provide blood for?
Anterior cerebral artery provides blood for the top of the brain and down the middle between the hemispheres (middle + superior parts of frontal + anterior parietal).
51
Where does middle cerebral artery provide blood for?
Middle cerebral artery provides blood for the sides of the brain.
| sides of the brain: temporal lobe, parietal and frontal
52
Where does posterior cerebral artery provide blood for?
Posterior cerebral artery provides blood for the back of the brain (occipital + inferior temporal).
53
What happens if you no longer can get blood?
Outside circle of willis
No longer getting blood = stroke. If blockage outside of the circle, cells will die. Examples of what will happen if blockage occurs at end of middle cerebral artery:
Can get global aphasia (Broca’s + Wernicke’s.)
Motor Cortex (Frontal Lobe): precentral gyrus - motor problems like paralysis
Paralysis can be flaccid or spastic. Upper motor neurons damage = spastic of contralateral side.
Somatosensory Cortex (Parietal Lobe): postcentral gyrus - loss of somatosensation (contralateral)
Loss of auditory function b/c damage to auditory area (bilateral)
54
What happens if you no longer can get blood?
Inside circle of willis
If blockage inside the circle, less severe symptoms b/c the circle will compensate. Most people don’t know until they get an angiogram.
55
External Features: Myelencephalon
pyramids and their decussation (corticospinal tract)
56
Pyramids
Pyramids are axons that belong to the corticospinal tract, a descending motor tract. Bundles of axons can start crossing over contralaterally (decussation.)
57
Myelencephalon
Principal structure: Medulla Oblongata
Major Division: Hindbrain
Ventricle: Fourth
58
External Features: Metencephalon
Trapezoid body: where dorsal cochlear nuclei fold into a bundle
Cerebellum: motor coordination + balance (fine details). Sensitive to alcohol.
Vernis: looks like an earthworm medial in cerebellum. Lesions result in posture problems. In cerebral cortex.
Folia: bumps/gyruses on cerebellum
Pons: motor-related and sends out inhibitory signals to muscles in your sleep (ventral)
Middle Cerebellar Peduncle (brachium pontis): arms of the pons; sends axons to the cerebellum (copy of info from the corticospinal tract) (Corticopontocerebellar tract)
59
Metencephalon
Major Division: Hindbrain
Ventricle: Fourth
Principle structures: cerebellum and pons
60
External Features: Mesencephalon
4 Bumps: Corpora Quadrigemina
Superior colliculus: Top two. Part of unconscious reflexes from retinal ganglion cells.
Inferior colliculus: Bottom two. Part of the auditory system.
Cerebral Peduncles: (Crus cerebri) (corticospinal tract). Axons of corticospinal cord. ( Dorsal)
61
Mesencephalon
Major Division: Midbrain
Ventricle: Cerebral Aqueduct
Principal Structure: Tectum Tegmentum
62
External Features: Diencephalon
Hypothalamus: produces releasing hormones. Fear/sexual motivation/aggression
Median eminence/Tuber cinereum: bring to anterior pituitary gland
Mammillary bodies: right underneath. Look like balls. Part of the limbic system. Role in memory
63
Mammilary body damage
(anterograde amnesia).
64
Diencephalon
Major Division: Forebrain
Ventricle: Third
Other Principal Structure: thalamus
65
External Features: Telencephalon
Cortex (everything in your hand when you hold the brain)
Corpus callosum: connects the hemispheres’ cortexes. White matter tract
Rhinencephalon: rhinal = nose cephalon = brain. Olfaction role.
66
Rhinal Fissure (External Features: Telencephalon)
acts as border
67
Olfactory bulb + 2 lateral olfactory tracts (External Features: Telencephalon)
olfactory bulb gives rise to two lateral olfactory tracts. Pear-shaped
lateral olfactory tract: bundle of axons that go from olfactory bulb to pyriform cortex
pyriform cortex/area:
entorhinal cortex- landmark for hippocampus. Below pituitary gland
Uncus- landmark for amygdala. Above hippocampus
68
Afferent Auditory Pathways + hearing loss
Hearing loss can be bilateral.
Unilateral hearing loss can happen if damage is in cochlea (snail-shaped) which extends to Cranial Nerve VIII, vestibulocochlear nerve
69
Auditory Pathway
Ventral cochlear nucleus projects to these two structures: Superior olivary complex (which gets info from both sides)
One synapses on the ipsilateral side. The other synapses on contralateral side which forms a bundle of axons that crosses the midline on the way leading to a bump on the ventral surface of the brain: Trapezoid body (decussating fibers)
Superior olivary complex sends info from lateral lemniscus that ascends to inferior colliculus.
Dorsal cochlear nucleus sends info from lateral lemniscus that ascends to inferior colliculus.
Both sides of inferior colliculus talk to each other. Lots of crossing over
Thalamic stop: Medial geniculate nucleus (MGN)
Projects to auditory cortex (Area 41) (Area A1)
70
Superior olives + pena + localization
Superior olives where some localization happens in the horizontal plane.
Get activated at different times depending on which direction noise comes from. Interaural time difference + intensity difference will affect excitation rates of the superior olives.
Pena: vertical plane localization
71
Difference between ventral and dorsal cochlear nuclei
Ventral cochlear nucleus projects to these two structures: Superior olivary complex (which gets info from both sides)
One synapses on the ipsilateral side. The other synapses on contralateral side which forms a bundle of axons that crosses the midline on the way leading to a bump on the ventral surface of the brain: Trapezoid body (decussating fibers)
Superior olivary complex sends info from lateral lemniscus that ascends to inferior colliculus.
Dorsal cochlear nucleus sends info from lateral lemniscus that ascends to inferior colliculus.
72
Somatosensory
Organization of spinal cord
Dorsal= up Ventral= down
73
2 Roots (bundle of axons): Dorsal & Ventral Root
exp. behind it
somatosensory vs. somatomotory
Charles Bell: cut ventral roots off cats and cat flexed its paw one last time so maybe carries somatomotor. Cut dorsal roots= no rxn so maybe carries somatosensation.
Magendie: Did controlled exp. In cats in which he compared to two groups to compare: one cut with ventral (paralyzed now but yelp when pinch toes) the other with dorsal (yelped when pinch toes)
Both also worked on donkeys together in which they cut trigeminal nerves. Discovered function together
Dorsal root--somatosensory
Ventral root--somatomotory
74
Dorsal Column System speed + info it carries
Axons are highly myelinated so carries 4x the info and fast.
Carries Epicritic: well localized touch and pain
Carries: Kinesthesis (movement)/proprioception (knowledge of your own body parts)
Carries: 2 pt tactile (related to epicritic: 2 pins that stab you and someone asks you how many pins was it and you know it is 2 even if they’re close together)
Carries: touch across time (write the letter A on someone’s back which is integrated over time through the system)
75
Pathway: Dorsal Column
Axons from sensory organs form the dorsal root. Dorsal root ganglion (lumbar spinal cord) is where the cell bodies of all those skin organs live. Not a synapse but a collection of axons in the peripheral system.
Enter spinal cord and ascend ipsilaterally and go up through Fasciculus gracilis or Fasciculus cuneatus (cervical spinal cord)
Fasciculus gracilis: carries info from lower part of body
Fasciculus cuneatus: carries info from upper part of body
Synapse in lower medulla in either Nucleus Gracilis (medial) or Nucleus Cuneatus (lateral) depending on which fasciculus it came from
Bundle of axons that will decussate and continue ascending through medial lemniscus (in pons and midbrain)
Thalamus stop: Ventral Posterolateral Nucleus (VPL) through internal capsule projects to somatosensory cortex (post central cortex)
end at post central gyrus
76
Pathway: Dorsal Column
structures
Through DRG through fasciculus gracilis/cuneatus → nuc. cuneatus/gracilis →decussate in lower medulla→ VPL of thalamus → Postcentral gyrus
77
Tabes Dorsalis: Syphilis
Attacks dorsal columns. Lose proprioception. If lights go out, then they will fall because they do not know where their legs are in space.
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Spinothalamic and Spinoreticular Systems
speed + info it carries
Poorly myelinated skinny axons so slow and evolutionarily older system
Carries: protopathic pain (except face b/c that is trigeminal): poorly localized like throbbing or soreness pain
Carries: temperature (free nerve endings in skin that detect temp)
79
Pathway: Spinothalamic
Axons from sensory organs form the dorsal root. Dorsal root ganglion (lumbar spinal cord) is where the cell bodies of all those skin organs live. Not a synapse but a collection of axons in the peripheral system.
Synapse in the dorsal horn in Substantia Gelatinosa: pain gate cells b/c rich in opioid receptors that respond to painkillers like endorphins or morphines which can result in analgesia (lack of pain)
Axons decussates right after to contralateral side and goes up the spinothalamic pathway to Ventral Posterolateral Nucleus (VPL). Same pathway as dorsal column
Difference from dorsal pathway is when first synapse happens
80
Pathway: Spinoreticular
Axons from sensory organs form the dorsal root. Dorsal root ganglion (lumbar spinal cord) is where the cell bodies of all those skin organs live. Not a synapse but a collection of axons in the peripheral system.
Synapse in the dorsal horn in Substantia Gelatinosa: pain gate cells b/c rich in opioid receptors that respond to painkillers like endorphins or morphines which can result in analgesia (lack of pain)
Axons decussates right after to contralateral side and goes up to lateral reticular formation. Stops there and does not go to post central gyrus. Goes to periaqueductal grey and Reticular formation projects all over the cortex and is excitatory. Causes alertness arousal.
81
Spinothalamic structures
Spinothalamic: Through DRG → Substantia gelatinosa →decussate in spinal cord→ VPL of thalamus → Postcentral gyrus
82
Spinoreticular Structures
Through DRG → Substantia gelatinosa →decussate in spinal cord→ Reticular formation or Periaqueductal grey
83
Periaqueductal grey
pain gate and contains opioid receptors and analgesia is result
84
If you accidentally hit your thumb w/ hammer and feel sleepy, no longer will feel sleepy then.
Why?
Reticular formation projects all over the cortex and is excitatory. Causes alertness arousal.
85
Double Pain: why we have multiple systems
Wake up at night to go to the bathroom. Stub toe at bed. Feel a flash of pain and then go away (Dorsal). Next, throbbing comes b/c slow and will keep firing as long as there is tissue damage. (spinothalamic + spinoreticular).
86
Cerebrospinal Fluid (CSF)
content
Only made of blood plasma. Goes everywhere!
87
Ventricles
fluid filled chambers inside the brain which provide mechanical protection and intracranial pressure (4 of these)
88
Choroid Plexus
exists in every ventricle and non-neural cell. Produces CSF
89
Lateral Ventricles
two largest, on each side
90
Foramen of Monro
connects lateral ventricles which CSF flows out of to third ventricle
91
Third Ventricle
lat, skinny, located on midline, squished between thalamus and hypothalamus
92
Cerebral Aqueduct
Carries CSF from third to fourth ventricle, in between tectum and tegmentum
93
Fourth ventricle
triangle shape, diamond shape from back that is on the midline and squished between the cerebellum and brainstem
94
Foramen of Luschka
2 lateral holes in the 4th ventricle which CSF flows out of laterally
95
Foramen of Magendie
hole behind 4th ventricle right on the midline which CSF flows out of medially
96
Interpeduncular Cistern
hole in between the cerebral peduncles filled by Luschka
97
Pontine Cistern
underneath pons filled by Luschka
98
Superior Cistern
cistern between cerebellum and cerebrum near the colliculi filled by Luschka
99
Cisterna Magna
enlarged CSF space at base of brain filled by Magendie
100
Mid-Sagittal Cut
along medial-longitudinal fissure.
101
Sagittal Cut: structures
Mylencephalon (most caudal)
4th ventricle
Choroid Plexus: not super visible
102
Sagittal Cut: structures
Metencephalon
4th ventricle
Arbor vitae of cerebellum (intricate branching of axons)
Bumps in cerebellum= folia
103
Sagittal Cut: structures
Mesencephalon
Cerebral aqueduct: separates tectum and tegmentum
Tectum: area, not structure. Sup + inf collilculi = copro quattrogemini
Tegmentum: cerebral peduncles (ventral area) related to corticospinal pathway
104
Sagittal Cut: structures
Diencephalon
Pineal Gland (does not have left/right section): makes melatonin/regulates sleep (endocrine gland)
Thalamus: caudodorsal end has pinecone stop: pineal gland
3rd Ventricle
Hypothalamus
- Fornix: axon tract
- Mammillothalamic Tract
105
4 sections of corpus callosum
rostrum, genu, body, splenium
105
Sagittal Cut: structures
Telencephalon
Cingulate Gyrus
Corpus Callosum
Lateral Ventricles: holes inside hemispheres
Fornix
Septal Nuclei
Anterior Commissure
106
Septal nuclei
not super visible. Part of the Limbic system. Role in pleasure + addiction
Damage = aggression
107
anterior commissure
bundle of axons that connects both olfactory bulbs, amygdalas, and parts of both temporal lobes
108
corpus callosum
commissure that connects CORTEXES of both hemispheres
109
Cingulate Gyrus
Limbic System (emotions) + conflict resolution
110
Fornix
Fornix splits into two has two destinations:
Rostral destination: Septa nuclei (2 way tract)
Ventral/Caudal destination: Mammillary bodies (1 way)
| hippocampus
111
Mammillothalamic Tract
Mamillary bodies connect to anterior nucleus of thalamus through axons parallel to fornix
112
Cerebellum + vermis
Coordination of motor movements.
Lesions of vermis (unpaired medial portion of cerebellum connecting both hemispheres) = postural problems
113
Corticopontocerebellar Tract
How cerebellum receives info from corticospinal pathway
Cerebral peduncle → Pyramid→Horn→Middle cerebellar peduncle in pons (synapses here) → Cerebellum→Cerebellum cortex
114
Spinocerebellar Tract
How cerebellum gets proprioceptive info from dorsal column pathway
Nucleus Gracilis/Cuneatus→Inferior Cerebellar Peduncle→Synapse on cerebellum cortex
115
Cerebellothalamic Tract
Deep cerebellar nuclei calculate error info that is sent to the precentral gyrus (motor cortex). Info sent via Superior Cerebellar Peduncle to thalamic stop: VA (ventral anterior)/VL (ventral lateral) nucleus. VA/VL projects to the precentral gyrus (motor cortex). Motor cortex tells body to move accordingly.
116
How to identify all peduncles given dorsal view with cerebellum removed:
Find the pons in order to find the middle peduncle. The one above disappearing under inferior colliculus is superior. The one below is inferior.
117
Coronal Cut #1 + Structures
Super Rostral so all Telencephalon
Cut at anterior commissure
Cortex
Corona Radiata (radiates all over cortex similar to arbor vitae)
Corpus Callosum
Lateral Ventricle
Septal Nuclei
Anterior Commissure
Internal Capsule
Basal Ganglia
118
Internal capsule
tree trunk of corona radiata
119
Basal Ganglia
Basal Ganglia aka Corpus striatum
Caudate (medial)
Putamen (lateral)
Globus pallidus (next to putamen)
120
Striatum
Caudate + Putamen =
121
lentiform nucleus
Putamen + Globus Pallidus =
122
Basal Ganglia projections
Striatum synapses on GP. GP sends projections to VA/VL. VA/VL projects to precentral gyrus.
123
Striatum 2 way projections
Striatum has 2 way projections with substantia nigra (in mesencephalon)
124
Substantia nigra damage
Parkinson’s (hypokinetic) involuntary rigidity/tremors
125
GABA neurons in basal ganglia die =
Huntington’s (hyperkinetic) Too much movement + genetic. Completely penetrant/progressive/lethal
126
Coronal Cut II + Structures
Cut at ancus (fat bottom of pear?). 2nd most rostral
Telencephalon
Cortex
Corona radiata
Corpus callosum
Fornix
Internal capsule
Amygdala
127
Coronal Cut II + Structures
Cut at ancus (fat bottom of pear?). 2nd most rostral
DIencephalon
Diencephalon
Thalamus
Hypothalamus
Fornix
4 dots: two most ventral (bottom) = fornix
Mammillothalamic tract (if present)
4 dots: two most dorsal (top) = mammillothalamic tract
128
Olfactory System
Olfactory bulb (synapse on mitral cells here)
Mitral cells give rise to lateral olfactory tract which goes laterally
Enters pyriform cortex which is also the olfactory cortex (destination option 1)
Other destinations exist as well:
amygdala
Medial olfactory tract is subcortical so we do not see it. Risen from an olfactory bulb. Join major freeway: anterior commissure. This is how both olfactory bulbs are connected
129
Olfactory System structures
Olfactory nerve → olfactory bulb → breaks off to two different tracts
Ipsilateral lateral olfactory tract → Ipsilateral pyriform cortex (including entorhinal cortex and amygdala)
Ipsilateral medial olfactory tract → anterior commissure → contralateral medial olfactory tract → contralateral olfactory bulb
130
James Papez + rabies
James Papez was wondering what happened to people who contracted rabies. Virus attacks something in the nervous system that causes change in temperament and behavior. What parts of the brain are attacked? Limbic system plays a role in emotional regulation.
131
Major Limbic Forebrain Structures
Olfactory bulb projects to amygdala.
Amygdala projects to the entorhinal cortex (caudal medial part of pyriform cortex) to the hypothalamus.
Entorhinal cortex 2 ways projects to hippocampus
132
How does amygdala send projections to hypothalamus
Amygdala sends projections to hypothalamus via stria terminalis.
133
H.M. + hippocampus
H.m. seizure always started from the media temporal lobe so they removed that. With that included removal of hippocampus. Became amnesic after that. Could not commit short term memory to long term memory.
134
what does hippocampus encode
Hippocampus encodes expression of spatial memory.
135
hippocampus + place cells
Place cells live in the hippocampus and they fire only when they are at a certain part of space.
Place field of region is where cell fires and different cells have different place fields. Each has a different field of firing.
136
what does hippocampus give rise to
Hippocampus gives rise to fornix and splits at anterior commissure. Rostral part goes to the septal nuclei (2 way). Ventral/caudal part goes to mammillary bodies
137
Korsackoff's syndrome
Korsakoff's syndrome is caused by thiamine deficiency.
Often occurs in chronic alcoholics when their digestive system is no longer able to absorb thiamine
Characterized by memory deficits such as anterograde amnesia, which is similar to that seen in hippocampal amnesics
The disorder always involves degeneration of the mammillary bodies, and often other brain areas as well
138
where do mammillary bodies send projections to
Mamillary bodies sends projections to anterior nucleus of thalamus via mammillothalamic tract
139
where does Anterior nucleus of thalamus sends projections to
cingulate gyrus or cingulate cortex
140
where does cingulate gyrus send projections to
entorhinal cortex
141
Limbic System Cell bodies
Amygdala – Hippocampus – Entorhinal cortex – Septal nuclei – Mammillary bodies – Anterior nucleus of the Thalamus – Cingulate gyrus
142
Limbic System Axonal Tracts
– Stria terminalis – Fornix – Mammillothalamic tract
143
Neurons destroyed in precentral gyrus=
spastic paralysis of contralateral side
144
Low motor neurons destroyed =
flaccid paralysis of ipsilateral side
145
Spinocortical tract (major motor system)
Precentral gyrus (upper motor neurons).
Axons go down via internal capsule and as it crosses mesencephalon, it is now called cerebral peduncles
If you cut through cerebral peduncles, you see substantia nigra
When it crosses myelencephalon, then it is called pyramids (decussation).
Keep going down to synapse at ventral horn of spinal cord
146
which root is somatosensory
Dorsal root
147
which root is somatomotory
ventral root
148
difference between Fasciculus gracilis and Fasciculus cuneatus and which pathway do they belong to
Fasciculus gracilis (medial): carries info from lower part of body
Fasciculus cuneatus (lateral): carries info from upper part of body
*dorsal column pathway
149
Thalamus stop of dorsal column pathway
Ventral Posterolateral Nucleus (VPL) through internal capsule
150
thalamus stop of retino-geniculo-calcarine pathway
lateral geniculate nucleus (LGN)
151
thalamus stop of Tectofungal Visual Pathway
Pulvinar Nuc. Of Thalamus (Diencephalon)
152
which two bumps does Tectofungal Visual Pathway go through
Superior colliculus (Mesencephalon)
153
what is the trapezoid body
where ventral cochlear nuclei fold into a bundle
154
what does pons do
motor-related and sends out inhibitory signals to muscles in your sleep (ventral)
155
what does Middle Cerebellar Peduncle (brachium pontis) do
arms of the pons; sends axons to the cerebellum (copy of info from the corticospinal tract) (Corticopontocerebellar tract)
156
Corpora Quadrigemina
Superior colliculus: Top two. Part of unconscious reflexes from retinal ganglion cells.
Inferior colliculus: Bottom two. Part of the auditory system.
157
where does Ventral cochlear nucleus project to
Superior olivary complex (which gets info from both sides)
158
which nerve does cochlea extend to
Cranial Nerve VIII, vestibulocochlear nerve
159
where do superior olivary complex and Dorsal cochlear nucleus send info to
info via lateral lemniscus that ascends to inferior colliculus.
160
Thalamic stop of auditory pathway
Medial geniculate nucleus (MGN)
161
where does MGN project to
auditory cortex (Area 41) (Area A1)
162
what is the role of periaqueductal grey and which system is it a part of
Periaqueductal grey: next destination: pain gate and contains opioid receptors and analgesia is result
Spinoreticular
163
role of reticular formation
Reticular formation projects all over the cortex and is excitatory. Causes alertness arousal.
164
thalamic stop for Spinothalamic pathway
Ventral Posterolateral Nucleus (VPL)
165
tegmentum
cerebral peduncles (ventral area) related to corticospinal pathway
166
tectum
area, not structure. Sup + inf collilculi = copro quattrogemini
167
Septal Nuclei
not super visible. Part of the Limbic system. Role in pleasure + addiction
Damage = aggression
168
Anterior Commissure
bundle of axons that connects both olfactory bulbs, amygdalas, and parts of both temporal lobes
169
Rostral destination of fornix
Septa nuclei (2 way tract)
170
ventral/caudal destination of fornix
Mammillary bodies (1 way)
171
Mammillothalamic Tract
Mamillary bodies connect to anterior nucleus of thalamus through axons parallel to fornix
172
lentiform nucleus
Putamen + GP
173
Striatum
caudate + putamen
174
where does striatum synapse on
globus pallidus
175
where does GP send projections to
VA/VL
176
where does VA/VL project to
precentral gyrus.
177
Coronal Cut #3 structures
Telencephalon
Hippocampus (behind hypothalamus now): projects to entorhinal cortex
Diencephalon
Lateral Geniculate Nucleus (retino geniculo calcarine pathway)
Mesencephalon
Cerebral Peduncles (crus cerebri)
Substantia Nigra: black bc of neuromelanin
178
Coronal Cut #4 structures
Mesencephalon
Superior colliculus (tectofungal)
Cerebral Aqueduct: CSF flows from 3rd to 4th ventricle
Periaqueductal Grey: Pain gate/ opioid receptors
Reticular formation: Role in alertness + arousal and goes through cerebral peduncle
179
what causes comas
Comas happen because the skull imposes a limit to brain swelling. This means the only direction the brain can swell is down which presses on reticular formation, causing these cells to stop working. Cells die. Coma happens
180
Horizontal Cut #1 structures
Telencephalon
Cortex
Corona Radiata
Lateral Ventricle
Caudate
Putamen
Globus Pallidus
Amygdala
Hippocampus
Septal nuclei
Diencephalon
LGN (vision)
MGN (auditory)
Hypothalamus
Fornix
Mammillothalamic tract
Mesencephalon
Inferior colliculus (auditory)
181
Horizontal Cut #2 Dorsal structures
Telencephalon
Cortex
Corona radiata
Corpus callosum
Internal capsule
Caudate
Putamen
Hippocampus
Septal nuclei
Lateral ventricles
Diencephalon
Thalamus
LGN
Pulvinar nucleus of thalamus (tectofungal)
Mesencephalon
Superior colliculus
