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2)
Name three places where the fibers in this pathway terminate.
The amygdala, the periamygdaloid
cortex and the contralateral olfactory bulb. See K. pg. 505
and ***
What loss would result if the
pathway were cut at the point where the pointer touches it?
The subject would be unable to detect
odors inhaled through the ipsilateral nostril. Testing might
be tricky, however, because of the way in which air circulates
at the back of the nasal cavity. Also, strong odors are often
"sensed" by the taste receptors of the tongue.
3)
Important vessels enter the brain in this region; give their
name(s) and give one structure that they supply. Medial
and lateral striates or lenticulostriates. They supply the
caudate, putamen, globus pallidus and much of the internal
capsule. ***
11)
Identify this small, dark purple structure with wiggly edges.
The flocculus.
Give two symptoms that result
when this structure is damaged. Nystagmus,
vertigo, difficulty with balance.
(Slide Review 1, slide GROSS 5)
4) Destruction of the gyrus lying just above
this sulcus on the right side of the brain (right hemisphere) would
result in what sensory loss? A left homonymous
inferior quadrantanopia.
9) Identify this cranial nerve. The
oculomotor nerve.
10) What (output) pathway originates in this
structure,and where does this pathway terminate? The
mammilothalamic tract. It will terminate in the anterior nucleus
of the thalamus.
1) Name this space. The
anterior horn of the lateral ventricle.
Describe the path of CSF as it leaves this space,
and, ultimately, returns to the venous system.
Interventricular foramen (of Monro) -- third ventricle -- cerebral
aqueduct -- fourth ventricle -- foramen of Lushka and Magendie
-- subarachnoid space -- arachnoid granulations -- superior
sagittal sinus
8) What sensory pathway passes through
this structure? The auditory pathway.
What loss would result if this structure were
badly damaged on the left side of the brainstem? Little
if any, because auditory information from each ear ascends on
both sides of the brainstem.
14) Identify this thalamic nucleus. The
lateral geniculate nucleus.
What would happen to the pupillary light reflex
if this nucleus were damaged on the left side of the brain?
It would be normal.
4)
Identify this surface "bump". The
uncus.
What nucleus lies just deep to this landmark?
The amygdala.
7)
This cranial nerve is exiting through the middle cereberal peduncle;
what motor loss would result if it were cut on the left side
of the brainstem?
The muscles of mastication
(and a few others) on the left side of the head would fail to
contract (lower motor neuron paralysis). See ***
What effect would the same cut have on:a)
the pupillary light reflex and b) the corneal reflex?
No effect on the pupillary light reflex. The corneal reflex
would be abnormal: touching the left cornea (with a wisp if
cotton) would result in no eye closure; touching the right
cornea would result in both eyes closing.
9) What
part of the motor cortex (from a somatotopic point of view) is
normally supplied by this blood vessel? The
leg area
Is this vessel a part of the
anterior or posterior systems? The
anterior circulation.
(Slide
Review 2, slide 2)
2)
Name this nucleus. The nucleus
gracilis.
Neurons here send their
axons to terminate in what nucleus? (include the word
ipsi/contralateral in your answer) The
contralateral nucleus ventralis posterolateralis of
the thalamus
5)
Name this pathway. The dorsal
spinocerebellar tract.
In what structure and "zone"
will these axons terminate? The
intermediate zone and vermis of the cerebellar cortex.
See ***
10)
Name this structure. The
inferior olive.
Neurons here send their axons to
the cerebellum. Through which peduncle do they travel
and with what cells in the cerebellar cortex do
they make synaptic contact? (include the word ipsi/contralateral
in your answer)
The axons
cross the midline and pass through the contralateral
inferior cerebellar peduncle to enter the cerebellum.
The axons terminate as climbing fibers, making synaptic
contact with purkinje cells.
3)
Identify the nucleus found in this region. Also
give the letters often used (GSA, etc.) to describe
its function. The dorsal
motor nucleus of the vagus. (GVE).
Describe, in words, the function
of the neurons in this nucleus. These
are are parasympathetic preganglionic neurons.
.
6)
How would you test this nerve? This
is the hypoglossal nerve. Ask the subject to stick
out her tongue. If nerve function is impaired, the
tongue will deviate to the impaired side. Atrophy
and fasciculations indicate a lower motor neuron
problem. Lack of these signs suggests damage to
the corticobulbar pathway descending from the contralateral
hemisphere.
How would you describe the nature
of the corticobulbar input to this nucleus? The
corticobulbar pathway is bilateral, but more crossed
than uncrossed. See ***
10)
What motor nucleus is found in this region? The
nucleus ambiguus.
Neurons here contribute axons
to which cranial nerve(s)? The
glossopharyngeal and vagus.
1)
Identify this nucleus. Also give the letters used
to describe its function. The
abducens nucleus (SE)
A lesion here would
also destroy the fibers of a cranial nerve (labeled
#2) that loops around the nucleus. What motor
loss would result because of damage to this second
structure?
That's
the facial nerve. There would be a lower motor
neuron type paralysis of all the muscles of facial
expression (plus a few others see ***)
3)
What somatic sensory pathway ascends in this area?
The anterolateral pathway.
Where do the axons
in this pathway have their cell bodies? (include
the word ipsi/contralateral in your answer). In
the contralateral dorsal horn. See ***
5)
Identify the pathway marked by all the dots. The
medial lemniscus.
What loss would
result if the axons marked by the yellow and green
dots were cut? These
are the axons of cells in the nucleus cuneatus.
They convey the senses of touch, vibration, position
from the upper part of the body. See ***
1)
Identify this compact bundle of fibers. It
is the mesencephalic root of the trigeminal
nerve.
Where do these
axons have their cell bodies?
In the nucleus of the mesencephalic root. See
***
2)
What ascending somatic sensory pathway is found
in this region? The
ventral secondary trigeminal tract.
In what nucleus
will the axons of this pathway terminate? The
nucleus ventralis posteromedialis (for touch,
sharp pain, and temperature) and the intralaminar
nucleus (for dull aching pain ). See ***
and ***
3)
Identify this motor nucleus and give the letters
used to describe its function. The
motor nucleus of the trigeminal nerve. (SVE)
What other motor
nuclei lie in the same functional cell column?
The facial nucleus,
the nucleus ambiguus and the accessory nucleus.
See ***.
2)
Identify this pathway. The
central tegmental tract.
Some of the
fibers within this bundle are part of a somatic
sensory pathway. Where will they terminate
and what sorts of sensations do they convey?
The
pathway is the so-called indirect spinothalamic
one. ***
***
The fibers will terminate in the intralaminar
nuclei (= centromedian) and they convey a
sense of dull, aching pain.
4)
Give the input and output pathways for this
structure. This is
the inferior colliculus. The input pathway
is the lateral lemniscus and the output pathway
is the brachium of the inferior colliculus.
What word is
used to describe how the neurons in this structure
are organized. Tonotopic.
5)
Describe how this cranial nerve exits from
the skull. This is
the trochlear nerve. It departs from the dorsal
aspect of the brainstem, wraps around the
brainstem, passes through the cavernous sinus,
and the through the superior orbital fissure
to enter the orbit.
In a subject
who has this cranial nerve (the right
one) damaged, what movements of the head are
used to minimize the resultant diplopia?
With damage to the nerve, and loss of tonic
contraction of the superior oblique muscle,
the unopposed action of other muscles will
cause slight elevation and extorsion of the
eye. To induce a similar movement in the normal
eye the subject will lower the head and tilt
it to the normal side.
4)
Where do these axons have their cell bodies?
In the retina.
Describe
what would happen to the pupillary light
reflex if this pathway were cut on the right
side of the brain. Also, what would happen
to the corneal reflex? Because
of the chiasm and the posterior commissure,
light shined in either eye will still activate
both Edinger-Westphal nuclei - so the pupillary
light reflex will be normal. Obviously the
corneal reflex will be normal as well.
5)
Where will this pathway terminate? Where did
it originate? This
is the stria terminalis. It originates in
the amygdala and terminates in the septal
area and the hypothalamus. To remind yourself
of it's course, call up some of the slides
in ***.
It's not very obvious -
so what's the best way to find it? It
(almost) always
lies just medial to the tail of the caudate
nucleus. see ***
8)
Identify this "C shaped" structure.
This is the dentate
nucleus.
4)
In what "division" of the brain
is this nucleus found? What pathway provides
the major input to the nucleus? This
is the lateral geniculate nucleus nucleus.
It is in the (dorsal) thalamus which is
part of the diencephalon. ***
What blood
vessels supply the region where this nucleus
is located? The
thalamogeniculate vessels.
6)
What pathway descends in this region?
The corticospinal,
or pyramidal, tract.
Damage
to this pathway is associated with a classical
group of symptoms. Give
three of them.
Hyperactive deep tendon reflexes, increased
resistance to passive stretch, clonus,
"positive" Babinski response
(the plantar response would be extensor)
9)
Identify this nucleus. The
oculomotor nucleus.
Describe
the clinical picture that results when
the nerve associated with this nucleus
is damaged on the left side of the brainstem.
The lid will
be closed. If you pull it up, the eye
will be seen to be abducted and depressed.
(While you won't be able to see it, in
will be rotated medially = intorsion).
The pupil will be dilated and fail to
react to light.
1)
Identify this nucleus. The
medialis dorsalis.
This
nucleus is one of many that could be
considered a part of the limbic system.
Why is that? Because
it receives a significant input from
the amygdala by way of the ventral amygdalofugal
path. See ***
.
2)
Identify this nucleus. Ventralis
lateralis
Of which
cerebellar "loop" or circuit
is this nucleus a part? The
"planning" loop. ***
10)
Damage to this nucleus gives rise to
what movement disorder? Hemiballismus.
Will
the abnormal movements be ipsilateral
or contralateral to the damaged nucleus?
Contralateral.
6)
Identify this nucleus. The
amygdala
Give
3 abnormal findings (symptoms)
associated with destruction
of this nucleus in experimental
animals. Descriptions
of this "Kluver-Bucy"
syndrome vary slightly but
here is one list. These animals:
1)are fearless and placid,
lacking in emotional reactions
2) do not react to threatening
situations 3) display indiscriminate
hypersexual behavior 4) are
inordinately attentive to
all stimuli = ceaselessly
curious 5) examine objects
with their mouth rather than
the eyes; eat food normally
avoided 6) seem to recognize
nothing (= visual agnosia)
8)
Identify this general region
of the brain. Hypothalamus.
Give
three sorts of problems that
might result following damage
to this region. Problems
with control of: 1) temperature,
2) food intake, 3) autonomic
functions, 4) pituitary function.
11)
Identify
this tract. The
mammillothalamic tract.
It
is one component of a famous
neural "circuit".
What is the name of the
circuit? The
Papez circuit.
1)
Identify this gyrus. The
cingulate gyrus
6)
Name one place where the
fibers in this "peduncle"
will terminate. The
red nucleus; the nucleus
ventralis lateralis of the
thalamus.
8)
Identify this structure.
The
inferior olive.
10)
Identify this pathway.The
fornix.
11)
What is this space, and
how does CSF exit from it?
The
anterior horn of the lateral
ventricle. CSF exits by
passing through the interventricular
foramen into the third ventricle.
1)
Identify this structure.
The fornix.
Where
did most of these fibers
originate and where
will most of them terminate?
Cells in the subiculum
contribute most of the
axons present in the
fornix. The most obvious
group of fibers terminate
in the mammillary body.
But fibers also terminate
elsewhere in the thalamus,
hypothalamus and septum.
5)
Identify this structure.
The putamen.
Where
does the major input to
this structure come from?
The cerebral cortex.
8)
Identify this structure.
The anterior commissure.
9)
Identify this blood vessel.
The middle cerebral
artery.
10)
Identify this fissure.
The
lateral fissure.
1)
Identify this structure.
The olfactory tract.
2)
Identify this structure.
The optic chiasm.
3)
Identify this nucleus.
The amygdala.
4)
Identify this space.
The inferior horn
of the lateral ventricle.
8)
Identify this structure.
The hippocampus.
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