English language

How to pronounce pyramidal tract in English?

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okay
now we've discussed motor system at
spinal level a few basic things
dealing with spinal reflexes
applies also to hindbrain
the first
a first wash at the motor looking at
higher control is just to continue
using the reflex model
and speak of motor control in terms of a
hierarchy of reflexes
in other words you
you have reflexes involving various
length of password pathways reaching
finally the neocortex
the idea is that
information from this one of the somatic
systems
reaches a primary sensory area of
neocortex
and from there it goes to association
areas and from there it finally will
reach
motor cortex
and that way influence movement
and
first of all
information does follow such pathways
okay
anatomical studies and physiological
studies that demonstrate that
there are such pathways
so isn't that been
the adequate way to think about it
and you'll see it written that about it
this way in textbooks and so forth
but there's a number of problems with it
one is that is an adequate theory
because one is that neocortical areas
have many outputs other than these
transcortical pathways that reach the
motor cortex
they can control movements
without any motor cortex
okay
for example visual cortex
doesn't just project
the
areas adjacent to it and then
and there are some very nice
transcriptable pathways and they are
made of major importance in our vision
but it also projects directly to
subcortical systems it projects to the
tectum for example as do other visual
areas okay
and they can affect movement directly
through their pathway to the midbrain
without going to motor cortex
and also we have this
issue of endogenous control you can have
movement that originates from activity
generated within the nervous system not
involving specific inputs
now in clinical neurology
frequently
a chapter on the motor system
will begin by defining the pyramidal
system and extra grammar systems
and in fact
a view that you will still still
sometimes see
taught is that the pyramidal system is
our system for voluntary motor control
extra parameter system for involuntary
movement
you will see in the film that that is
very very unlikely but you don't have
this if the film is about monkey work
even with human work you can have people
that have had sections of pyramidal
track
they lack the pramble system for motor
control and yet
they certainly have voluntary movement
it may not be completely normal
they have motor defects
and we'll see that for the monkeys in
the film
okay but it's this initial consideration
that it has to do with
voluntary and involuntary is certainly
not the case
but their anatomical considerations that
also show that this is unlikely
at least some of the major
extrapyramidal systems the two major
ones usually discussed in medical school
textbooks are the cerebellar system and
corpus
triada in fact their major outputs in
higher mammals
is to the pyramidal system
and i pointed out here how that works
cerebellum projects to these more
anterior parts of the ventral nucleus of
the thalamus the vl in the va
cerebellum goes
mainly to vl
which then projects to motor cortex
sorry did i
not reading what i'm writing here
cerebellum goes mainly to vl copies
triadon to va okay but they both project
to both those areas and they go to the
motor cortex okay
and which then is the major contributor
at least forty percent of the pyramidal
track comes from the motor cortex
and these neocortical areas even the
motor cortex have many other projections
other than to the pyramidal tract
for example
almost the entire neocortex projects to
the corpus triatum which has outputs
separate
from those that go back to the thalamus
and motor cortex so
the way we're going to do this is we're
going to follow lawrence and kuipers and
their classic work which was began with
neuroanatomical studies of descending
pathways
and the organization of spinal cord
motor neurons
okay
so we'll look at the spinal cord at one
of the enlargements
and
the organization of motor neurons and
then we'll talk about how the higher
systems project to that
so these are their two pictures
i have an enlargement of this one okay
so i want you to understand what this is
showing
at the top there you have these are all
cross sections of the spinal cord at the
lumbar enlargement okay controlling the
lower limb muscles okay
so first look at the bottom here
they're showing motor neurons
they're located
all across from medial
to lateral here
we'll call this dorsolateral here we'll
just call it lateral
this is ventromedial we'll call it
medial okay
now those motor neurons are arranged
in an orderly way so that the most
distal muscles are represented laterally
okay
so if you wanted to find a neuron
controlling the toe
you would look way out here
if you wanted to find a motor neuron
controlling
say the muscles along the back
you would look
in the most medial area okay here
and in between you would find motor
neurons controlling the hip
okay similarly now for the
cervical enlargement
the lateral motor neurons would be
controlling our fingers
and then
the arms as you move medially
and then the girdle muscles the shoulder
and then most immediately the axial
muscle
keeping us upright controlling our
balance and posture
okay
so what connects to those well first of
all the interneuronal pool
of neurons that are not motor neurons
but they connect to motor neurons they
also connect in an orderly way so the
lateral or dorsolateral part here
connect the lateral motor neurons the
medial ones connect the medial there's
one other point about that the medial
interneurons tend to have axons that go
to both sides
but not the lateral ones okay
and that will see
a consistent pattern here that those
medial ones tend to be more bilateral in
their connections
and we'll see that's because they're
controlling whole body movements
movements of large part of the body
okay
so then the next step for lawrence and
kuipers was to say okay what projects to
those interneurons
they knew that major contributors were
coming from the brain so they looked at
the corticospinal tract and they saw
these were degeneration studies they're
looking at the pattern of projections
shown by degenerating axons after legion
of motor cortex or a section of the
parameter and they see that it goes to
the whole thing here
it goes laterally it goes medially and a
little bit to the other side but when it
goes to the other side it goes only to
that ventral medial area almost entirely
okay so now
other than the pyramidal tract
where the other descending connections
that come from the brainstem go
they saw that they were nicely divided
into two types of connections
the red nucleus the rubric spinal tract
connects to the more lateral internal
pool
connecting then to the left which then
would be influencing the lateral motor
neurons so and that fits functional
studies that show that the red nucleus
is particularly important in limb
control
limb and hand control okay
whereas the pathways that follow
the
that come from the ventromedial hind
brain
and they tend to travel
in the ventral and these ventral columns
of the core the ventral
funiculus okay
they project to that ventral medial area
controlling axial muscles
and again axons coming here down the
left side will also tend to cross over
and go to the other side
now what are those pathways
vestibulospinal
tactile spinal
cerebellospinal the vestigial spinal
sometimes we call it because it comes
from the this digital nucleus the most
medial nucleus in the cerebellum okay
and also from the medial reticular
formation large neurons in the reticular
formation which we know are concerned
with
various fixed action patterns and so
forth controlled often often concerned
with whole body movements
okay
i just list them there for you
so now
this just shows the same pathways
instead of on a cross section here i put
them on a picture of the monkey brain
and i show here the motor cortex
with the areas representing the distal
muscles
in the dark lines and then i also show
the the other they i show that both
systems are going throughout the cord
if you're just looking at motor neurons
representing hands they would go to the
upper enlargement the feet the lower
enlargement
but
basically the neocortex goes to all
levels and all parts
of that system medial and lateral
okay
now if we go
here's the red nucleus and i show its
cross projection here you see where it
travels laterally in the hindbrain and
here it's on the longitudinal view it's
crossing over it projects to the lateral
hind brain and then it projects mainly
laterally in the core of the
enlargements
the medial pathways
travel medially in the cord and they
tend to distribute bilaterally here they
are going through the hindbrain
here's the origin of the tectospinal
tract
here i'm showing the way that the
stimulospinal tract originates okay
descends
to all levels of the chord now not just
the enlargements but all levels okay and
tends to terminate in that medial part
of the chord
okay
this is just to show you that my
pictures are a lot better than appears
in the textbooks
i these are very difficult to understand
if you study it for a while you might be
able to make it out and relate it to
what i've shown you
showing here the corticospinal tract
traveling laterally here
the lateral funiculus of the cord and
trying to depict various levels
okay
so now let's we're going to look at this
film and this is what we're going to see
first
they did paramedotomies they section the
pyramidal track
okay
here's the first lesion on that
anatomical diagram they cut the primal
tract here in the hindbrain so here in
this picture that's where they cut it
they cut it bilaterally
okay
so we'll see a monkey then with no
paranormal track and we'll see he has a
lot of voluntary movement we'll see what
he lacks he doesn't have single digit
control he loses some
he loses some manual dexterity also
loses speed
okay then lesion two
they made a bilateral cut
in the hind brain sectioning all those
medial pathways they're going right
there through the primal track but
that's already degenerating and we'll
see the histological sections
demonstrating that okay
and i'll explain that when we see it so
here on this view there's where they're
cutting it
they if they do that lesion you know i
believe they didn't get much effect but
remember that system tends to be
bilateral in its connections so you
really have to cut it on both sides the
most impaired monkey you'll see in the
film is one with that
the pyramidal track lesion first and
then this
the medial hindbrain
pathways section
because he can't write himself not for
40 days anyway he finally
recovers enough that the sensory control
of writing
that he can write himself again he lacks
those vestibular pathways okay
and then finally
in some of the parameterized monkeys
they tried just doing the lateral
pathways but only on one side and then
we'll compare the two hands
okay and you'll see
how they affect the limp the hand
movements now are mainly under control
of that system
okay so
could you hit that button and see if we
can get the video
oh good
okay so first just a normal animal and
you'll see how they're testing him
they have him strapped to the chair so
he can't run around and they're
presenting little pieces of apple here
you see the normal animal
very dexterous moves very fast
can grab
just about as well as we could
the pieces of apple
and on this little board they make the
holes smaller and smaller so he has to
be more dexterous to get the
apple out of the tiny holes and when he
gets so excited he has a little problem
but he can do it
monkeys have hands similar to ours
they're very dexterous okay they also
have the opposing thumb
although not nearly as good as ours
in order to prevent the animal from
using both hands they often have to hold
or hold one hand down
okay
they
monkeys that just get their dry food
will always want this fruit
okay so you don't have to deprive them
much to do this
like hamsters with
hamsters with sunflower seeds okay
so now in these little holes he can't
get it out unless he can use one digit
he has to have some independent control
of the one digit that's what they're
showing here
just like a person
just like a person they're pretty good
at that okay
okay so now they do the pyramidal tract
lesion and we're going to see him this
first monkey five months later
after that bilateral section at behind
brain level of the pyramidal tract
and on these histological sections
if they're standing for myelin see the
one at the bottom it's white at the
bottom because the paranal tract it's
lost it smile and this section this
section
there you see some torn tissue but you
also see these dark areas
that's an accumulation of glial cells
it's called gliosis that happens with
lesions okay
the the glial cells are phagocytic they
eat up the dead tissue and they
accumulate and remain in these these
lesions at least some of them remain
okay so now this is five months he's
recovered pretty well and pay attention
to how he's using the hands he's not
quite as fast but you will see that he
moves the into all his fingers together
like a baby grasping something
okay a baby a newer human in the first
few months of life doesn't have
pyramidal track connections yet so he
moves his hand like this
or she's
and you'll see that's pretty consistent
here they use the whole hand together
they have pretty good control
they tend to flex a little more than
usual they have a flexor bias so they
have to move the board a little closer
but he can definitely
do it
now if you look
sooner after the lesion you'll see a
greater impairment because of the
diasthesis effects
of the removal of all those axons to the
cord
and later when they did the histology
you saw the demyelinization of the
primal tract it appeared to be a
complete lesion
and here you see the gliosis in the
primal tract here you see the torn
picture so with enough sections you can
reconstruct the pathway of the knife
difficult surgery to do because if you
don't do it right in this part of the
brain the animal will lose
vital functions
first of all you see that he's actually
able to climb
his reflexes are slowed a bit
but he's able to climb grasp his cage
bars and so forth
shows a lot of voluntary movement
here's the slow placing reflexes
when you touch his chin this should be
the most this is the greatest impairment
you'll see just after parameter
pyramidal track section now just
corticospinal tract axons
their lesions were pretty good
this
this animal died earlier but you do see
the course of the knife here it has not
had time to accumulate too many of the
glia
now if they spare some of the primal
tract you will get
you will get some sparing of the
individual digit control
many pathways in the brain in order to
get a complete deficit you pretty much
have to get the entire thing
so neurologists who have not seen this
study and
have not seen humans of course very rare
will have a parallel track section like
this
they might be surprised that their
textbooks
are not correct about voluntary movement
but notice here how he can climb
sorry
oh yes they can climb once they
pretty much spinal mechanisms but they
do learn of course
details of
cages
compared with trees
i think this animal when they feed him
because he has difficulty reaching well
he tries to get the food with like a dog
just directly with his mouth
they're just doing this to demonstrate
that he has a lot of movement control
left
and here you see him he's a little
reluctant to reach he wants to just
reach out with his mouth and grab it
because after just such a short time
after the lesion he doesn't have good
control of his hands
okay but we know that not
just give him a little time and that
will come back
now before this study was done i should
point out that
clinical
neurologist you know we're
a little bit in the dark about
what
these lesions would do and so it was a
very important study for human clinic
okay so now remember these animals now
you'll see all had the pyramid atomy
first
okay and there's the
demolition of the pyramidal track the
gliosis the pyramidal track but here
they've shown you with they've drawn
onto the section here the reconstructed
path
of the knife
that so that in addition to the primal
track section now they move the knife
that
through the brain stem so it cut all the
pathways that travel medially in the
hind brain all right
so this will be the most impaired animal
you'll see
i know it's a little disturbing to some
of you to see the animal that can't get
up
but it didn't last forever
but he's
now with no pyramidal tract and without
the medial pathways he's
he doesn't have good axial control
okay so he doesn't have his writing
responses it was only with recovery from
diasthesis that he was able then to
recover some sensory control final
control of writing and he was able to
get up after 40 days
and you'll see in a minute here that
these animals that can be so entirely
almost helpless in these situations
actually have quite a bit of control for
one thing they have good head control
this is now
a little later
five months after param diatomy one
month after the medial reticular
formation lesion
it's a different animal they're showing
the lesion here
showing the gliosis in the pyramidal
tract and there you can see
where the knife passed the medial lesion
they're not showing the midbrain so we
can't see the red nucleus but they did
look at that and they know they spared
the lateral brainstem pathways that come
from the red nucleus
they'll show those sections when they in
the cases where they did that lesion
they cut off a lot of the section the
cerebellum would be
huge here in the monkey
and these are at
this one is at the cerebellar level
and there you see a little bit of
cerebellum at the top there that's
cerebellar granule cells
okay now they're starting out with
showing the animal in the reaching
situation now he's strapped to the chair
they have to strap into the chair
because he doesn't have good balance so
they they hold him like
that and now he's holding his arms and
usually flex but in fact he can grasp
the food
as long as they allow him to
be a little bit hyper flexed he can
grasp the food he does it with whole
hand movements he's still pretty slow
because he hasn't recovered enough from
the lesion yet so this is just a month
later
and you see he's recovered a little bit
he's now better at grasping the apple
and we'll see later that that movement
is more dependent on that pathway from
the midbrain from the red nucleus
again they're holding one hand down so
you can just use one at a time
they test the two hands separately
when they offer him
when he has to use one digit to get the
apple out of the small holes he can't do
it
it shows that he's got pretty vigorous
responses of his limbs in the tests of
placing
you know this is a different monkey
again with the pyramidal tract lesion
and then two months after the medial
hind brain reticular formation so this
is just a replication
of that experiment
you see the
demyelinization and the gliosis and the
primal tract
and then the reconstruction of the you
see a little bit of the lesion here
nucleotic areas
you need to see all the sections
okay
so this animal when he walks
in very good poor control of his
direction
you know
they're just making him and there he
falls over
and you see he wasn't able to write
himself very rapidly his medicine
writing responses haven't
come back much
of course now if this were a normal
monkey he would just pick it up
but without the primal trackies a little
more like a dog
in the way he responds
very unsteady with the lack of
vestibular spinal
and without the tactile spinal he's also
not very good at orienting his head and
eyes
his eye movements by the way are
actually pretty normal if you
see him in the chair and study them and
that's because he has the connections to
the ocular motor nuclei intact
they've cut those pathways further down
behind brain
okay so now this will be the first of
the
third type of animal where they have
paramidotomy first and then
this is just a short a few days five
days after the lesion of the lateral
behind brain you see it right here
he's missing the primal tract
this is working less and less okay there
you see it
see the gliosis
and the question is now did they cut the
ribospinal tract if you look up here
there's some big neurons in the red
nucleus there and we can't see any there
in the red nucleus in the midbrain this
is midbrain level that's the
the
cerebral peduncle down there
okay so it looks like a good lesion even
though it was small it seemed to have
severed the ribospinal tract in the
hindbrain
now they're going to test the two hands
separately
you see the left hand
is pretty good and he can reach he's got
some control of his shoulders
but very very poor control almost no
control now left of his
most distal muscles there with the left
hand
if he can he learns later to sort of
engage his whole body in doing it and
then sometimes he can get the spinal
mechanisms of whole body control
activated and he gets a little bit
better control of that
okay so we'll see him one and then two
months after the right
lateral pontine lesion so the same
simulation
the hand that's not affected
by the
section of the descending lateral
pathway
and here's the side that is affected
and again if they let him engage his
whole arm
he can sometimes do it he's learned a
little bit about that but
if he doesn't get his whole body
and doing it
he can't
he doesn't have good individual control
of the hand at all
so much worse than just the medial
pathway
sorry just the pyramidal tract
it's it's added a considerable amount of
deficiency to the
control of the hand
and then you'll see that something quite
remarkable here in a minute
poor individual control when they're
getting to use that limb by itself
here they're just showing that it
doesn't depend on
his posture some there are some
neurological deficits where you change
the posture they might do a lot better
but you'll see is about the same
in this posture
i can control the arm a little bit from
the shoulder but that's about it
unless he can make his scooping movement
with his whole body
and they tried very hard to get them to
recover and they they did get a little
bit it was important for the human
studies to know just how far can the
recovery go
you know and there's anything they could
do to promote it
and now you'll see some other responses
where he's now
able to use whole body movements more
and you'll see it's much harder now to
tell which is the limb affected by the
that
lesion
especially here he's using both hands
he's grasping the cage
the same hand that could not grasp the
apple pieces is grasping the cage why
because when we think of the word
paralysis
it's sometimes very specific to the type
of movement
okay he cannot use the hand in one
situation
but in climbing
fixed action patterns governed by a
hindbrain and spinal cord he can do
quite well
okay
that's an important point
this is the very same animal
very hard to tell which is the defective
hand
so this is now
a similar
replication of that experiment
in this case though
the lesion of the hindbrain it looks
larger here but in fact they missed some
of the rubospinal tract because you see
some large neurons here in the red
nucleus soy if i'm right i think this
animal shows more sparing
that was why it's always important when
you do such studies to do careful
histology and do your best to
reconstruct exactly what you did in the
surgery
it's not always possible to control it
perfectly and also there's a little bit
of variation
from animal to animal and exactly how
those pathways travel
see the central gray there
several pineapples down here
this would
it's
certainly deficient but
more control than the other animals
just with the sparing of a
small part
of that pathway
and that's why in human cases
a tumor or something that's gradually
destroying more and more of a pathway
sometimes you will not see the defect
until it's almost completely destroyed a
pathway
okay now here they're making the lesion
further down so now they're getting the
lateral pathway
in the medullary region
it's a little easier to get all of it
here you see in the this is medulla
oblongata the coral part of the
hindbrain and you see the lesion there
an animal had already had the primal
tract and here's the red nucleus with
neurons on this side and not on this
side these are akira motor nuclei here
there's the central gray there's the
aqueduct of silvius going through the
midbrain
here's the larger ventricle and the
fourth ventricle the hindbrain
the cola hindbrain is looking more like
spinal cord but you can still see the
widened ventricle there
here you're almost at the beginning of
the spinal cord
i think we'll look at this one and then
we won't look at any more because at the
time they do some control experiments
where they
they look to just make sure they're not
getting to some of these effects because
of some other sensory effects they could
be it was important to figure that out
these were really motor control
effects and not due to sensation
so again with a pretty complete lesion
of the rubber spinal tract he's almost
completely unable
to move his limbs
uh we'll have to try to
see if we can get that working again
it's still on video hit that
there we are
okay
so the result
is that we have they were able to
separate two systems one for control of
axial muscles and whole body movements
the other for control of distal muscles
and
fractionated movements not just control
the distal muscles but the ability to
move individual digits
something that
we don't see in humans until they've
developed
in the salmon monkeys until there's a
maturation
of the
connections between neocortex and motor
neurons in the spinal enlargements
okay and this just summarizes for you
what you saw
in the film okay the effects of
paramidotomy
the medial pathway lesion
and the lateral hind brain
okay
now just a few more things on motor
control if you look at a human
who's lost
control of his movements because of
severance of descending pathways
you might have spinal reflexes
in fact the brain areas
in the motor cortex
will still be active if he's
wanting to move
so if you ask him try to move your hand
nothing his hand doesn't move but in the
imaging you'll see
a hand area become active
and these are functional imaging studies
showing that
this was a study just a couple years ago
now does this help us understand other
systems well if you look at the
cerebellum you do see a related
organization
there's many aspects of cerebellum here
we're not talking about
but they're definitely medial and
lateral systems and the lat the
hemispheres which are huge in humans
uh are definitely more concerned with
distal muscle control they're concerned
with other things too but
it's only the most medial part of the
cerebellum which is also the most
ancient part remember the cerebellum
develop seems to have evolved out of the
vestibular system okay
and the part
the medial
and caudal cerebellum that's connected
to the vestibular system it affects
spinal cord through the vestibular
spinal tract and also connections to the
reticular formation
and it
correspondingly
to what we just saw
its coordinates axial muscles whole body
movements the lateral cerebellum
and i mentioned here
its outputs it has a
name i don't require you to learn it
here but it projects forward to the
opposite hemisphere and also that
pathway connects to the red nucleus then
it goes to the primarily the vl of the
thalamus
goes to the which projects the motor
cortex and very important for
coordinating the timing of neocortical
control movements
if we get a lesion
we can affect those things for example a
lesion of the hemispheres that affect
hand control
when a hand in arm control if a person
has a cerebellar lesion when he tries to
reach you know he'll say he reaches out
here for the stylist as he nears the
stylus he starts he gets a bad dreamer
it's called intention dreamer it happens
when he's trying to do something he's
trying to make a movement and he will
shake okay he has poor control timing
timing and
gain now you do get recovery from
cerebellar lesions but they take a long
time and they coordinate it's not a
complete recovery
okay because other parts of the brain
particularly parietal cortex
can take over some of those functions
now what about corpus triadum this has
been much more complex and difficult to
study
but the main
evidence we have of its important
movement importance in movement control
where the
the dyskinesis of
of basal ganglia
pathologies so for example in
huntington's disease
the patient makes as the as the disease
gets worse he makes involuntary writhing
movements that sometimes are called
choreoform because they look like
they're dance movements
korea means dancing
okay and another pathology of the output
circuitry of the corpus tree atom
when part of that degenerates you can
get people that when they try to move
their arm move it in a ballistic way so
they're flinging movements of the arm
instead of smooth coordinated movements
that's called ballisticus and hemi
ballism is a if they have the problem
the degeneration on one side of the
output pathways in corpus triad and
they'll develop that problem on only one
side of the body
the best known
basal ganglia disease is parkinson's
disease
where
they have a different kind of tremor
when they're just sitting at rest they
will shake many of you seen this many
older people get
at least some of this
but it's a specific disease and when it
strikes younger people it's particularly
tragic
they develop the resting creamer they
become increasingly rigid their
movements slow down
and then they get a loss of emotional
displays it begins to affect these
control of these higher functions
and it's correlated with loss of neurons
in the substantia which is part of
the midbrain
that contain dopamine and they project
forward to the corpus tree atom and as
dopamine becomes depleted you begin to
get these symptoms
okay and this is what it shows
in here
in dopamine receptors increase with the
loss of axons to come in compensate
compensation for the loss
but then with more and more neurons lost
and here you see the loss of pigmented
neurons in the
finally the receptors go down too and
the parkinson's symptoms
appear late after there's been a lot of
loss as i mentioned before you these
slow
pathologies slower slowly at developing
lesions
often the the
behavioral change is seen late okay
and they've developed ways of trying to
replace the dopamine in the striatum
and then i've mentioned that implicit
learning
especially the word at work and graybill
and other people working on this they
find that somehow there's an interaction
in the corpus triadum
when we learn habits
reward and reinforcement for movements
seems to act in the corpus triad and
alter the connections
okay
and we know of course that over time
things movements that were initially
voluntary become habitual
and that always seems to involve the
corpus triadum and that's all we have
time for i will

okay

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pyramidal tract::noun | Spocien Dictionary

pyramidal tract

noun

any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord

Type	Words
Synonyms	corticospinal tract, pyramidal motor system
Type of	efferent, efferent nerve, motor nerve

Examples of pyramidal tract

pyramidal tract

The whole of roots forms a pyramidal tract to hold the trunk.

From the en.wikipedia.org

Voluntary expression travels from the primary motor cortex through the pyramidal tract, specifically the corticobulbar projections.

From the en.wikipedia.org

The primary motor cortex sends projections to the subcortical motor areas, but also sends a massive projection directly to the spinal cord, through the pyramidal tract.

From the en.wikipedia.org

How to pronounce pyramidal tract in English?

pyramidal tract::noun | Spocien Dictionary

abandonment

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Examples of pyramidal tract

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