[Music]
next I want you to understand a very
important functional aspect of the
thalamus the thalamus is a very
important relay Center for sensory
information all sensory information is
relayed through thalamic connections up
then to the cerebral cortex with the
exception of a faction this slide is
simpler in that it's not overwhelmed
with labels but it is demonstrating the
thalamic radiations so these would be
the the connections that exist between
the thalamic nuclei and the cerebral
cortex lamech fibers are shown in
through here these darker colored
structures this is a more anterior view
of those florrick radiations this is a
more posterior view of lamech radiations
the thalamic radiations travel in the
internal capsule so they do accompany
the motor axon fibers that are
descending within the internal capsule
and the motor fibers are shown here in
the lighter color descending through the
internal capsule the thalamus may be
considered the gate to consciousness
here we see the oval flamming nuclei
these are bilateral each one of these
bilateral structures contains multiple
nuclear components that make this a very
complex structure and then here in the
axial view we can see various phonic at
nuclei and their relationships to one
another don't mean to overwhelm you at
the beginning here but the purpose of
this slide is just to provide you a menu
of the various thalamic nuclei
we are going to take a look at each one
of these in greater detail so I'm not
going to read all these off to you at
this moment but let's now take a look at
the anterior thalamic nucleus the
anterior lamech nucleus is shown in
through here and has been highlighted
for you when we think about flamming
nuclei and get skates the anterior one
we need to think about input/output so
what kind of information is coming in to
this anterior thalamic nucleus well the
input here is from the mammillary body
and the hippocampal of formation so now
that the anterior of lamech nucleus has
received this input where is it going
what's its output well the output will
be to the cingulate gyrus which is in
the cerebral cortex the function of your
anterior flamming nucleus is that it's
involved in the limbic pathway the
limbic pathway is discussed in detail in
another lecture next we have the ventral
posteromedial at nucleus or simply VPM
and it is highlighted here yet to would
have an input consideration in an output
consideration input to the VPM is
sensory from the face and taste
gustation the output from this nucleus
is going to be to the somatosensory
cortex consequently this nucleus is
involved in relaying somatosensory
cranial nerve inputs cranial nerve
inputs and taste or gas station to the
cortex we also have for your
consideration the ventral posterolateral
nucleus of the thalamus
vpl and it is highlighted here
it's input is going to be sensory from
the body and the limb so this is gonna
process a lot of information coming into
the thalamus and as it processes it it's
going to output it send it to the
somatosensory cortex so we can perceive
various sensations touch pressure
vibration for example and again it's
gonna relay somatosensory spinal inputs
up to the somatosensory cortex so that
we can perceive those various senses
next on our list is the ventral anterior
slash lateral thalamic nuclei the VA /l
these are highlighted in the image so
they can be seen here their input is
going to be from the basal ganglia as
well as from the cerebellum output from
this collection of two nuclei is going
to be to the motor promoter in
supplemental motor cortices and these
are located in the frontal lobe so
consequently this is the relay then
between the basal ganglia and cerebellum
in puts to the motor cortical areas
another 'fl an igneous is the medio
dorsal nucleus this is not shown in the
plaintiff section that we have in the
image the inputs here are from the
amygdala and olfactory inputs as well as
limbic basal ganglia so multiple inputs
here but the output is all to the
frontal cortex and as a result one of
the functions here is for the limbic
pathway then to allow a major relay to
the frontal cortex allowing for that
interconnectedness and then
seria can be damaged can be lesion and
result in Verna key Korsakoff syndrome
next is the pulvinar nucleus the
pulvinar nucleus is shown here in a
light blue color it's receiving input
from the visual pathway auditory pathway
and then there are other sensory
pathways that will contribute input into
this nucleus output is going to be to
the parietal temporal occipital
Association area and this is going to
allow us to orient ourselves toward
visual auditory and other sensory
stimuli here's another flamming nucleus
that I want you to think about remember
this is the medial geniculate body MGB
it's labeled a little slender portion of
it right along in through here the input
into the medial geniculate body is going
to be from the inferior colliculus and
its output is going to be to the
auditory cortex of the temporal lobe
thus it functions as a relay for
auditory input to the cortex if we have
a medial geniculate body it stands to
reason that we have a lateral geniculate
body LGB and that we can see yet right
in this particular area not much there
in the illustration or image but this is
the area that's going to receive
information from the retina so that's
the input
output then will be to your primary
visual cortex in the occipital lobe and
so this is a very important relay
nucleus then of visual input to the
cortex for the perception of vision this
thalamic nuclei collection is the intra
laminar / midline lamech nuclei and they
are shown in this general area on the
medial side of this collection of lamech
nuclei these are involved in arousal and
as a result of that they will activate
the reticular will be part of the
activation of the reticular activating
system
I hear we could focus on the lower
portion of the slide and we'll just come
right in here to this Center box and
right below it you see various sensory
inputs vision audition olfaction for
example and so let's just say you have a
visual stimulus now let's take a look at
what happens next in response to the
visual stimulus this will have
excitatory output to the reticular
activating system and we can see that
excitatory input from the visual
stimulus into the reticular activating
system that is found in the brainstem
from here there is input that's
excitatory to fill a McNew Clee eye and
so we see the excitatory input to
nonspecific flamming nuclei and then
from here you relay to the cortex to
activate to stimulate yet
so that's the connectiveness the
circuitry that exists between Flajnik
nuclei and the reticular activating
system
[Music]
you