Neuroscience External Features - Lateral Surface.

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Neuroscience

External Features - Lateral Surface

Lateral Sulcus (Sylvian Fissure)

• separates the frontal and temporal lobes• note: both “fissure” and “sulcus” are used

Central,Precentral & Postcentral sulci

• Boundary between primary motor cortex (precentral gyrus) and primary somatosensory cortex (postcentral gyrus)

Precentral/Postcentral gyri

• precentral gyrus - primary motor cortex• postcentral gyrus - primary somatosensory cortex

Frontal gyri

• note: parts of inferior frontal gyrus (orbital, triangular, opercular)

• triangular + opercular = Broca’s area (center for expressive speech)

Temporal sulci

Temporal inferior sulcus

Temporal gyri

Temporal lobe (superior aspect)

• transverse temporal gyri also shown

Insula (coronal)

• also known as “insular cortex”• the insula is an area of cortex (including sulci and gyri)

Insula (horizontal)

• note: the insula is hidden deep inside the sylvian fissure

Insula(temporal removed)

• In a gross brain,you can only locate the insula by removing the temporal

Transverse temporal gyrus

• “Heschel’s gyrus;”are the primary auditory cortex• lies inside the sylvian fissure • runs perpendicular to the superior temporal gyrus (which runs the

length of the temporal lobes)

Supramarginal gyrus

• to locate, trace the sylvian fissure posteriorly to its termination

Angular gyrus

• to locate, trace the superior temporal sulcus posteriorly to its termination

Superior parietal lobule

Superior parietal lobule (lateral view)

Superior parietal lobule & Intraparietal sulcus

• separates the inferior and superior parietal lobules• note: angular + supramarginal gyri form the inferior

parietal lobule

Lateral Overview

Coronal Overview

Neuroscience

External Features - Medial Surface

Corpus callosum

• is a massive body of white matter pathways that interconnect the left and right hemispheres

• 4 parts (ant -> post) : rostrum, genu, body & splenium

Fornix

• white matter pathway that forms the output of the hippocampal formation in the medial temporal lobes (crucial part of limbic system)

• arcs down underneath the corpus callosum• fornix is bilaterally represented (join @ midline)

Anterior Commissure

• white matter pathway that connects the left and right hemispheres

• MUCH smaller than the corpus callosum • to locate, follow the arc of the fornix

Paracentral lobule

• the medial continuation of precentral and postcentral gyri

Cingulate gyrus and sulcus

• the gyrus that sits just superior to the corpus callosum• important part of the limbic system (similar to fornix)

Parietooccipital fissure (or sulcus)

• from this aspect (the medial) is the only way you can see this separation of the occipital and parietal lobes by a clear, deep parietooccipital fissure; the lateral aspect shows no clear boundary

Calcarine sulcus

• its banks form the primary cortex• cuneus - the portion of medial occipital lobe superior to the

calcarine sulcus• lingual gyrus - below the calcarine sulcus; resembles a tongue

Medial Overview

Neuroscience

External Features - Ventral Surface

Gyrus rectus(straight gyrus)medial view

Gyrus rectus(straight gyrus)ventral view

Orbital gyri

• sits just above the orbits of the eyes• this cortex is crucial to higher level

behavioral regulation

Parahippocampal gyrus

• the medial most aspect of the inferior temporal lobe• contains the hippocampal formation• runs continuously with the cingulate gyrus• important part of the limbic system

Parahippocampal gyrus (medial view)

Occipitotemporal gyrus (ventral view)

• located between the hippocampal gyrus and inferior temporal gyrus

• note: not responsible for medial and lateral distinctions

Occipitotemporal gyrus (medial view)

Collateral sulcus

• separates the parahippocampal gyrus and the occipitotemporal gyrus

Uncus (ventral view)

• the medial “protrusion” of the temporal lobe

Uncus (medial view)

Ventral Overview

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Arteries

Circle of Willis• Internal carotid artery• Middle cerebral artery• Anterior cerebral artery• Posterior cerebral artery• Anterior/posterior communicating artery

• Superior cerebellar artery• Anterior/posterior cerebellar artery (AICA & PICA)

• Vertebral artery• Basilar artery

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Ventricles and Miscellaneous Structures

Lateral ventricles

Septum Pellucidum

• thin membrane separating the lateral ventricles

Interventricular foramen of Monroe

Third ventricle

• is not specifically labeled, but is surrounding the thalamus

Cerebral aqueduct

Fourth ventricle (medial view)

• note: cerebellum removed

Fourth ventricle (close-up)

Foramen of Magendie

• the “median apertures”

Foramina of Luschka

• the “lateral apertures”• atlas does not have this structure labeled, just know

its approximate location & that is has two lateral aperatures

Choroid plexus

• produces CSF• can be found in ALL of the ventricles • most is found in the lateral ventricles

Pineal body

Infundibulum (Pituitary stalk)

• Note the relationship to the optic chiasm

Optic chiasm(medial view)

Optic chiasm (ventral view)

Optic tract

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Diencephalon & Brain Stem

Hypothalamus

Mammilary Bodies(medial view)

• Mammilary bodies are technically nuclei of the hypothalamus

• have specific functional significance as part of the limbic system

Mammilary Bodies (ventral view)

Thalamus

• note: the thalami “touch” at the midline (but are not functionally interconnected)

• this point of contact is called the “massa intermedia” and it accounts for the ring-shape of the third ventricle

Midbrain

• note: the tectum and tegmentum are labeled separately (not important for now)

Cerebral peduncles (ventral view)

• part of the midbrain• are the big “columns” of white matter pathways

that support the cerebral hemispheres

Cerebral peduncles(anterolateral view)

Corpora quadrigemina (medial view)

• (includes superior and inferior colliculi)

Corpora quadrigemina(close-up)

Pons(ventral view)

Pons(medial view)

Medulla

Pyramids (ventral view)

• part of the medulla

Pyramids(anterolateral view)

Inferior Olive (ventral view)

• part of the medulla

Inferior Olive (anterolateral view)

Neuroscience

Coronal Sections (9)

Slices 1-9

Structures you are responsible for knowing in coronal sections:

Corpus Callosum Cingulate gyrus Lateral ventricles 3rd Ventricle 4th Ventricle Septum Pellucidum Caudate nucleus (head, body, and tail) Putamen Nucleus accumbens Globus pallidus Thalamus Hippocampal formation Fornix Anterior commissure Claustrum External capsule Extreme Capsule Insular cortex Cingulate gyrus Amygdala

Slice 1 - unlabeled

• In this slice, we catch the anteriormost portion of the corpus callosum (the genu). • We just see the lateral ventricles, and note to the right we have just clipped the head of

the caudate on the right side (a small spot of grey next to the lateral ventricle). • We also see the tips of the temporal lobes (i.e., the temporal poles). Many of the

structures on our list are not yet visible, however.

Slice 1 - outlined

• In this slice, we catch the anteriormost portion of the corpus callosum (the genu).

• We just see the lateral ventricles, and note to the right we have just clipped the head of the caudate on the right side (a small spot of grey next to the lateral ventricle).

• We also see the tips of the temporal lobes (i.e., the temporal poles). Many of the structures on our list are not

yet visible, however.

Slice 1 - labeled

• In this slice, we catch the anteriormost portion of the corpus callosum (the genu).

• We just see the lateral ventricles, and note to the right we have just clipped the head of the caudate on the right side (a small spot of grey next to the lateral ventricle).

• We also see the tips of the temporal lobes (i.e., the temporal poles). Many of the structures on our list are not

yet visible, however.

Slice 2 - unlabeled

• In this slice, we are cutting the anterior aspect of the basal ganglia where the caudate and putamen are beginning to separate into distinct structures.

• Note the faint beginnings of what will become the internal capsule (anterior limb) between them. The body of the corpus callosum is still visible.

• Below it we see the septum pellucidum, which is the thin membrane separating the lateral ventricles. • Also note above it the cingulate gyrus, which we’ve seen on a midsaggital view.

Slice 2 - outlined

• Below it we see the septum pellucidum, which is the thin membrane separating the lateral ventricles.

• Also note above it the cingulate gyrus, which we’ve seen on a midsaggital view.

Slice 2 - labeled

• Below it we see the septum pellucidum, which is the thin membrane separating the lateral ventricles. • Also note above it the cingulate gyrus, which we’ve seen on a midsaggital view.

Slice 3 - unlabeled

• Here we see further differentiation of the caudate and putamen, with a more pronounced internal capsule (anterior limb) visible. Note that at the inferior aspect of where they connect is the nucleus accumbens.

• You also see the beginning of a couple of new structures that are helpful to learn with the basal ganglia (morphologically, not necessarily functionally).

• Lateral to the putamen is a thin white matter pathway called the external capsule. • Lateral to that is a thin strip of grey called the claustrum. • Lateral to the claustrum is the extreme capsule. • The claustrum is labeled in this atlas, although the external and extreme capsule are not. • You will see these structures in successive slices along the length of the basal ganglia. • We have also clipped the optic chiasm, just a bit of the hypothalamus, and third ventricle. • We are well into the temporal pole, but have not yet reached the amydala (which should be the first major

temporal lobe structure we encounter as we keep moving posteriorly).

Slice 3 - outlined

Slice 3 - labeled

Slice 4 - unlabeled

• Here we see the caudate and putamen fully separated, with the globus pallidus visible medial to the putamen.

• We have cut the anterior commisure such that it is clearly visible, as are the columns of the fornix (which come right down to the anterior commissure).

• We are approaching the anterior end of the temporal horn of the lateral ventricles, so the amygdala is visible.

Slice 4 - outlined

Slice 4 - labeled

Slice 5 - unlabeled

• Here we still see the various parts of the basal ganglia clearly. • We can still see hypothalamus, and are not posterior enough to see the thalamus just yet. • The amygdala is still visible. • The interesting thing in this slice is that we are just posterior to the anterior commissure, so you can see

the columns of the fornix where they are arcing down to the anterior commissure (at lower part of the septum pellucidum).

Slice 5 - outlined

• Here we still see the various parts of the basal ganglia clearly. • We can still see hypothalamus, and are not posterior enough to see the

thalamus just yet. • The amygdala is still visible. • The interesting thing in this slice is that we are just posterior to

the anterior commissure, so you can see the columns of the fornix where they are arcing down to the anterior commissure (at lower part of the septum pellucidum).

Slice 5 - labeled

• Here we still see the various parts of the basal ganglia clearly. • We can still see hypothalamus, and are not posterior enough to see the thalamus just yet. • The amygdala is still visible. • The interesting thing in this slice is that we are just posterior to the anterior commissure, so you can see

the columns of the fornix where they are arcing down to the anterior commissure (at lower part of the septum pellucidum).

Slice 6 - unlabeled

• In this slice, we have cut perfectly through the intraventricular foramen of Monroe, so you have a perfect view of the lateral ventricles emptying into the third ventricle.

• It’s a bit difficult to find, but we have clipped just a bit of the anterior thalamus. • This lets us know that we are probably in the area of the genu of the internal capsule and will soon be transitioning

into the posterior limb. • Note that part of the amygdala is still visible, although we are starting to open the temporal horn of the lateral

ventricles.

Slice 6 - outlined

• It’s a bit difficult to find, but we have clipped just a bit of the anterior thalamus.

• This lets us know that we are probably in the area of the genu of the internal capsule and will soon be transitioning into the posterior limb.

• Note that part of the amygdala is still visible, although we are starting to open the temporal horn of the lateral ventricles.

Slice 6 - labeled

• It’s a bit difficult to find, but we have clipped just a bit of the anterior thalamus. • This lets us know that we are probably in the area of the genu of the internal capsule and will soon be transitioning

into the posterior limb. • Note that part of the amygdala is still visible, although we are starting to open the temporal horn of the lateral

ventricles.

Slice 7 - unlabeled

• Now we start to see some significant changes as new structures are visible. • We have a good view of the thalamus. • The caudate, putamen, and globus pallidus are still visible, although they are not so prominent. • The temporal horns of the lateral ventricles are clearly visible, as is the hippocampus. The hippocampus here actually looks a bit

like a seahorse (especially on the left), which is where the name comes from. It often looks more like an indistinct jelly roll. • Down to the bottom right, we have clipped part of the cerebral peduncle. • You can see the descending and ascending white matter pathways fairly clearly.

Slice 7 - outlined

• Now we start to see some significant changes as new structures are visible. • We have a good view of the thalamus. • The caudate, putamen, and globus pallidus are still visible, although they are not so

prominent. • The temporal horns of the lateral ventricles are clearly visible, as is the hippocampus.

The hippocampus here actually looks a bit like a seahorse (especially on the left), which is where the name comes from. It often looks more like an indistinct jelly roll.

• Down to the bottom right, we have clipped part of the cerebral peduncle. • You can see the descending and ascending white matter pathways fairly clearly.

Slice 7 - labeled

• Now we start to see some significant changes as new structures are visible. • We have a good view of the thalamus. • The caudate, putamen, and globus pallidus are still visible, although they are not so prominent. • The temporal horns of the lateral ventricles are clearly visible, as is the hippocampus. The hippocampus here actually looks a bit

like a seahorse (especially on the left), which is where the name comes from. It often looks more like an indistinct jelly roll. • Down to the bottom right, we have clipped part of the cerebral peduncle. • You can see the descending and ascending white matter pathways fairly clearly.

Slice 8 - unlabeled

• This slice offers another great view of the ascending and descending white matter pathways passing through the cerebral peduncle and pons.

Slice 8 - outlined

Slice 8 - labeled

Slice 9 - unlabeled

• This slice is much more posterior. • Basal ganglia, thalamus, etc are no longer visible. • However, you can see the posteriormost aspect of the hippocampus, including

the fornix on each side moving to the midline. • Note also that we can see the 4th ventricle.

Slice 9 - outlined

• This slice is much more posterior. • Basal ganglia, thalamus, etc are no longer visible. • However, you can see the posteriormost aspect of the

hippocampus, including the fornix on each side moving to the midline.

• Note also that we can see the 4th ventricle.

Slice 9 - labeled

• This slice is much more posterior. • Basal ganglia, thalamus, etc are no longer visible. • However, you can see the posteriormost aspect of the hippocampus, including

the fornix on each side moving to the midline. • Note also that we can see the 4th ventricle.

Neuroscience

Horizontal Sections (6)

Slices 1-6

Structures you are responsible for knowing in horizontal sections: Corpus callosum

Lateral Ventricles 3rd ventricle Caudate nucleus Putamen Nucleus accumbens Globus pallidus Thalamus Internal capsule (anterior limb, genu, posterior limb) Claustrum External capsule (Not labeled directly, thin white band between putamen and claustrum) Extreme capsule (Not labeled directy, thin white band between claustrum and insular cortex) Insular cortex

Slice 1 - unlabeled

• Beginning from the superior aspect of the brain, this first slice open the lateral ventricles.

• If you look down into the ventricles, you can see the thalamus from above.

• At the anterior end of the ventricles, you can find a very thin slice of the head of the caudate.

Slice 1 - outlined

• If you look down into the ventricles, you can see the thalamus from above.

• At the anterior end of the ventricles, you can find a very thin slice of the head of the caudate.

Slice 1 - labeled

• If you look down into the ventricles, you can see the thalamus from above. • At the anterior end of the ventricles, you can find a very thin slice of the head of

the caudate.

Slice 2 - unlabeled

• As we move downward a bit, you clearly see the thalamus (posterior) and caudate (anterior).

• We are still too high to see much of the putamen, although we see the upper edge of it on the right.

• We also see a thin little strip of the claustrum. The external and extreme capsules are visible on either side of the claustrum (just like the coronal sections), although they are not labeled here in the atlas.

• Note the fornix arcing upward, inward, and forward.

Slice 2 - outlined

• As we move downward a bit, you clearly see the thalamus (posterior) and caudate (anterior).

• We are still too high to see much of the putamen, although we see the upper edge of it on the right.

• We also see a thin little strip of the claustrum. The external and extreme capsules are visible on either side of the claustrum (just like the coronal sections), although they are not labeled here in the atlas.

Slice 2 - labeled

• As we move downward a bit, you clearly see the thalamus (posterior) and caudate (anterior). • We are still too high to see much of the putamen, although we see the upper edge of it on the right. • We also see a thin little strip of the claustrum. The external and extreme capsules are visible on

either side of the claustrum (just like the coronal sections), although they are not labeled here in the atlas.

Slice 3 - unlabeled

• Here we again see the thalamus and caudate clearly. • The putamen is also visible on each side, offering some definition to the

internal capsule (anterior limb, genu, and posterior limb). • The globus pallidus is still not yet visible, because it is smaller than the

putamen. Note on the right (posterior aspect of the ventricle) that we see the hippocampal formation.

• It looks similar to what we saw in coronal sections. • Remember, this is possible because it essentially curves upward along the

temporal lobe (from anterior to posterior).

Slice 3 - outlined

• Here we again see the thalamus and caudate clearly. • The putamen is also visible on each side, offering some definition to the

internal capsule (anterior limb, genu, and posterior limb). • The globus pallidus is still not yet visible, because it is smaller than the

putamen. Note on the right (posterior aspect of the ventricle) that we see the hippocampal formation.

• It looks similar to what we saw in coronal sections. • Remember, this is possible because it essentially curves upward along the

temporal lobe (from anterior to posterior).

Slice 3 - labeled

• Here we again see the thalamus and caudate clearly. • The putamen is also visible on each side, offering some definition to the internal capsule (anterior limb, genu, and

posterior limb). • The globus pallidus is still not yet visible, because it is smaller than the putamen. Note on the right (posterior aspect of

the ventricle) that we see the hippocampal formation. • It looks similar to what we saw in coronal sections. • Remember, this is possible because it essentially curves upward along the temporal lobe (from anterior to posterior).

Slice 4 - unlabeled

• This section is probably the classic horizontal section in terms of showing the basal ganglia, thalamus, and internal capsule.

• Note that you can still see the hippocampal formation.

Slice 4 - outlined

Slice 4 - labeled

Slice 5 - unlabeled

• This is the level of the anterior commissure. • Note that the caudate and putamen are once again

seen close to where they join, so just a bit further down we should find the nucleus accumbens (but not yet in this slice).

Slice 5 - outlined

• This is the level of the anterior commissure. • Note that the caudate and putamen are once again

seen close to where they join, so just a bit further down we should find the nucleus accumbens (but not yet in this slice).

Slice 5 - labeled

• This is the level of the anterior commissure. • Note that the caudate and putamen are once again seen close

to where they join, so just a bit further down we should find the nucleus accumbens (but not yet in this slice).

Slice 6 - unlabeled

• Finally, the caudate and putamen look very similar to the more anterior coronal slices(last slide).

• This is where the nucleus accumbens can be located.

Slice 6 - outlined

Slice 6 - labeled

Slice 6 - extra slide

• Finally, the caudate and putamen look very similar to the more anterior coronal slices.

Neuroscience External Features - Lateral Surface.

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