2/Temporal lobe can be divided centrally & peripherally. Centrally is the hippocampus. It’s a very old part of the brain & is relatively well preserved going all the way back to rats. Its main function is memory—getting both rats & us through mazes—including the maze of life
3/Peripherally is the neocortex. Although rats also have neocortex, theirs is much different structurally than humans.
So I like to think of neocortex as providing the newer (neo) functions of the temporal lobes seen in humans: speech, language, visual processing/social cues
4/So let’s start w/the oldest part of the temporal lobe, the hippocampus, and we will move clockwise from there.
5/Next to the hippocampus is the parahippocampal gyrus. I remember this b/c the hippocampus is the oldest part of the temporal lobe & older folks love to go in pairs. So this is the PAIR-ahippocampal gyrus—it pairs w/the old hippocampus
6/Next to the parahippocampal gyrus is the fusiform gyrus. I remember this b/c this gyrus bridges (some might say FUSES) the older, allocortex part of the temporal lobe (hippocampus/parahippocampal) w/the newer, neocortical structures. Fusiform gyrus is the neocortical bridge
7/Fusiform gyrus bridges the older temporal lobe w/the new lateral temporal neocortex.
I think the lateral neocortex looks like a parfait—w/the superior, middle, & inferior temporal gyri layered on top of the fusiform gyrus. Heschl’s transverse gyrus forms the strawberry on top
8/You can remember that the fusiform gyrus is at the bottom of this parfait b/c fusiform means elongated—and the stem of a parfait glass is elongated—almost fusiform!
9/You can remember that Heschl’s gyrus is the fruit on top b/c Heschl sounds like Bushel, and fruit to put on top comes in Bushels!
10/You can also see this parfait in the coronal plane, although it is a little tilted!
11/Last temporal lobe structure is the temporal stem. It is the white matter connecting the gyri of the temporal lobe to the rest of the brain. I remember this b/c I think the temporal lobe looks like an upside-down cauliflower—& the STEM of that cauliflower is the temporal STEM
12/So now you can remember the anatomy of the temporal lobe:
An old couple
A bridge fusing them to the next generation
A delicious parfait
All connected by a cauliflower stem.
I hope this new anatomy knowledge will be anything but temporary!
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@TheAJNR 2/Vascular cognitive impairment, or its most serious form, vascular dementia, used to be called multi-infarct dementia.
It was thought dementia directly resulted from brain volume loss from infarcts, w/the thought that 50-100cc of infarcted related volume loss caused dementia
@TheAJNR 3/But that’s now outdated. We now know vascular dementia results from diverse pathologies that all share a common vascular origin.
It’s possible to lose little volume from infarct & still result in dementia.
So if infarcts are common—which contribute to vascular dementia?
@TheAJNR 2/In the lumbar spine, it is all about the degree of canal narrowing & room for nerve roots.
In the cervical spine, we have another factor to think about—the cord.
Cord integrity is key. No matter the degree of stenosis, if the cord isn’t happy, the patient won’t be either
@TheAJNR 3/Cord flattening, even w/o canal stenosis, can cause myelopathy.
No one is quite sure why.
Some say it’s b/c mass effect on static imaging may be much worse dynamically, some say repetitive microtrauma, & some say micro-ischemia from compression of perforators
1/Do radiologists sound like they are speaking a different language when they talk about MRI?
T1 shortening what? T2 prolongation who?
Here’s a translation w/an introductory thread to MRI.
2/Let’s start w/T1—it is #1 after all! T1 is for anatomy
Since it’s anatomic, brain structures will reflect the same color as real life
So gray matter is gray on T1 & white matter is white on T1
So if you see an image where gray is gray & white is white—you know it’s a T1
3/T1 is also for contrast
Contrast material helps us to see masses
Contrast can’t get into normal brain & spine bc of the blood brain barrier—but masses don’t have a blood brain barrier, so when you give contrast, masses will take it up & light up, making them easier to see.