Intro to Brain Anatomy - Cortical Cytoarchitecture Flashcards
(37 cards)
1
Q
Cytoarchitecture
A
- Cyto = cell
- Architecture = structure
- Study of how the layers change in thickness and density provides us insight into function
2
Q
Early Studies
A
- End 19th century
- Alcohol harden the brain
- Could inspect thin sections of tissue and stain
- Many pertinent studies in early 20th century
3
Q
Staining Techniques
A
- Golgi stain
- Nissl stain
- Weigert stain
4
Q
Golgi Stain
A
- Stains about 10% of neurons
- Can see the morphology of the neuron
5
Q
Nissl Stain
A
- Stains the cell bodies of all neurons
- Great for cytoarchitecture since determines the cell densities
6
Q
Weigert Stain
A
- Stains the axons
7
Q
Cortical Cytoarchitecture
A
- Two main types of neurons in the cortex:
- Pyramidal neurons
- Granule/stellate neurons
8
Q
Pyramidal Neurons
A
- Soma shaped like a pyramid
- Basal dendrites
- Apical dendrite
- long axon that exits the cortex
- The typical cortical neuron
9
Q
Granulate (stellate) neurons
A
- Smaller and rounder
- Axons usually do not leave the cortex
- Mainly distribute information to neighbouring layers
- Does not always appear in old cortex
10
Q
Cortical Layers
A
- Layer I:
Few cells
Info from apical dendrites of neurons in lower levels - Layer II:
External granular layer although now understood to consists of mainly pyramidal layers. -
Layer III:
External pyramidal layer
Pyramidal cells increase in size from outer to inner boundary
Project axons to cortical areas
cortico-cortical connections -
Layer IV:
Internal Granular layer
Granular neurons
Receive input from cortical and subcortical areas -
Layer V:
Internal Pyramidal layer
Pyramidal neurons
Axons extend to subcortical structures
cortical-subcortical connections - Layer VI:
Spindle-shaped neurons (modified pyramidal form neuron)
Axons mainly project to subcortical structures
11
Q
Function Example 1 :
Primary Motor Cortex is _______
A
- Agranular
- Large pyramidal neurons occupy layer V and project to the spinal cord to control movement
Motor cortex cares more about sendin**g information than receiving.
12
Q
Function Example 2:
Primary sensory areas are ________
A
- Hypergranular
- referred as korniocortex (dust cortex)
- Receive a lot of input from the thalamus
13
Q
Agranular
A
Separation between pyramidal cells of layers III and V is not clear.
14
Q
Dysgranular
A
Separation between layers III and V is interrupted
15
Q
Granular
A
Separation between layers III and V is very clear
16
Q
Old Cortex
A
- Fewer than 6 layers
-
Hippocampus
- Part of it just 1 layer
17
Q
Parahippocampal Gyrus
A
- Contains (From up to down):
- Thalamus
- Hippocampal Sulcus
- Pyriform Cortex
- Entorhinal Cortex
- Parahippocampal Cortex
- Rhinal Sulcus
- Collateral Sulcus
- Fusiform Gyrus
- Occipito-Temporal Sulcus
- Inferior Temporal Gyrus (ITG)
- L4 p.22:
- Used to be referred as Rhinencephalon (nose brain)
- Patient H.M.
- Important for Memory consolidation
- Pyriform cortex
- Entorhinal cortex
- Parahippocampal cortex
18
Q
Pyriform cortex
A
- Primary olfactory cortex
- Also known as: Paleocortex (old cortex)
19
Q
Entorhinal cortex
A
- Above amygdala and anterior hippocampus
20
Q
Parahippocampal cortex
A
- Above the posterior hippocampus
21
Q
From where did all the cortex evolved?
A
From the archicortex and paleocortex
22
Q
Which is the most famous cytoarchitectonic map?
A
- Brodmann’s
- Brodmann areas
23
Q
Precentral Gyrus
A
- At least two cytoarchitectonic areas:
-
Area 4
- Real M1
- Fast direct projections to spinal cord
- Layer V: Beltz cells
-
Area 6
- Premotor cortex
-
Area 4
- Both agranular
24
Q
Beltz Cells
A
- Extremely large pyramidal neurons
- In layer V of Area 4
- Axons are big and very myelinated
25
Why are the Beltz cells the largest on the *dorsal motor cortex*?
* Given Penfield's schema, the dorsal part of the motor cortex is the one in charge of controlling the legs.
* The information needs to get further down the spinal cord
* Longer axon = larger cell body
26
Postcentral Gyrus
* 3 cytoarchitectural areas:
* **Area 3:**
* Real S1 (primary somatosensory cortex)
* posterior bank of **central sulcus**
* Input from **thalamus**
* **Area 1:**
* ****Postcentral gyrus
* **Area 2:**
* ****Anterior bank of postcentral sulcus
27
What are those!
* Green: **Pars Triangularis**
* Pink: **Pars Opercularis**
* Blue: **Pars Orbitalis**
28
Area 44
* Approximately Pars Opercularis
* Dysgranular
29
Area 45
* Approximately Pars Triangularis
* Granular frontal cortex
* Unusually large pyramidal neurons
30
Area 47/12
* Approximately Pars Orbitalis
* (Not a Brodmann Area)
* Granular frontal cortex
* lacks usually large pyramidal neurons
31
True or False
Brodmann's Areas only exists in the language dominant hemisphere.
False
They exist in both hemispheres and their functionality is pretty much the same.
We say that the **left hemisphere** is dominant for language.
32
True or False
The left hemisphere is the language dominant hemisphere.
True
33
Traditional Broca's Area
* Areas 44 and 45
* Some people don't include the pars triangularis
* Some people don't include the pars opercularis
34
Primary Auditory Cortex A1
* Area 41
* Occupies the transverse temporal gyrus within the Sylvian fissure
* **Heschl's gyrus**
35
Heschl's Gyrus
* Area 41
* A1
* Can be one or two:
* Is two the Area 41 is in the most anterior
36
Areas to know
* 4: M1
* 6: Premotor cortex
* 3: S1
* 1, 2: Somatosensory cortex
* 17: V1 (superior to calcarine sulcus)
* 18: "V2"
* 41: A1
* 44: pars opercularis
* 45: pars triangularis
* 47/12: pars orbitalis
* 22: STG
* 40: Supramarginal gyrus
* 39: Angular Gyrus
L5 p. 17
37
