Lecture 5 & 6 - Limbic System And Cortex Flashcards
What is the role of the limbic system?
Survival and spatial memory
What are the four Fs of the autonomic nervous system?
Fighting feeding fleeing and FUCKING
What are the roles of parasympathetic and the sympathetic system?
Relax and panic respectively
What are the outputs of the parasympathetic nervous system?
Craniosacral
What are the outputs of the sympathetic nervous system?
Thoracolumbar
What are the 5 parts of the limbic system?
Limbic cortex
Amygdala
Hippocampus
Hypothalamus + mammillary bodies
What is the hypothalamus?
A collection of nuclei with control over autonomic nervous and hormone secretion
What can you see of the hypothalamus on the ventral surface of the brain? (Looking up at it basically)
The mammillary body’s between the peduncles
What does the hippocampus look like in 3d?
Like two curved bananas on the inside of the brain, on certain coronal cuts its super ventral from the lateral ventricle
Where is the amygdala in terms of the hippocampus?
Anterior
What are the functions of the hippocampus?
Consolidation of memory and spatial memory
What are the connections of the hippocampus?
Input from entorhinal cortex
Outputs through fimbria, fornix to mammillary bodies/hypothalamus, cortex
Where besides the olfactory bulbs are new neurons created in adulthood?
The dentate gyrus
Describe the hippocampal circuitry
Entorhinal cortex -> dentate gyrus -> CA3 -> CA1 -> fimbria then fornix
What are the functions of the amygdala?
Fear, rage and aggression, sexual behavior
Describe the basolateral amygdala
- slower, cognitive
- inputs from hippocampus, association cortex, sensory cortex/thalamus
- outputs to medial prefrontal cortex, association cortex, ventral striatum/nucleus accumbens
Describe the central amygdala
- faster, automatic
- lower level sensory input
- output to autonomic nervous system and modulators systems
What are both basolateral and central nuclei of the amygdala controlled by?
Medial prefrontal cortex
Where is the amygdala in a coronal cut?
Where you think the hippocampus would be
Where is the limbic cortex?
Above the corpus collosum and wraps around the front of it
What is Korsakoff Syndrome?
Amelia and confabulation caused by damage to mammillary bodies and limbic thalamus
What is toxoplasmosis?
Parasite found in cat feces that causes mice to be i afraid of cats
What is Kluver-Buddy Syndrome
Causes hyperarousal due to lesions of the medial temporal lobe
What is the order of gray and white matter in the cortex?
Gray on the outside and white on the inside
How many layers are there in the cortex?
6
Where do the layers of the brain output to?
I - Nearby cortex
II -ipsilateral cortex
III - contralateral cortex
IV - no major outputs
V - Brainstem/spinal cord
VI - Thalamus
What are the inputs of the cortical layers?
Thalamus - IV
Brainstem - II-VI
Cortex - I-V
What layer of the cortex is responsible for the corticospinal tract?
Layer 5
Where is the basal ganglia system in terms of cortical layers?
Layer 6
What layer is the thickest for S1?
IV (due to receiving info from the thalamus)
What layer of M1 is the thickest?
V (sends a lot of information to the spine)
What layer of the association cortex in the thickest?
III (sends a lot of information within cortex)
What are the four lobes?
Frontal, parietal, occipital, and temporal
What’s a gyri and sulci?
gyrus - top of the hill
Sulcus - the pit of the hill
The primary cortex is also known as ____ _____
Precentral gyrus
Primary sensory cortex is also known as
Post central gyrus
What are the anatomical division in the association cortex?
SFG - Superior frontal gyrus
MFG - Middle frontal gyrus
IFG - Inferior frontal gyrus
STG - superior temporal gyrus
MTG - Middle temporal gyrus
ITG - Inferior temporal gyrus
SPL - superior parietal lobe
IPL - inferior parietal lobe
What are Brodmann’s Areas?
Just distinctions of the brain based on the distribution of cells and structure
Where is the visual network?
Occipital lobe which is the posterior brain
Determines WHAT an object is
Where is the somamotor network?
S1 and M1 which is in the middle (horizontal wise) superior cortex
Motor and sensory work together
Where is the dorsal attention network?
Blobs near the somamotor network and just anterior of the visual network
Determine whether an object is moving, where it is, and guides saccades
Where is the ventral attention/salience network?
Anterior inferior to the somamotor network and has bits inferior to middle somatomotor and inferior posterior somamotor
Important for monitoring the environment and detecting unexpected stimuli to shift attention
Where is the limbic network?
Inferior anterior of the cortex
For the limbic cortex, is the orbitofrontal or entorhinal the most anterior part of the cortex?
Orbitofrontal
Where is the control network?
Anterior of the brain but posterior to the default mode network, scattered bits in the superior posterior of the cortex and inferior posterior cortex
Important for complex cognition
Where is the default mode network?
Most anterior of the brain and has large patches in middle inferior of the brain along with posterior middle of the brain
Task negative areas, responsible for internally-directed thought like the past, the future, and the minds of other people
What are association fibers?
- Short range U shaped fibers that communicate within a hemisphere of the brain
- Long range includes superior longitudinal fasciculus which connects all lobes, accurate fasciulus which connects language areas, and uncinate which connects limbic areas in temporal lobe to limbic areas in frontal lobe
What are commissural fibers?
Communicate between hemisphere
- corpus callous
- anterior commissuer: olfaction
- posterior commissure: pupillary light reflex
What are projection fibers?
Communicate with brainstem and body
What is gray matter thinning?
With age sensory regions thin first and association regions thin last
Are functional networks fully adult like at 10?
No
Does white matter expansion increase or decrease coherence?
Increase, driven by myelination
