Limbic System Flashcards

1
Q

Limbic function

A

1) Emotion

2) memory

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2
Q

Olfactory Bulb Diagram

A

1) Strong communication to memory and emotion
- some of the strongest memories w/smell
2) Olfactory sensory neuron extends through the cribiform plate and olfactory epithelium
- receives signal
- synapse on cells in Glomeruli/olfactory bulb
- tufted cell and Mitral Cell
3) Tufted Cell and Mitral Cells
- both travel to the lateral olfactory tract
4) Mitral Cells project to 5 different regions of olfactory cx:
- anterior olfactory nucleus-> contralateral olfactory bulb via medial olfactory stria and anterior commissure
- olfactory tubercle
- piriform cortex
- parts of amygdala and entorhina cx
5) Tufted cells project primarily to:
- anterior olfactory nucleus
- olfactory tubercle

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3
Q

Olfactory bulb splits into:

A

1) Medial Olfactory Stria or Anterior Commisure
- contralateral olfactory bulb
2) Lateral Olfactory Tract

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4
Q

Vomeronasal Organ

A

1) receptors in nasal cavity
2) sends info to accessory olfactory bulb
- Mitral Cell-> AMYGDALA only
3) Pheromone Pathway
- only animals, not humans
- Pheromones drive the sexual behavior when females are ovulating
- Unconscious Process

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5
Q

Enterohinal Cortex

A

1) Major input into hippocampus

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6
Q

Hippocampus

A

Memory formation

-memory is laid down here first

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7
Q

Septal Area

A

Pleasure center

-strong connection to Nucleus Accumbens

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8
Q

NT involved in Pleasure Complex/Addiction

A

1) Dopamine
2) Endorphins-opoid
3) Enkephlin-opoid
4) Serotonin
5) GABA

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9
Q

Opiate Agonist

A

1) Endorphin

2) Enkephaline

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10
Q

Opiate Antagonist

A

1) Naltrexone

- used for alcoholic to take the pleasure out of drinking

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11
Q

Basal Nucleus of Meynert (BNM)

A

1) AKA substantia innominata
2) emotion, motivation, and memory
3) sends Ach efferents throughout the cortex
4) Degenerates with Alzheimers->basis for memory loss

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12
Q

Nucleus Accumbens

A

1) Addiction
2) dopamine receptors
3) Drugs like cocaine enhance dopamine activity in nucleus

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13
Q

Septal Nuclei

A

1) Pleasure Center/Addiction
2) strong dopaminergic input
3) When stimulated-euphoric feeling/orgasm

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14
Q

Ventral Tegmentum Area (VTA)

A

1) Found in midbrain
2) Pleasure center/addiction
3) Dopamine as NT
4)Dopamine projects to:
-Nucleus Accumbens
-Limbic system
-prefrontal cortex
-insular cortex
&project back to VTA
5) major center for addiction

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15
Q

Nicotine

A

1) most addictive chemical substance

2) works w/ Nucleus Accumbens

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16
Q

Fornix

A

1) some of the fibers connect to:
- hippocampus
- mammilary bodies
2) some fibers go into:
- hippocampal commisuri
- connecting to other side
3) Afferent and Efferent fibers found here

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17
Q

Fimbria of hippocampus

A

1) Major efferent pathway
- goes through fornix
- major targer=mammilary bodies

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18
Q

Amygdala location

A

slightly anterior to hippocampus

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19
Q

Mammillary Bodies Fxn:

A

Memory Formation

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20
Q

Major vs Minor Afferents: Hippocampus

A

CHASE U

1) Cingulate gyrus
- higher cortical areas->cingulate gyrus->entorhinal cortex-> hippocampus
2) Entorhinal Cortex
- major input into hippocampus
3) Amygdala
4) Hypothalamus via fornix
5) Septal Area via fornix

6) Uniculate Fasciculus
- tract from frontal cortex to temporal lobe
- minor input to hippocampus

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21
Q

Major vs minor Efferents: Hippocampus

A

FANTHEMS

1) Frontal Cortex
2) Nucleus Accumbens
3) Septal Nucleus
4) Mammilary Bodies
5) Thalamus-Anterior Nucleus
6) Amygdala
7) Hypothalamus
8) Entorhinal Cortex

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22
Q

Cingulate Gyrus

-function

A

1) Important role in maternal behavior

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23
Q

Left Anterior Cingulate Gyrus Lesion

A

1) Right side emotional facial paralysis
-interferes w/limbic connection w/facial nerve
(blank Face)
-CN7stays intact

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24
Q

CA

A

Pyramidal Cells of hippocampus

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25
Q

Dentate Gyrus

A

Granule cells=neurons

26
Q

Entorhinal Cortex

A

1) major afferent pathway to hippocampus

2) minor efferent pathways

27
Q

Subiculum

A

1) associated with the hippocampus

2) sends efferents via entorhinal cortex and fimbria

28
Q

Afferent fibers tract into hippocampus

A

1) Afferent fibers tract into hippocampus
2) Synapse on dentate gyrus-> pyramidal neurons->
3) Pyramidal neurons send info out by:
- subiculum (mostly)
- fimbria

29
Q

Papez circuit

A

1) AKA Mammallothalamic tract
2) Sustains Mood and emotion
3) Once tract is going hard to stop
- own momentum
- why we can’t snap out of mood
4) Septal Nuclei Not involved

30
Q

Major Afferents: Amygdala

A

No Smoking On The Hammocks Because THC

1) Nucleus of Stria terminals
2) Septal Nucleus
3) Olfactory
4) temporal lobe
5) Hippocampus
6) Brain stem nuclei
7) Thalamus
8) Hypothalamus
9) Cingulate Gyrus

Travel through Stria Terminals NOT FORNIX

31
Q

Major Efferents: Amygdala

A

Students Never Smoke THC Because of Hippies

1) Substantia Innominata
2) Nucleus Accumbens
3) Septal Nucleus
4) Brainstem Nuclei
5) Hippocampus
6) Hypothalamus
7) Thalamus
8) Caudate and Putamen

Ventral Amygdala fugal tract=major tract out

32
Q

Amygdala 2 major tracts

A

1) Stria Teminalis
- major afferent
2) Bentral Amygdala Fugal Tract
- major efferent

33
Q

Major Afferent tract to Habenula

A

1) Stria Medullaris Thalami

34
Q

Major Efferent tract from Habenula

A

1) Habenulointerpeduncular Tract

- travels within the dorsal longitudinal fascicles to various parts of brain

35
Q

Stria Terminalis

A

1) located on top of the thalamus
- goes lateral and then inferior to amygdala
2) Bilateral

36
Q

Stria Medullaris thalami

A

1) links habenula to amygdala

2) Bilateral

37
Q

Habenula Tract

A

1) Striamedullaris of thalami-> Stria Terminalis-> Amygdala

2) Projects to brainstem

38
Q

Amygdala

-function

A

Part of limbic System; bilateral-base emotion
1) stimulation
-increase or decrease heart rate and Blood pressure depending on which nucleus
-Base emotion-arousal, aggression, and attack behavior
Sexual Desire-erection, ejaculation, orgasms, copulatory movements, and ovulation
-rhythmic movement-eating/chewing
-defensive
2) Contains many nuclei
3) highest density of receptors for sex hormones

39
Q

Bilateral Amygdala lesion

A

1) gets rid of natural occurring fear response

40
Q

Working Memory

A

1) Short term memory, not stored
- mins
2) lateral Prefrontal Cortex
- -not hippocampal function

41
Q

Hippocampus

A

1) Declarative memory
- learning nonprocedural/motor tasks
ex: learning neuro notes
2) memories are stored
- months to few years
3) long term memories
- not stored here but in various parts of cortex

42
Q

Damage to Hippocampus

A

1) cannot learn anything new
2) still remembers long term memories
- ex: name bc they are stored somewhere else

43
Q

What are the 3 types of memory

A

1) Declarative
- learning notes (hippocampus)
2) Procedural
- how to tie shoes (not hippocampus)
3) Emotional
- amygdala (not hippocampus)

44
Q

2 types of long term memory

A

1) episodic narrative
- humans are wired to remember sortes
- stories stick to us
2) Semantic Facts:
- ex: history dates
- 1492columbus sailed the ocean blue

45
Q

Medial Geniculate

A

1) Nuclei of thalamus

2) Processes auditory

46
Q

Fear conditioning Experiment

  • initial experiment
  • condition/uncondition
  • results
  • tract
A

1) Tone and Foot shock
-freezing fear response in rat
2)
Foot shock=unconditioned stimulus (US)
Tone=Conditioned Stimulus (CS)
Fear= Conditioned Response (CR)
3) Results:
-does not involve the auditory cortex
-thalamus-amygdala connection necessary
-ablation of medial geniculate eliminated fear conditioning
4) Tract
Ear-> Medial Geniculate of thalamus:
1) Auditory cortex- conscious appreciation of sound
2) Amygdala-emotional response to sound

47
Q

Edouard Claparede

A

1) pt could not form new memories
-Bilateral hippocampal lesion
2)Fear Conditioned
-didn’t recognize doctor, taped tack to palm to shake
hand
-after a few wouldn’t shake hand-didn’t know why
3) Absence of Declarative memory BUT NOT EMOTIONAL MEMORY
-not hipppocampal dependent

48
Q

H.M

A

1) pt w/both hippocampus removed due to epilepsy
2) ANTEROGRADE MEMORY DEFICIT
- no new memories
- severe
3) RETROGRADE MEMORY DEFICIT
- recalling old memory (long term memory)
- mild
4) Did have Procedural Memory
- ability to perform motor skill tasks (drawing a star)

49
Q

Development of Memory in children

A

1) Before age of 3
- amygdala fully developed when born
- hippocampus circuit not fully developed until 2-3y.o
2) emotional memories before declarative memories in development

50
Q

Westermarck Effect

A

1) Gut instinct of moral wrongness without reason
- believe morally wrong to have sex with sister
- not genetic
- evolutionary advantage to allow genetically variable and decrease genetically recessive diseases

51
Q

How do we change out morals or mind?

A

1) Personal Life experience

- food stamps example

52
Q

Propanolol

A

1) Non selective beta blocker
- beta adrenergic blocking
2) Blocks adrenaline(sympathetic response) during PTSD episodes, so they don’t remember it
3) manages:
- agina pectoris
- hypertension
- congestive heart failure

53
Q

Flashbulb memories

  • 9/11
  • traumatic car crash
A

1) 9/11/2001
- amygdala turns on sympathetic nervous system
- Epinephrine, NE, adrenaline bathe hippocampus
- makes you remember everything after that
2) Adrenaline helps strengthen memories

3) IF amygdala too turn on TRAUMATIC CAR CRASH
- memories fail to form
- Anterograde Amnesia
- AMygdala->Hypothalamus-> Anterior Pituitary-> Adrenal Gland Large amounts of Cortisol
- Blocks or destroys declarative memories

54
Q

PTSD

A

-Causes you to relive memories
-flashbulb memories
-brains are efficient to saving fear memories but hard to undo
Give Propanolol

55
Q

Goal of psychotherapy for PTSD

A

1) teach neocortex to control the amygdala

- neocortex taps down impulses to fear memories

56
Q

Wernicke-Korsakoff Syndrome

A

AKA Korsakoff psychosis -irreversible
1) Severe anterograde and retrograde amnesia
2) Caused by vitamin B1 (thiamine) deficiency
3) resulting from:
-malnutrition
-chronic alcoholism
4) Involves lesions in:
-dorsal medial thalamus
-mammilary bodies
-hippocampus
-frontal cortex
5) Symptoms:
-difficulting understanding written material
-conducting meaningful conversations
BC they forget what they just read or said
-ataxia
6) pts tend to confabulate
-take fragmented memories and make new reality

57
Q

Kluver Brucy Syndrome

A

MPS VTAP

1) Bilateral loss of amygdala
2) Symptoms:
- hypermetamorphosis
- hyperorality
- hyperphagia
- hypersexuality (inanimate objects and either sex)

Agnosia:

  • Visual
  • tactile
  • auditory
  • placidity
58
Q

Limbic system in ANS

A

1) Hypothalamus higher center of control for parasympathetic and sympathetic
2) parasympathetic
- brainstem and sacral
3) Sympathetic:
- T1-L2
4) Limbic also affects hormones secretion

59
Q

Pseudobulbar affect PBA

A

1) AKA IEED-involuntary emotion expression disorder
- head injury or strok
- strong disconnect from facial emotion and what they are really feeling
ex: laughing at funeral

60
Q

Addiction/Pleasure Centers

A

MAST
MEM/A/PAP

M: Basal Nucleus of Meynert
-Ach
-Memory
-emotion
-motivation 
A: Nucleus Accumbens:
-Dopamine
-Addiction
S: Septal Nuclei
-Dopamine
-Pleasure Center
T: Ventral Tegmentum Area
-dopamine
-Addiction and pleasure center
61
Q

Hippocampal formation

A

1) Archicortex
2) composed of:
- subiculum
- hippocampus
- dentate gyrus