Lectures 41, 42: Limbic System Flashcards Preview

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Flashcards in Lectures 41, 42: Limbic System Deck (66):
1

Major functions of limbic system and associated structures (4)

Emotions and drives (amygdala), memory (hippocampus), homeostasis (hypothalamus), olfaction

2

Amygdala

Emotional valence to sensory inputs and declarative memories, major output pathway to the anterior hypothalamus (autonomic and endocrine responses), fear conditioning

3

Nucleus accumbens

Reward, pleasure, laughter, addiction, aggression, fear, placebo effect

4

Hippocampus

Memory, inhibit HPA axis

5

Areas of PFC and major functions (3)

Dorsolateral PFC (executive function, cognitive control), Orbitofrontal cortex (corrects/inhibits maladaptive responses and socially appropriate behavior), Anterior Cingulate Cortex (reward, anticipation, motivation)

6

Modulatory input NTs

5-HT, ACh, DA, NE

7

Major brain area modulating limbic system

Prefrontal cortex

8

Process of emotional perception

Stimulus --> appraisal (amygdala, insula) --> affective state (amygdala, insula, ACC, OFC, NA) --> regulation (PFC, ACC, hippocampus)

9

Schizophrenia involves which DA projections? What is hypo/hyper active

Mesolimbic (hyperactive), Mesocortial (hypoactive)

10

Learning (theory)

Strengthening of existing responses/behaviors or formation of new responses to existing stimuli that occurs because of practice or repetition

11

Habituation

Repeated stimulus --> decreased responses

12

Sensitization and some examples

Repeated stimulus --> increased response (LTP, kindling, chronic pain, addiction)

13

Classical conditioning

Neutral stimulus w/ unconditioned stimulus --> neutral stimulus causes response of unconditioned stimulus

14

Classical conditioning symbols

US --> UR; US + NS --> CR; CS --> CR

15

Spontaneous recovery

Increase in the strength of an extinguished behavior after
the passage of a period of time

16

Stimulus generalization

Conditioned response as a result of a new stimulus that resembles conditioned stimulus

17

Learned helplessness

Association (by classical conditioning) between aversive stimulus and inability to escape leads to hopeless, apathetic response during subsequent exposure to same or new aversive stimulus

18

Imprinting

Learning occurring at a particular
age or a particular life stage that is rapid and independent of the consequences of behavior

19

Fear conditioning requires what structure?

Amygdala

20

Fear Network pathway, long loop

Afferents --> sensory thalamus --> cortex (appraisal) --> amygadala --> brainstem, hypothalamus for flight/fight response

21

Fear Network pathway, short loop

Afferents --> sensory thalamus --> straight to amygdala!

22

Operant Conditioning is basically...based on what feedback?

Trial and error learning based on reinforcement (positive or negative, punishment)

23

What is negative reinforcement?

Behavior strengthened by avoiding an aversive consequence

24

Which is better, reinforcement vs punishment?

Reinforcement

25

Two schedules of reinforcement and subtypes

Fixed (continuous, fixed ration/interval) or Variable (ratio/interval)

26

Best schedule of reinforcement for extinction. Down side?

Variable; slow

27

Neurobiology of operant conditioning and NTs

Nucleus basalis (ACh) activated after conditioned stimulus; DA for positive reinforcement

28

All drugs of abuse activate...increase DA where?

Mesolimbic DA system and increase DA in NA

29

Describe Kluver-Bucy Syndrome

No amygdala = hyperorality, hypersexuality, no fear/aggression

30

Describe Urbach-Wiethe disease

Rare genetic disorder, calcifications on amygdala --> cannot rate intensity of emotion/recognize fear expression

31

Structures involved in empathy and associated functions (3)

Insula (experience painful emotions, imitate them, observe similar emotions); ACC (error in behaviors); Amygdala and frontal regions (empathy and maintaining socially acceptable behavior)

32

In socipathy, where is dysfunction?

Amygdala/OFC/VMPFC/Insula/ACC

33

Describe limbic encephalitis

Group of autoimmune disorders predominantly affecting of limbic system related to a tumor but usually presents BEFORE malignancy diagnosis

34

How does limbic encephalitis present?

Subacute short term memory loss w/ other psych symptoms; other causes are ruled out

35

Three major groups of limbic encephalitis

1. Classical onconeural Abs against intracellular neuronal antigens; 2. Abs against neuonral surface/synapses; 3. No known Ab

36

Examples of onconeuronal (ovary)

F

37

Describe herpes simplex encephalitis cause, presentation, prognosis

HSV-1; confusion, personality change, seizures, impaired consciousness, fever, impaired memory --> quickly fatal if untreated

38

Temporal lobe epilepsy

Seizures associated with fear, emotional responses

39

Two types of dementia associated with limbic system

Frontotemporal dementia and Alzheimer's Dementia

40

Hippocampus critical to what memory function?

Forming (not storing) new memories

41

Describe limbic control of the HPA axis

Excitatory control from amygalda, inhibitory control from hippocampus (via GABAergic cells) --> CRF

42

Cortisol excites/inhibits hippocampus. This is what kinda of feedback? So, excessive levels of cortisol can cause what?

Excites; negative feedback; hyperactivity in hippocampus, leading to damage and pathological feed-forward (more cortisol)

43

The cellular circuity of hippocampus is all (NT) modulated by what? (2)

Glutamatergic; GABAergic interneurons and ACh from septum

44

Amygdala is critical to what memory function?

Associative memory

45

Bilateral lesions of amygdala comprise what syndrome. Describe.

Kluver-Bucy Syndrome; placidity, loss of fear, hypersexuality, and hyperphagia

46

T/F: Amygdala and hippocampus are rarely foci of epilepsy

False: major epileptic focus

47

Amygdala circuitry sends projections to which two major regions?

Forebrain AND hypothalamus (CRF release) & brainstem nuclei

48

Two primary functions of PFC

1. Working memory; 2. Executive control

49

Nucleus accumbens and septal nuclei are both...

Reward regions

50

Septal nuclei provide...

Strong cholinergic innervation of hippocampus

51

Bed nucleus of stria terminalis gets output from? What psych disorder is this important for?

Output of amygdala, particularly implicated in anxiety

52

Lateral habenula

Important interconnections with most other limbic structures

53

Long-term memory storage is called what and requires what? Retrieving memory is called what? What does this do?

Consolidation, requires gene transcription; reconsolidation strengthens memory but also makes in unstable

54

Three molecular bases for memory

Synapse-specific (LTP, LTD), whole cell plasticity (altered excitability) and changes in dendritic spines/nerve terminals

55

Define declarative memory and what mediates it (2 brain regions)

Semantic/episodic with exquisite temporal features; hippocampus and amygdala

56

Fear conditioning is a type of what kind of memory?

Declarative

57

What type of cell has shown us that the hippocampus is important for spatial memory?

"Place Cells"

58

Hippocampus required for _______ fear conditioning, amygdala required for _______ fear conditioning

Contextual (environment); cue (unconditioned stimulus)

59

Define procedural memory and what mediates it (brain region)

Habit/motor memory; striatum

60

Define working memory and what mediates it (brain region)

The ability to keep things in mind (prefrontal cortex)

61

NA/VTA are crucial for signaling what aspect of memory?

Rewarding/punishing memory (good or bad)

62

The septum uses what NT to contribute to memory?

ACh

63

Where are memories likely stored?

PFC

64

Emotional memory storage mediated by what system?

Monoamine systems

65

Define social cognition

Ability to perceive others feelings from subtle cues

66

What hormones are implicated in social cognition and what are each related to?

Oxytocin (affiliation) and vasopression (anxiety)

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