Limbic System Part 1 Flashcards

1
Q

What cortical and subcortical regions make up the limbic sytem?

A

cortical: prefrontal, cingulate, insula, parahippocampual gyrus
subcortical: amygdala, hippocampus, ventral striatum/nucleus accumbens

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2
Q

What does the limbic system do?

A

memory, motivation, emotions

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3
Q

What part of the brain is responsible for planning?

A

prefrontal cortex and cingulate gyrus

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4
Q

What part of the brain is responsible for cognition?

A

cerebral cortex

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5
Q

What part of the brain is responsible for stress?

A

HPA axis, hippocampus, amygdala

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6
Q

What part of the brain is responsible for fear?

A

amygdala

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7
Q

What part of the brain is responsible for memory?

A

hippocampus and entorhinal cortex

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8
Q

What does the reticular formation do?

A

projects to cortex, thalamus, brain stem and spinal cord with long neurons for wakefulness, alerting. ARAS (ascending reticular activating system)

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9
Q

What does the neurotransmitter norepinephrine modulate?

A

attentional selectivity during stress

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10
Q

What does the neurotransmitter dopamine modulate?

A

promote motivationally based behavior

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11
Q

Where is norepinephrine released from?

A

locus ceruleus (in the pons)

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12
Q

What does the neurotransmitter serotonin modulate?

A

mood, sleep and wakefulness cycles (5-HT)

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13
Q

What does the neurotransmitter acetyl choline modulate?

A

facilitates hippocampal and cortical memory and cognition

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14
Q

What is the function of the lateral prefrontal cortex?

A

working memory, executive control (motivation, goals that regulate behavior)

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15
Q

What is the function of the orbitofrontal cortex?

A

reward, motivation, emotional decisions

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16
Q

What is the function of the ventromedial cortex (frontal)?

A

includes medial PFC and anterior cingulate. emotional responses, declarative memory. connects with amygdala, hippocampus, n accumbens

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17
Q

What is the overall function of the prefrontal cortex?

A

planning, top-down control of attention, behavior, emotion. connections to reticular nuclei regulate PFC inputs. intelligent thought

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18
Q

Where is the hippocampus?

A

medial temporal lobe, up against the third ventricle in the three-layered archicortex

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19
Q

What is the afferent pathway to the hippocampus?

A

cortical regions for sensory, assoication etc –>parahippocampal gyrus –>entorhinal cortex –> hippocampus

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20
Q

What is the efferent pathway from the hippocampus?

A

hippocampus –> entorhinal cortex–>parahippocampal gyrus –> cortical regions, processed as memory

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21
Q

What are the two forms of long term memory?

A

implicit (procedural) and explicit (declarative)

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22
Q

What part of the brain modulates declarative (explicit) memory?

A

hippocampus and medial temporal lobe (this is events/episodic and facts/semantic memory)

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23
Q

What part of the brain modulates the emotional type of procedural (implicit) memory?

A

the amygdala

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24
Q

What part of the brain modulates working memory?

A

prefrontal cortex

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25
Q

What are two types of declarative (explicit) memory?

A

episodic and semantic

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26
Q

What area of the brain encodes episodic memory? What type of memory is episodic memory?

A

The hippocampus encodes it, then sends it to areas of the cortex. episodic memory is auto-noetic consciousness (with self in it) and declarative (explicit)

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27
Q

In what two areas of the brain are semantic memory consolidated?

A

anterior temporal lobe and lateral prefrontal cortex

28
Q

What kind of memory is semantic memory?

A

noetic declarative (explicit). consciousness of knowledge without a sense of self/ accompanying experience

29
Q

What are the two distinctive regions of declarative memory consolidation and what information do they extract from memory?

A

anterior system: relates representations of specific entities
posterior system: matches cues about context to interaction of entities and environment (spatial landmarks, cues, location…)

30
Q

What area of the brain coordinates precise recall of various aspects of episodic memory?

A

retrosplenial area of the cingulate gyrus

31
Q

What is an EEG and what does it measure?

A

electroencephalogram, measures summation of synchronous postsynaptic potentials (EPSP and IPSPs)

32
Q

What happens to EEG waves during sleep progression from stages 1-4?

A

the EEG waves increase in amplitude and decrease in frequency

33
Q

What does the EEG wave look like during REM sleep?

A

similar to waking- low amplitude, high frequency

34
Q

The first half of nocturnal sleep is dominated by_________, whereas the second half of nocturnal sleep is dominated by ______.

A

slow-wave sleep, REM sleep

35
Q

What happens to sleeping patterns as we age?

A

slow-wave sleep amount declines

36
Q

wakefulness/arousal is initiated and maintained by:

A

ascending pathways from the reticular formation to the thalamus and cortex. regulated by SCN–>VLPO–>hypothalamus and brainstem (via GABA mediated inhibition)

37
Q

cholinergic pathways that activate the thalamus, facilitating thalamo-cortical transmission are generally most active during _____ sleep

A

waking and REM sleep

38
Q

monoaminergic pathways that activate the cortex, facilitating the processing of thalamic input is generally more active during______ sleep

A

slow-wave sleep

39
Q

What pathway is degenerated in narcolepsy?

A

orexin/hypocretin pathway from the lateral hypothalamus (normally activating the cortex)

40
Q

What nucleus regulates sleep and how does it do it?

A

ventrolateral preoptic nucleus (VLPO) regulates sleep by inhibiting hypothalamic and brain stem nuclei that normally participate in wakefulness. VLPO inhibits these via GABA and discharges selectively throughout sleep

41
Q

How does the SCN regulate wakefulness during light phases?

A

SCN–>SPZ–>DMH of hypothalamus, inhibit VLPO with GABA and stimulates orexin neurons via glutamate

42
Q

What happens to the sleep cycle during sickness?

A

cytokines disrupt the circadian cycle to permit sleep during the day (TNF, IL…)

43
Q

Activation of the cortex during wakefulness is mediated by release of ______ and ______ neurotransmitters from ______.

A

norepinephrine and serotonin from the reticular formation (that was activated by the hypothalamus)

44
Q

activation of thalamic processing of sensory informaiton during wakefulness if mediated by release of ______neurotransmitter from ______.

A

acetylcholine released from the reticular formation (that was activated by the hypothalamus)

45
Q

What happens to the cholinergic and adrenergic corticothalamic pathways during slow-wave sleep?

A

are inhibited by GABA

46
Q

Why can’t we hear anything during slow-wave sleep?

A

transient downregulation of cortical areas inhibits the auditory cortex ( a sleep protection mechanism)

47
Q

During slow-wave sleep the body is ______ but the mind is ______ (active/inactive?)

A

decrease in muscle tone, HR, BP… during SWS but still can toss/turn. thus active body, inactive mind during SWS.

48
Q

during what stage of sleep does sleep walking occur?

A

SWS

49
Q

What happens to cholinergic pathways and thalamocortical transmissions during REM sleep?

A

increase in cholinergic stimulation (greater than waking!) and thalamo-cortical transmission similar to when waking

50
Q

During REM sleep the body is ______ but the mind is ______ (active/inactive)?

A

body is inactive (paralyzed actually) and the mind is active

51
Q

What are the two types of REM sleep and what are they characterized by?

A

Phasic REM: extensive REM, high brain activity (dreaming?) and external sounds suppressed.
Tonic REM: no REM, increased reactivity to outside stimuli (espsecially auditory)

52
Q

When are we most susceptible to auditory stimuli (alarm clock, eg) during sleep?

A

Tonic REM stages

53
Q

What are four physiological functions that correlate with REM stage?

A

eye movements, heart rate (increased), respiratory rate (increased), penile erection

54
Q

What activity might regulate how long an REM cycle is?

A

cholinergic/serotonergic feedback cycles

55
Q

What happens to acetylcholine levels during wakefulness and how does that affect memory?

A

Ach increases during wakefulness. this increases sensory input and encoding of memories in the hippocampus

56
Q

What happens to Ach levels during SWS and how does this affect memory?

A

Ach decreases during SWS, this increases the reactivation of memories in the hippocampus, transfering memories to the neocortex

57
Q

cortical slow waves are associated with _______activity and therefore memory ______.

A

cortical slow waves are associated with increased hippocampus acitivity and therefore memory reactivation (for consolidation in the cortex)

58
Q

Memories are stored in the _____ during SWS

A

the cortex

59
Q

Reactivation of memories during waking results in:

A

disruption by interference of other sensory inputs (easily labile)

60
Q

Reactivation of memories during SWS results in:

A

stabilization and consolidation of the memory

61
Q

Reactivation of memories during REM results in:

A

insight, discovery of correlations across episodes

62
Q

How does the septum affect memory consolidation?

A

separates periods of encoding of current sensory stimuli and retrieval to avoid interference

63
Q

How does the nucleus basalis affect memory?

A

projects to the neocortex to facilitate memory consolidation

64
Q

What part of the brain and memory storage is damaged in Alzheimers?

A

imparied cortical cholinergic neurotransmission, degeneration of the cortex, degeneration of the nucleus basalis. defective processing of beta-amyloid precursor–> amyloid plaques. –> inability to consolidate long and short term memories

65
Q

What are the symptoms of Korsakoffs Syndrome? What is it caused by?

A

loss of memory consolidation, with confabulation.

due to degeneration of thalamic nuclei and mamillary bodies from alcoholism.

66
Q

What happens after a bilateral hippocampectomy?

A

loss of memory consolidation. only long term memory is present