L48 - Limbic system and central autonomic function Flashcards

1
Q

<p>List some primary and secondary emotions</p>

A

<p>Primary (reflexive) : Fear, anger, surprise, disgust, happiness, sadness.

Secondary (cognitive) : Envy, shame, guilt, etc.</p>

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2
Q

<p>What modulates emotions and drive motivated bahaviors?</p>

A

<p>Rewards, both good and bad</p>

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3
Q

<p>List general brain regions involved in the limbic system.</p>

A

Prefrontal and association cortex

Cingulate gyrus

Hippocampal formation

Mamillary body of hypothalamus & Hypothalamus

Anterior nucleus of Thalamus

Amygdala

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4
Q

<p>Function of the limbic system?</p>

A

<p>integrate information about sensory stimuli, memories, and cognitive plans

>> produce emotional learning and experience</p>

> > modulate emotional responses

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5
Q

Role of the hypothalamus in the limbic system?

A

 Modulate autonomic output in emotional responses

 Generation of aggressive behavior patterns **

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6
Q

Describe the connection between neocortex and hippocampus?

A

<p>Via Entorhinal area</p>

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7
Q

Describe the brain regions involved in the Papezcircuit?

A
Hippocampal formation 
>> fornix (connect temporal lobe to diencephalon)
>> Mamillary body of hypothalamus 
>> Mammilothalamic tract 
>> Anterior nucleus of thalamus
>> Cingulate gyrus 
>> Cingulum (tract)
>> Entorhinal cortex
>> Hippocampal formation
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8
Q

Role of Amygdala in the limbic system?

A

1) Key coordinator: Linking cortical processing to the hypothalamus and other subcortical brain structures
2) expression of fear
, anxiety, stress
3) Response to emotional facial expression + emotional arousal

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9
Q

List some functions of primary reflexive emotions?

A

Aid survival:

  • Fear = danger, fleeing, fast escape
  • Anger = fight
  • Surprise = response to novel stimuli and prepare for reaction
  • Disgust = avoid poisoning, infection (limbic system connected to olfactory bulb)
  • Joy = motivator, drive
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10
Q

Changes in behavior due to amygdala damage? ( Kluver-Bucy syndrome )

A
  • Tame, loss of fear, blunted emotions, less aggression
  • Forget rapidly
  • Increase oral activity and sexual behavior
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11
Q

Describe the 2 neural pathways for processing emotional stimulus into emotional response?

A

For evaluating emotions, long-term memory:
- Central/ Indirect pathway: Thalamus > Cortex > Amygdala > descending efferent output

For autonomic responses:
- Peripheral/ Direct pathway: Thalamus > Amygdala > descending efferent output

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12
Q

List some autonomic responses triggered by the posterior** hypothalamus after emotional stimuli?

A
  • Sympathetic- like responses:
    Increase BP, shivering
    GI stimulation: hunger and thirst, feeding reflexes
    Rage
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13
Q

List some autonomic responses triggered by the anterior** hypothalamus after emotional stimuli?

A

Parasympathetic-like response:

  • Oxytocin release
  • Decrease BP, HR
  • Bladder contraction
  • Panting, sweating
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14
Q

Which brain region is responsible for eliciting hunger, thirst and feeling of fullness (satiety)?

A

Lateral hypothalamus: feeding/ hunger center

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15
Q

Consequences of lateral hypothalamus lesion?

Lesion in Ventromedial hypothalamus?

A

Lesions in lateral hypothalamus (feeding / hunger center) :

  • Hypophagia (decrease in food intake) / aphagia (lack of eating)
  • Adipsia (absence of thirst)

Lesions of ventromedial hypothalamus (satiety center) = loss of satiety

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16
Q

Describe the output of the amygdala for modulating autonomic emotional expression/ response?

A

2 tracts to reach branstem nuclei:

1) Indirect: Central nucleus in amygdala&raquo_space; Hypothalamus (medial and lateral)&raquo_space; Brainstem nuclei
2) Direct: Central nucleus in amygdala&raquo_space; brain stem nuclei

Both tracts output to modulate sympathetic and parasym. neurons = change emotional response

17
Q

Which sensory input can directly impact the autonomic output of the amygdala for emotional response?

A

1) visceral organs and taste** receptors&raquo_space; solitary nucleus&raquo_space; brain stem
2) Olfactory system > directly to amygdala > brain stem

Modulate emotional response through changing sympathetic and parasym. output

18
Q

Which brain region is associated with euphoria and pleasant sensations?

A

Septal region: pleasure centre

Closely connected with the dopaminergic limbic system

19
Q

Describe the sequence of structures in the mesolimbic pathway.

A

mesolimbic pathway:

septal area&raquo_space; dopaminergic connection» ventral tegmental area**&raquo_space; Nucleus accumbens

(Pathway through lat. hypothalamus to reach frontal cortex is mesocortical pathway)

20
Q

Which brain region is associated with reward and addiction?** (not euphoria/ pleasure)

A

Nucleus accumbens

21
Q

Which brain area forms most of the mesolimbic system?

A

Ventral tegmental area

mesolimbic and mesocortical projections involved in reward by dopamine release

22
Q

Describe the autonomic output when fear stimuli activates the amygdala (corticomedial area)?

A

Amygdala: indirect or direct output to brainstem, trigger sympathetic activation (fight-or-flight response):

 Tachycardia 
 Sweating
 Paleness 
 Pupil dilation 
 Piloerection  
 Adrenal release of adrenaline
23
Q

How is the olfactory system connected to the limbic system?

A

Olfactory system > Medial amygdala group > hypothalamus

24
Q

What is the role of the Ventral Tegmental area? What emotions/behavior does it regulate?

A

Form most of mesolimbic/ mesocortical pathways: for REWARD ANTICIPATION:

  • VTA neurons provide a learning signal that reflects reward expectation
  • i.e. seeing reward cause VTA neurons to fire in prediction and anticipation of getting the reward
25
Input and output of the nucleus accumbens?
Input: dopaminergic input from midbrain dopamine neurons (e.g. septal area for euphoria) Output: hypothalamus and limbic structures mediating emotional responses
26
Which brain region is affected by addictive drugs i.e. Cocaine and amphetamines? explain the physiological effects?
Medial Forebrain Bundle that innervates the Ventral Tegmental Area: especially Nucleus Accumbens***: - increase dopamine release in shell of the nucleus accumbens - Block dopamine reuptake at synapses - Enhance dopamine release by acting on presynaptic cholinergic receptors (Nicotine) >> Enhance pleasure
27
List functions of the Dopamine pathways?
Nigrostriatal, mesolimbic, tuberoinfundibular: - Reward (motivation) - Pleasure, euphoria - Motor function (fine tuning) - Compulsion - Perseveration
28
List functions of the serotonin pathways?
- Mood - Memory processing - Sleep - Cognition
29
Define the parasympathetic tracts/ CN nuclei that are modulated to produce emotional responses?
CN 3,8,9,10 + Sacral outflow tracts
30
Which brain area has increased firing activity in the learned anticipation of reward?
VTA
31
What is the function of the VTA in the mesolimbic system?
VTA neurons provide a learning signal that reflects reward expectation >> guide behavior and to modulate emotional responses to reward-predicting stimuli.
32
Which area in the mesolimbic system uses NE as neurotransmitter?
Locus coeruleus
33
Which area in the mesolimbic system uses Dopamine as neurotransmitter?
VTA, Substantia nigra
34
Which area in the mesolimbic system uses Serotonin as neurotransmitter?
Raphe Nucleus
35
Which area in the mesolimbic system uses Ach as neurotransmitter?
Basal forebrain
36
List the structures that make up the hippocampal formation?
(dentate gyrus, hippocampus, subiculum)