Unit 11 - Emotion

Question 1

neural circuit of the limbic system

Answer 1

cerebral cortex (cingulate, parahippocampal gyrus, frontal lobes)

hypothalamus (mamillary body, lateral nuclei)

amygdala

septal nuclei

striatum (nucleus accumbens - caudate and putamen for movement)

RICH INTERCONNECTIONS

Question 2

important aspects of limbic neural circuit

Answer 2

Question 3

circuit hypothesis based on

Answer 3

emotions reach consciousness

thoughts can affect emotions

e.g. if you’re embarrassed you cannot stop blushing by talking to yourself

nervousness - GI implications

Question 4

hypothalamus

active from…

hypothalamus - men vs women

age

what does it control

Answer 4

functional at birth - As we develop in utero, grown at 3 months - babies have same neurogenesis when they’re born as they were in utero - especially up to 2, but generally until 4 HOWEVER thermoregulation is poor

dissimilar in men and women

ancient phylogenetically

control over autonomic responses, eating, drinking and expression of primitive emotions

Question 5

hypothalamus - influence on emotion

Answer 5

primitve, undirected, short-lived response (cerebral cortex input is limited)

stimulation of hypothalamus in cats ⇒ attack behaviour

electrical stimulation of hypothalamus in humans ⇒ feelings of pleasure

Question 6

tumours in hypothalamus

Answer 6

produce sham mirth or rage

Question 7

lateral hypothalamic nuclei

Answer 7

destruction ⇒ severe attenuation of emotional responsiveness and experience

stimulation ⇒ can induce extremes in emotionality

Question 8

medial hypothalamic nuclei

Answer 8

stimulation ⇒ termination of behaviour

Question 9

amygdala involved in

Answer 9

higher order emotional and motivational activities

stronger connection to cerebral cortex

involved with expression and perception of emotion

sexually dimorphic (differences between males and females)

Question 10

medial nuclei of amygdala

Answer 10

stimulation of central nucleus - cessation of behaviour

Question 11

lateral nuclei of amygdala

Answer 11

primates

emotional significance is assigned

amygdala can overwhelm neocortex

Amygdala is a NEWER structure, specifically lateral nuclei

Question 12

amygdaloid stimulation ⇒

Answer 12

fear response

anger, pleasure

involved in more sophisticated emotions e.g. disappointment, surprise

Question 13

temporal lobe epileptic seizures

Answer 13

feelings of depression, pleasure, fear

crying, tantrum, laughing, sexual behaviour

Question 14

directed, long lasting emotional response of amygdala is due to

Answer 14

strong interactions with cerebral cortex

role in mood and affective disorders

(hypothalamus is short lasting, so not implicated in affective disorders)

Question 15

Kluver-Bucy syndrome - amygdaloid lesion

Answer 15

tameness

visual agnosia - difficulty recognising things

fear conditioning is affected

social impairment (hyperactivity, hypersexuality, hyperorality)

Question 16

Urbach-Wiethe disease - amygdaloid lesion

Answer 16

failure to discern facial expressions, especially fear

can be specific to fear recognition

less likely to be fearful

Question 17

other roles of amygdala

Answer 17

social drive

perception of social signals

interpretation of emotion in faces

memory and learning - faces

attention and abstract anticipation

threat detection

motivation to vocalise

interpretation of emotive sounds

Question 18

septum

age

function

Answer 18

phylogenetically new

dampening influence on arousal and limbic system functioning

dampens socialising tendencies and emotions

septum and amygdala have an antagonistic relationship - counterbalance

destruction results in increased aggressive behaviour and rage - generalised tendency to over-respond persists

destruction also causes a persistent drive for social and physical contact

Question 19

septum and amygdala

Answer 19

antagonistic relationship - counterbalance

Question 20

destruction of septum

Answer 20

a persistent drive for social and physical contact

Question 21

role of nucleus accumbens

Answer 21

increasing dopamine in the NA is associated with reward

pleasurable

enhanced likelihood of repeat of behaviour

Question 22

reward pathway

Answer 22

mesolimbic pathway

dopaminergic projections

ORIGIN = ventral tegmental area of brainstem

dopamine released in the NA

signal sent from NA to the cerebral cortex via globus pallidus and thalamus

Question 23

cingulate cortex

Answer 23

motivation, emotion, self control

Question 24

prefrontal and anterior cingulate cortices

Answer 24

response selection, decision making, volitional behaviour (self control)

planning

response to punishment

manners

concern for others

recognition of faux pas

hunches

self control

Question 25

anterior cingulate cortex

Answer 25

important response selection, decision making based on emotion, self control

Question 26

lesions in prefrontal and anterior cingulate cortices

Answer 26

impaired social function in primates

Question 27

what is implicated in depression and anxiety

Answer 27

overactivation of amygdala

underactivation of prefrontal and altered activity in cingulate gyrus cortical areas

reduced GM volume in amygdala, prefrontal cortex and cingulate gyrus

Question 28

what can stress do

Answer 28

block neurogenesis in the dentate gyrus of hippocampus

Question 29

in depression -

Answer 29

structural alterations in hippocampus

decreased cell proliferation in granule cell layer

atrophy of CA3 pyramidal neurons

reversed by antidepressants

time course consistent with therapeutic effect

increased cell proliferation/block of atrophy

neurotrophic factors implicated e.g. BDNF