Emotion

Purves et al., Chapter 29 (and part of Chapter 21) (and Chap 25 figure, Chap 17 figure)

General - historical

Darwin - Expression of emotion in man and animals - 1872
James-Lange theory: physiological changes -> emotional experience "we are afraid because we tremble" counterintuitive
Cannon-Bard theory: emotional experience is primary (Cannon coined "fight or flight") (and, of course, it is the sympathetic nervous system that prepares the body for both)

Hypothalamus

Fig. 29.1, p. 650
Bard did experiment implying that cortex inhibits hypothalamic (sham - directed at everything) rage unless the caudal hypothalamus is also disrupted.
Hypothalamus -> reticular formation for rage
Walter Hess (1949 Nobel prize) - rage or fear if hypothalamus stimulated.
(shared with Moniz who developed frontal lobotomy)
not in book: Electrical self-stimulation (Olds and Milner) - of hypothalamus is positive reinforcement in operant conditioning paradigm in a Skinner box

Fig Box 21A, p. 456
hypothalamus
surprisingly not in book: Lesions to ventromedial nucleus makes a fat rat, so older literature called this a satiety center, lesions to lateral hypothalamus makes a thin rat, so LH was once called a hunger center. There are problems with calling a small lesioned area a such-and-such-center based on the defect. Also, LH is where medial forebrain (reward) system goes (dopamine, covered repeatedly already).

Facial expression of emotion

Fig Chap 29 Box A, p. 648
Duchenne demonstration, electrical stimulation of face ("faradization") mimics emotional expressions
Photos to demonstrate
Duchenne (1862) cannot will certain spontaneous smiles
Inability is over-riden (symmetrical) in involuntary movement ["Duchenne smile"] as hypothalamus and amygdala feed to reticular formation and hence to motor neurons.
Interesting story - voluntary facial paresis inability to volontarily move lower facial muscles on one side due to lesion [pyramidal smile]

Fig. (no longer in text) like Box29A p. 649
paresis

Fig Box29A p. 649
block diagram

Fig, box A, Chapter 17, p. 379
(related to moter coverage)

Brain areas

Limbic system
Started with Broca (1879)- limbic = "border"

Fig. 29.3, p. 652
Fig. 29.4, p. 653
Limbic system
Papez (1937) circuit
Note that in sheep brain tract dissection, the fornix and mammillo-thalamic tract were shown in slide 11

rabies affects hippocampus - exxagerated fear etc.
tumors in cingulate cortex - fear & other emotions

Figs A & B, etc., Box 29B, p. 654
Amygdala
Amygdala connects to hypothalamus so it is related to the Papez (limbic) circuit.
lesions - fearlessness, difficulty recognizing emotions
stimulation - fear and violence

Box C (no figure) p. 656
Kluver-Bucy syndrome with amygdala lesion.
A terribly hostile monkey becomes docile with temporal lobe lesion (loss of fear) - hypersexuality, mouthing objects, etc.

Box D, pp. 657-658
Patient SM has degeneration of amygdala - cannot recognize or draw fear
Urbach-Wiethe disease (autosomal recessive)

Interesting stories:

Fig (no longer in text)
Lesions can be big- Phineas Gage - spike through brain then acted oddly (is it any wonder?)
Aprosody - inability to express emotion (like with monotone) with suprasylvian parietal cortex (on right side)

Box E, pp. 659-660 - Affective disorders
Lincoln "I am now the most miserable man living...I must die or be better, it appears to me,"
Depression (counting several categories) will affect 10 % of people.
Relieved by lots of drugs, fluoxetine (brand name Prozac) [serotonin uptake inhibitor] widely prescribed likened to "soma" in Aldous Huxley's "Brave New World" Late 1980's, now one of the most prescribed drugs. Also sertraline (Zoloft) and paroxetine (Paxil)
Depression more common in females
Other coverage of depression in transmitters outline
and in "alumnus e-interview."

Exam questions from 2005 - 2012 relating to this outline

Say something about where the brain was severed in the classic Bard experiments addressed to the presence or absence of "sham" rage.

if a hypothalamus that is deprived of cortical connection is still able to feed down to the reticular formation, there is sham rage

56. "The 'pyramidal smile' (voluntary facial paresis) results from an inability to voluntarily move the lower facial muscles on one side due to a unilateral lesion. Answer either how you could over-ride this distorted smile or what the symmetrical smile is called.

in the involuntary response, say, to humor, one gets the Duchenne smile

How do you prepare an animal to demonstrate that electrical self stimulation can serve as a positive reinforcement?

anesthetize, install electrodes with head mount, allow recovery, plug in

Duchenne noted that people with certain kinds of brain damage could not "will" a symmetrical smile. How could you elicit a symmetrical smile from such people (without resorting to "faradizations")?

elicit a spontaneous smile (emotional, tell a joke)

"The limbic system has been implicated in olfaction, emotion and memory - whew!" Which part was involved in classic studies of long term potentiation directed toward understanding memory?

hippocampus

A graduate of a neuroscience course is required to be able to say who Phineas Gage was.

a guy who had a spike blown through his brain and acted strangely after that

Patient SM has Urbach-Wiethe syndrome that caused bilateral destruction of the amygdala. In terms of recognition and drawing of facial expressions, what was her specific and unusual deficit?
 
could not draw or recognize fear

What is the main motor nerve to control facial expression?

facial (7)

Why would paralysis be a more likely consequence of stroke in the lower portion of the face than in the upper portion?

upper is bilaterally innervated, lower is not

Lesions to the lateral hypothalamus resulted in a thin rat, and so the lateral hypothalamus was referred to as a hunger center. An alternative interpretion involved the disruption of
what system involved in affect and motivation?

interrupt dopaminergic motivational tract

What part of the cerebral cortex is in the limbic system?

cingulate

Dopamine comes to the caudate from what brain structure?

substantia nigra

With brain cuts in and around the hypothalamus and with stimulations of the hypothalamus, Bard and (the Nobel prize-winning) Hess (respectively) studied what process?

rage (emotion)

Under what circumstances would a rat give itself electrical stimulation of the brain?

electrode in hypothalamus, stimulation is reinforcement (reward), will press bar in Skinner box

In voluntary facial paresis, a person with unilateral damage to fibers from the motor cortes, the smile will be crooked. Under what circumstances will the same person give a symmetrical smile?

a spontaneous smile resulting from humor

What happens to a monkey with a lesion in the amygdala?

get less aggressive, hypersexual

Why is it an oversimplification to call the lateral hypothalamus a hunger center on the basis of lesion experiments?

there are logical problems, also the medial forebrain bundle traverses the LH, and it has many controls on motivation

In the many functions attributed to the limbic system, what function did Kluver & Bucy attribute to the amygdala?

mood on a scale from cuddly to ferocious

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