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5 The Emotional Brain (historical development (Darwin (innate emotions: …

5 The Emotional Brain (

historical development

Blokboek

anatomy

Tranel 2004

Altered experience of emotion following bilateral amygdala damage

patient SM, bilateral focal amygdala damage which is know to impair emotional perception & processing
blind interviews nature of her emotional experience
SM Expressed a normal range of affect and emotion, yet remarkably dispassionate when relating highly emotional and traumatic life experiences,
when asked about emotional reactions to these adverse life experiences, and she ``denied feeling strong emotion
In contrast to her demeanor when discussing negative experiences and events, SM displayed ``strong positive affect'' when relating aspects of her life that she views favourably
very trusting

First, this report emphasizes the close link between impaired recognition of emotions, and impairments in their experience.
Unlike the conclusions drawn from the classic Kluver and Bucy studies, we conclude that the amygdala is not necessary for relatively normal social behaviour as such. Instead, it is necessary for linking stimuli to the appropriate elicitation of such behaviours, and to the appropriate experience of emotion.,

Questions

LeDoux

emotion: feelings, bodily responses (in soma: , in brain: cognition)
feelings are the concious perception of emotions

emotionally competent stimuli
endocrine glands, the autonomic motor system,
and the musculoskeletal system

The Modern Search for the Emotional Brain Began in the Late 19th Century

Cannon does lesions in cats: hemisphere removal in/excluding hypothalamus → sham rage
Cannon & Bard propose theory based on thalamus Input of stimulus, hypothalamus (bodily response) and cortex (concious feeling)
Papez extends circuit based on Cannon & Bard
Klüver & Bucy experiment
MacLean extends Papez theory

In general, damage to areas of the limbic system did not have the expected effects on emotional behavior.
evolutionary perspective on emotion → involves old circuits
The Amygdala Emerged as a Critical Regulatory Site in Circuits of Emotions
Pavlovian fear conditioning is actually the first phase of avoidance conditioning. The pairing of US and CS initially results in the conditioning of a response, but in the second phase the animal learns to perform an instrumental response to avoid the shock.
The lateral nucleus is the input nucleus receiving information about the CS (eg, a tone) from the thalamus. The central nucleus is the output region; neurons here project to brain stem
Studies of patients with bilateral damage to the amygdala or hippocampus illustrate the separate contributions of the amygdala and the hippocampus to implicit and explicit memory, respectively. Patients with damage to the amygdala show no physiologi- cal responses to a CS (indicating no implicit learning) but have good memory of the conditioning experience (indicating explicit learning), whereas patients with hip- pocampal damage respond normally to the CS but have no conscious memory of the conditioning experience.
Other Brain Areas Contribute to Emotional Processing
implicated the ventral region of the anterior cingulate cortex, the insular cortex, and the ventromedial prefrontal cortex in various aspects of emotional processing

prefrontal cortex (ML) damage changes social behaviour, no bodily responses to stimuli - knowledge is there but, is not used as much in needed situations (dissociation)

The Neural Correlates of Feeling Are Beginning to Be Understood

Ss recollect, relive situation in frmi: pattern of change differed with each emotion (Figure 48–9). Patterns of activation did not overlap
The amygdala is not activated dur-ing conscious feeling, evidence that it deals mainly with unconscious emotional states
signals in the afferent somatosensory pathways play a role in the processing of feelings

The loss or impairment of the neural processes responsible for feelings diminishes the abil- ity to anticipate and plan behavior.,

terms

visceral brain = limbic system

Literature

motivation & emotion

Motivations are states, two kinds:
- Basic states: physiological states (bodily changes) that
  unconsciously prompt a subject to act; to maintain bodily
  homeostasis. Drives.
- Complex/cognitive states: maybe conscious; (part of) emotion

2 types of arousal

non-limbic arousal
- (1) ARAS stimulation → sympathetic NS response
limbic system arousal
- (2) limbic midbrain areas (central gray area around the ventricle & VTA) → motivation + strong affect + sympathetic NS response
- resistant to habituation
- dominated by instinctive attractions

↑ regulated by forbrain, e.g. hypothalamus

hypothalamic cell groups as central patterns generators (output to midbrain, hindbrain, spinal cord)

hypothalamus - neocortex

(1) via limbic endbrain structures
(2) histaminergic/ orexinergic projection from laternal neurons
(3) via MD of thalamus to orbito PFC
(4) via mammilothalamic tract & cingulate cortex to association areas

gating influence via intrathalamic axons of a fairly diffuse sort

)