1. Limbic forebrain Domina Petric, MD
Leonard E. White, PhD, Duke University
Limbic forebrain
Domina Petric, MD

2. Amygdala, hippocampus http://knowingneurons.files.wordpress.com
Leonard E. White, PhD, Duke University

3. Neurobiology of emotion
Emotion is associated with implicit modes of processing.
James-Lange theory of emotion:
Emotion-provoking stimulus activates peripheral receptors.
Smooth and striated muscle activities are engaged.
Peripheral responses are detected.
Emotion is elicited by peripheral feedback.
Leonard E. White, PhD, Duke University

4. Neurobiology of emotion
Emotion can be considered as a form of associative learning.
Emotions result from association of sensory stimuli with primary reinforcers.
Sensory stimuli can be interoceptive (derived from within the body) and exteroceptive (derived from outside the body).
Primary reinforcers can be rewards and punishers.
Leonard E. White, PhD, Duke University

5. Neurobiology of emotion
Amygdala is important for the associative learning and emotions.
Leonard E. White, PhD, Duke University

6. Emotional processing Subjective (feelings)
Somatic/visceral (effectors)
Cognitive (significance)
Leonard E. White, PhD, Duke University

7. Limbic forebrain functional divisions
Olfactory division (olfactory bulb and cortex): special sensory function (smell, flavor).
Parahippocampal division (hippocampus, posterior hippocampal formation, posterior cingulate gyrus, thalamic anterior nucleus, posterior hypothalamus): explicit processing (episodic memory acquisition and consolidation spatial mapping).
Leonard E. White, PhD, Duke University

8. Limbic forebrain functional divisions
Amygdala/orbital prefrontal division:
amygdala, orbital-medial prefrontal cortex, anterior hippocampal formation, anterior cingulate gyrus, temporal pole cortex, ventral striatum, ventral pallidum, thalamic mediodorsal nucleus, medial hypothalamus
implicit processing (visceral motor control, emotional experience and expression, appetitive drives, social behavior)
Leonard E. White, PhD, Duke University

9. Orbital-medial prefrontal cortex
Key brain systems for associative learning between primary and secondary reinforcers:
Amygdala
Orbital-medial prefrontal cortex
Leonard E. White, PhD, Duke University

10. Amygdala Medial group of cells.
Central group of cells: output from the amygdala to the medial part of the hypothalamus.
Basal-lateral group of cells: connections with the medial-orbital prefrontal cortex (bidirectional connections).
Basal-lateral group of cells is very important source of inputs for the nucleus accumbens.
Leonard E. White, PhD, Duke University

11. Fear conditioning in amygdala
Auditory pathways
Medial geniculate nucleus
Auditory cortex
Other projections (somatic sensory pathways)
Amygdala
Output to circuits that govern somatic and visceral motor activity

12. Urbach-Wiethe disease
Rare, autosomal recessive disorder that producess bilateral calcification and atrophy of the anterior, medial temporal lobe.
There is bilateral destruction of amygdaloid complex.
There is sparing of temporal neocortex and hippocampal formation.
There are no primary sensorimotor deficits.
Patients have impaired fear recognition in facial expressions and impaired experience of fear.
Leonard E. White, PhD, Duke University

13. Amygdala and trustworthiness
When activity in the amygdala is high, our judgement of someone´s trustworthiness is low.
Amygdala is a warning system.
Leonard E. White, PhD, Duke University

14. Amygdala functions overview
Amygdala plays a primary role in association of sensory stimuli with reward or punishment.
Amygdala modulates information processing in the forebrain.
Enchances awareness of aversive or arousing stimuli.
Enchances memory for emotionally charged events.
Amygdala hypofunction produces deficits in the efficacy of information processing.
Amygdala hyperfunction produces excessive vigilance and anxiety.
Leonard E. White, PhD, Duke University

15. Orbital-medial prefrontal cortex
Recieves inputs from amygdala and multi-modal sensory inputs from sensory and associational cortex.
Functions of orbital-medial prefrontal cortex are:
emotional learning
interpretation of social cues
planning appropriate social behavior
formation of advantageous decisions in real-life circumstances
Leonard E. White, PhD, Duke University

16. Orbital-medial prefrontal cortex functions (more detailed):
Emotional processing, interpretation of social cues and planning appropriate social behavior.
Emotional learning, especially when rewards are scents and food.
It is involved in the ongoing analysis and modification of behavior when reinforcement contingencies are rapidly changing (emotional re- learning).
Social agility!
Assessment of future consequences and the implementation of advantageous decisions.
Leonard E. White, PhD, Duke University

17. Orbital-medial prefrontal cortex injury
No impairments in sensorimotor control, except for olfactory and taste impairments.
No impairments on standard neuropsychological assessments.
Impaired emotional experience and expression.
Impaired rational decision making, especially in the domain of personal and social affairs.
Pathological inability to make advantageous (good) decisions in real-life situations.
Leonard E. White, PhD, Duke University

18. Somatic marker hypothesis by Damasio A. R., MD
Rational decision making entails subconcious evaluation of future consequences.
Mental images representing possible outcomes trigger somatic states that mark the mental images with emotional valence.
Somatic states can be truly somatic and involve activity of autonomic and musculosceletal effector systems OR can be VICARIOUS (involve only neural representations of viscero and somato-motor activity in parietal and insular cortex).
Leonard E. White, PhD, Duke University

19. Neurobiology of feelings
Feelings are kind of emotional working memory.
Triggering (interoceptive, exteroceptive) stimuli activate amygdala dependent associative learning and hippocampal dependent explicit memory.
Immediate conscious experience of emotional feelings occurs in prefrontal cortex (working memory).
Leonard E. White, PhD, Duke University

20. Human emotions characteristics
wide range of brain and body states
expressive somatic behavior
stereotypical physiological responses
distinct subjective experiences
Leonard E. White, PhD, Duke University

21. Human emotions
Human emotions arise as a result of associative learning that attaches emotional valence to sensory stimuli.
Associative emotional learning involves the amygdala and the orbital-medial prefrontal cortex.
The amygdala is primary neural center for associative learning.
The orbitofrontal cortex is especially important when contingencies of reinforcement are rapidly changing.
Leonard E. White, PhD, Duke University

22. Literature
Leonard E. White, PhD, Duke University
Leonard E. White, PhD, Duke University