Emotion, Feelings and Motivation

Stimulus Brain Pleasure

Stress Brain Depression

Periphery

Periphery

The particular emotion experienced is a function of cross-talk between neocortical and subcortical structures, as well as feedback from peripheral receptors.

Stimulus

Susan Iversen; Irving Kupfermann; Eric R. Kandel

• Whether conscious feeling follows bodily changes (James-Lange) or bodily changes follow feeling ?

Emotion & Feeling• An emotional state has two components, one

evident in a characteristic physical sensation and the other as a conscious feeling

• “Emotion” sometimes is used to refer only to the bodily state (ie, the emotional state) and “feeling” is used to refer to conscious sensation

• When frightened we not only feel afraid but also experience increased heart rate and respiration, dryness of the mouth, tense muscles, and sweaty palms

James-Lange Theory (1880s)

• James wrote: “We feel sorry because we cry, angry because we strike, afraid because we tremble.”

Epinephrine’s effects

Not Informed

How nervous are you?

Epinephrine Saline

Group 3 Group 4

Patients in whom the spinal cord has been accidentally severed appear to experience a reduction in the intensity of their emotions.

Cannon's study of peripheral responses to intense emotion

• fight-or-flight response (1920)

• the physiological responses to emotionally significant stimuli are too undifferentiated to convey to the cortex specific, detailed information about the nature of an emotional event.

Bard’s Experiments (1920s)

Sham rage: animals with the whole cerebral cortex removed retain fully integrated emotional responses

Cnnon-Bard Theory

• The Hypothalamus mediating both the cognitive and peripheral aspects of emotion

By progressive transections the coordinated response disappeared when the hypothalamus was included in the ablation

Schachter-Singer

Epinephrine’s effects

Informed

Epinephrine’s effects

Not Informed

How nervous are you? How nervous are you?

Epinephrine EpinephrineSaline Saline

Group 1 Group 2 Group 3 Group 4

Schachter’s Cognitive Experiment (1960s)

James-Lange Cannon-Bard Schachter

Peripheral stimuli

Peripheral stimuli

Emotional state: autonomic, endocrine,

skeletomotor responses

Conscious feelings

Peripheral stimuli

Hypothalamus

Emotional state: autonomic, endocrine,

skeletomotor responses

Memories in amygdala

Conscious feelings &

emtional state

Neuroanatomy

Memory has two major forms: a conscious (explicit) memory for facts and personal events and an unconscious (implicit) memory for motor and sensory experiences.

Central or Peripheral sti

Cognitivetranslation

When the sound alone is given, it evokes physiological changes in blood pressure and freezing similar to those evoked by the sound and shock together (right)

The Hypothalamus Coordinates the Peripheral Expression of Emotional States

• In anesthetized animals, Ranson (1932) evoked individual conceivable autonomic reaction by stimulating different regions of the hypothalamus

• In 1940s, Walter Hess extended Ranson's approach to awake, unanesthetized cats and found that different parts of the hypothalamus produce characteristic constellations of reactions

Fear and Amygdala• Electrical stimulation of the amygdala in

humans produces feelings of fear and apprehension.

• Urbach-Wiethe disease disrupts the unconscious processing: The patients fail to learn the cues that normal subjects use to discern fear in facial expressions, but they can accurately identify familiar people from photographs.

Fear and Amygdala

• When subjects were asked to view photographs of fearful or happy faces, the PET responses in the amygdala were significantly greater to fearful expressions than to happy expressions. The response in the left amygdala increases with increasing fearfulness and decreases with increasing happiness

Fear and Amygdala

• Bilateral lesions of the basolateral complex of the amygdala in experimental animals abolish this learned response to fear.

• Patients with damage to the amygdala do not learn to fear the neutral sound even though most were consciously aware that the neutral sound and the offensive noise were paired together.

The Amygdala also mediates the cognitive experience of emotion, particularly in fear.

Stimuli from the cortex

• Electrical stimulation of the orbitofrontal cortex produces many autonomic responses. Lesions of the orbitofrontal cortex reduce the normal aggressiveness and emotional responsiveness of primates, and lesioned animals sometimes fail to show anger when they do not receive expected rewards in a training task.

Egas Moniz performed the first prefrontal lobotomy in humans in 1935.(1949 Nobel Prize)

Stimuli from the cortex

• In 1935 John Fulton and Carlyle Jacobsen first reported that removing the frontal cortex (lobotomy) had a calming effect in chimpanzees. Within a few months of Fulton and Jacobsen's report, Egas Moniz, a Portuguese neuropsychiatrist, performed the first prefrontal lobotomy in humans, isolating the orbital frontal cortex. The patients became tamed.

Stimuli from the cortex

• Cortical mechanisms provide a means by which memory and imagination, not just external stimuli, can evoke emotional feelings and they enable us to use emotional information generally in cognitive processing.

• Cortical structures also provide the means by which conscious thought can suppress reflex emotional responses. Once we know that a “bear” is only a shadow that looks like a bear, the fear subsides.

The Amygdala Mediates the Autonomic Expression

β-adrenergic blocker selectively impaired the memory for the emotional story

• Lawrence Cahill, James McGaugh, and co-workers investigated the effect of propranolol, a β-adrenergic receptor blocker, on the long-term memory of an emotionally arousing short story or a closely matched, but more emotionally neutral, story. The β-adrenergic blocker selectively impaired the memory for the emotional story. The drug did not block the subjects' initial emotional reaction to the story when it was first presented, suggesting that nonspecific effects of the drug on arousal or attention could not account for the result.

Mood & Monoamines

1. Long-term use of reserpine may cause depression (1959)

2. Some people got euphoric when treated with iproniazid (1952)

3. Imipramine is an effective antidepressant (1958)

A. Reserpine almost irreversibly blocks the uptake (and storage) of norepinephrine and dopamine into synaptic vesicles by inhibiting the Vesicular Monoamine Transporters

B. Iproniazid inhibits synaptic monoamine oxidase

C. Imipramine inhibit reuptake of norepinephrine and serotonin

Motivation

• how individuals respond to internal rather than external stimuli. This is the domain of motivation.

• Motivation is a catch-all term that refers to a variety of neuronal and physiological factors that initiate, sustain, and direct behavior. These internal factors are thought to explain, in part, variation in the behavior of an individual over time.

Pleasure

Love

Hierachical Drive States of Motivations

Drive states are characterized by tension and discomfort due to a physiological need followed by relief when the need is satisfied.

Physiological Needs

• Temperature regulation involves integration of autonomic, endocrine, and skeletomotor responses

• Feeding behavior Is regulated by a variety of mechanisms

• Drinking is regulated by tissue osmolality and vascular volume

Recombinant human leptin0.01-0.04 mg/kg/day, 18 months

Noningestive behavior of all three patients was consistently observed to change from very docile and infantile to assertive and adult-like, within 2 weeks of the onset ofleptin treatment, before weight loss occurred.

PNAS 2004

Motivational States Can Be Regulated by Factors Other Than Tissue Needs

Experimental Self-Stimulation of the Brain Reward Pathway

The Mesolimbic Dopaminergic Pathways Important for Reinforcement

In the presence of the drugs animals self-stimulate with a lower-frequency current that was previously ineffective.