Kapitel 17: Følelser, stress og sundhed

Biopsychology of Emotion, Stress, and Health

• Chapter Overview and Learning Objectives: The chapter covers the biopsychology of emotion, stress, and health, focusing particularly on fear. Learning objectives include summarizing historical research on emotion, the relationship between the autonomic nervous system and emotions, facial expressions of emotions, and the distinction between aggression and defensive behaviours in mammals, and the relation between testosterone levels and aggression in males.

Neural Mechanisms of Fear Conditioning

• Amygdala's Role: The amygdala plays a key role in fear conditioning. Lesions to the amygdala block fear conditioning, suggesting its critical involvement.

• Hippocampus's Role: The hippocampus is involved in contextual fear conditioning. Damage to the hippocampus impairs the ability to associate the context with fear but does not affect fear conditioning to explicit stimuli like a tone.

• Specific Amygdalar Nuclei: Specific amygdalar nuclei are involved in fear conditioning, particularly the lateral nucleus.

Brain Mechanisms of Human Emotion

• Cognitive Neuroscience of Emotion: Contemporary research emphasises the widespread nature of brain activity associated with emotions, rather than specific centres.

• Universality of Facial Expressions: Ekman and Friesen's research indicates the cross-cultural universality of basic emotional expressions like happiness, surprise, anger, sadness, disgust, fear, and happiness via facial expressions.

• Facial Feedback Hypothesis: Facial expressions influence emotional states. Making a happy face can induce feelings of happiness, and a frowning face promotes feelings of anger.

Emotions and Facial Expression

• Primary Facial Expressions: Surprise, anger, sadness, disgust, fear, and happiness are considered primary emotions, with other facial expressions being combinations of these.

• Microexpressions: Brief, fleeting facial expressions that reveal genuine emotions are called microexpressions, and can be detected with training.

• Duchenne Smile: A genuine smile involves the contraction of two specific facial muscles (Orbicularis oculi and Zygomaticus Major).

Voluntary Control of Facial Expressions

• Substituting False Expressions: Individuals can voluntarily control facial expressions and substitute false ones, potentially for social reasons.

• Methods to Detect Fake Expressions: Micro-expressions and subtle differences between genuine and false expressions can be used to detect deception.

Amygdala and Human Emotion

• General Role: The human amygdala plays a general role in the evaluation of emotional situations, including positive and negative contexts.

• Case of S.P.: Damage to the amygdala can impair the ability to recognize fear in facial expressions, although other emotional expressions can be identified and used to express emotions typically.

Medial Prefrontal Lobes and Human Emotion

• Emotion and Cognition: Prefrontal lobes, primarily the medial portions, are crucial in regulating and integrating emotional responses with cognitive processes.

• Suppression and Reappraisal: Emotional responses to negative stimuli can be suppressed or reinterpreted by the medial prefrontal lobes resulting in decreased emotionality.

Lateralization of Emotion

• Right Hemisphere Model: The right hemisphere is believed to be dominant in processing many aspects of emotion. However, current research challenging this complete dominance,

• Valence Model: Negative emotions might be processed by the right hemisphere and positive emotions by the left.

Neural Mechanisms of Fear Conditioning

• Contextual Fear Conditioning: Associating a specific context with a fear-provoking event can induce learned fear responses to that context.

• Amygdala Complex: Different nuclei within the amygdala complex have distinct roles in fear conditioning, specifically lateral nucleus for acquisition, storage, and expression of conditioned fear.

Stress and Health

• Stress Response Components: Stress involves physiological responses including activation of the anterior pituitary-adrenal cortex system and the sympathetic-nervous-system adrenal medulla system. These systems are part of the body's natural mechanism for coping with stressors.

• Chronic Stress: Chronic (long-term) stressors have detrimental effects on the adaptive immune system, potentially leading to increased illness vulnerability.

• Acute Stress: Brief stressors generally improve immune function.

Psychoneuroimmunology

• Immune System Components: The immune system comprises the innate immune system (immediate, general defense against pathogens) and the adaptive immune system (specific, targeted response to pathogens; slower).

• Stress and Immune Function: Stressor effects on the immune system are complex, with chronic stress often correlating with impairment. The effects of stress vary between innate and adaptive immune functions.

• Psychoneuroimmunology Definition: Psychoneuroimmunology examines how psychological factors, brain function, and immune function interact.

Aggression and Testosterone

• Correlation, Not Causation: Increased testosterone levels in males are linked to social aggression in many species and the correlation often highlights a complex interaction between these factors - higher testosterone in male animals does not always lead to aggression, or aggression always resulting from higher testosterone levels .

• Species Differences: The effect of testosterone on aggression can vary significantly across different species.

• Brain Areas: Testosterone may act on specific neural areas rather than simply affecting blood levels, to impact aggression.

Psychosomatic Disorders

• Gastric Ulcers: Prior beliefs that stress causes ulcers are more complicated. Although stress and ulcers are correlated, bacteria are a major cause more than stress.

• Stress as a Contributing Factor: While medical conditions may be caused by known factors, stress can influence their development

Early Experience of Stress

• Adverse Effects: Early exposure to severe stress (e.g., abuse, neglect) can result in long-lasting effects on brain function and stress responses in children, including alterations in endocrine and brain development.

The Case of Charles Whitman

• Amygdala Tumour: Whitman's case highlighted the crucial relationship between the brain’s amygdala and violent behavior. His autopsy revealed a tumour affecting the amygdala.

Denne quiz dækker biopsykologien om følelser, stress og sundhed, med fokus på frygt. Det vil undersøge amygdalaens og hippocampus' roller i frygtkonditionering og deres betydning for adfærd. Test din viden om historisk forskning og sammenhængen mellem følelser og det autonome nervesystem.