Presentation on theme: "1 Chapter Fourteen Emotion. 2 What is an Emotion? Emotions subjective experiences that arise spontaneously and unconsciously in response to the environment."— Presentation transcript:
2 What is an Emotion? Emotions subjective experiences that arise spontaneously and unconsciously in response to the environment around us. Emotions have two components: physical reaction (rapid heartbeat, etc.). conscious experience or feeling (sadness, anger, etc.).
9 Is Cognition Necessary? Pathway for Fear Without “Thought” Sensation of threat can reach the amygdala via direct path from thalamus The fast “low road” Sensation of threat also travels from the thalamus to the cortex The slow “high road” Cortical judgment can override direct path
10 Brain Mechanisms of Emotion: The Limbic System Amygdala Frontal cortex lobotomies
14 Genetics and Schizophrenia Concordance rate in identical twins is 50%. Adoption studies support a strong genetic role. As many as 70 genes may be involved.
15 Medial forebrain bundle (MFB): midbrain (ventral tegmental area – VTA) limbic system (nucleus accumbens) Many neurons in this system use dopamine. This system may function as a “reward circuit.” Mesolimbic System
16 Schizophrenia How are positive symptoms related to dopamine? Hypothesis: Mesolimbic system important for reinforcement of behavior We all have irrational thoughts, but usually brush them aside But if mesolimbic system was active when the thought occurred, we might take it more seriously, leading to delusions
17 Schizophrenia Negative symptoms Brain damage Many of the negative symptoms are also seen in people with brain damage Hypofrontality Decreased activity in prefrontal cortex
19 Control: Cell bodies arranged neatly. Patient with schizophrenia: Cell bodies relatively disorganized. Courtesy Arnold B. Scheibel, University of California, Los Angeles Negative symptoms: Brain damage
20 Loss of gray matter with age Cause of delay of onset?? Negative symptoms: Brain damage
21 Environmental Contributions to Schizophrenia Rh incompatibility Father’s age Maternal exposure to viruses during pregnancy Geographical patterns Seasonality effect Negative symptoms: Brain damage
The Hypofrontality Hypothesis At rest: both groups show similar activation levels in the brain Effortful task: patients with schizophrenia show less frontal lobe activity than participants w/o schizophrenia Courtesy Dr. Karen F. Berman, Clinical Brain Disorders Branch, SchiNIMH, NIH Normal Schizo. Normal Schizo. At rest Effortful cognitive test
24 How are positive & negative symptoms related? VTA Prefrontal Cortex NA Dopamine Hypoactivity (negative symptoms) GABA neurons Dopamine hyperactivity “reward pathway” (positive symptoms)