Amygdala lesions blocks fear conditioning Amygdala role in emotional

Amygdala lesions blocks fear conditioning amygdala

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Amygdala lesions blocks fear conditioning - Amygdala= role in emotional significance of sensory signals - Diagram***important for the exam - Periaqueductal grey—freezing response Contextual Fear Conditioning and the Hippocampus - Just as fear of an auditory stimulus can be learned, so can fear of a place - Hippocampus involved Lesions before conditioning prevents development of contextual fear Lesion after blocks retention of contextual fear response Other fear responses intact Case Study - Charles Whitman - Tumour on amygdala Sham Rage - Decorticate cats= extreme and unfocused aggressive responses - Hypothalamus must be intact - Hypothalamus necessary for expression of aggressions - Cortex serves to inhibit and direct responses Kluver- Bucy Syndrome - Rare cerebral neurological disorder - Results from bilateral damage anterior temporal lobes - Major symptoms urge to put objects into mouth, memory loss, extreme sexual behaviour, placidity, visual distractibility - First seen in monkey, then other special (including humans) Brain Mechanisms of Human Emotion - Cognitive neuroscience is a current approach to study human emotion Activity associate with emotion is diffuse Emotion and empathy- correlated with activity in motor and sensory cortices Similar brain activity is associated with experiences emotion, imagined emotion, or observation of someone experiencing and emotion May indicate a mirror like system in the brain - Amygdala, hippocampus and prefrontal cortex clearly play a role - Lesion amygdala= unable to perceive fearful emotions in others, but can still express emotions fine Biopsychology of Psychiatric Disorders Psychiatric disorder
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- Also called psychological disorders - Psychiatric disorders disruptions of psychological function severe enough to require treatment - Diagnosed using the DSM-5 Schizophrenia - “Splitting of psychic functions” Refers to the breakdown of the integration of emotion, thought and action Individual splits off from what reality is External world does not match internal world - Affects 1% of population Equal between males and females However, earlier in males (teens, early 20’s), later in females (late 20’s, early 30’s) - A diverse disorder- multiple types exist with varied profiles Symptoms - Delusional thinking (grandeur, persecution) - Hallucinations (usually auditory) - Inappropriate affect - Incoherent thought - Odd behaviour catatonia (don’t move for hours), echolalia (repetitive), waxy flexibility (hold same position, move them hold that position) - Alogia absence of speech - Anhedonia inability to experience pleasure Positive Symptoms - Something that is there that shouldn’t be there - Usually helped by medication Negative Symptoms - Something that isn’t there that should be - Cannot be helped by medication Causal Factors - Evidence for a genetic contribution Inherit an increased risk for the disorder- then match with environment factors - Multiple causes Several different chromosomes implicated Associated with various early insults- infections, autoimmune reactions, toxins,
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  • Fall '09
  • CAIN
  • Psychology, brain damage, Traumatic brain injury

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