NEUR346 #21 Fa24
Lesson 21: Emotions and Motivated Behaviors
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SYSTEMS NEUROBIOLOGY FALL 2024 Lesson 21 Emotions and Motivated Behaviors
Page 2: Objectives for Lesson 21
Discuss the pyramidal and extrapyramidal contributions to emotional expression.
Identify principal neuroanatomical structures of the limbic system and key inputs and outputs.
Describe roles of the amygdala, nucleus accumbens/mesolimbic dopamine system, and hypothalamus in emotional responses and motivated behaviors.
Understand the concept of hypothalamic-pituitary-target organ cascade.
Describe emotional circuits and dysfunctions in clinical conditions such as affective disorders and addiction.
Page 3: Emotions
Definition of Emotion: A complex psychological state involving a subjective experience, physiological response, and behavioral or expressive response.
Evolutionary Utility: Emotions enhance survival by promoting adaptive behaviors.
Generation of Emotions:
Physiological changes could lead to emotional perception.
Emotions may also trigger physiological responses.
Neural Circuitry Involved: Anticipated circuits for emotional responses could include the limbic system and cortical processing.
Facial Expressions: Connects with emotional expression through motor components.
Page 4: Components of Emotions
Behavior: Observable response to emotions.
Physiology: Bodily responses to emotions, such as heart rate increase.
Emotion: Subjective feeling state.
Feeling: Conscious experience of emotion.
Page 5: Emotional Circuits
Inputs:
Sensory signals from sense organs, muscles, and internal organs.
Complex processing in the forebrain.
Outputs:
Regulation of hormonal systems via the hypothalamus.
Activation of brainstem reticular formation.
Activation of somatic and autonomic motor systems.
Page 6: Expression of Emotional Experience
Volitional Movement:
Pyramidal Projections: From limbic and motor cortex, fine control of movements.
Emotional Expression:
Extrapyramidal Projections: Nonvolitional movements related to emotions.
Involvement of brainstem reticular formation and motor neuron pools.
Page 7: Emotional Expression
Somatic Motor Processes:
Volitional: Controlled by pyramidal pathways from motor cortex to brainstem/spinal cord.
Nonvolitional: Controlled by extrapyramidal pathways from cingulate cortex via reticular formation.
Page 8: The Limbic System
Key Structures:
Amygdala
Nucleus accumbens (ventral striatum)
Hypothalamus
Limbic cortex (cingulate gyrus, orbitofrontal cortex, prefrontal cortex)
Hippocampus
Current Understanding: Shift from integrated emotional systems to functions of specific brain regions.
Page 9: The Amygdala
Emotional Significance: Crucial for interpreting emotional context through converging sensory inputs.
Emotional Behavior Expression: Outputs to hypothalamus and brainstem regulating emotional behaviors.
Emotional Learning: Involvement in complex behaviors and reciprocal connections with limbic cortex, and other structures.
Page 10: Evidence for Role of Amygdala in Emotional/Fear
S.M. Case Study:
Extensive amygdala damage resulted in lack of fear and inability to recognize fear in others.
Difficulty interpreting negative facial expressions.
Page 11: Emotional Experience and Decision Making
Influence of Emotion on Behavior: Emotional context greatly affects social interactions and decision-making processes.
Impact of Damage: Certain brain region damages can impair risk/benefit evaluation, affecting decision-making abilities such as those observed in affective disorders (depression, bipolar disorder, PTSD).
Page 12: Lateralization of Emotionality
Language Prosody:
Right hemisphere responsible for expression and comprehension of emotional aspects of speech.
Mood Asymmetry:
Left hemisphere linked to positive emotions; right hemisphere to negative emotions.
Dysfunction in the left hemisphere associated with depression.
Page 13: Internal Drives and Motivated Behaviors
Necessary for Survival:
Hunger, thirst, thermoregulation, etc.
Non-survival Drives:
Mating, exploration, social affiliation, aggression, pleasure-seeking.
Page 14: Motivated Behaviors
Consummatory Behaviors:
Directly address needs (eating, drinking).
Appetitive Behaviors:
Indirectly achieve goals; involve seeking and proceptive behaviors.
Page 15: Neural Mechanisms of Motivation (Slide 1 of 2)
Brainstem and Spinal Cord: Execution of consummatory actions.
Hypothalamus:
Integration of internal drives and sensory inputs.
Outputs influence autonomic functions in the brainstem.
Page 16: Neural Mechanisms of Motivation (Slide 2 of 2)
Dopaminergic Pathways:
Nigrostriatal system: Activation of behaviors triggered by endogenous stimuli.
Mesolimbic system: Activation in response to learned incentives; changes in dopamine levels affect reward anticipation.
Page 17: Basal Ganglia Limbic Loop
Nucleus Accumbens: Critical for reward motivation.
Inputs from limbic system, prefrontal cortex, and other brain structures.
Outputs to various brain areas associated with rewards and locomotion.
Dysfunction: Linked to addiction, affective disorders, and other psychological conditions.
Page 18: Reward and Reinforcement
Pleasure Centers: Identification through intracranial self-stimulation; involve areas like locus coeruleus and VTA.
Page 19: Ventral Striatal Circuits in Reward
Reward stimuli elevate dopamine release in the nucleus accumbens, enhancing VTA neuron activity.
Page 20: Changes in Ventral Striatal Circuits in Addiction
Addiction alters baseline dopamine and glutamate release, leading to compensatory receptor changes and tolerance development.
Page 21: Role of the Hypothalamus in Emotional Behavior Integration
Regulates physiological states, neuroendocrine functions, and motivated behaviors.
Page 22: The HPA Axis
Hormonal Cascade: Involved in stress response and energy homeostasis; involves multiple hormonal interactions across various organs.
Page 23: Actions of Glucocorticoids
Physiological Effects: Enhance cardiovascular tone, regulate energy storage, and interact with other endocrine systems.
Page 24: End of Lesson 21
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SYSTEMS NEUROBIOLOGY FALL 2024 Lesson 22 Learning and Memory
Page 26: Objectives for Lesson 22
Distinguish between declarative, procedural, and emotional memory.
Identify key structures and circuits in mediating different types of memory.
Page 27: Functional Categories of Memory
Memory Types:
Working Memory
Long-term Memory (Declarative and Nondeclarative)
Declarative: Episodic (events) and Semantic (facts)
Nondeclarative: Priming, Skill Learning, Conditioning
Page 28: Functional Categories of Memory
Conscious Accessibility:
Declarative memory is expressible in language; nondeclarative memory is not available in detail.
Page 29: Working Memory vs. Long-term Memory
Working Memory:
Immediate recall, compromised by damage to the prefrontal cortex.
Long-term Memory:
Hours to years, includes qualitative distinctions and relies on specific brain regions.
Page 30: Modulation of Memory
Influencing Factors:
Priming effects, significance and associations, motivational states, and practice through repetition.
Page 31: Conditioned Learning
Conditioning: Process of eliciting responses to stimuli through repeated pairing (classical and operant conditioning).
Page 32: Forgetting
Normal Forgetting: Influenced by factors like time and significance; issues can arise as amnesia.
Page 33: Declarative Memory
Components: Involves encoding, storage, and retrieval of facts/events, particularly linked to the hippocampus and associated areas.
Page 34: Storage of Declarative Memory
Neocortex and Hippocampus: Projecting connections crucial for memory output and integration with cortical areas.
Page 35: Effects of Lesions on Declarative Memory
Lesions: Impact memory retention; specific cases (H.M., N.A., R.B.) demonstrate varying deficits linked to damaged structures.
Page 36: Effects of Lesions on Declarative Memory
Spatial Learning: Rodent models show that hippocampal damage impairs the ability to generalize from learned associations.
Page 37: Declarative vs. Nondeclarative Memory
Acquisition and Storage Differences: Variation across memory types regarding sites of long-term storage.
Page 38: Procedural Memory
Skill Acquisition: Involves the neostriatum and cerebellum, focusing on habits, skills, and adjustments in motor behaviors.
Page 39: Emotional Memory
Key Aspects: Influenced by emotionally charged stimuli, independent of declarative memory; facilitated by the amygdala.
Page 40: Emotional Memory Circuits
Anatomy: Involves pathways from sensory input to various regions, controlling neuroendocrine and autonomic responses.
Page 41: Emotional Memory
Conditioned Fear: Requires specific pathways highlighting the importance of amygdala function over mere auditory cues.