Psych Exam 3

Chapter 24: Memory — Concepts and Explanations

How do we know there are different types of memories?

• Different types of memories exist because brain lesions affect different memory types differently. Some brain injuries impair one type (e.g., declarative memory) but not others (e.g., procedural memory), showing separate systems​.
  
  

Examples of Memory Types:

• Declarative Memory: Facts/events. Example: Knowing Bangkok is the capital of Thailand​.
  
  

• Procedural Memory: Skills/habits. Example: Learning how to ride a bike​.
  
  

• Associations: Classical conditioning. Example: Salivating at the sound of a bell because it was paired with food​.
  
  

• Emotional Responses: Stored in the amygdala. Example: Fear response to a previously neutral sound​.
  
  

Basic Differences: Declarative vs. Non-Declarative Memories

• Declarative (explicit): Conscious recall (facts, events).
  
  

• Non-Declarative (implicit): Unconscious skills (motor responses, emotional reactions)​.
  
  

Differences: Working, Short-Term, and Long-Term Memory

• Short-Term Memory: Lasts hours, vulnerable to disruption.
  
  

• Working Memory: Lasts seconds, requires active rehearsal, very limited capacity.
  
  

• Long-Term Memory: Stable over time, formed via consolidation​​.
  
  

How do we know these are different types?

• Observations of patients: some lose short-term memory but keep long-term memory or vice versa, indicating distinct systems​.
  
  

What is Consolidation?

• The process of converting short-term memories into stable long-term memories​.
  
  

Where is sensory information stored for short-term memories?

• Likely in various cortical areas, depending on the sensory modality (visual cortex for sight, auditory cortex for sound)​.
  
  

Retrograde vs. Anterograde Amnesia

• Retrograde Amnesia: Loss of memories before trauma.
  
  

• Anterograde Amnesia: Inability to form new memories after trauma​.
  
  

Evidence that memory storage changes over time

• Retrograde amnesia shows a graded loss: more recent memories are more vulnerable, suggesting memories "move" or become more stable over time​.
  
  

Hebb’s Model of Short-Term Memory

• Hebb proposed that memories are stored as the activation of groups of interconnected neurons called cell assemblies​.
  
  

Neurons and Memory of Stimuli

• Perception neurons activate memory neurons through simultaneous activity, strengthening their connections​.
  
  

What is a Cell Assembly?

• A network of neurons that, once activated together, can reactivate each other, maintaining short-term memory​.
  
  

Hebb’s Description of Consolidation

• Consolidation occurs when repeated activation of a cell assembly leads to long-lasting changes (stronger connections)​.
  
  

If Memory Is Based on One Sensory Modality

• It would be stored in the corresponding sensory cortex (e.g., visual information in visual cortex)​.
  
  

Experiment with Monkeys (Visual Information)

• Delayed non-match to sample task: Monkeys with medial temporal lobe damage could not remember previously seen objects, showing visual memory depends on higher-order visual cortex areas like the inferotemporal cortex​.
  
  

Inferotemporal Cortex: Location and Function

• Location: Temporal lobe.
  
  

• Function: Visual object recognition and long-term visual memory​.
  
  

Experiment Figure 24.6

• Single neuron recording: Neurons in inferotemporal cortex fire selectively to particular faces, suggesting visual memories are encoded there​.
  
  

Temporal Lobe Stimulation (Humans)

• Stimulating the temporal lobe sometimes evokes vivid memories, but not reliably, suggesting partial involvement but not straightforward memory storage​.
  
  

H.M.’s Brain and Symptoms

• Removed: Medial temporal lobes, including hippocampus.
  
  

• Symptoms: Severe anterograde amnesia (could not form new declarative memories), intact procedural memory​.
  
  

Brain Regions and Memory Types

Connections: Medial Temporal Lobe, Hippocampus, Diencephalon

• Sensory input → Perirhinal & Entorhinal cortex → Hippocampus → Fornix → Mammillary bodies → Thalamus​.
  
  

Delayed-Non-Match to Sample Task (DNMS)

• Task showed monkeys with medial temporal lobe damage could not perform, supporting its role in memory​.
  
  

Which Medial Temporal Lobe Area Is Most Important?

• Hippocampus appears critical​.
  
  

N.A.’s Brain Damage and Symptoms

• Damaged: Dorsomedial thalamus.
  
  

• Symptoms: Severe anterograde amnesia, some retrograde amnesia​.
  
  

Korsakoff’s Syndrome

• Damage: Mammillary bodies, thalamus.
  
  

• Development: Chronic alcoholism → Thiamine deficiency.
  
  

• Symptoms: Severe anterograde and some retrograde amnesia​.
  
  

Hippocampus and 3 Memory Functions

1. Declarative Memory (facts/events).
   
   

2. Spatial Memory.
   
   

3. Relational Memory (relationships between different types of information)​.
   
   

Hippocampal Lesions in Rats

• Radial Arm Maze: Rats forget which arms they already visited (spatial memory loss).
  
  

• Morris Water Maze: Rats struggle to find hidden platform (impaired spatial learning)​.
  
  

Place Cells

• Neurons in the hippocampus that fire when an animal is in a specific location​.
  
  

Human Hippocampus and Memory

• Damage leads to deficits in episodic memory, supported by H.M.’s case​.
  
  

Relational Memory Hypothesis

• Hippocampus stores relationships among items (rather than items individually), important for episodic memories​.
  
  

Striatum and Procedural Memory Studies

• Rats: Striatal lesions impaired habit learning.
  
  

• Humans: Patients with Parkinson’s (striatal damage) showed impaired habit formation​.
  
  

Prefrontal Cortex and Working Memory Studies

• Monkeys: Prefrontal lesions impaired delayed-response tasks​.
  
  

• Humans: Damage caused problems in planning and task-switching (Wisconsin card-sorting test)​.
  
  

Class Notes 

Overview

• Memory is a complex neurological process involving multiple brain systems

• Memories range from factual knowledge to ingrained motor patterns

• Learning and memory are lifelong adaptations of brain circuitry

Types of Memory

1. Declarative Memory (Explicit)

• Conscious recollection

• Easily formed and forgotten

• Includes:

• Facts

• Events

• Short-term memories

• Long-term memories

2. Non-Declarative Memory (Implicit)

• Non-conscious knowledge

• Long-term experience

• Less prone to forgetting

• Includes:

• Procedural memory

• Skills

• Habits

• Behaviors

• Associations

• Emotional responses

Memory Processes

Memory Consolidation

• Process of converting short-term to long-term memories

• Involves multiple brain regions

• Stages:

1. Sensory information intake

2. Short-term memory storage

3. Consolidation

4. Long-term memory storage

Memory Storage Regions

• Hippocampus:

• Declarative memory processing

• Spatial memory

• Recognition memory

• Relational memory

• Striatum:

• Procedural memory

• Habit learning

• Includes caudate nucleus and putamen

• Prefrontal Cortex:

• Working memory

• Problem-solving

• Planning behaviors

Amnesia Types

1. Retrograde Amnesia

• Forgetting previously known information

2. Anterograde Amnesia

• Inability to form new memories

3. Transient Global Amnesia

• Short-term memory loss

• Disorientation

• Repeated questioning

Key Concepts

Neural Basis of Memory

• Engram: Physical representation of memory

• Stored in:

• Neurons

• Neural circuits

• Firing patterns

• Synaptic connections

Hebb's Memory Model

• "Neurons that fire together, wire together"

• Memory distributed across linked cells

• Can involve neurons from sensation and perception

Research Insights

Experimental Evidence

• Studies on:

• Macaque monkeys

• Rat maze learning

• Temporal lobe patients (e.g., H.M.)

Brain Regions and Memory

• Different cortical areas contribute differently to learning

• Memories are distributed across multiple regions

Practical Implications

• Memory is adaptive

• Involves complex interactions between brain systems

• Can be affected by:

• Disease

• Trauma

• Neurological conditions

Conclusion

Memory is a dynamic, multi-system process crucial for learning, adaptation, and survival.

Chapter 22: Mental Illness — Concepts and Explanations

Freud and Skinner: Causes and Treatments of Mental Illness

• Freud believed mental illness came from unconscious conflicts shaped by childhood experiences. His psychoanalysis method aimed to uncover hidden memories and resolve conflict​.
  
  

• Skinner rejected unconscious conflict ideas. He believed mental illness is learned maladaptive behavior. Treatment was behavior modification: replacing bad behaviors with positive ones​.
  
  

Biological Breakthrough: General Paresis and Arsphenamine

• General paresis (severe mental illness) was found to be caused by brain infection with syphilis bacteria (Treponema pallidum).
  
  

• Arsphenamine (developed by Ehrlich) treated syphilis, showing that biological causes can underlie mental illness​.
  
  

Anxiety Disorders

Normal Fear Response vs. Anxiety Disorder

• Normal fear: Protective, appropriate reaction to real danger.
  
  

• Anxiety disorder: Inappropriate or exaggerated fear response when there is no immediate threat​.
  
  

Panic Disorder

• Symptoms: Sudden intense terror, palpitations, shortness of breath, dizziness, fear of death or insanity​.
  
  

Obsessive-Compulsive Disorder (OCD)

• Obsessions: Intrusive, inappropriate thoughts (e.g., germs, harm, violence).
  
  

• Compulsions: Ritualistic behaviors to reduce anxiety (e.g., hand washing, checking things)​.
  
  

Hypothalamic-Pituitary-Adrenal (HPA) Axis

• 
  Function: Orchestrates stress response: prepares the body for "fight or flight"​.
  
  

Amygdala and Hippocampus: Roles

• Amygdala: Activates the HPA axis (initiates stress response).
  
  

• Hippocampus: Inhibits the HPA axis, providing feedback to shut off stress once the threat is gone​.
  
  

How Chronic Stress Affects the Hippocampus

• Chronic cortisol exposure leads to hippocampal atrophy, which weakens its ability to regulate the HPA axis, worsening stress and anxiety​.
  
  

Treatments for Anxiety Disorders

• 
  CRH Receptor Antagonists (new class): Block CRH receptors, potentially lowering stress response​.
  
  

Affective Disorders (Depression and Bipolar)

Types:

• Major Depression: Long periods of profound sadness, anhedonia.
  
  

• Dysthymia: Chronic, low-grade depression.
  
  

• Bipolar Disorder: Alternating periods of depression and mania​.
  
  

Monoamine Hypothesis

• Depression results from deficiency of monoamine neurotransmitters (serotonin and norepinephrine)​.
  
  

Monoamine Neurotransmitters:

• Serotonin
  
  

• Norepinephrine
  
  

Antidepressant Drugs

• 
  All increase monoamine levels in synapse, but relief of depression symptoms takes weeks, suggesting secondary brain changes are needed​.
  
  

Long-Term Effects of Antidepressants

• Promote hippocampal neurogenesis (new neuron formation) and increase glucocorticoid receptor expression, which helps regulate stress​.
  
  

Diathesis-Stress Hypothesis

• Depression arises from the interaction between genetic vulnerability (diathesis) and early life stressors that dysregulate the HPA axis​.
  
  

Study on Early Sensory Experience and Stress Response

• Rats with more maternal care had more hippocampal glucocorticoid receptors, better HPA feedback, and lower anxiety​.
  
  

Lithium and Bipolar Disorder

• Lithium stabilizes mood, likely by affecting second messenger systems like inositol signaling pathways​.
  
  

Schizophrenia

Genetic and Environmental Evidence

• Runs in families (genetic link), but early prenatal environmental factors also contribute​.
  
  

Brain Changes

• Enlarged ventricles, reduced cortex thickness, fewer interneurons​.
  
  

Neurotransmitter Systems

• Dopamine Hypothesis: Excess dopamine activity leads to schizophrenia​.
  
  

• Glutamate Hypothesis: NMDA receptor hypofunction causes symptoms​.
  
  

Schizophrenia Symptoms Categories

Treatments for Schizophrenia

• Conventional antipsychotics: Block D2 dopamine receptors (reduce positive symptoms).
  
  

• Atypical antipsychotics: Act on multiple receptors (dopamine and serotonin) with fewer motor side effects.
  
  

• Future therapies: Focus on enhancing NMDA receptor function​.
  
  

Class Notes

Main Takeaway

This chapter explores the scientific understanding of mental illness, highlighting how neuroscience has transformed our perception of mental health from supernatural explanations to a complex interplay of biological, genetic, and environmental factors.

Introduction to Mental Health Disciplines

Neurology

• Branch of medicine concerned with diagnosing and treating nervous system disorders

• Helps illustrate physiological processes in brain function

Psychiatry

• Branch of medicine focused on diagnosing and treating disorders affecting the mind

• Examples of disorders: Anxiety disorders, affective disorders

Defining Mental Illness

• Definition: A diagnosable disorder of thought, mood, or behavior causing distress or impaired functioning

• Historically viewed as separate from bodily disorders

• Modern understanding recognizes complex interactions between biology and environment

Approaches to Understanding Mental Illness

Traditional Approaches

• Supernatural explanations

• Treatments involving spirit possession and rituals

Modern Psychosocial Approaches

• Secularized understanding

• Based on individual experiences

• Treatment relies on psychotherapy

Key Theoretical Perspectives

Sigmund Freud

• Emphasized the unconscious

• Key points:

1. Much of mental life is unconscious

2. Experience shapes unconscious and conscious life

3. Mental illness results from conflicts between unconscious and conscious elements

4. Psychoanalysis aims to uncover unconscious elements

B.F. Skinner

• Behavioral approach

• Behaviors (including maladaptive ones) are learned responses to environment

• Treatment focuses on behavior modification

Major Psychiatric Disorders

1. Anxiety Disorders

• Characteristics:

• Inappropriate expression of fear

• Approximately 15% of Americans experience annually

• Types:

• Panic disorder

• Agoraphobia

• Generalized anxiety disorder

• Specific phobias

• Social phobia

• Post-traumatic stress disorder (PTSD)

• Obsessive-compulsive disorder (OCD)

2. Affective Disorders

• Major Depression

• Diagnosis requires symptoms for > 2 weeks

• Symptoms include decreased interest, lowered mood, changes in appetite/sleep

• Bipolar Disorder

• Repeated episodes of mania and/or depression

• Types include Type I, Type II, and Cyclothymia

3. Schizophrenia

• Symptoms:

• Positive symptoms: Delusions, hallucinations

• Negative symptoms: Reduced emotional expression, speech difficulties

• Types:

• Paranoid schizophrenia

• Disorganized schizophrenia

• Catatonic schizophrenia

Biological Foundations

Genetic and Environmental Interactions

• Mental illnesses result from complex interactions between:

1. Genetic predispositions

2. Environmental factors

• Stress response regulated by hypothalamic-pituitary-adrenal (HPA) axis

Treatment Approaches

Anxiety Disorders

• Psychotherapy

• Medications:

• Benzodiazepines

• Serotonin-selective reuptake inhibitors (SSRIs)

• CRH receptor targeting drugs

Affective Disorders

• Electroconvulsive Therapy (ECT)

• Psychotherapy

• Antidepressants

• Deep Brain Stimulation

• Transcranial Magnetic Stimulation

• Psychedelics (in clinical settings)

Schizophrenia

• Drug therapy

• Psychosocial support

• Neuroleptic medications

• NMDA receptor drugs

Conclusion

Modern understanding of mental illness emphasizes:

1. Neuroscience's impact on psychiatry

2. Recognition of physical bases for mental illness

3. Complex interactions between genes and environment