Chapter 12

CHAPTER 12: LEARNING AND MEMORY

LEARNING AS THE STORAGE OF MEMORIES

  • Unlearned Behaviors:
    • Some behaviors innate to humans from birth (e.g., reflexes).
    • These innate behaviors may serve survival purposes.
  • Definition of Learning:
    • Defined as a change in mind or behavior due to experience.
    • Described as a form of neural plasticity which alters behavior by remodeling neural connections.
    • Reference: "a form of neural plasticity that changes behavior [or mind] by remodeling neural connections" (p. 399).
  • Definition of Memory:
    • Memory is the result of learning, functioning as the storage of information in the brain.
  • Examples of Memory Recall:
    • Examples include personal experiences such as learning to ride a bike or swim.
    • Questions posed for recall:
    • What is your earliest memory?
    • What did you have for breakfast this morning or last Wednesday?

MEMORY DURATION AND TYPES

  • Memory Duration:
    • Memory can last from a few seconds to a lifetime.
  • Models of Memory:
    • Emphasis on long-term memory (LTM) and working memory.
  • Long-term Memory (LTM):
    • Defined as the storage of memory for longer than 60 seconds.
    • Types of LTM:
    • Declarative (Explicit) Memory:
      • Information that can be consciously recalled (e.g., facts, events).
      • Episodic Memory:
      • Relates to personally experienced events (e.g., your 16th birthday).
      • Semantic Memory:
      • General knowledge/concepts (e.g., the identity of the first president).
    • Non-declarative (Implicit) Memory:
      • Behaviors or responses that cannot be consciously recalled.
      • Procedural Memory:
      • Skills and actions (e.g., riding a bike, shooting a basketball).
      • Emotional Memory:
      • Conditioned responses tied to emotions (e.g., feeling fear at the sight of a specific animal).

WORKING MEMORY (WM)

  • Definition of Working Memory:
    • WM is described as the temporary storage of information for conscious processing.
  • Duration of Information:
    • Can hold information for up to 60 seconds.
  • Functions of WM:
    • Actively used to manipulate information from current experiences or existing memories.
    • Functions as a "mental workspace" for conscious thought and processing to retrieve LTM.
  • Example Uses of Working Memory:
    • Remembering a password, engaging in conversation, solving division problems.
  • Capacity of WM:
    • Limited capacity; adults can typically hold around 7±2 items in memory.
  • Control of WM:
    • Primarily controlled by the prefrontal cortex (PFC), which acts as the "central executive":
    • Controls attention and integrates information from various brain areas, enabling functions such as thinking, planning, and decision-making.
    • Relevant Tests:
    • Letter Test and a multitasking test often used to assess WM.

PRACTICE EXAMPLES FOR LTM

  • Categorization by Type of LTM:
    • Teaching friends how to cartwheel - Procedural Memory.
    • Feeling anxious walking barefoot after stepping on a bee - Emotional Memory.
    • Remembering first hearing about Covid-19 - Episodic Memory.
    • Better brushing teeth with one hand vs another - Procedural Memory.
    • Recalling a favorite dessert recipe - Declarative Memory (Semantic).
    • Knowing a red shirt exists in the closet - Semantic Memory.

AMNESIA AND MEMORY LOSS

  • Definition of Amnesia:
    • Loss of long-term memory (LTM) due to disease or trauma, primarily affects declarative memory.
  • Types of Amnesia:
    • Anterograde Amnesia:
    • Inability to store new information following an injury.
    • Retrograde Amnesia:
    • Inability to retrieve past information prior to the injury.
  • Cultural Reference:
    • Film example: "Memento" (2000) depicts anterograde amnesia.
  • Case Study: Patient H.M.
    • Notable case demonstrating the effects and types of amnesia.
  • Severity and Impact:
    • Severity of amnesia is linked to the amount and location of brain damage, particularly in the temporal cortex.
    • Focus on damage to hippocampal formation and amygdala.

HIPPOCAMPAL FORMATION AND AMYGDALA

  • Role of Hippocampal Formation (HF):

    • Comprises the hippocampus and adjacent structures, including portions of the temporal cortex.
    • More damage to HF leads to worse amnesia.
    • Specific damage types dictate memory loss characteristics.
    • Example: Damage to area CA1 within the hippocampus is linked with anterograde amnesia.

  • Role of Amygdala:

    • Critical for emotional processing of memories.
    • Activity of the amygdala increases hippocampal activity when emotions (positive/negative) or stress are involved.
    • Enhances learning retention and memory impact through emotional conditioning.
    • Example: Fear associated with visiting the dentist can persist even if the original event is forgotten.
    • Cultural Reference: Discusses PTSD related to veterans (e.g., "American Sniper").

MEMORY CONSOLIDATION AND RETRIEVAL

  • Definition of Consolidation:
    • The process by which the brain forms a physical representation of an experience.
    • Experiences remain fragile until fully consolidated.
  • Definition of Retrieval:
    • The process of accessing stored memories.
  • Importance of Hippocampal Formation in Memory Processes:
    • Consolidation and retrieval of declarative memories significantly involve the HF.
  • Experimental Evidence:
    • Example: When the HF is inhibited, rats fail to consolidate escape route information during maze tasks.
    • Neuronal activation in HF observed during both consolidation and retrieval of words.

MEMORY AGING AND CORTICAL REPLACEMENT

  • Temporary Role of HF:
    • Functionality tends to diminish over time, particularly impacting recent memories.
  • Memory Aging:
    • Older memories may transition to other cortical areas:
    • Prefrontal Cortex: Broca’s area (language production).
    • Temporal Cortex: Wernicke’s area (language comprehension), fusiform face area (face recognition).
    • Parietal Cortex: Processes location memories.

BRAIN CHANGES DURING LEARNING

  • Memory Consolidation Preferences:
    • Consolidation appears to occur primarily when the HF is not engaged in immediate learning, often during sleep.
  • Activation Patterns:
    • Similar patterns of activation in HF and cortex noted during sleep correlate with improved memory performance.
  • Studying Tips for Students:
    • Understanding when consolidation occurs can help enhance study strategies.

HEBB'S RULE AND LONG-TERM POTENTIATION (LTP)

  • Hebb Rule:
    • Neurons that fire together wire together; simultaneous activity strengthens synapses.
  • Definition of Long-term Potentiation (LTP):
    • Persistent strengthening of synapses resulting from the simultaneous activation of both presynaptic and postsynaptic neurons.
    • Leads to new dendritic spines or enlargement of existing synapses, increasing synaptic sensitivity.
    • Crucial for forming new memories and associations.

LEARNING DEFICIENCIES AND DISORDERS

  • Brain Dysfunction:
    • Cognitive and behavioral deficits arise from developmental issues, injury, or disease.
  • Definition of Dementia:
    • A collection of diseases reflecting cognitive and behavioral impairments due to brain deterioration, which impact daily activities.

ALZHEIMER’S DISEASE

  • Overview of Alzheimer’s Disease:

    • A degenerative impairment of memory and cognitive function; impacts approximately 5 million individuals in the U.S., with a significant proportion over 65 years old.

  • Typical Progression:

    • Early stages typically affect declarative memory; symptoms include forgetfulness with names and misplacing items.
    • Progresses to working memory challenges, affecting decision-making and reasoning abilities.
    • Changes in personality such as increased aggressiveness may occur.

  • Neuropathological Changes in Alzheimer's:

    • Excessive proteins disrupt neuron functioning, leading to synapse loss, interruption of LTP, and neuron death.
    • Key markers include amyloid beta plaques present outside neurons and tau neurofibrillary tangles found within.
    • Particularly damaging to the temporal cortex and frontal cortex and their interconnections.
    • Linked to genetic factors influencing protein formation and inflammation.

  • Considerations for Alzheimer’s:

    • Risk factors for developing Alzheimer’s disease and the potential fatal progression of the condition.