Feb 20 Memory 3

• Memories

  Not reflections of the truth; subject to distortion
• Memories are About the Future

  1. Mental simulations of novel events

  2. Memories are useful to solve a problem, plan for the future, be creative
• Semantic Memory Organization

  • Spreading Activation in the Semantic Network
  • Semantic Priming
  • Dissociations in Long Term Memory: Amnesia Due to Brain Injury
• Forming & Breaking Habits

  1. Habit Formations

  2. Breaking Habits
• Virtues of Reconstructed Memory


  • The same processes that help us construct the past help us imagine the future and plan for our lives
• Habits: When Deliberate Actions Become Routine

  • Initially rely on explicit memory; with training and exposure then rely on implicit memory
  • Basis of some addictions
• Semantic Priming


  Exposure to one word or concept facilitates the recognition or response to a related word or concept due to their close association in the semantic memory network
• Memory

  Driven by what is expected
• Implicit Emotional Responses


  • Automatic, unconscious emotional reactions to certain stimuli without conscious awareness
  • Conditioned emotional responses
• Episodic Memories

  1. Impacted by prior knowledge

  2. Reconstructed at retrieval
• Spreading Activation


  Activating one concept triggers the activation of related concepts, facilitating information retrieval
• Implicit Memory: Priming


  • Prior exposure facilitates information processing without awareness
• Distortions can be false memories, but reflect an adaptive characteristic
• Implicit Memory: Procedural Memory


  • Skills and habits acquired that can be performed without conscious thought/active recall
  • More immune to forgetting compared to other types of memory
• Patient HM played a pivotal role in understanding the hippocampus's function in episodic memory
• Network

  Related ideas triggered at retrieval
• Patient HM & the Role of the Hippocampus in Episodic Memory

  • Intact Short-Term Memory: can remember a short list of words for 30 seconds
  • Intact Procedural Memory: could learn new skill-based tasks
  • Intact Semantic Memory: could recall major historic events of childhood
  • Profound Episodic Memory Loss: he couldn’t learn new information and recalled his past in sparse detail
• Clive Wearing suffered from profound anterograde and retrograde amnesia following a herpes simplex virus encephalitis that damaged his hippocampus and surrounding areas
• Dreams are linked to memory
• Medial temporal lobe (MTL) regions are the first to be affected by Alzheimer's disease pathology
• Dissociations in Long Term Memory: Amnesia Due to Brain Injury

  1. Experimental neurosurgery to reduce seizure activity

  2. Bilateral medial temporal lobe, including the hippocampus, removed

  3. Selective episodic memory loss
• Dementia: Progressive cognitive and functional impairments due to neuronal death
• Earliest symptom of Alzheimer's disease is a deficit in episodic memory
• Patient HM was stuck in the present
• Patient HM had profound anterograde amnesia for episodic (autobiographical) events, while retaining other cognitive functions
• Retrograde Amnesia: the loss of memories from before the onset of amnesia
• Anterograde Amnesia: is the inability to form new episodic memories
• Patient HM underwent a bilateral medial temporal lobe resection including the hippocampus to alleviate severe epilepsy
• Patient HM demonstrated the crucial role of the hippocampus in the formation of new episodic memories; distinguishing it from other types of memory
• Dissociative Amnesia: characterized by temporary memory loss that is too extensive to be explained by ordinary forgetfulness, typically involving an inability to recall personal information, usually after a traumatic or stressful event
• Dementia cases

  • 63% are Alzheimer's disease
• Semantic Dementia: progressive neurodegenerative disorder characterized by the gradual erosion of semantic memory
• Domain-General Cognitive Aging Theories

  • Older adults have deficits in general executive cognitive processes from frontal lobe atrophy
  • Older adults will have trouble focusing on one picture and ignore all other pictures on a busy wall
• It is ok to forget some things
• Alzheimer's disease


  • progressive neurological disorder that leads to the deterioration of cognitive functions, primarily affecting memory, thinking, and behavior
  • Medial temporal lobe (MTL) regions are the first to be affected by AD pathology
  • Earliest symptom is a deficit in episodic memory
• Cases of Extreme Memory: Taxi Drivers


  • Memory and space are intimately linked
  • 'The knowledge': memorize a labyrinth of 25,000 streets within a 10-kilometer radius
  • Taxi drivers performed better on tests of spatial memory than bus drivers
  • Taxi drivers have greater posterior hippocampus gray matter volumes
  • The volume of the posterior hippocampus in taxi drivers is related to years of experience as a taxi driver
• The Associative Deficit Hypothesis

  • Decline in memory observed with aging is primarily due to difficulties in forming and retrieving connections between pieces of information
  • Older adults have problems encoding and retrieving associations in memory due to hippocampal atrophy
• Semantic Dementia


  • Progressive neurodegenerative disorder characterized by the gradual erosion of semantic memory
  • Neurodegeneration begins in the left anterior temporal lobe
  • Deficits recognizing faces of friends, words, and uses of objects
• Goldilocks Principle: memory works well with just the right amount of it – not too little and not too much
• Highly Superior Autobiographical Memory


  • HSAM people can remember every single day from their lives in detail
  • Recalling very detailed daily memories
  • HSAM does not involve mnemonic strategies
  • HSAM is specific to autobiographical memory (personal memories)