Models of Memory Introduction to Cognitive Science Lecture 7: Memory/Sleep September 29, 2009

Lecture Overview The Modal Model (Atkinson & Shiffrin) ACT* Model (Anderson) Working Memory Model (Baddeley) Change Blindness The Hippocampus Sleep & Memory

MODELS OF MEMORY

RETRIEVAL Short-term Memory Long-term Memory Sensory Memory STIMULUS INPUT The Modal Model (Atkinson & Shiffrin) Figure 5.3, p 134 in text RESPONSE OUTPUT ENCODING e.g. Visual (iconic) Auditory (echoic), etc. Some Control Processes: Rehearsal, Coding, Decisions, Retrieval Strategies

ACT* Model: Adaptive Control of Thought (Anderson) Working Memory Declarative Memory Production Memory External Environment EncodingPerformance StorageMatch ExecutionRetrieval Figure 5.4, p 136 in text

The Working Memory Model (Baddeley) Visuo-spatial Sketchpad Processing of Visual Information Executive Control System Supervises and controls processes Articulatory Loop Rehearsal and processing of auditory information Figure 5.5, p 138 in text

Occurs when major changes to a visual scene go unnoticed by the observer. TESTING THE CAPACITY OF VISUAL WORKING MEMORY: CHANGE BLINDNESS

Pay Attention….

Change Blindness Differences between the two images can be detected only if we attend to one of the changing objects. This experiment demonstrates that we memorize only very little information from visual scenes. We typically use visual scenes as our “external memory” rather than filling our working memory with a large amount of scene information.

The Hippocampus Long-Term Memory Learning Navigation

THE HIPPOCAMPUS = Dentate Gyrus, CA1-CA3, & Subiculum Marjor input from Entorhinal Cortex which is  other brain areas such as the Prefrontal Cortex Information Flow: Entorhinal Cortex  Dentate Gyrus  CA3  CA1  Subiculum

Neurogenesis: birth of new neurons Highly active throughout development Also adult hippocampal neurogenesis (dentate gyrus)! What might this mean for learning and memory?

Hippocampal Damage Retrograde Amnesia: loss of memories before damage to the hippocampus Anterograde Amnesia: inability to form new memories Some causes: aging, Alzheimer’s disease, stress, temporal lobe epilepsy

Patient H.M CCD2AA287/0/chp_9_10_hip_enc.jpg&imgrefurl= 2004/CourseHome/index.htm&usg=__baapQ1i44dpgT7ZDQuuBuOVnwnw=&h=307&w=350&sz=26&hl=en&start=2&um=1&tbnid=n5pajUYXebb7tM:&tbnh=105&tbnw=120&prev=/images%3Fq%3Dcoronal%2Bhippocampal%2Bhuman%26hl%3Den%26client%3Dfirefox- a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG%26um%3D1 Anterograde Amnesia: Intact working and procedural memory Could not commit to long-term SOME Retrograde Amnesia: Couldn’t remember 3–4 -day prior to surgery, + some events up > 11 years prior Able to commit new motor skills to long-term memory without actually remembering learning them After Surgery for Temporal Lobe Epilepsy

Sleep & Memory Consolidation Born & Marshall The contribution of sleep to hippocampus-dependent memory consolidation MP Walker Stickgold

Matthew P. Walker* and Robert Stickgold* Sleep-Dependent Learning and Memory Consolidation Neuron, Vol. 44, 121–133, Sept 30, 2004 Relaxed Wakefulness NREM Stage 1 NREM Stage 2 NREM Stage 3, 4/Slow Wave Sleep Delta Waves REM Sleep Can Be Divided Into: NREM (Stages 1-4) REM Different stages are identified using EEG SLEEP: Overview NREM & REM cycle about every 90 minutes Early in the night: NREM 3 & 4 dominate Later in the night: Stage 2 and REM dominate

Neurobiology of Sleep Regulation Many subcortical regions are involved: Thalamus Hypothalamus Pons Dreaming also involves: Cortical: Prefrontal and Posterior (vision) Subcortical: limbic (emotion) Some key neurotransmitters: Serotonin (5-HT) Noradrenaline (NA) Acetylcholine (Ach) 3, (September 2002) Hobson & Pace-Schott

Influence of sleep on a motor skill task (A-C) and a visual skill task (D-F) (A)Motor performance increase after sleep (B) Such performance increase is not strengthened during subsequent wake phase (C) Performance improve is strongly correlated with amount of stage 2 NREM sleep. (D) Increased level of visual performance after one night of sleep. (E) Performance iprovement with regular sleep periods (red) and no improvement after sleep deprivation during first night after training (green). (F) Improvement is correlated with amount of slow-wave sleep and REM sleep.

Replay of hippocampal firing during sleep Rodent Running path Hippocampal cells and location-specific firing during running Timecourse of firing patterns of 10 cells (rows) during running Timecourse of firing patterns of 10 cells (rows) during REM Louie & Wilson. Temporally Structured Replay of Awake Hippocampal Ensemble Activity during Rapid Eye Movement Sleep. Volume 29, Issue 1, January 2001, Pages