Slide 1Learning & MemoryTypes of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)Types of memory (and lack thereof)The engramThe engram: Lashley’s experimentsThe engram: Lashley’s experimentsThe engram: Lashley’s experimentsThe engram: Hebb’s modelThe engram: Hebb’s modelThe engram: in the neocortexThe engram: in the neocortexThe engram: in the neocortexThe engram: in the neocortexThe engram: in the neocortexThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe temporal lobesThe diencephalonThe diencephalonThe HippocampusThe HippocampusThe HippocampusThe HippocampusThe HippocampusThe HippocampusThe striatumThe striatumThe striatumPrefrontal cortexPrefrontal cortexPrefrontal cortexSlide 50MEMORY SYSTEMSNEUR 3000Dr. Joseph J. NormandinLEARNING & MEMORY•Learning is a lifelong adaptation to an organism’s environment through acquisition of new information or knowledge•Memory is the retention of learned information•Experience shapes memories•Memories range from stated facts to ingrained motor patterns•Several brain regions are involved in learning and memoryTYPES OF MEMORY (AND LACK THEREOF)•Declarative memory•The “facts” that we know and can communicate to each other•What you had for breakfast•What color the sky is•The slowly setting sun as a backdrop for your first kiss•Your awesome neuroscience lecturer• Yeah! Remember him? What a weirdo.•Easily learned but easily forgotten•No idea what I had for breakfast•Um no, don’t remember that lecturer dude, I was texting lolzTYPES OF MEMORY (AND LACK THEREOF)•Nondeclarative memory •Procedural memory•Memories for skills and behaviors•“You never forget how to ride a bike”•Learned fear•You get stung by a wasp when you are little, at the beach, and it scares you•You are forever afraid of buzzing insects•These memories are not easily forgottenTYPES OF MEMORY (AND LACK THEREOF)TYPES OF MEMORY (AND LACK THEREOF)•Short- and long-term memory•Short-term memories last on the order of seconds to hours•You may remember what you ate for dinner last night, but a week from now you probably will not•Long term memories may last a lifetime•Not all memories become long-term memories•Because some short-term memories become long-term memories one hypothesis of memory formation is that it is a serial process•A competing hypothesis is that these processes happen in parallelTYPES OF MEMORY (AND LACK THEREOF)TYPES OF MEMORY (AND LACK THEREOF)•Working memory•Working memory is a temporary storage of information that is limited in capacity •We keep such memories in our head as we are doing different tasks, and then quickly forget them•A memory that you are “rehearsing” in your mind is a working memory•If rehearsed enough, the memory can be consolidated into a long-term memory•The capacity of working memory is known as a “digit span” and is 7 +/- 2 arbitrary units•Most easily understood as a sequence of 7 numbers•6883314 (7 units)•If divided into more units you can “increase” capacity•978 688 3314 (3 units)TYPES OF MEMORY (AND LACK THEREOF)•Memory systems are diverse and may be dependent on the sensory modality•Individuals with specific cortical lesions may remember a sequence of number if they see it, but cannot remember the sequence if they hear itTYPES OF MEMORY (AND LACK THEREOF)•Amnesia•A loss of memory and or ability to learn beyond normal every day “forgetting”•A consequence of disease or trauma•Concussion•Alcoholism•Encephalitis•Stroke•Tumor•The type of amnesia where a person has a trauma and completely forgets who they are, as portrayed in movies, is quite rare•More commonly trauma or disease produced limited memory loss with other non-memory deficits•When memory problems are not associated with other deficits, it is called dissociated amnesia and this state is useful for understanding memory systemsTYPES OF MEMORY (AND LACK THEREOF)•Amnesia•Can be divided into two categories•Retrograde amnesia•Loss of memory of events before the traumaTYPES OF MEMORY (AND LACK THEREOF)•Amnesia•Can be divided into two categories•Anterograde amnesia•Inability to form new memoriesTHE ENGRAM•Engram•A physical representation or location of a memory•Where and how is information stored in the brain?•Different types of memory are stored differentlyTHE ENGRAM: LASHLEY’S EXPERIMENTS•Karl Lashley, American psychologist, 1920s•Trained rats to find food in a maze•Learning the maze took many trials, but eventually rats will remember the direct path to food•Lesions of cortex could produce deficits in learning the maze (i.e. needed more trials to learn)•Lesions of cortex could produce deficits in remembering the maze (i.e. would not go directly to food as before)•Effects correlate with the size of the lesionTHE ENGRAM: LASHLEY’S EXPERIMENTSTHE ENGRAM: LASHLEY’S EXPERIMENTS•Karl Lashley, American psychologist, 1920s•Lashley concluded that memories are stored throughout the cortex, and that there is no specific place that memories are storedBecause the lesion are so large, they each might have encompassed the place(s) where memory is storedIn fact, memories are stored in specific locations, but the locations are widely distributedTHE ENGRAM: HEBB’S MODEL•Donald Hebb, American psychologist, 1940’s•Reasoned that the representation of an object consisted of all the cortical cells activated by that object•Cell assembly•Short term memory = the cells in the assembly remain active•Long term memory = assembly activity persists and a “growth” process occurs that strengthens connections in the assembly•At a later time, if a fraction of the assembly was activated, the entire assembly would be active because of strengthened connections•This model as stood the test of time, but we are still understanding the details and refining the modelTHE ENGRAM: HEBB’S MODELTHE ENGRAM: IN THE NEOCORTEX•One consequence of Hebb’s model is that the engram is dependent on the modality of the experience•We