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Biology and Cognition. IB Psychology. Memory Recap. The three main stages of memory: Encoding --> Storage --> Retrieval Explicit Memory: Fact Based Memory: Requires conscious retrieval. Episodic Semantic Implicit Memory: Procedural and Emotional Memories
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Biology and Cognition IB Psychology
Memory Recap • The three main stages of memory: • Encoding --> Storage --> Retrieval • Explicit Memory: • Fact Based Memory: Requires conscious retrieval. • Episodic • Semantic • Implicit Memory: • Procedural and Emotional Memories • Do not require conscious retrieval. • Amnesia • Anterograde Amnesia: the loss of short-term memory, the loss or impairment of the ability to form new memories. • Retrograde Amnesia: the loss of pre-existing memories to conscious recollection, beyond an ordinary degree of forgetfulness
Brain Structures that appear to be important for memory processes. • Hippocampus • Amygdala (limbic system) • Cerebral Cortex • Other Brain Structures
Hippocampus • Crucial for memory storage. • Without hippocampi you will be unable to create any new memories. • Does not seem to affect working memory. • Does NOT affect recall of stored memories, but does affect the formation/ storage of new memories. • “Skill” / procedural memory does NOT appear to require the hippocampus. • Key in the creation of episodic or explicit memories.
Amygdala (Limbic System) • Crucial for the creation of emotional memories. • “Proof” of this seems to be evident in the first two years of life. • May play a role in the formation of procedural or implicit memories.
Cerebral Cortex • Lots of different information is stored in your cerebral cortex. • In this instance, each person is different because long-term memories are stored in different parts of your cerebral cortex. • Damage in on place for one person will not do the same thing as damage in the same place for another.
Other Brain Structures • In implicit memory, larger and more primitive parts of the brain seem to be involved: • Basal ganglia • Cerebellum • Their many connections to one another and to the cerebral cortex. • This may explain why people with damage to their hippocampi can still retain procedural memories and/or learn new procedures.
Case Study: Clive Wearing • This Case Study was performed by Oliver Sacks. • CAUSE of Clive’s Condition: • Herpes Simplex Encephalitis • Effects of his illness: • Retrograde and antrograde amnesia • His memory only lasts between 7 and 30 seconds. • He remembers very little of his life before 1985. • His procedural memory was not damaged by the virus: This is why he can remember how to play the piano and do daily activities. • His emotional memory was not damaged: This is why he can remember his wife.
Case Study: HM • This case study was recorded by Scoville and Milner (1957). • CAUSE of HM’s condition: • HM suffered from severe epilepsy in his left and right medial temporal lobes. • Scoville suggested surgical resection of these lobes as treatment. • HM lost approximately 2/3 of his hippocampus, parahippocampla gyrus, and amygdala.
Case Study: HM • EFFECTS of the surgery: • The surgery successfully stopped his epilepsy! • Severe anterograde amnesia. • Moderate retrograde amnesia: could not remember most events in the 1-2 year period before surgery, nor some events up to 11 years before. • His working memory (7 + or - 2) and procedural memory were intact. This allowed him to learn new motor skills (although he couldn't remember learning them).
Strengths of these Studies • Allowed psychologists and scientists to study the affects of brain damage on memory. • Provided valuable insights to the functions of different brain structures and how they relate to memory. • Allowed researchers to generate testable hypotheses about how memories are formulated in the brain and how different brain structures work together.
Limitations of these Studies • Using case studies limits generalization. • No two patients will have the exact same damage to his/her brain. • Long-term memory storage is different from person to person. • Too few participants to generalize. • Researcher Bias