Biology and Cognition IB Psychology

Memory Recap The three main stages of memory: Explicit 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