Part III Neural Systems and Memory 07 28 2013 Chapter 12 Memory Systems The Hippocampus We are nothing without our memories they are essential to our survival skills in life We would not be able to anticipate dangers situations locate food and water or acquire the rudimentary skills such as driving a car I The Multiple Memory Systems Perspective Multiple Memory Systems sorts content and assigns its storage to CORTEX different regions of the brain HIPPOCAMPUS Figure 1 Input suggests polymodal association area Multiple senses from frontal lobe temporal lobe parietal lobe all send to the hippocampus to form a single memory Ascending output to Cortex is broad and topographically organized Abstracted sensory information Figure 2 Feedback of polymodal input hippocampus is divided up and sent to regions in the cortex output opposite information from Descending output to amygdala medial prefrontal cortex lateral septum Bed Nucleus of the Stria Terminals INDIRECT influence on motor regions of the Hypothalamus that control motivated behavior Influence on motivated behavior the memory system extracts and stores the content of our personal experiences in a manner that allows them to be consciously retrieved A Example 1 Personal Facts Emotions a The details that make up an episode and impact of the experience are stored in different brain regions i Ex French psychologist Edouard Claparede 1951 concealed a pin in his hand and then shook hands with the amnesic patient who quickly withdrew her hand in pain A few minutes later Claparede offered his hand to the patient again The patient resisted shaking it When asked why the patient replied Doesn t one have the right to withdrawal her hand With no explanation as to why she did not want to shake his hand B Example 2 Personal Facts and Skills a Once a skill is acquired it can be performed without your having any sense of awareness The many hours of practice have left an enduring impression in your brain that now supports the skill i Practice sessions ii Where they occurred iii Who your instructors were iv How difficult it was to perform 1 However the conclusion is that the memory system that supports skillful behaviors is outside of the region of the brain that supports our ability to recollect the training episodes b Researches believe o 1 Complete understanding of memory requires being able to recognize the content of the experience is important o 2 Memories are segregated into different brain regions according to their content o The hippocampus was named after the trpical fish Hippocampus leria aka the seahorse C The Case of H M a Brenda Milner and her case studies with H M have provided insight to regions of the brain that are responsible for our ability to remember our experiences b Background At age nine H M sustained a head injury that led to epilepsy His seizures became more frequent and by 27 he was no longer able to function normally The decision was made to bilaterally remove regions in the brain associated with the temporal lobe H M no longer had seizures and his cognitive abilities were still in tact however he suffered severe memory problems c Anterograde Amnesia not being able to acquire some types of new memories for ex never recognizing psychologists Milner d Retrograde Amnesia cannot recall memories from the past i In H M s case he could recall some childhood memories but the majority was severely damaged allowing researchers to reveal that some of his memory capacities were spared ii Ex Mirror Tracing H M s performances improved with training it required coordination of hand movements with an inverted image of the object being traced and a totary pursuit task This required acquiring a new motor skill 1 H M improved on these tasks with time but never recalled having taken the test 2 II Episodic Memory System Many researches believe that the removal of H M s brain region disrupted his episodic memory a system that supports what most people Episodic Memory System mean when they use the term memory what place Episodic Memory diary who did what to whom at what time and in o Extracts stores content from experiences episodes allowing one to answer questions o Supports ability to consciously recollect and report on facts and events that you have experienced Learned that during H M s surgery the following brain regions were removed o Hippocampus o Amygdala o Surrounding regions of Neocortex There are two ways to study episodic Memory Testing Rodent Testing Patients with selective brain damage III The Animal Model Strategy Advantage Researcher has control over location of brain damage and can selectively target different regions Disadvantage no real communication can be conveyed whether the animal recalled an experience or not The Delayed Nonmatching to Sample Task o Mishkin decided to use primates to determine which brain regions contributed to H M s memory loss by developing a testing procedure called Delayed Nonmatching to Sample DNMS Each trial has 2 components Shown 3 D object key the sample Then presented with a choice sample or new object choice IF the monkey chooses the choice it will receive a reward food 1 New objects are sued on every trial 2 The experimenter can vary the interval between the sample and the choice trial The idea is for the monkey to succeed it will remember the sample object and choose the new object because it is new Thus relaying on the episodic memory system o The initial purpose of the experiment was to determine which region of the brain caused H M s amnesia Hippocampus Amygdala Found that despite damage to both region neither had an effect on DNMS performance damage to both regions hippocampus amygdala showed extreme impairment to performance o o However Larry Squire pointed out that surgical approaches to remove those brain regions also caused damage to immediate surrounding cortical tissue compared to when only the hippocampus was removed o Finding that damage to the rhinal cortex not the hippocampus or amygdala caused impaired performance on DNMS task Two Process Theories of Recognition Memory o DNMS task belong to a memory category called recognition memory tasks o These tasks require subject to make a judgment based on previous event whether or not it has occured o 1 Familiarity Recognize faces often but not where you met Depends on surrounding cortices Also known as Perceptual Memory o 2 Recollection This would include where you met how you know each other and specific details Typically familiar