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Memory ------ \ OUTLINE +--------+--------+--------+--------+--------+--------+--------+--------+ | **Type | | **Time | | | | **Mech | | | of | | Course | | | | anism | | | Memory | | ** | | |...

Memory ------ \ OUTLINE +--------+--------+--------+--------+--------+--------+--------+--------+ | **Type | | **Time | | | | **Mech | | | of | | Course | | | | anism | | | Memory | | ** | | | | of | | | ** | | | | | | Loss** | | +========+========+========+========+========+========+========+========+ | **Sens | | Millis | | | | Primar | | | ory** | | econds | | | | ily | | | | | to | | | | decay | | | **Shor | | second | | | | Primar | | | t-Term | | s | | | | ily | | | and | | Second | | | | decay | | | Workin | | s | | | | Primar | | | g | | to | | | | ily | | | Long-T | | minute | | | | interf | | | erm | | s | | | | erence | | | Nondec | | Days | | | | Primar | | | larati | | to | | | | ily | | | ve | | years | | | | interf | | | Long-T | | | | | | erence | | | erm | | Days | | | | | | | Declar | | to | | | | | | | ative* | | years | | | | | | | * | | | | | | | | +--------+--------+--------+--------+--------+--------+--------+--------+ 1. **Encoding** is the processing of incoming information that creates *memovy tvaces* to be stored. It has two sepa- rate steps, the first is **acquisition**. Sensory systems are constantly being bombarded by tons of stimuli. Most only produce a very brief transient sensory response that fades quickly (about 1000 ms aher presentation) without ever reaching short term memory. During this period, however, the stimuli are available for process- ing. This state is known as a *sensovy buffev*. Only some of these stimuli are sustained and make the cut into short term memory, the acquisition. The second step is **consolidation**, in which changes in the brain stabilize 2. **Storage** is the result of acquisition and consolidation and represents the permanent record of the information. 3. **Retrieval** involves accessing stored information and using it to create a conscious representation or to execute a learned behavior, such as a motor act. ### The Anatomy of Memory TAKE-HOME MESSAGES - Learning is the process of acquiring new information, the outcome of which is memory. - Learning and memory have many stages, including encod- ing (acquisition and consolidation), storage, and retrieval. - What is known as the medial temporal lobe memory sys- tem is made up of the hippocampus and the surrounding rhinal and parahippocampal cortices. - Other areas involved with memory include the prefrontal cortex, the parietal cortex, and subcortical structures. ### Memory Deficits: Amnesia ##### Brain Surgery and Memory Loss ##### Recent Studies on Memory Loss ##### Short-Term Forms of Memory [ ] cent sentence accurately enough to say, "Sure I did; you said that the neighbor's goat is in our yard again eating TAKE-HOME MESSAGES - Anterograde amnesia is the loss of the ability to form new memories, as in the case of H.M. - Patient H.M. developed amnesia after bilateral removal of his medial temporal lobes to treat epilepsy. - Retrograde amnesia is the loss of memory for events that happened in the past. - Retrograde amnesia tends to be greatest for the most recent events, an effect known as a temporal gradient or Ribot's Law. - Patients with retrogade amnesia may have normal short- term memory as shown by digit span tests. ### Mechanisms of Memory 0.75 1.5 3 6 9 12 The ensuing decades have seen intense debate over this model £om the standpoint of the psychology of Deficits in short-term memory abilities, such as re- membering items on a digit span test, can be correlated Temporal lobe ##### Long-Term Forms of Memory a. Verbal memory b. Spatial memory -- -- ------------------------- -- -- -- --- 2 4 1 -- -- ------------------------- -- -- -- --- Time a. CS b. US CS US d CS TAKE-HOME MESSAGES - Traditional memory theories include two main distinc- - Memory classified by duration includes sensory memory, - Echoic memory is sensory memory for audition; iconic memory is sensory memory for vision. - Long-term memory is split into two divisions defined - Hippocampal memory consolidation is quick. - Lesions to the anterior temporal cortex can cause severe retrograde amnesia. - Damage to the temporal lobe outside of the hippocam- pus can produce the loss of semantic memory even while the ability to acquire new episodic memories remains intact. ### Cellular Basis of Learning and Memory Most models of the cellular bases of memory hold that memory is the result of changes in the strength of syn- TAKE-HOME MESSAGES - Two prominent theories of long-term memory consoli- dation are the standard consolidation theory and the multiple trace theory. ##### Long-Term Potentiation and the Hippocampus CA3 p 1. *Coopevativiy.* More than one input must be active at the same time. 2. *Associativiy.* Weak inputs are potentiated when co-occurring with stronger inputs. 3. *Specificiy.* Only the stimulated synapse shows potentiation. PSPs LTP increases PSPs Normal PSPs LTD reduces PSPs ##### Long-Term Potentiation and Memory Performance \ TAKE-HOME MESSAGES - In Hebbian learning, if a synapse is active when a postsynaptic neuron is active, the synapse will be strengthened. Long-term potentiation is the long-term strengthening of a synapse. - NMDA receptors are central to producing LTP but not to maintaining it.