Neurobiology and Communication Memory

What do you know about memory?

What will you be learning? What is memory? How does memory work? What are the different levels of memory? Where is memory located in the brain?

What is memory? Memory involves the encoding, storage, retention and retrieval of information. Memories include past experiences, knowledge and thoughts. All information entering the brain passes through sensory memory (SM) and enters the short-term memory (STM). Information is then transferred to the long-term memory (LTM) or discarded.

Sensory memory (SM) This is all the information being received from a person’s sensory experience. It lasts for a few seconds (approximately 0.5 seconds for visual and 2 seconds for auditory input). Relevant pieces of information will be sent to the short-term memory.

Short-term memory This mostly consists of visual and auditory images. STM holds limited information approximately 7 items at a time. It is held here for approximately 30 seconds, during which time information that is retrieved is usually done so very accurately. Information is then either transferred to LTM, displaced by new information or it decays loss of fragile neural path).

STM and the serial position effect The recall of information in sequence i.e. objects viewed is best at the end (recent effect) or from the beginning (primary effect) of the sequence. Objects viewed in the middle of a sequence are least well remembered.

STM and maintaining items by rehearsal Retention of information can be improved by repeating a piece of information over and over again (silently or out loud) in the STM

STM and working memory Working memory is an extension of the STM. It will actively process, manipulate and control information held in the STM. This enables simple cognitive tasks to be performed (i.e. working out how many stairs there are to get to C floor)

STM improved by chunking A chunk is a meaningful unit of information made up of several smaller units. Remembering an 11 digit number can be split into chunks of 3 or 4 pieces of information containing several numbers for example. This means the STM capacity can be increased if information is chunked.

LONG-TERM MEMORY (LTM) It is possible that the LTM can hold an unlimited amount of information. To be transferred from STM to LTM information is encoded. The action of transfer to the LTM is promoted by the processes of rehearsal, organisation and elaboration.

LTM and transfer from STM Rehearsal – repeating information at regular intervals. It is thought doing short periods of work and rehearsal is better than a longer period of work with rehearsal. Organisation – putting information into categories or groups helps transfer from STM to LTM and retention. Elaboration – analysis, taking note and using features and properties helps transfer information from STM to LTM.

LTM and encoding Encoding is the process of converting 1 or more nerve impulses into a form which can be received and held by the brain but then retrieved from the STM or LTM. As information is encoded it is stored or filed into distinct categories. The type of encoding determines the quality of the memory. Shallow encoding i.e. just repetition gives less quality. Elaborative encoding i.e. association with previous memories, analysing gives better quality.

LTM and retrieval of information The LTM is a vast store of information, constantly revised, reorganised and increased. Retrieving information from the LTM is helped by contextual cues. These are a signal or reminder associated with the time when the information was encoded. These signals or reminders relate to the conditions or circumstances under which the memory was encoded. Having information stored under many categories means it will have many contextual cues associated with it. Elaboration and analysis help with the building of contextual cues as does organisation.

Location of memory in the brain The LTM has different types of memory. These are associated with particular areas of the brain but they probably overlap to some extent with close communication. These include episodic and semantic memories, procedural memories, emotional and spatial memories.

Episodic and Semantic memories Personal facts, experiences and events are examples of episodic memories. General knowledge, non personal facts and concepts are semantic memories. These are associated with specific regions in the cerebral cortex such as the temporal lobes (at sides of cerebrum). These are often stored in the area of the cortex where the information was first received and encoded.

Procedural memories Performing motor skills and mental skills are examples of procedural memories (how to). These do not need conscious control and are linked to the cerebellum and to long term changes in the motor area of the cerebral cortex.

Emotional and Spatial memory Emotional memories often have positive or negative associations with certain stimuli. These involve the cerebral cortex and the limbic system which have close links. Spatial memories of environment and orientation are associated with the limbic system.

Complexity of memory As memories are encoded with a variety of stimuli and associations involved, the storage of them is complex. As many areas of the brain are involved and links exist between many areas damage to one area can affect others.

What do you know? (processing) What is memory? Memories include ………? What happens to information in the STM? How long does the STM hold an item? How many items can the STM hold? What is chunking and how does it help improve STM? What 3 things help with transfer of information from STM to LTM? What are the 2 types of encoding? What helps with retrieval of information?

What do you know? (processing) Complete the table about memory location and type Type of memory Characteristics of the memory Area of brain Episodic Semantic Procedural Emotional Spatial Environment and orientation Limbic system

More consolidation Complete the summary points 8 – 15 Complete the matching exercise on page 115 of the book Complete the multiple choice questions 6 – 25 pages 118 to 121 in the book Make your own notes at home Read scholar materials and answer questions Make a mind map or revision cards summarising the information

Apple, orange, banana, pear Spring, summer, autumn, winter Mother, father, sister, brother Copper, lead, iron, tin Jacket, shirt, trousers, skirt