short term / working

short term memory

• processes that maintain info for very short periods (<1 min)

• material specific; capitalise on the systems we already have to remember things

• loss does not effect long-term learning 

verbal STM regions 

• left temporo-parietal region

• prefrontal cortex

• junction between ventral and dorsal streams

visuospatial STM regions

• right parietal

• prefrontal cortex 

corsi blocks task

• visuospatial sequence that doesn’t require or benefit from verbal information

• alzheimers; grey matter loss in posterior areas and dorsal visual processing stream predict poor corsi block scores

• more degeneration on the right side is more likely to have problems with visuospatial STM

rehearsal loop

• when we rehearse material, we engage more prefrontal structures

baddeleys model of working memory

• includes two ‘passive’ stores; one for verbal, one for VS

• plus a control centre, the central executive

• CE can manipulate stored information to solve problems

cowans model, WM

• short term memory into a seperate set of systems

• STM involves temporarily activating & maintaining knowledge elements from LTM

• storage engages the same processes we use when were processing the information in real time

• what we hold onto in short term memory is a way of activating or maintain activations in a set of long term representations

• we can deliberately focus our attention on 3-4 elements that are active

prefrontal cortex & WM

• prefrontal areas especially active during rehearsal

• fMRI: prefrontal activated only during delay 

•  when we rehearse verbal material, we engage left hemisphere frontal regions, anterior structures (repetition of words or letters with a delay)

• when we rehearse VS material, we engage parietal and prefrontal, on the right (mental rotation + delay condition)