Three components of Working Memory:
Central Executive System (CES)
- Functions to coordinate and schedule different mental operations including the processing and immediate storage of info-controls the functioning of the 2 slave systems
- Core feature of the CES is that the capacity of the system is limited, performance begins to break down as the demands on the CES increase-concept for CES grew out of results of dual-task experiments-any individual task requires cognitive processes that draw on the resources of the CES-placing two demanding tasks together is thought to exceed the capacity of the CES resulting in mutual interference between tasks with a subsequent decrement in performance
Phonological or articulatory loop system (ALS)
- Repository for verbally encoded items combined with a rehearsal mechanism which recycles verbal material to refresh the memory trace-split into a phonological Short term store (PSS) and an articulatory rehearsal mechanism (ARM) which contribute to retaining verbally encodable material in STM
Visuospatial sketchpad (VSSP)
- Retains visuospatial material in STM-split into separate visual and spatial storage mechanisms
Functional Neuroanatomy of WM
- WM is complex multimodal system, therefore makes sense that physiological substrate would be distributed throughout the neocortex
- Evidence that ALS is localized in the language dominant hemisphere-neuroimaging studies of pts with with selective auditory-verbal STM imps show pts tend to have lesions in the post portion of the left perisylivan region-Paulesu, et al 1993-PET study-localization of phonological input store in healthy normals-activation attributable to the phonological input store identified in the left supramarginal gyrus, whereas the subvocal rehearsal system of the articulatory loop was associated with activation in Broca’ s area of the left frontal cortex
- Evidence for the localization of the VSSP is less direct, mainly because pts with selective imps in visuospatial WM haven’t been reported-electrophysiological evidence in nonhumand primates-Goldman-Rakic-neuroanatomical localiztion in the prefrontal cortex in the principal sulcus and arcuate regions of monkey and with the inferior convexity a region just inf to the PS
- Proposed the CES is located in the prefrontal cortex
Long-term Memory or Secondary Memory
- Organism’s ability to store info-organized on basis of meaning rather than sensory properties like in STM
- Consolidation-process of storing info as LTM may occur quickly or continue for considerable lengths of time without requiring active involvement -initial acquisition of information is followed by 2 parallel events:gradual forgetting and gradually developing resistance to disruption of what remains