Verbal Working Memory Flashcards
Sternberg Verbal Working Memory Task
What is it? What are the three phases?
What are the advantages of the task?
Remember letters and retrieve them after period of time. Encoding phase, maintenance phase and retrieval phase.
Can examine brain activation during different phases of the task. Parametric modulation is possible, so we can vary the WM load in the same task.
What are the two systems of verbal working memory (VWM)? What are they and where are they located? Together, what do they form?
Articulatory control system and the phonological store.
Phonological store keeps verbal information for matter of seconds, but would fade if not refreshed by articulatory control system. Together, they form the phonological loop.
Temporal parietal regions for phonological store and Frontal regions for articulatory control system.
How could cerebellum contribute to the VWM system?
Superior cerebellum affect frontal regions via the Medial Pons.
Inferior cerebellum affect temporal-parietal regions via the lateral pons.
Testing Cerebellar involvement in the two systems of VWM.
What was the working memory task?
What was the motoric rehearsal task?
What predicted subsystems do each of these tasks engage?
How did these two differ in fMRI activations?
Working Memory task had high load and low load with maintenance period. This engaged BOTH subsystems, articulatory control and phonological loop, and would engage inferior and superior CBM.
Motoric Task had high and low load but the letters were repeated to subjects very often. This engaged ONLY the articulatory control subsystem and activate only the superior CBM.
During which phases of the VWM task (motoric and working memory) does cerebellar activation occur and where?
Encoding related response - right superior cerebellum and left inferior frontal activation.
Maintenance condition - right inferior cerebellum and left inferior parietal regions.
fMRI experiment: Auditory vs Visual Encoding in Sternberg WM Task.
What areas responded to both stimuli? What responded to just auditory stimuli?
Parietal and Frontal regions respond to both stimuli.
Superior Cerebellum activation for both. Left inferior cerebellum for auditory stimuli.
FACT: Many studies show selective verbal working memory deficits from cerebellar lesions.
Also digit span deficits, VWM task, in cerebellar patients with auditory presentation.
NO results for spatial WM.
Increased activation in parietal regions maybe as compensation for loss of cerebellum.
What cerebellar lobule is correlated with auditory digit span?
HVIII. Supported by regression analysis and Italian group’s clinical analysis.
What are TMS effects on reaction time of verbal working memory tasks? (sternberg)
Superior cerebellar TMS disrupts normal encoding function of cerebellum, making it difficult to utilize that information.
Verbal working memory in Alchoholic vs non-alchoholic men.
What were the behavioral results?
What were the activation results?
What is the interpretation of these results?
There were no behavioral differences.
Alcoholics showed significant increase in activation in left front and right superior cerebellum.
Fronto-cerebellar system is working harder to maintain performance relative to controls.
Sensory Acquisition Demands Task.
What did degrading the stimuli result in?
What region of cerebellum was activated for degraded stimuli?
Increased sensory acquisition demands, as seen with increased visual cortex activations.
Vermis activated for degraded > non-degraded stimuli. NOT CBM hemisphere ROIs.
Phonological Similarity Effect:
What is it?
What do patients with Ltemporal/parietal lesions see with this effect?
Phonologically similar letters/words are more difficult to remember than dissimilar ones.
Lesioned patients have no phonological similarity effect. Same activation for similar and dissimilar words.
What fMRI results do you see for increased phonological storage demand for the cerebellum and cortex regions?
No difference in dissimilar vs similar for encoding phase.
Maintenance phase shows increased activation in cortex and cerebellar regions for similar phonological stimili.
What are of cerebellum activated in maintenance phase for high load trials?
Right inferior cerebellum lobule VIII is sensitive to phonological storage demand.
What were the common regions of cerebellar activation for patients with cerebellar lesions when presented with auditory and visual PSE tasks?
Auditory showed activation in left lobule VIII.
Visual showed activation in right lobule VIII.
