L23 Memory 2

• What is the basal ganglia important for?

  Implicit memory, non-declarative.

  Skill learning.

  
• What is the weather task?


  Participants are given symbols and asked to predict the weather.

  They build a probabilistic model.

  Amnesiacs = normal performance

  Parkinson’s disease = impaired performance because PD affects basal ganglia.

  Normally participants use a declarative strategy then move onto an implicit strategy, but PD patients only use declarative.
• Perceptual priming study


  Lists read by participants.

  Tested after a week with word stems - words which had been primed were more likely to be said.

  Brain areas show reduction (repetition suppression): left prefrontal cortex, left occipital-temporal lobe.
• What is neural sharpening?

  When a stimulus is repeated, non-essential neurons respond less and less.
• Which side of the fusiform gyrus shows a repetition effect for same and different exemplars?

  Left
• Why does the right fusiform gyrus have a repetition effect only for the same stimuli?


  The right hemisphere is more perceptive whereas the LH is more specialised in language.
• Conceptual priming:


  Left anterior inferior prefrontal gyrus = suppression effect within-task only = conceptual processing.

  Left posterior IPFG = suppression effect within and across = non-semantic processing.
• What happens with familiar faces?


  Repetition suppression effects - can activate a representation in LTM and allows for a ‘sharper’ representation on the second presentation.
• what happens with unfamiliar faces?

  Repetition enhancement - need to create a new representation - greater cortical activity in perceptual areas and need to invoke episodic memory retrieval, which is associated with greater levels of activation.