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Yushen Zhu

A role for right medial prefrontal cortex in accurate feeling-of knowing judgments : evidence from patients with lesions to frontal cortex. Yushen Zhu. Introduction. Feeling of Knowing (FOK) judgements refer to feelings of knowledge to a certain subject. A form of meta-memory.

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Yushen Zhu

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  1. A role for right medial prefrontal cortex in accurate feeling-of knowingjudgments: evidence from patients with lesions to frontal cortex Yushen Zhu

  2. Introduction • Feeling of Knowing (FOK) judgements refer to feelings of knowledge to a certain subject. • A form of meta-memory. • FOK Paradigm used to examine memory for semantic information and new episodic learning

  3. Introduction Cont’d. 2 Hypotheses on how FOK works: • Accessibility View • Cue Familiarity Questions of Researchers: How does damage to prefrontal cortex affect memory abilities, including: Do FOK impairmentslead to general deficits in meta-memory? Are FOK judgements localized in a specific brain region?

  4. Ways of Measuring FOK Accuracy • 2 ways: • Goodman-Kruskall Gamma correlation • Measure of “association” • Hamann Statistic • Actually measures correlation • Suggested that they provide distinct, but complementary information

  5. Method • 14 patients with frontal cortex damage (10 females, 4 males) • 18 control participants (14 females, 4 males) • Mean age = 54.05 ± 8.45 • Matched in verbal IQ and age • 24 sentences chosen out of a pool, 2 sets created • Study phase and test phase • 18 sentences asked to be read out loud and retained in study phase • 24 sentences given in test phase, whilst asking participants to guess the last word of each sentence • Confidence ratings and FOK accuracy ratings given afterwards • Participants asked to select correct word out of 6 choices after ratings

  6. Results

  7. Results Cont’d.

  8. Results Cont’d.

  9. Results Cont’d. • 4 patients with a FOK accuracy rating lower than the 5th percentile of the control group • Top pictures represent regions of overlap between patients, red being region where there is overlap in all 4 • Bottom 2 diagrams represent overlap in right medial prefrontal cortex (red region above) • a = Hamman index • b = Gamma index

  10. Discussion • Patients with damage to prefrontal cortex exhibit impairments in free recall and recognition • While memory plays an important role in FOK accuracy impairment, it is not the only factor • FOK impairments is selective, did not affect confidence • Specialized in right ventromedial prefrontal cortex • Recognition and recall accuracy were enabled when assessments were easy and rapid, but failed when assessments required additional probing • Lateral prefrontal cortex may play a very important role in memory assessment following retrieval • Retrieval monitoring is regionalized in a part of dorsolateral prefrontal cortex • Memory monitoring is not a unitary function

  11. Confounds and Limitations • FOK judgements based only on incorrect answers • Small sample size • Strengths • Good graphs • Excellent Results • Weaknesses • Confusing statistics My Opinion

  12. Future Directions • Isolate other aspects of meta-memory (feeling of not knowing, remembering vs. knowing, judgements of learning) • Practical application to increase FOK judgements -> increase in ability to retrieve episodic memories

  13. References • D. M. Schnyer, M. Verfaellie, M. P. Alexander , G. LaFleche ,L. Nicholls , & A. W. Kaszniak. (2004). A role for right medial prefrontal cortex in accurate feeling-of-knowing judgments: evidence from patients with lesions to frontal cortex, Neuropsychologia, 42: 957-966.

  14. Questions?

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