Schmolck

Schmolck

1. AIM- To find out if semantic LTM is linked to a particular part of the brain.

   • If so, patients with lesions in that part of brain should underperform in semantic LTM tests.

2. IV - extent of brain damage.

   • 1) 3 patients with damage to hippocampus/ MTL only
     • 2) 3 patients with damage to MTL and temporal cortex too (MLT+)
       • 3) Control group with no damage

3. DV- 9 separate tests on semantic LTM

4. Sample- 6 patients with severe damage to the MTL and 8 control with no damage. 3 of the patients also had damage to temporal cortex generally.

5. PROCEDURE

   • Created 9 semantic tests for LTM function. All based on 48 drawings, half animal and half objects.
     • These pics were grouped in sixes. ( 6 land animals, 6 birds, 6 vehicles, 6 musical instruments etc.)
       • Similar pictures- shown 6 pictures sharing same theme and asked to pick out the one the researcher says
         • Category fluency- pps asked to give as many examples from each theme within in a minute
           • Category sorting- pps given all 48 pics and told to sort into 'living' and 'man made'
             • Definitions- shown a pic and asked to define it by the theme it fitted into
               • Dementia patients had extra test- 30 pics shown of real and not real objects. ppts had to say whether object is real or not
                 • ppts were tape recorded and responses transcripted (typed) 14 rates checked transcript for reliability and language/ grammar used

6. RESULTS

   • Similar pictures- controls 100%, hippocampus damage 100%, HM scores 98% for living creatures and 100% for objects, MTL+ performed worst 85% for living and 90% for objects
     • MTL+- did worse in all tests (p<0.005)
       • Patient H.M- He did better than MTL+ but slightly worse than MTL patients who only had damage to Hippocampus
         • Overall- controls 99%, , MTL (excluding HM) scored 100%, MTL+ 78%

7. CONCLUSION

   • Clear link between damage to temporal cortex generally and semantic LTM
     • Patients with damage to hippocampus suffered loss of episodic memory
       • This suggests semantic and episodic LTM are encoded in diff parts of the brain. The hippocampus and MTL dealing with episodic memory and temporal cortex with semantic memory
         • HM performed similar to control with odd lapses. He had specific brain damage. Hard to generalise due to his background as he spent most time in hospital with psychologists and had epilepsy

8. GENERALISABILITY

   • Small sample, easily distorted by anomalies like HM.
     • Schmolck did single him out at an anomaly and researchers analaysed him into detail
     • Brain lesions and memory problems are rare- unrepresentative of wider population

9. RELIABILITY

   • Standardised procedures- can be replicated by other researchers
     • 14 rates checked ppts scored- inter rater reliability
     • ppts hard to replicated, HM died in 2005

10. APPLICATION

    • Understanding the brain's role in memory
    • Risks of brain surgery and side effects and weight up risks of surgical procedures
      • If HM knew before, he may not of agreed to his surgery
    • Can lead to cure for patients (like Clive Wearing( with this type of memory loss and repairing lesions

11. VALIDITY

    • Healthy controls and matched pairs help validity
      • Can say the scores were to do with the diff brain lesions
        • Backed up by MRI scans as they show temporal lobe activating when making semantic judgements
          • Not ecological valid- artificial task. Games and puzzles, not the type of memory needed for real life

12. ETHICS

    • ppts would not be able to give valid consent as they would not remember having study explained
      • Presumptive consent- from doctors and family
    • HM has been studied his whole life and could never consent to any of it (human life guinea pig)
    • Social responsibility- for the common good
      • Failure to respect dignity and autonomy
    • cost-benefit calculation