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Right Medial Thalamic Lesion causes Isolated Retrograde Amnesia

Right Medial Thalamic Lesion causes Isolated Retrograde Amnesia. (Miller, Caine , Harding, Thompson, Large & Watson, 2001). Soomi Kim PSYC 260. Introduction. What is amnesia? Temporary or/and permanent loss of memory. There are two types of amnesia. Anterograde Retrograde.

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Right Medial Thalamic Lesion causes Isolated Retrograde Amnesia

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  1. Right Medial Thalamic Lesion causes Isolated Retrograde Amnesia (Miller, Caine, Harding, Thompson, Large & Watson, 2001) Soomi Kim PSYC 260

  2. Introduction • What is amnesia? • Temporary or/and permanent loss of memory. • There are two types of amnesia. • Anterograde • Retrograde

  3. Types of Amnesia Anterograde Amnesia Retrograde Amnesia • Short term memory loss • e.g. black out after excessive alcohol consumption. • Long term memory loss • e.g. wedding day

  4. Hypothesis • The right mediodorsal thalamic nucleus and immediately surrounding areas are responsible for central processing mechanisms such as recalling cortically stored memories, which are suggested by McClelland (1994) and Markowitsch (1995).

  5. Case Presentation • JG is a 33 years old, right-handed, healthy male patient. • He has isolated retrograde amnesia caused by right medial thalamic lesion • Normal day to day memory • Trouble recalling: • Autobiographical information • Procedure memory • Knowledge of famous people and events

  6. Case Presentation • He said “I don’t remember anything”. • He had no memory of where he worked and what he was supposed to do at work.

  7. Neurological Findings • CT scan showed the patient’s brain is normal. • MRI showed that there are three lesions in the patient’s thalamus. • Right: • More anterior and mediodorsal thalamic nuclei (a) • More posterior part of mediodorsal nucleus (b) • Left: • Posterior part of the mediodorsal nucleus and paraventricular nucleus (c)

  8. Neurological Findings Anterior Right Left Posterior

  9. Neuropsychological Assessments • Initial Assessment • JG’s recognition ability for autobiographical material • “Major Life Events Test” • Recognizing a familiar face among the picture of three strangers • Matching Christian names with each photograph of his family members or friends • Results: • He was unable to correctly identify faces of people in his past. • But he identified people whom he recently met.

  10. Neuropsychological Assessments • JG’s non-autobiographical information • “Famous People Test” • “Famous Events Test” • Results: • His performance was at near-chance level when compared with three men without any known neurological disorders. • No significant differences between recognizing famous people’s names and faces before and during his life time. • He barely remembered any of famous events regardless of time.

  11. Neuropsychological Assessments • Famous People Test

  12. Neuropsychological Assessments • Famous Events Test

  13. Neuropsychological Assessments • Follow-up Assessment • JG showed no improvements in • Recalling of personal events and semantic details from childhood • His memory of distant past autobiographical events • Recalling famous events that occurred before the onset of his lesion • JG showed improvements in recognition of famous people whom he recently saw. • But he could not match faces with names.

  14. Neuropsychological Assessments • Procedural Memory • JG kept long-standing procedural memories. • e.g. driving and playing golf • However, JG’s procedural knowledge was slightly impaired. • e.g. using a cash register at the shop he worked a few weeks before his admission

  15. Discussion • JG’ severe and chronic retrograde amnesia was found to be caused by the recent lesion. • Posterior part of the mediodorsal nucleus and paraventricular nucleus (c) • JG’s symptoms are due to other related cortical area dysfunctions as well. • He had difficulties accessing more distant memories, which are stored in neocortex.

  16. Discussion • Knowledge of people, events and other unique material differs form other factual knowledge and they are also correlated with personal experiences.

  17. Conclusion • The results are consistent with McClellend and Markowitsch’s finding that the right mediodorsal thalamic nucleus and the surrounding regions engage in central procession mechanism such as recalling cortically stored memories.

  18. My Opinion Strengths Weaknesses • It is heuristic • It can provide background information for future study. • Combined method and result sections make hard to reproduce. • Confusing • The conclusion is hard to generalize to the entire population.

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