Differential Effects of Early Hippocampal Pathology on Episodic and Semantic Memory By: Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., & Van Paesschen, W. Presented by: Meinas Elmusharaf Safiah Mai Seung Ju Na Adam Ouellette Enakshi Singh

Methodology Subject Recruitment Sample size and representativeness Meinas Methodology Subject Recruitment Sample size and representativeness Control for between subject variance

Meinas Contradiction relating to subjects’ overall quality of life and capabilities Parents reported that everyday memory loss is: Disabling No child can be left alone Cannot lead lives that are standard to their age, circumstances or aspirations The paper later goes on to report: “all three patients are not only competent in speech and language but have learned to read, write and spell at levels standard of their VIQs” “all three patients obtained scores ( on VIQS) within the normal range”

Meinas What if parents give bias rating that either exaggerate or underestimate their children’s memory impairment? Does the loss of episodic memory reduce the quality of life as the parents stated although an individual is still able to comprehend and express ideas through reading and writing?

Validity & Reliability Adam Validity & Reliability Neuropsychological examinations - Rey-Osterreith Complex Figure Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., & Van Paesschen, W. (1997) Differential Effects of Early Hippocampal pathology on Episodic and Semantic Memory. Science, 277, 376-379

Validity & Reliability Adam Validity & Reliability Magnetic Resonance Techniques (1H MRS) 2008-07-16 16:41 Dwayne Reed 256×256×8 (6156703 bytes) {{Information |Description=An animated gif of MRI images of a human head. For additional information contact me on my talk page. |Source=I created this image from an MRI performed on me last year at [[Stony Brook University Medical Center]]. |Date=July 16 Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., & Van Paesschen, W. (1997) Differential Effects of Early Hippocampal pathology on Episodic and Semantic Memory. Science, 277, 376-379

Validity & Reliability Is it necessary to have all these tests? Adam Validity & Reliability Computerized Tests Howard Echienbaum Is it necessary to have all these tests?

General Experimental Approach Seung Ju General Experimental Approach Purpose is to assess the following views: Both semantic and episodic memory is a unitary process that is dependent on the hippocampal system. Temporal lobe amnesia results in a loss of episodic memory but preserves semantic memory Single Dissociation: Damage to hippocampus resulted in loss of episodic memory but semantic memory remained intact

Conclusiveness Paper yields conclusive results based on: Seung Ju Conclusiveness Paper yields conclusive results based on: Results from computerized tasks & neuropsychological tests Evidence suggesting differential preservation of semantic memory Findings in monkeys with hippocampal damage

Conclusiveness Cont’d Seung Ju Conclusiveness Cont’d Anatomical evidence (1H MRS) - ⓐ Control vs. ⓑ Beth Conclusions made by Zola-Morgan and colleagues Case of HM Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., & Van Paesschen, W. (1997) Differential Effects of Early Hippocampal pathology on Episodic and Semantic Memory. Science, 277, 376-379

Enakshi Relevance First to study cases of bilateral hippocampal damage that occurred at a very young age Provided anatomical & behavioural evidence Dissociation between episodic and semantic memory processing This paper was the first to study cases of bilateral hippocampal damage that occurred at a very young age Their results provided great evidence that episodic and semantic memory must be processed separately in the brain – since these 3 patients that acquired global anterograde amnesia were able to attend school and obtain factual knowledge at a low average to average range They provided anatomical & behavioral results to prove that there is definitely some dissociation with the way episodic and semantic memory are processed

Relevance cont’d Hippocampus  episodic memory Enakshi Relevance cont’d Hippocampus  episodic memory Parahippocampal cortices  semantic memory Conflicting findings: Some memory is spared because of lesion-induced plasticity Squire & Reed: impaired semantic learning adult hippocampal damage Brain reorganization after early MTL lesions? However – their conclusion that the hippocampus is responsible for episodic memory and the parahippocampal cortices are responsible for semantic memory may not be the correct theory – there are conflicting findings: that state that the reason that some memory is spared is because of lesion-induced plasticity This paper found that there is preserved semantic learning with infant to juvenile hippocampal damage but Reed & squire found a year later that there is impaired semantic learning with adult hippocampal damage ` So the reason for these conflicting findings may be because of significant brain reorganization that may occur after early brain MTL lesions (Reorganization of associative memory in humans with long-standing hippocampal damage - Mischa Braun1, Carsten Finke1, Florian Ostendorf1, Thomas-Nicolas Lehmann2, Karl-Titus Hoffmann3 and Christoph J. Ploner) This is an important idea – because this indicates that forms of plasticity may occur in memory systems if damage to the hippocampus and surrounding areas occur at a young age – this has yet to be fully proven – but it is an idea that would not have come up in the field of Neuroscience if Vargha et al hadn’t published their findings.

Autism and the Medial Temporal Lobe Safiah Autism and the Medial Temporal Lobe Medial temporal lobe damage  Autism vs. Temporal-occipital cortex damage  Autism This paper demonstrated that those with damage to the medial temporal lobe had preserved cognitive and social development It was hypothesized that bilateral damage to the medial temporal lobe resulted in autistic-like behaviour in children This paper demonstrated that those with damage to the medial temporal lobe had preserved cognitive and social development since all three were able to accommodate for their disabilities and attended regular schooling This suggests that the severe dysfunction seen in children with autism is the result of damage to the temporal-occipital cortex rather than the medial temporal lobe, as previous believed Autism and visual agnosia in a child with right occipital lobectomy. I Jambaqué, L Mottron, G Ponsot, and C Chiron (1998) J. Neurol. Neurosurg. Psychiatry 65, 555-560

Hypoxic-Ischaemic Injury and Medial Temporal Lobe Damage Safiah Hypoxic-Ischaemic Injury and Medial Temporal Lobe Damage Hypoxic-ischaemic brain injury  medial temporal lobe damage causing amnesia Further studies also conducted by Vargha- Khadem include an additional two cases consistent with this finding The question arose as to whether such an impairment may be a previously unrecognized consequence of hypoxic–ischaemic brain injury sustained perinatally. ***LIMITATIONS! Thus it appears that, in all five children, their pathology and associated memory impairments can be attributed primarily to hypoxic–ischaemic episodes sustained very early in life. We suggest that the degree of hypoxia–ischaemia was sufficient to produce selective damage to particularly vulnerable regions of the brain, but not sufficient to result in more severe or more global brain damage, and hence more severe neurological and cognitive deficits. Further studies also conducted by Vargha-Khadem demonstrate that all three cases of amnesia caused by medial temporal lobe damage discussed in the paper can be traced to hypoxic-ischaemic injury at birth Two similar cases were found to be consistent with this hypothesis in addition to those discussed in the paper. Developmental amnesia associated with early hypoxic-ischaemic injury. D. G. Gadian, J. Aicardi, K. E. Watkins, D. A. Porter, M. Mishkin, and F. Vargha-Khadem (2000) Brain 123, 499-507

References Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., & Van Paesschen, W. (1997) Differential Effects of Early Hippocampal pathology on Episodic and Semantic Memory. Science, 277, 376- 379. Gadian, D. G. , Aicardi, J., Watkins, K. E. , Porter, D. A., Mishkin, M. , & Vargha-Khadem, F. (2000). Developmental amnesia associated with early hypoxic-ischaemic injury. Brain 123, 499-507. Jambaqué, I., Mottron, L., Ponsot, G., &Chiron, C. (1998). Autism and visual agnosia in a child with right occipital lobectomy. ). J. Neurol. Neurosurg. Psychiatry 65, 555-560. Reed, J. & Squire, L. R. (1998). Retrograde Amnesia for Facts and Events: Findings from Four New Cases . J. of Neurosci 10, 3943- 3954. Braun, M, Carsten Finke1, Florian Ostendorf1, Thomas-Nicolas Lehmann2, Karl-Titus Hoffmann3 and Christoph J. Ploner