Working Memory Deficits in Hippocampal Amnesia are Associated with Apathy
Bahaaeddin Attaallah1,2, Maria Raquel Maio2, Younes A Tabi2
1Department of Brain Sciences, Imperial College London, London W12 0NN, United Kingdom b.attaallah@imperial.ac.uk.
Summary
Hippocampal damage in LGI1-antibody limbic encephalitis (aLE) patients impairs memory binding and motivation. Apathy correlated with memory misbinding errors, suggesting shared neural mechanisms for working memory and goal-directed behavior.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neurology
Background:
- The hippocampus is recognized for its role in working memory and goal-directed behavior.
- It remains unclear if these functions share common neural substrates.
- LGI1-antibody limbic encephalitis (aLE) primarily affects the hippocampus.
Purpose of the Study:
- To investigate short-term memory performance in aLE patients.
- To determine if hippocampal dysfunction impacts memory binding and motivation.
- To explore the relationship between apathy, memory errors, and hippocampal function.
Main Methods:
- Object-location continuous report task with Bayesian mixture modelling.
- Comparison of 27 aLE patients with 27 age- and gender-matched healthy controls.
- Neuroimaging (hippocampal volume, functional connectivity) in a subset of patients.
Main Results:
- aLE patients showed predominantly elevated misbinding errors in short-term memory.
- Apathy was positively associated with misbinding errors, independent of depression and global cognition.
- Reduced hippocampal volume and hippocampal-medial prefrontal connectivity correlated with apathy and misbinding.
Conclusions:
- Hippocampal dysfunction leads to convergent deficits in memory binding and motivation.
- These deficits may reflect disruption of a common neural mechanism linking working memory and goal-directed behavior.
- Findings have potential clinical implications for cognitive and motivational symptoms in hippocampal disorders.
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