At the inception of the Memory Project, questions remained regarding the development, nature (e.g., encoding, retrieval), and neural underpinnings of the declarative memory deficit in schizophrenia. Based on neuropsychological studies, there was a general consensus that neurocognitive deficits do not progress over time after illness onset, but little was known with regard to putative deficits prior to the onset of illness. Our initial studies focused on clinical and neuropsychogocal measures in the prodrome and their continuity with first-episode schizophrenia (Niendam et al. 2006; Willhite et al. 2008).
We also started to examine similar questions in the domain of working memory (Karlsgodt et al. 2008; Karlsgodt et al. submitted). Within the Center, we were able to translate the basic science remember-know paradigm to evaluate the development, nature (e.g., encoding, retrieval), and neural underpinnings of the declarative memory deficit in schizophrenia.
We published a study validating the paradigm behaviorally in a chronic schizophrenia sample, and are the first to interpret the schizophrenia memory deficit based on the two most prominent basic science memory models to date (Van Erp et al. 2008).
The Center also allowed us to evaluate at-risk for psychosis (prodromal) and first-episode schizophrenia samples on this paradigm with fMRI. Collectively, these studies reveal a progressive deficit in recollection across the phases of illness. fMRI data indicate that both the first-episode and prodromal samples show aberrant neural activation in the declarative memory network during encoding and recognition (Van Erp et al. submitted; Van Erp et al. submitted).