یاداوری و شناسایی در کمبود اکسیژن خفیف: استفاده از مدل سازی ساختاری کوواریانس برای تست نظریه های رقیب حافظه آشکار

To test theories of explicit memory in amnesia, we examined the effect of hypoxia on memory performance in a group of 56 survivors of sudden cardiac arrest. Structural equation modeling revealed that a single-factor explanation of recall and recognition was insufficient to account for performance, thus contradicting single-process models of explicit memory. A dual-process model of recall in which two processes (e.g., declarative memory and controlled search) contribute to recall performance, whereas only one process (e.g., declarative memory) underlies recognition performance, also failed to explain the results adequately. In contrast, a dual-process model of recognition provided an acceptable account of the data. In this model, two processes—recollection and familiarity—underlie recognition memory, whereas only the recollection process contributes to free recall. The best-fitting model was one in which hypoxia and aging led to deficits in recollection, but left familiarity unaffected. Moreover, a controlled search process was correlated with recollection, but was not associated with familiarity or the severity of hypoxia. The results support models of explicit memory in which recollection depends on the hippocampus and frontal lobes, whereas familiarity-based recognition relies on other brain regions.

Examinations of memory-impaired patients have played a critical role in shaping theories of explicit memory. Extensive empirical and theoretical work has been done to characterize the relationship between recall and recognition. Early theories assumed that a single underlying form of memory was responsible for both recall and recognition. More recently, neuropsychological dissociations between recall and recognition resulting from different types of brain injury have contributed to the rise of two competing classes of theory proposing at least two processes underlie recall and recognition. One class assumes that declarative memory, a general form of memory, contributes to recall and recognition whereas additional processes related to executive control contribute to recall but not recognition. The other class assumes that two memory processes, recollection and familiarity, contribute to recognition, whereas only recollection contributes to recall. A large body of empirical evidence has contradicted single-process models, but differentiating between the latter two classes of models has proven difficult. In the current study, structural equation modeling was used to directly test the ability of these competing theories to explain observed relationships among recall performance, recognition performance and amnesic severity. The models of interest are first described in more detail, and previous attempts to contrast the models are briefly reviewed. Then, structural modeling methods are described and applied to a study that examined the amnesic effects of mild hypoxia on recall and recognition memory.