The Role Of Working Memory Play In The Forming Of Episodic Long-term Memory

The working memory model established by Baddeley and Hitch (1974) consist of central executive, Visuo-spatial sketch pad and Phonological loop. Central executive play a crucial role that making our attention on the related information processing, inhibiting irrelevant information, responsible for the information to transform among various processes in the complex tasks. The working memory model was supported by the findings of neuropsychological research. Whereas, the relationship between working memory and episodic long-term memory have seldom been studied deeply. Recently, researchers used fMRI to find that the similar brain regions were activated during working memory task and episodic long-term memory task. Some researchers explained the findings that it reflects the role of working memory involved in long-term memory task. In all related studies, there have two viewpoints. Some researchers proposed that maintain of working memory is a unitary processes to play a important role in long-term memory task. The other researchers suggested that maintain of working memory is consisted of two parts, i.e. early phase and late phase. The early phase plays a decisive role in the successful forming of long-term memory, but the late process is automatic process. The relationship between working memory and long-term memory is also disputed so far.Using an event-related potentials technology, our study employed words and pictures materials to explore the role of working memory play in episodic long-term memory in a modified working memory and long-term memory task paradigm.Our study was composed of three experiments. Experiment one aims to study the role of working memory play in long-term memory when without interference in working memory task. The results are as following. First, there has working memory effect to both words and pictures. The ERPs wave of working memory task when episodic source can be successful recalled in long-term memory task was more positive, in contrast to the ERPs of working memory task when episodic source can not be successful recalled. Moreover, the above working memory effects showed materials specific. It began to show a significant variance from 150ms in words andfrom 200ms in pictures. The scalp map showed that words activated central brain region at 400-500ms and pictures activated frontal region at 300-400ms. Second, there has materials specific on the old-new effects. The old-new effects of words showed activity on parietal region, but the effects of pictures focus on frontal region. In both materials, the old-new effects of remember activated stronger than that of similarity.Experiment two aims to explore whether early phase of working memory determines the successful forming of episodic long-term memory. Our results showed that there have interference effects on words and pictures, i.e. there have not significant variance between ERPs wave of working memory task when episodic source can be successful recalled and that of working memory task when episodic source can not be successful recalled. The other hand, there has material specific on old-new effects. The parietal region was activated in words' old-new effects, whereas the frontal region in pictures' old-new effects. Moreover, this effects of remember activated stronger than that of similarity. It is noted that the parietal old-new effects showed a significant reduction when present an interference stimuli during the early phase of working memory.The final experiment aims to study whether late phase of working memory is a automatic process, which cannot effect the successful forming of episodic long-term memory. We find that similar to experimental one there has working memory effect on both words and pictures. And, the old-new effect in words and pictures were similar to prior two experiments.In conclusion, the findings of current study are as followings. Firstly, working memory task play a crucial role to form episodic long-term memory, which no material-specific. Secondly, the brain regions activated by various materials are not similar, in detail the frontal region in pictures but the central brain in words. Thirdly, early phase of working memory has more decisive to form successful long-term memory. Moreover, late phase of working memory has not stronger effects than early phase although we cannot say the late phase was not any effects. Fourthly, the old-new effects of words focus on the activity at parietal region but that of picturesfocus on the frontal region. Finally, our study show that the activated brain was similar by remember and similarity. The results suggested that it may be a quantitative difference between remember and similarity.The above findings confirm that working memory play a crucial role in the successful forming of episodic long-term memory in spite of materials. Meanwhile, our study suggests that early phase of working memory has more decisive than late phase of it. The findings provide further supports to make better understanding the relationship between working memory and long-term memory.