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In other words, SM is specific to the stimulus' modality of presentation. Nevertheless, one hears the terms STM and WM often used interchangeably.įurthermore, one must distinguish STM from the ‘sensory memory’ (SM) such as the acoustical echoic and iconic visual memories which are shorter in duration (fraction of a second) than STM and reflect the original sensation, or perception, of the stimulus.

STM, indeed, is a set of storage systems whereas WM indicates the cognitive operations and executive functions associated with the organization and manipulation of stored information.

The former concerns broad knowledge of facts, rules, concepts, and propositions ('general knowledge'), the latter is related to personal and experienced events and the contexts in which they occurred ('personal recollection').Īlthough STM is closely related to the concept of ‘working memory’ (WM), STM and WM represent two distinct entities. Declarative memory includes semantic and episodic memory.

On the other side, information collected in the LTM storage consist of memories for the performance of actions or skills (i.e., procedural memories, “knowing how”) and memories of facts, rules, concepts, and events (i.e., declarative memories, “knowing that”). Practically, STM works as a kind of “scratchpad” for temporary recall of a limited number of data (in the verbal domain, roughly the George Miller’s ‘magical’ number 7 +/- 2 items) that come from the sensory register and are ready to be processed through attention and recognition. Nevertheless, the two systems are closely related. The difference between the two memories, however, is not just in the 'time' variable but is above all functional. In contrast, long-term memory (LTM) may hold an indefinite amount of information. The memory enhancement and transition of the memristor device was explained from the microscopic picture of impurity redistribution and can be qualitatively described by the same equations governing biological memories.Short-term memory (STM), also referred to as short-term storage, or primary or active memory indicates different systems of memory involved in the retention of pieces of information (memory chunks) for a relatively short time (usually up to 30 seconds). We verify that not only the shape or the total number of stimuli is influential, but also the time interval between stimulation pulses (i.e., the stimulation rate) plays a crucial role in determining the effectiveness of the transition. By stimulating the memristor with repeated voltage pulses, we observe an effect analogous to memory transition in biological systems with much improved retention time accompanied by additional structural changes in the memristor. In this study, we show experimentally that the retention loss in a nanoscale memristor device bears striking resemblance to memory loss in biological systems. Eventually, only memories that are of significance are transformed from short-term memory into long-term memory through repeated stimulation. Yet, forgetfulness is not always a disadvantage since it releases memory storage for more important or more frequently accessed pieces of information and is thought to be necessary for individuals to adapt to new environments. Unlike modern semiconductor memory devices, needless to say, human memory is by no means eternal. "Memory" is an essential building block in learning and decision-making in biological systems.