Short-Term Memory: Psychological and Neural Aspects

'Short-term memory' refers to a number of systems, with limited capacities, which secure the temporary (in the range of seconds) retention of a variety of materials. Short-term memory systems are distinct from the more peripheral and short-lasting components of echoic memory for auditory stimuli, and iconic memory for visual stimuli. The three more extensively investigated short-term memory systems include: a phonological component, concerned with the retention of verbal material; a visual component, involved in recognition memory for objects; and a spatial component, retaining information about location. The general functional architecture of short-term memory includes a store and a rehearsal process, which preserves the temporary trace. These three retention systems are functionally independent, have discrete neural correlates in the association cortical areas, and may be selectively disrupted by brain damage. Phonological short-term memory is a mainly left-hemisphere-based system, including the posterior-inferior parietal (store component), and premotor (rehearsal component) regions. Memory for spatial location is a mainly right-hemisphere-based system, comprising the association occipital, posterior parietal, and dorsolateral frontal cortices ('dorsal visual stream'). Visual recognition memory for objects is associated with a network including the association occipital, temporal, and frontal cortices ('ventral visual stream'), possibly with a greater contribution from the left hemisphere. Short-term memory systems, in addition to supporting temporary retention for a variety of purposes, participate in the long-term learning of new information. One such case is the acquisition of new vocabulary in native or second language by children and adults.