The nature of early memory

Despite tremendous gains in our understanding of the development of memory during the infancy period, relatively little is known about the neural bases of early memory. This is unfortunate, as elucidating the neurobiological mechanisms that mediate changes in memory would likely yield important insight into the concept of infantile amnesia, that is, the inability to recall those events that occur during the first 3-4 years of life. This paper begins by describing the major types of memory adults are capable of and the corresponding neural substrate of each type. A brief exposition of the neural bases of memory development is then provided, including a description of recent work that examines long-term memory in infancy. It is concluded that maturation of cortical areas in the temporal and frontal cortices that transpires between the ages of 1 and 4 years likely accounts for our lack of access to our earliest memories. It is also argued that the examination of the electrophysiological correlates of memory development may shed light on these cortical changes.