The role of executive function in autobiographical memory retrieval: does the type of cue word matter?

Autobiographical memories are memories for personally experienced life events. Previous research has revealed individual differences in the ability to recall specific memories that happened at a particular time and place. Some studies suggest such differences can be attributed to the varying capacity of executive function. However, little is known regarding which specific executive function skills predict autobiographical memory specificity. Participants were asked to complete multiple measures of executive function as well as an autobiographical memory task in which they were asked to recall a specific personal memory connected to concrete and abstract cue words. We hypothesised that executive function will be positively related to autobiographical memory specificity and that this relation will be moderated by the cue word type. The results revealed that individuals with higher executive function skills, specifically, higher inhibitory control and cognitive flexibility, recalled significantly more specific memories than those with lower executive function skills; however, no significant interaction between executive function ability and cue word type was found.

Developmental differences in the neural correlates of relational encoding and recall in children: an event-related fMRI study.

Despite vast knowledge on the behavioral processes mediating the development of episodic memory, little is known about the neural mechanisms underlying these changes. We used event-related fMRI to examine the neural correlates of both encoding and recall processes during an episodic memory task in two different groups of school age children (8-9 and 12-13 years). The memory task was composed of an encoding phase in which children were presented with a series of unrelated pictorial pairs, and a retrieval phase during which one of these items acted as a cue to prompt recall of the paired item. Age-related differences in activations were observed for both encoding and recall. Younger children recruited additional regions in the right dorsolateral prefrontal and right temporal cortex compared to older children during successful encoding of the pairs. During successful recall, older children recruited additional regions in the left ventrolateral prefrontal and left inferior parietal cortex compared to younger children. The results suggest that the prefrontal cortex contributes to not only the formation of memories but also access to them, and this contribution changes with development. The protracted development of the prefrontal cortex has implications for our understanding of the development of episodic memory.

It's all about location, location, location: children's memory for the "where" of personally experienced events.

Episodic memory is defined as the ability to recall specific past events located in a particular time and place. Over the preschool and into the school years, there are clear developmental changes in memory for when events took place. In contrast, little is known about developmental changes in memory for where events were experienced. In the current research, we tested 4-, 6-, and 8-year-old children's memories for specific laboratory events, each of which was experienced in a unique location. We also tested the children's memories for the conjunction of the events and their locations. Age-related differences were observed in all three types of memory (event, location, and conjunction of event and location), with the most pronounced differences being in memory for conjunctions of events and their locations. The results have implications for our understanding of the development of episodic memory, including suggestions of protracted development of the ability to contextualize events in their spatial locations.

An exploratory study of brain function and structure in mucopolysaccharidosis type I: long term observations following hematopoietic cell transplantation (HCT).

AIM: Although hematopoietic cell transplantation (HCT) arrests the cognitive decline in mucopolysaccharidosis type IH (Hurler syndrome, MPS IH), these children continue to have neuropsychological deficits as they age. Both compromised attention and effects on white matter have been observed in cancer patients who have had chemotherapy. Therefore, we explored the effects of disease and treatment on brain function in children with MPS I who have had HCT with those with attenuated MPS I treated with enzyme replacement therapy (ERT). SUBJECTS: 7 MPS IH participants at least 5 years post-HCT were compared with 7 attenuated participants who were treated with ERT. MEASURES: IQ, attention, spatial ability, and memory were assessed. Medical history and an unsedated MRI scan using diffusion tensor imaging (DTI) were acquired. RESULTS: Despite clinically equivalent IQ and memory, children with MPS IH had poorer attention span than those with attenuated MPS I as well as decreased fractional anisotropy (FA) of the corpus callosum. A relationship between attention scores and FA was found in the MPS IH group but not the attenuated group. FA was also related to the frequency of medical events. INTERPRETATION: In children with MPS IH, both the treatment and the disease affect attention functions associated with poor white matter integrity.

Electrophysiological evidence of altered memory processing in children experiencing early deprivation.

Associations between early deprivation and memory functioning were examined in 9- to 11-year-old children. Children who had experienced prolonged institutional care prior to adoption were compared to children who were adopted early from foster care and children reared in birth families. Measures included the Paired Associates Learning task from the Cambridge Neuropsychological Test and Automated Battery (CANTAB) and a continuous recognition memory task during which ERPs were also recorded. Children who experienced prolonged institutionalization showed deficits in both behavioral memory measures as well as an attenuated P300 parietal memory effect. Results implicate memory function as one of the domains that may be negatively influenced by early deprivation in the form of institutional care.

Equal Learning Does Not Result in Equal Remembering: The Importance of Post-Encoding Processes.

Explanations of variability in long-term recall typically appeal to encoding and/or retrieval processes. However, for well over a century, it has been apparent that for memory traces to be stored successfully, they must undergo a post-encoding process of stabilization and integration. Variability in post-encoding processes is thus a potential source of age-related and individual variance in long-term recall. We examined post-encoding variability in each of two experiments. In each experiment, 20-month-old infants were exposed to novel three-step sequences in each of three encoding conditions: watch only, imitate, and learn to criterion. They were tested for recall after 15 min (as a measure of the success of encoding) and either weeks (1, 2, or 3: Experiment 1) or days (1, 2, or 4: Experiment 2) later. In each experiment, differential relative levels of performance among the conditions were observed at the two tests. The results implicate post-encoding processes are a source of variance in long-term recall.

Using cue words to investigate the distribution of autobiographical memories in childhood.

The cue-word technique is frequently used with adults to examine the distribution of autobiographical memories across the life span. Such studies demonstrate childhood amnesia: a paucity of memories of events from the first 3(1/2) years of life, and a gradually increasing number of memories from age 3 to age 7. The pattern is remarkable in light of findings of autobiographical competence among children in the period of life eventually obscured by this amnesia. In the present study, we modified the cue-word task for use with school-age children. Seven- to 10-year-olds successfully generated and dated memories of past events. Girls provided more complete narratives than boys. Across the sample, the resulting distribution of memories was better fit by an exponential than by a power function, implying that early memories may not consolidate and instead remain vulnerable to interference. Implications for explanations of childhood amnesia are discussed.