Table of Contents
Participants
My sample population will be comprised of 100 typically developing children (with no neurological damage or developmental disorders). Ideally, children will be recruited from different socioeconomic statuses (SES) and races so that these variables do not act as confounds. With a variety of SES and races included in the study, the sample should be generalizable for children between the ages of 4 and 7 that reside in the United States.
This population will be useful to use as participants because as we grow up, autobiographical memories from our early childhood (before age 6) tend to dissipate and we are unable to recall many experiences and memories from this time period despite being able to initially recall them as a child (Riggins, Geng, Blankenship, & Redcay, 2016). As such, the long-term effects and implications of sleep on children’s memory consolidation capacity is a very compelling topic for this age group.
Recruitment and Compensation
Children will be randomly selected from school districts with different SES in order to make sure the sample is generalizable and results are not biased towards a certain SES or race. Participants will receive small toy prizes for their participation in the study during each visit (e.g., a yo-yo, stickers etc.). Additionally, the families of these children will receive monetary compensation for their child’s participation. Since the study is longitudinal in nature and requires long-lasting visits as well as multiple scans in an MRI, families will receive $100 per visit in correspondence to their child’s participation.
127 our experts are availableright now
Exclusion Criteria
In order to ensure that the data will be generalizable to children between the ages of 4 and 7 that reside in the United States, there are several exclusion criteria for this study. Firstly, children with any known neurological damage or developmental disorders will not be eligible to participate. Secondly, children outside of the designated age range (4 to 7 years old) as well as non-native English speakers and children who do not currently reside in the United States (e.g., not here just for the summer). Additionally, children with any metal in their body (e.g., pacemaker, metal plates/pins, stent etc.) will not be eligible as their participation could be potentially fatal since the MRI scanner is essentially a giant magnet. Moreover, after the scans are completed, children who exhibited excessive movement in the MRI scanner will not be included in data analysis.
Stimuli
While in the MRI scanner, children will receive either visual or auditory stimuli from playing memory games (e.g., viewing pictures or listening to stories) which they will later be asked to recall details about. Trials will be sorted according to the stimulus type (e.g., visual or auditory) and percent accuracy (e.g., # correct – # false alarms for pictures and # of correct details remembered from the story). The primary contrasts of interest given the predictions by theories about the relationship between sleep and memory are the effects of sleep versus sleep deprivation (awake condition) on memory consolidation.
Procedure
Depending on the type of visit, procedures will vary. Since the study is a longitudinal, within-participants design, visits at the Maryland Neuroimaging Center will alternate between conditions (e.g., sleep or awake). Additionally, children will come into the lab in 6 month intervals throughout the three year duration of the study and will be prompted to recall past memories or stories provided by the parents. Prior to any of these visits, the child and a parent will come in and be required to sign consent documentation.
All of the participants will first complete training in a mock scanner before any data is acquired in order to become comfortable in the scanner environment and receive motion feedback (Riggins, Geng, Blankenship, & Redcay, 2016). They will additionally be checked with a metal detector to ensure their safety throughout the procedure. The child will be asked to sit still and relax while watching a television show of their choosing. After the mock scan, during both sleep visits and awake visits, the child will go into the scanner and play a memory game. These games will consist of either remembering pictures that they saw or remembering details of a story that had listened to (e.g., either visual or auditory stimuli).
Depending on the condition, children will either be prompted to sleep or stay awake in the scanner post-learning and recall/recognition will be assessed afterwards. Once these steps are completed, the children will receive a small toy prize and will be scheduled to come in for their next visit 6 months later. This procedure will continue throughout the three year duration of the study with alternating conditions (e.g., sleep visit, awake visit, in-lab visit etc) and the families will be compensated accordingly.
Data Collection
Retrieval cues will be obtained when the children are prompted by the researcher to recall a past memory during their in-lab visit. In order to operationalize these memories, parental accounts will be used as a basis for comparison and the number of correct/matching details the child provided will be determined and scored. To obtain these quantitative measures, each session in the lab will be recorded (in 6 month intervals) then later transcribed and coded for specific variables (e.g., # of details correctly recalled).
MRI data will include both structural and functional images which will be acquired at the University of Maryland Neuroimaging Center using a 3T Siemens Trio scanner equipped with a 12-channel phased array head coil (O’Neill & Diana, 2017). The regions of interest for this study are primarily the hippocampus and the anterior temporal lobe (ATL). They are of particular interest because the hippocampus is considered the ‘center’ of memory consolidation and the anterior temporal lobe is thought to be critical for semantic memory (e.g., knowledge of people, words, facts, etc.) both of which will be tested.
Once the fMRI data is obtained, t-tests will be used to determine if there are any significant differences in children’s memory consolidation between the sleep condition and the awake condition. A priori predictions for this study are that the sleep condition will increase activation in the ATL and hippocampus during memory consolidation as compared to the awake condition in which activation in these areas is expected to decrease.
ATL regions and hippocampal regions, for which I have a priori predictions, will be assigned a minimum cluster size of 10 voxels at p < .005. Regions outside the ATL and hippocampus will be assigned a voxel threshold of p < .001 which will be combined with an FWE-corrected cluster threshold of p < .05 (as implemented in SPM8). Reported coordinates are based on the Montreal Neurological Institute (MNI) template brain.
Utilizing both fMRI data and retrieval cues will help provide a more holistic approach to better understanding children’s brain development (e.g., hippocampus and ATL) over the course of three years in conjunction with sleep and memory consolidation.
References
- Riggins, Geng, Blankenship, & Redcay (2016) – Autobiographical Memory and Sense of Self
- Maccari, Garcia-Segura, & van Reeth (2004) – Effects of Sex Steroids on Sleep and Circadian Rhythmicity
- Matthews et al. (2006) – Influence of Sex on Sleep Regulatory Mechanisms
- Microsoft Academic Search Results – Sleep and Memory research articles
- Herman-Giddens et al. (2012) – Timing of Puberty and its Effects on Obesity and Cardiometabolic Disease in Adolescence and Adulthood
- Nader-Grosbois (2014) – The Influence of Executive Functions on School Achievement in Children Aged 6 to 14: A Neuropsychological Study
