Differential development of relational memory and pattern separation.

Researchers have taken a number of different approaches in their exploration of hippocampal function. One approach seeks to describe hippocampal function by probing the memory representations that the hippocampus supports. Another approach focuses on the role of the hippocampus in pattern separation and completion. Each of these approaches to understanding hippocampal function utilizes a distinct set of specialized tasks, and both of these task sets are known to be sensitive to changes in hippocampal function with age and disease status. But the question remains whether the tasks utilized in these two approaches tap into the same aspects of hippocampal function. We explored this question in the context of hippocampal development. Preadolescent children (N = 73) and young adults (N = 41) completed an identical battery of cognitive tasks consisting of a spatial reconstruction relational memory task, the mnemonic similarity task (MST)-an object-based pattern separation task, and a novel hybrid task-the Object Discrimination and Distribution (ODD) Task-designed to integrate and simultaneously tax pattern separation and spatial relational memory. Children did not demonstrate impairments in lure discrimination relative to young adults on either the object-based pattern separation task or for aspects of the ODD task that required pattern separation in the absence of relational memory demands but performed more poorly across aspects of tasks that required relational binding.

Added sugar and dietary fiber consumption are associated with creativity in preadolescent children.

Objectives: Creativity requires the ability to combine existing mental representations in new ways and depends, in part, on the hippocampus. Hippocampal function is, in turn, affected by a number of health factors, including aerobic fitness, excess adiposity, and diet. Specifically, in rodent studies, diets high in saturated fatty acids and sugar - hallmarks of a western diet- have been shown to negatively impact hippocampal function and thereby impair performance on cognitive tasks that require the hippocampus. Yet relatively few studies have examined the relationship between diet and hippocampal-dependent cognition in children. Methods: The current study therefore sought to explore the relationship of several diet quality markers including dietary lipids (saturated fatty acids and omega-3 fatty acids), simple carbohydrates (added sugars), and dietary fiber with creativity in preadolescent children. Participants (N = 57; mean age = 9.1 years) completed the Verbal Form of the Torrance Test of Creative Thinking (TTCT), a standardized test of creativity known to require the hippocampus. Additionally, participants completed a 3-day food intake record with the assistance of a parent, underwent dual energy x-ray absorptiometry (DXA) to assess central adiposity, and VO2max testing to assess aerobic fitness. Results: Added sugar intake was negatively associated, and dietary fiber was positively associated with overall TTCT performance. These relationships were sustained even after controlling for key covariates. Discussion: These findings are among the first to report an association between added sugar consumption and hippocampal-dependent cognition during childhood and, given the key role of the hippocampus in learning and memory, as well as creative thinking, have potential educational and public health implications.

Macular Carotenoids, Aerobic Fitness, and Central Adiposity Are Associated Differentially with Hippocampal-Dependent Relational Memory in Preadolescent Children.

OBJECTIVES: To examine the associations of macular pigment carotenoids (lutein, meso-zeaxanthin, and zeaxanthin), aerobic fitness, and central adiposity with hippocampal-dependent relational memory in prepubescent children. STUDY DESIGN: Children between 7 and 10 years of age (n = 40) completed a task designed to assess relational memory performance and participated in aerobic fitness, adiposity, and macular pigment optical density (MPOD) assessment. Aerobic fitness was assessed via a modified Balke treadmill protocol designed to measure maximal oxygen volume. Central adiposity was assessed via dual-energy x-ray absorptiometry. MPOD was measured psychophysically by the use of customized heterochromatic flicker photometry. Statistical analyses included correlations and hierarchical linear regression. RESULTS: Aerobic fitness and MPOD were associated negatively with relational memory errors (P < .01), whereas central adiposity was associated positively with relational memory errors (P < .05). Hierarchical regression analysis revealed that MPOD accounted for a significant amount of the variance in relational memory performance even after we accounted for aerobic fitness (ß = -0.388, P = .007). CONCLUSIONS: Even after we adjusted for aerobic fitness and central adiposity, factors known to relate to hippocampal-dependent memory, MPOD positively and significantly predicted hippocampal-dependent memory performance. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01619826.

Serum Lutein is related to Relational Memory Performance.

Dietary carotenoids, plant pigments with anti-oxidant properties, accumulate in neural tissue and are often found in lower concentrations among individuals with obesity. Given previous evidence of negative associations between excess adiposity and memory, it is possible that greater carotenoid status may confer neuroprotective effects among persons with overweight or obesity. This study aimed to elucidate relationships between carotenoids assessed in diet, serum, and the macula (macular pigment optical density (MPOD)) and relational memory among adults who are overweight or obese. Adults aged 25-45 years (N = 94) completed a spatial reconstruction task. Task performance was evaluated for accuracy of item placement during reconstruction relative to the location of the item during the study phase. Dietary carotenoids were assessed using 7-day diet records. Serum carotenoids were measured using high-performance liquid chromatography. Hierarchical linear regression analyses were used to determine the relationship between carotenoids and task performance. Although initial correlations indicated that dietary lutein, beta-carotene, and serum beta-carotene were positively associated with memory performance, these relationships were not sustained following adjustment for age, sex, and BMI. Serum lutein remained positively associated with accuracy in object binding and inversely related to misplacement error after controlling for covariates. Macular carotenoids were not related to memory performance. Findings from this study indicate that among the carotenoids evaluated, lutein may play an important role in hippocampal function among adults who are overweight or obese.

Resting state cortico-cerebellar functional connectivity networks: a comparison of anatomical and self-organizing map approaches.

The cerebellum plays a role in a wide variety of complex behaviors. In order to better understand the role of the cerebellum in human behavior, it is important to know how this structure interacts with cortical and other subcortical regions of the brain. To date, several studies have investigated the cerebellum using resting-state functional connectivity magnetic resonance imaging (fcMRI; Krienen and Buckner, 2009; O'Reilly et al., 2010; Buckner et al., 2011). However, none of this work has taken an anatomically-driven lobular approach. Furthermore, though detailed maps of cerebral cortex and cerebellum networks have been proposed using different network solutions based on the cerebral cortex (Buckner et al., 2011), it remains unknown whether or not an anatomical lobular breakdown best encompasses the networks of the cerebellum. Here, we used fcMRI to create an anatomically-driven connectivity atlas of the cerebellar lobules. Timecourses were extracted from the lobules of the right hemisphere and vermis. We found distinct networks for the individual lobules with a clear division into "motor" and "non-motor" regions. We also used a self-organizing map (SOM) algorithm to parcellate the cerebellum. This allowed us to investigate redundancy and independence of the anatomically identified cerebellar networks. We found that while anatomical boundaries in the anterior cerebellum provide functional subdivisions of a larger motor grouping defined using our SOM algorithm, in the posterior cerebellum, the lobules were made up of sub-regions associated with distinct functional networks. Together, our results indicate that the lobular boundaries of the human cerebellum are not necessarily indicative of functional boundaries, though anatomical divisions can be useful. Additionally, driving the analyses from the cerebellum is key to determining the complete picture of functional connectivity within the structure.