Biology subjects

Preston, M.

Publications and source records attributed to Preston, M..

3 recordsLinked to original sources

bioRxiv2022

Oscillations and aperiodic activity: Evidence for dynamic changes in both during memory encoding

Electrical recordings of human brain activity via electroencephalography (EEG) show prominent, rhythmic voltage fluctuations. These periodic oscillations have been linked to nearly every cognitive and perceptual process, as well numerous disease states. Recent methodological and theoretical advances, however, have given rise to evidence for a functional role for non-oscillatory, aperiodic neural activity. Physiologically, this aperiodic activity has been linked to the relative contributions of neuronal excitatory and inhibitory signaling. Most importantly, however, traditional data analysis methods often conflate oscillations and aperiodic activity, masking the potentially separate roles these processes play in perception, cognition, and disease. Here we present a reanalysis of intracranial human EEG recordings from Fellner et al., 2019, using new methods for separately parameterizing oscillations and aperiodic activity in a time-resolved manner. We find that human memory encoding is not related to just oscillations or aperiodic activity, but rather that both processes are rapidly co-modulated during memory encoding. These results provide strong evidence for event-related dynamics of aperiodic and oscillatory activity in human memory, paving the way for future investigations into the unique functional roles of these two independent, but linked, processes in human cognition.

neuroscience↗

bioRxiv2021

Are some commercial diets inadequate in essential nutrients?

BackgroundCommercial manufacturers have formulated diets to promote not only weight reduction but also to reduce risks of chronic diseases. The objective of this study is to determine if these formulations satisfy requirements for essential nutrients. MethodsWe have selected two established commercial diets, one low fat, high carbohydrate (diet 1) and the other, high fat, low carbohydrate (diet 2) and determined "representative meals" through use of recipes suggested in the manufacturers manuals. Nutrition Data System for Research (NDSR) software has been used to perform the most extensive nutrient analysis to date of these diets. Tables report macronutrients (energy), vitamins, minerals, essential amino acids, essential lipids and nutrient-related components for a total of 62entries. ResultsDiet 1 satisfied requirements for 50 of these (81%) with only vitamin B12, vitamin D, and essential fatty acids not reaching recommended levels, while fiber and glycemic load exceeded suggested values. Diet 2 satisfied requirements for 46 of the components (71%) but had excess percentage of fat, especially saturated fat, sodium and cholesterol as well as decreased percentage of carbohydrate resulting in suboptimal intake of B-complex vitamins (B1, niacin and total folate) as well as fiber. ConclusionsNeither diet satisfied adequacy for all reported nutrients. However, based on nutrient content alone diet 1, if supplemented or modified, could be sustained over the long term whereas diet 2 should not be encouraged for long term adaptation

scientific communication and education↗

bioRxiv2017

Targeted capture of complete coding regions across divergent species

Despite continued advances in sequencing technologies, there is a need for methods that can efficiently sequence large numbers of genes from diverse species. One approach to accomplish this is targeted capture (hybrid enrichment). While these methods are well established for genome resequencing projects, cross-species capture strategies are still being developed and generally focus on the capture of conserved regions, rather than complete coding regions from specific genes of interest. The resulting data is thus useful for phylogenetic studies, but the wealth of comparative data that could be used for evolutionary and functional studies is lost. Here we design and implement a targeted capture method that enables recovery of complete coding regions across broad taxonomic scales. Capture probes were designed from multiple reference species and extensively tiled in order to facilitate cross-species capture. Using novel bioinformatics pipelines we were able to recover nearly all of the targeted genes with high completeness from species that were up to 200 myr divergent. Increased probe diversity and tiling for a subset of genes had a large positive effect on both recovery and completeness. The resulting data produced an accurate species tree, but importantly this same data can also be applied to studies of molecular evolution and function that will allow researchers to ask larger questions in broader phylogenetic contexts. Our method demonstrates the utility of cross-species approaches for the capture of full length coding sequences, and will substantially improve the ability for researchers to conduct large-scale comparative studies of molecular evolution and function.

evolutionary biology↗