Inter-individual variation shapes the human microbiome

2019 ◽  
Vol 42 ◽  
Author(s):  
Emily F. Wissel ◽  
Leigh K. Smith

Abstract The target article suggests inter-individual variability is a weakness of microbiota-gut-brain (MGB) research, but we discuss why it is actually a strength. We comment on how accounting for individual differences can help researchers systematically understand the observed variance in microbiota composition, interpret null findings, and potentially improve the efficacy of therapeutic treatments in future clinical microbiome research.

Author(s):  
C. Terlouw ◽  
A.B. Lawrence ◽  
A.W. Illius

Animals show considerable individual variation in many behaviour patterns such as feeding and mating behaviour. Often, this individual variability is ignored in favour of a more general description of the population. However, this may mask important information regarding the causes and functions of this individual variability. Behavioural work on other species has suggested that individuals tend to respond actively or passively to environmental challenge. It is of interest to know if a similar dimension of responsiveness exists in pigs as it may serve, amongst other things, to explain the considerable individual variability in pigs responses to putitive stresses such as tethered housing. This paper describes a series of tests made of behavioural responsiveness in pigs to assess the extent of consistent variability in individuals responses to a wide variety of environmental challenges.The subjects were two groups [Group A and B: n = 26 and 36 respectively) of modern hybrid non-pregnant gilts [Cotswold Pig Development Company Ltd, UK). Initially, the gilts were subjected to a number of tests of behavioural responsiveness at the Cotswold unit.


1968 ◽  
Vol 27 (2) ◽  
pp. 499-504 ◽  
Author(s):  
A. V. Carron ◽  
J. L. Leavitt

50 boys, age 14 to 15 yr., were tested on a tracking task (pursuit rotor) and a large-muscle motor-learning task (stabilometer) to examine the effect of relatively massed practice upon individual differences and intra-individual variation. The practice schedule, which was identical for both tasks, called for 20 50-sec. practice trials with a 10-sec. intertrial rest period. A 5-min. rest was also interpolated every fourth trial. The greatest change in individual differences and intra-individual variation in both tasks occurred during the first 4 practice trials and in the 5-min. interpolated rest which immediately followed. Additional practice and interpolated rest over the remaining 15 practice trials had little additional effect upon either of the sources of variation. The changes in the sources of variation did not, with the exception of intra-individual variability in the stabilometer, appear to be proportional to changes in the mean.


2019 ◽  
Author(s):  
Ting Xu ◽  
Darrick Sturgeon ◽  
Julian S.B. Ramirez ◽  
Seán Froudist-Walsh ◽  
Daniel S. Margulies ◽  
...  

ABSTRACTBackgroundNonhuman primate models (NHP) are commonly used to advance our understanding of brain function and organization. However, to date, they have offered few insights into individual differences among NHPs. In large part, this is due to the logistical challenges of NHP research, which limit most studies to five subjects or fewer.MethodsWe leveraged the availability of a large-scale open NHP imaging resource to provide an initial examination of individual differences in the functional organization of the nonhuman primate brain. Specifically, we selected one awake fMRI dataset (Newcastle: n = 10) and two anesthetized fMRI data sets (Oxford: n = 19; UC-Davis: n = 19) to examine individual differences in functional connectivity characteristics across the cortex, as well as potential state dependencies.ResultsWe noted significant individual variations of functional connectivity across the macaque cortex. Similar to the findings in human, during the awake state, the primary sensory and motor cortices showed lower variability than the high-order association regions. This variability pattern was significantly correlated with T1w/T2w map, the degree of long-distance connectivity, but not short-distance connectivity. However, the inter-individual variability under anesthesia exhibited a very distinct pattern, with lower variability in medial frontal cortex, precuneus and somatomotor regions and higher variability in the lateral ventral frontal and insular cortices.ConclusionsThis work has implications for our understanding of the evolutionary origins of individual variation in the human brain, as well as methodological implications that must be considered in any pursuit to study individual variation in NHP models.


2018 ◽  
Vol 41 ◽  
Author(s):  
Benjamin C. Ruisch ◽  
Rajen A. Anderson ◽  
David A. Pizarro

AbstractWe argue that existing data on folk-economic beliefs (FEBs) present challenges to Boyer & Petersen's model. Specifically, the widespread individual variation in endorsement of FEBs casts doubt on the claim that humans are evolutionarily predisposed towards particular economic beliefs. Additionally, the authors' model cannot account for the systematic covariance between certain FEBs, such as those observed in distinct political ideologies.


1986 ◽  
Vol 56 (03) ◽  
pp. 371-375 ◽  
Author(s):  
Peretz Weiss ◽  
Hillel Halkin ◽  
Shlomo Almog

SummaryWithin-individual variation over time in the clearance (Cl) and effect (PT%) of warfarin, was measured in 25 inpatients (group I) studied after standard single or individualized split loading doses and 1-3 times (n = 16) 8-16 weeks later during maintenance. Mean Cl (2.5 α 0.9 ml/min) was similar in both phases but significant changes occurred in 6/16 patients, exceeding those expected from within-individual variation alone (defined by its 95% tolerance limits -24% to +62%). Initial PT% (21 α 5) was unaffected by dosing schedule, total or free plasma warfarin, varying between patients by only 18-24%. Mean initial and maintenance dose-PT% ratios (8.2 mg/d: 21% and 4.1 mg/d: 40%) were similar but significant changes in sensitivity to warfarin occurred in 4/16 patients. In group I and 64 other outpatients on maintenance therapy, between-individual variability was 36-52% for Cl and 49-56% for effect. PT% correlated best (r = 0.56) with free and total plasma warfarin but poorly with dose (r = 0.29), with only 30% of PT% variance explained at best, due to high between patient variability.Warfarin dose prediction whether based on extrapolation from initial effects to the maintenance phase, or on iterative methods not allowing for between- or within-patient variation in warfarin clearance or effect which may occur independently over time, have not improved on empirical therapy. This, due to the elements of biological variability as well as the intricacy of the warfarin - prothrombin complex interaction not captured by any kinetic-dynamic model used for prediction to date.


2021 ◽  
Vol 42 (2) ◽  
pp. 417-446
Author(s):  
Hasibe Kahraman ◽  
Bilal Kırkıcı

AbstractResearch into nonnative (L2) morphological processing has produced largely conflicting findings. To contribute to the discussions surrounding the contradictory findings in the literature, we examined L2 morphological priming effects along with a transposed-letter (TL) methodology. Critically, we also explored the potential effects of individual differences in the reading networks of L2 speakers using a test battery of reading proficiency. A masked primed lexical decision experiment was carried out in which the same target (e.g., ALLOW) was preceded by a morphological prime (allowable), a TL-within prime (allwoable), an substituted letter (SL)-within prime (allveable), a TL-across prime (alloawble), an SL-across prime (alloimble), or an unrelated prime (believable). The average data yielded morphological priming but no significant TL priming. However, the results of an exploratory analysis of the potential effects of individual differences suggested that individual variability mediated the group-level priming patterns in L2 speakers. TL-within and TL-across priming effects were obtained only when the performance of participants on nonword reading was considered, while the magnitude of the morphological priming effects diminished as the knowledge of vocabulary expanded. The results highlight the importance of considering individual differences while testing L2 populations.


2020 ◽  
Vol 86 (22) ◽  
Author(s):  
Manuel G. García ◽  
María D. Pérez-Cárceles ◽  
Eduardo Osuna ◽  
Isabel Legaz

ABSTRACT Numerous studies relate differences in microbial communities to human health and disease; however, little is known about microbial changes that occur postmortem or the possible applications of microbiome analysis in the field of forensic science. The aim of this review was to study the microbiome and its applications in forensic sciences and to determine the main lines of investigation that are emerging, as well as its possible contributions to the forensic field. A systematic review of the human microbiome in relation to forensic science was carried out by following PRISMA guidelines. This study sheds light on the role of microbiome research in the postmortem interval during the process of decomposition, identifying death caused by drowning or sudden death, locating the geographical location of death, establishing a connection between the human microbiome and personal items, sexual contact, and the identification of individuals. Actinomycetaceae, Bacteroidaceae, Alcaligenaceae, and Bacilli play an important role in determining the postmortem interval. Aeromonas can be used to determine the cause of death, and Corynebacterium or Helicobacter pylori can be used to ascertain personal identity or geographical location. Several studies point to a promising future for microbiome analysis in the different fields of forensic science, opening up an important new area of research.


2016 ◽  
Vol 33 (S1) ◽  
pp. S504-S505
Author(s):  
C. Cotta ◽  
G. Jesus ◽  
V. Vila Nova ◽  
C. Moreira

IntroductionThere is growing evidence of the importance of nutrition in mental disorders. Gut microbiota, influenced by environmental factors such as diet and stress, has been proposed as one of the players on a dynamic called gut-brain axis, which is thought to have an influence on behaviour and mental health.Objectives and aimsTo summarize recent evidence on the topic, and its potential role in psychiatric interventions.MethodsThe authors review updated literature collected from online scientific databases.ResultsThe development of the brain itself has been shown to be influenced by the gut microbiome. Research demonstrates that the composition of the microbiota has influence on behaviour through neuroendocrine and other neuroactive messengers production by the bacteria within the gut lumen. Studies in germ-free animals, animals exposed to bacterial infections, probiotic suplements or antibiotic drugs suggest a role for the gut microbiota in the regulation of anxiety, mood, cognition and pain. The gut microbiome has been implicated in brain disorders including anxiety and depression, multiple sclerosis, Alzheimer's disease, Parkinson's disease, and autism.ConclusionsThe treatment of mental disorders is usually based on pharmacological and psychotherapeutic interventions, and little attention is given to dietary interventions. The emerging field of research focused on the human microbiome suggests an important role for the gut microbiota in influencing brain development, behaviour and mood in humans, and points new strategies for developing novel therapeutics for mental disorders.Disclosure of interestThe authors have not supplied their declaration of competing interest.


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