Wes Nichols

Nichols, Wes

doi:10.1287/7344689d-7ff2-47d3-8989-e1effd71b344

Cited by 2 publications

(2 citation statements)

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“…For both negative and positive effects, we also reported the results of a conjunction analysis (Nichols et al, 2005) which specifies regions where both variables are significantly below zero (for negative effects, top row in Figure 2) or above zero (for positive effects, bottom row in Figure 2). This conjunction analysis was performed as described in (Nichols et al, 2005) using Tom Nichol's easythresh_conj.sh script (Nichols, 2019). The third analysis was performed as two one sample t-tests with FSL randomise (5000 permutations, p < 0.01) on the signed differences (i.e., both inverse decision entropy minus subjective value and subjective value minus inverse decision entropy) between the Z statistics estimated at the second level GLM after pooling estimates with a fixed effects model across the four runs.…”

Section: Model-based Fmrimentioning

confidence: 99%

Subjective value and decision entropy are jointly encoded by aligned gradients across the human brain

Bobadilla-Suarez

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2020

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We evaluated whether the brain organises value and confidence signals in a systematic fashion that reflects the overall desirability of decision options. If so, regions that respond positively to increases in value should also respond positively to increases in confidence. Likewise, regions that respond negatively to both value and confidence should be widespread. We strongly confirmed these predictions through a model-based fMRI analysis of a mixed gambles task that assessed subjective value (SV) and inverse decision entropy (iDE), which is related to confidence. Purported value areas more strongly signalled iDE than SV, underscoring how intertwined value and confidence are.Smooth maps tied to the desirability of actions transitioned from positive SV and iDE in ventromedial prefrontal cortex to negative SV and iDE in dorsal medial prefrontal cortex. This non-accidental organisation of SV and iDE signals was found across the brain and was strongest in purported value areas.

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Section: Model-based Fmrimentioning

confidence: 99%

Subjective value and decision entropy are jointly encoded by aligned gradients across the human brain

Bobadilla-Suarez

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Love

2020

Preprint

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“…Laboratory infrastructure, sample transportation and storage problems are the main challenges that affect HIV-1 RNA viral load quantification in developing countries [ 22 , 23 ]. Ethiopia is among high HIV prevalent countries with a recent national prevalence of 0.9% [ 24 ] and according to the latest spectrum modeling, an estimated 610,335 people were living with HIV in 2018 [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of sample management on quantitative HIV-1 viral load measurement at Saint Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia

et al. 2022

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Purpose This study was meant to determine the effect of time to plasma separation, storage duration, freeze-thawing cycle and dilution proportion on the HIV-1 viral load level. Methods Experimental study design was employed by collecting 10mL whole blood samples into two EDTA tubes from 88 eligible HIV infected patients at St Paul’s Hospital Millennium Medical College. The viral load test was done using Abbott m2000sp/rt analyzer. Data was entered into Microsoft excel and analyzed by SPSS version 20. Repeated measure analysis of variance was used to compare HIV RNA viral load mean difference between different time to plasma separation, storage, freeze-thawing cycles and dilution levels. Post-hoc analysis was employed to locate the place of significant differences. P value less than 0.05 was used to declare statistical significance while viral RNA level of 0.5 log copies/ml was used to determine clinical significance. Results There was significant HIV-1 RNA viral load log mean difference between plasma separation time at 6 hours (hrs) and 24hrs (p<0.001). There was also significant HIV-1 RNA viral load log mean difference between plasma tested within 6hrs and those stored at 2–8°C for 15 days (p = 0.006), and between plasma stored at 2–8°C for 6 days versus 15 days (p<0.001). There was significant log mean difference between plasma that was exposed to fourth cycle of freeze-thawing after storage at -20°C when compared with plasma tested within 6hrs (p = 0.013). Conclusion Plasma separated at 24hrs, stored at 2–8°C for 15 days or freeze-thawed for four cycles had significant effect on HIV viral load level. However, the differences were not clinically significant at a cut-off viral load level of 0.5 log copies/ml. Avoiding delays to plasma separation beyond 24 hrs, storing at 2–8°C for 15 days and freeze-thawing for no more than 4 cycles is recommended to improve the result quality.

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Wes Nichols

Cited by 2 publications

References 0 publications

Subjective value and decision entropy are jointly encoded by aligned gradients across the human brain

Subjective value and decision entropy are jointly encoded by aligned gradients across the human brain

Effect of sample management on quantitative HIV-1 viral load measurement at Saint Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia

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