NIDM‐Results: a Neuroimaging Data Model to share brain mapping statistical results→

NIDM-Results data format for sharing neuroimaging data. Looks great!

Balancing family with a successful career in neuroscience→

Good overview with lots of helpful suggestions.

High productivity doesn’t mean squat if the things you’re getting done aren’t truly important→

Good thoughts from SVN.

You need to carve out more unproductive time. Get less done for a while. You’ll probably realize that a bunch of the shit that zaps your attention and time needn’t be done at all. Just let it slide and see that it probably just didn’t matter. Very few things ultimately do.

Productivity is all about focus, which in turn is all about a narrowing field of view. Shutting out the rest of the world. But many novel solutions require just the opposite: An expansive field of view, letting in the rest of the world.

Look, you obviously can’t have your head in the clouds all year long. But for highly motivated people that doesn’t seem to be a danger as much as having your head in the grind 24/7.

Practical policies can combat gender inequality→

So what have we done? Simply, we asked the people affected — women in their postdoctoral period — for their ideas.

For our institute, some of the simplest changes included steps to ensure that all important meetings are held within school hours, to make sure that researchers with child-care duties can attend.

We have also set up a dedicated office with hot-desks and an adjoining room in which small children can play and older children can do homework or watch television, under the supervision of their parents.

Statistically Controlling for Confounding Constructs Is Harder than You Think→

Social scientists often seek to demonstrate that a construct has incremental validity over and above other related constructs. However, these claims are typically supported by measurement-level models that fail to consider the effects of measurement (un)reliability. We use intuitive examples, Monte Carlo simulations, and a novel analytical framework to demonstrate that common strategies for establishing incremental construct validity using multiple regression analysis exhibit extremely high Type I error rates under parameter regimes common in many psychological domains. Counterintuitively, we find that error rates are highest—in some cases approaching 100%—when sample sizes are large and reliability is moderate. Our findings suggest that a potentially large proportion of incremental validity claims made in the literature are spurious. We present a web application (http://jakewestfall.org/ivy/) that readers can use to explore the statistical properties of these and other incremental validity arguments. We conclude by reviewing SEM-based statistical approaches that appropriately control the Type I error rate when attempting to establish incremental validity.

How Warren Buffet schedules meetings→

If someone wants to see him, they are told to call and set up the meeting when they can see him tomorrow. So if you want to meet with him next Friday, you call next Thursday and say “Can I see Mr. Buffet tomorrow?”

I love the simplicity of the rule: I can see you today if you asked me yesterday, but I can’t fill up my schedule any further in advance. This way he can determine how he wants to spend his time within the context of the next 24 hours instead of booking things weeks or months in the future. Now his schedule is relevant instead of prescient.

I’m sure many people will say “well, he’s Warren Buffet so he can do that”. Yes he’s Warren Buffet, but no one granted him the power to do that or say that. He decided that.

Speak up about subtle sexism in science→

Every woman, but not one man, whom I asked had a story to tell, but none had ever told it.

8 Strategies For Men To Combat Gender Bias→

Great suggestions.

1. Understand the ways that the system is biased against women and the role that we all play in maintain the status quo.
2. Revise your syllabi to include work by women.
3. Reach out to women (especially junior women) by incorporating them in professional networks and inviting them to participate in special issues and topical conferences.
4. Refuse to participate in men only events (i.e. panels, forums with all men).
5. Call out instances of bias when you see them.
6. Don’t hijack women’s conversations in professional settings, and work to ensure everyone is expected to speak in important conversations when you are in charge.
7. Ask women about their research.
8. Work to change the system when you can (advocate for parental leave policy, advocate for attention to genders issues in your department like uneven service obligation, bring up gender bias in teaching evaluations whenever this is used to evaluate faculty, advocate for back-up care, subsidized daycare, attention to public school breaks and holidays in establishing academic calendars, and spousal hiring).

The ASA's statement on p-values: context, process, and purpose→

Good summary and interesting background on the ASA's statement on p-values.

Let’s be clear. Nothing in the ASA statement is new. Statisticians and others have been sounding the alarm about these matters for decades, to little avail. We hoped that a statement from the world’s largest professional association of statisticians would open a fresh discussion and draw renewed and vigorous attention to changing the practice of science with regards to the use of statistical inference.

Task-free MRI predicts individual differences in brain activity during task performance→

Nice use of resting state and HCP data.

When asked to perform the same task, different individuals exhibit markedly different patterns of brain activity. This variability is often attributed to volatile factors, such as task strategy or compliance. We propose that individual differences in brain responses are, to a large degree, inherent to the brain and can be predicted from task-independent measurements collected at rest. Using a large set of task conditions, spanning several behavioral domains, we train a simple model that relates task-independent measurements to task activity and evaluate the model by predicting task activation maps for unseen subjects using magnetic resonance imaging. Our model can accurately predict individual differences in brain activity and highlights a coupling between brain connectivity and function that can be captured at the level of individual subjects.

Factors affecting characterization and localization of interindividual differences in functional connectivity using MRI→

Much recent attention has been paid to quantifying anatomic and functional neuroimaging on the individual subject level. For optimal individual subject characterization, specific acquisition and analysis features need to be identified that maximize interindividual variability while concomitantly minimizing intra-subject variability. We delineate the effect of various acquisition parameters (length of acquisition, sampling frequency) and analysis methods (time course extraction, region of interest parcellation, and thresholding of connectivity-derived network graphs) on characterizing individual subject differentiation. We utilize a non-parametric statistical metric that quantifies the degree to which a parameter set allows this individual subject differentiation by both maximizing interindividual variance and minimizing intra-individual variance. We apply this metric to analysis of four publicly available test-retest resting-state fMRI (rs-fMRI) data sets. We find that for the question of maximizing individual differentiation, (i) for increasing sampling, there is a relative tradeoff between increased sampling frequency and increased acquisition time; (ii) for the sizes of the interrogated data sets, only 3-4 min of acquisition time was sufficient to maximally differentiate each subject with an algorithm that utilized no a priori information regarding subject identification; and (iii) brain regions that most contribute to this individual subject characterization lie in the default mode, attention, and executive control networks. These findings may guide optimal rs-fMRI experiment design and may elucidate the neural bases for subject-to-subject differences

Exploring the Early Organization and Maturation of Linguistic Pathways in the Human Infant Brain→

Linguistic processing is based on a close collaboration between temporal and frontal regions connected by two pathways: the “dorsal” and “ventral pathways” (assumed to support phonological and semantic processing, respectively, in adults). We investigated here the development of these pathways at the onset of language acquisition, during the first post-natal weeks, using cross-sectional diffusion imaging in 21 healthy infants (6–22 weeks of age) and 17 young adults. We compared the bundle organization and microstructure at these two ages using tractography and original clustering analyses of diffusion tensor imaging parameters. We observed structural similarities between both groups, especially concerning the dorsal/ventral pathway segregation and the arcuate fasciculus asymmetry. We further highlighted the developmental tempos of the linguistic bundles: The ventral pathway maturation was more advanced than the dorsal pathway maturation, but the latter catches up during the first post-natal months. Its fast development during this period might relate to the learning of speech cross-modal representations and to the first combinatorial analyses of the speech input.

Overview of molecular fMRI→

Comprehensive analysis of brain function depends on understanding the dynamics of diverse neural signaling processes over large tissue volumes in intact animals and humans. Most existing approaches to measuring brain signaling suffer from limited tissue penetration, poor resolution, or lack of specificity for well-defined neural events. Here we discuss a new brain activity mapping method that overcomes some of these problems by combining MRI with contrast agents sensitive to neural signaling. The goal of this “molecular fMRI” approach is to permit noninvasive whole-brain neuroimaging with specificity and resolution approaching current optical neuroimaging methods. In this article, we describe the context and need for molecular fMRI as well as the state of the technology today. We explain how major types of MRI probes work and how they can be sensitized to neurobiological processes, such as neurotransmitter release, calcium signaling, and gene expression changes. We comment both on past work in the field and on challenges and promising avenues for future development.

White-matter diffusion fMRI of mouse optic nerve→

Non-invasive assessment of white-matter functionality in the nervous system would be a valuable basic neuroscience and clinical diagnostic tool. Using standard MRI techniques, a visual-stimulus-induced 27% decrease in the apparent diffusion coefficient of water perpendicular to the axonal fibers (ADC⊥) is demonstrated for C57BL/6 mouse optic nerve in vivo. No change in ADC|| (diffusion parallel to the optic nerve fibers) was observed during visual stimulation. The stimulus-induced changes are completely reversible. A possible vascular contribution was sought by carrying out the ADC⊥ measurements in hypercapnic mice with and without visual stimulus. Similar effects were seen in room-air-breathing and hypercapnic animals. The in vivo stimulus-induced ADC⊥ decreases are roughly similar to literature reports for ex vivo rat optic nerve preparations under conditions of osmotic swelling. The experimental results strongly suggest that osmotic after-effects of nerve impulses through the axonal fibers are responsible for the observed ADC decrease.

Open access in a time of illness→

A personal and frustrating story.

Please don’t tell me, then, that it’s OK because everyone who needs access to the literature has it. I can’t get everything I wanted and, spending weeks in a hospital, I could hardly “go to the library”. I’ve been lucky to find a few pieces spread here and there.

The academic, economic and societal impacts of Open Access: an evidence-based review→

Great review.

You don't have to publish in open access journals to be an open scientist→

Journal choice, preprints, and social media are all ways to be more open.

Useful guide to network visualization in R→

Nice stuff here.

Five reasons to hire you for our open faculty position→

The most important thing to remember is probably that there is not a best person. There are probably at least ten people in any pool that are excellent and would do splendidly. Our applicant pools run from over a hundred to two hundred self-selected people, so this is not too surprising. Also, I have generally viewed nearly all the people we interview as potentially great picks. So how do we decide?

Provoking relationship between pupil diameter and global hemodynamic signal in mice→

Imaging techniques such as fMRI seek to estimate neural signals in local brain regions through measurements of hemodynamic activity. However, hemodynamic activity is accompanied by large vascular fluctuations of unclear significance. To characterize these fluctuations and their impact on estimates of neural signals, we used optical imaging in visual cortex of awake mice. We found that hemodynamic activity can be expressed as the sum of two components, one local and one global. The local component reflected presumed neural signals driven by visual stimuli in the appropriate retinotopic region. The global component constituted large fluctuations shared by larger cortical regions, which extend beyond visual cortex. These fluctuations varied from trial to trial, but they did not constitute noise: they correlated with pupil diameter, suggesting that they reflect variations in arousal or alertness. Distinguishing local and global contributions to hemodynamic activity may help understand neurovascular coupling and interpret measurements of hemodynamic responses.