Felix Felmy and Nikolaos Kladisios discuss their paper, “Synaptic Mechanisms underlying Temporally Precise Information Processing in the VNLL, an auditory brainstem nucleus”, published in Vol. 42, Issue 34 of JNeurosci, with Reviewing Editor Ruth Anne Eatock. 

Measuring neurite length is crucial in neurobiology because it provides valuable insights into the growth, development, and function of neurons. In particular, neurite length is fundamental to study neuronal development and differentiation, neurons responses to drugs, neurodegenerative diseases and neuronal plasticity. Surprisingly, there is currently a lack of tools for high throughput neurite analysis. In this article, we present CABaNe, as an open source, high throughput, rule based Image J macro for cell analysis, including their neurite length. This macro possesses a graphical interface, metadata production, as well as verification means before and after analysis. Rule based and machine learning based programming have been tested for cell identification. Cell tested were N2A, a mouse neuroblastoma cell line. After testing, we had better precision and adaptability using rule based cell identification. We challenged CABaNe with currently used techniques, which are manual or assisted. When tested on a sm...

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Dopaminergic inputs to various brain regions, such as the striatum, orbitofrontal cortex, and amygdala play a critical role in processing reward acquisition information. While reward-related activity is also observed more broadly in motor, parietal, and hippocampal regions, the functional significance and potential hierarchy of reward-related representation across these latter areas remain unclear. We investigated this by quantifying neural predictive power using machine learning. Specifically, neural activity was examined in six brain areas—the primary and secondary motor cortices (M1 and M2), posterior parietal cortex (PPC), dorsal and ventral CA1 (dCA1 and vCA1), and lateral entorhinal cortex (LEC)—in male rats performing a self-initiated left-right choice task. Machine learning models classified rewarded versus non-rewarded trials based on neuronal firing properties significantly above chance for all regions. Crucially, classification revealed a clear performance gradient, forming a functional hierarch...

Neurexins (Nrxns) are presynaptic cell adhesion molecules essential for synapse development and function. Of the many neurexin isoforms, only β-Nrxns contain the histidine-rich domain (HRD). While the HRD has been implicated in several pathological contexts, its normal physiological role remains unclear. To address this, we used a CRISPR-Cas9 method to generate a new mouse line expressing in-frame truncated Nrxn1β lacking the HRD. We found that HRD deletion did not affect mouse viability, gross brain development, or general behavior of either sex. However, loss of the HRD significantly altered neuroligin-1-dependent excitatory, but not inhibitory, presynaptic differentiation in primary cultured neurons. Moreover, this deletion affected presynaptic short-term plasticity, but not basal synaptic transmission, at hippocampal Schaffer collateral-CA1 synapses. These findings identify the Nrxn1β HRD as a potential contributor to excitatory presynaptic organization and function, providing new insight into the mole...

Leila Reddy discusses her paper, “Human Hippocampal Neurons Track Moments in a Sequence of Events,” published in Vol. 41, Issue 31 of The Journal of Neuroscience, with Editor-in-Chief Marina Picciotto. 

The cerebellum is well-established in sub-second motor timing, but its role in supra-second interval timing remains unclear. Here, we investigated how cerebellar output influences time estimation over longer timescales. Male rats performed a nose-poke interval timing task in which reward availability could be predicted either from a fixed 2.5 s auditory cue (cued trials) or had to be estimated internally during uncued 3.5 s trials that demanded self-timing. Chemogenetic inhibition of the lateral cerebellar nucleus produced bidirectional effects: delayed action initiation in predictable trials and premature (∼100-160 ms) responses when self-timing was required. Despite a slowing of movement, overall task success rates remained unchanged. Because motor slowing is likely to lead to later, not earlier, action initiation, these results implicate the lateral cerebellar nucleus in computing internal time estimates. These findings demonstrate that the cerebellum integrates motor and cognitive processes for supra-s...

Much conversation has occurred regarding increasing wealth inequality over the years in the United States. We wished to examine this issue with respect to National Institutes of Health (NIH) funding. Substantial increases have occurred in NIH funding over recent years. According to SfN’s congressional testimony on NIH funding, the agency’s budget has grown by $9 billion in the past six years. While many have acknowledged the value of this increased investment in research, colleagues at smaller institutions have anecdotally not noticed a major change. We examined whether relevant data could address if there is, indeed, an increase in wealth inequality in NIH-research funding across institutions in the United States.

Much conversation has occurred regarding increasing wealth inequality over the years in the United States. We wished to examine this issue with respect to National Institutes of Health (NIH) funding. Substantial increases have occurred in NIH funding over recent years. According to SfN’s congressional testimony on NIH funding, the agency’s budget has grown by $9 billion in the past six years. While many have acknowledged the value of this increased investment in research, colleagues at smaller institutions have anecdotally not noticed a major change. We examined whether relevant data could address if there is, indeed, an increase in wealth inequality in NIH-research funding across institutions in the United States.

Investigations into the neural basis of behavior frequently employ calcium imaging to measure neuronal activity. Across studies, however, seemingly reasonable but highly diverse methodological choices are typically made to assess the selectivity of individual neurons to task states. Here, we examine systematically the effect of parameter choices, along the pipeline from data acquisition through statistical testing, on the inferred encoding preferences of individual neurons. We use as an experimental testbed, calcium imaging in the medial prefrontal cortex of freely behaving mice engaged in a classic exploration-avoidance task with animal-controlled state transitions, namely, navigation in the elevated zero maze. We report that most of the key parameters in the pipeline substantially impact the inferred selectivity of neurons, and do so in distinct ways. Using novel accuracy and robustness metrics, we directly compare the quality of inference across combinations of parameter levels, and discover an optimal ...