Most human navigation studies in MRI rely on virtual navigation. However, the necessary supine position in MRI makes it fundamentally different from daily ecological navigation. Nonetheless, until now, no study has assessed whether differences in physical body orientation (BO) affect participants’ experienced BO during virtual navigation. Here, combining an immersive virtual reality navigation task with subjective BO measures and implicit behavioral measures, we demonstrate that physical BO (either standing or supine) modulates experienced BO. Also, we show that standing upright BO is preferred during spatial navigation: participants were more likely to experience a standing BO and were better at spatial navigation when standing upright. Importantly, we report that showing a supine virtual agent reduces the conflict between the preferred BO and physical supine BO. Our study provides critical, but missing, information regarding experienced BO during virtual navigation, which should be considered cautiously ...

The detection of a single photon by a rod photoreceptor is limited by two sources of physiological noise, called discrete and continuous noise. Discrete noise occurs as intermittent current deflections with a waveform very similar to that of the single-photon response to real light and is thought to be produced by spontaneous activation of rhodopsin. Continuous noise occurs as random and continuous fluctuations in outer-segment current and is usually attributed to some intermediate in the phototransduction cascade. To confirm the origin of these noise sources, we have recorded from retinas of mouse lines with rods having reduced levels of rhodopsin, transducin, or phosphodiesterase. We show that the rate of discrete noise is diminished in proportion to the decrease in rhodopsin concentration, and that continuous noise is independent of transducin concentration but clearly elevated when the level of phosphodiesterase is reduced. Our experiments provide new molecular evidence that discrete noise is indeed pr...

Real science is not only about “the data” but also about theoretical, sociological, economic, and political matters. Reflecting on the struggles of the ongoing adversarial collaboration to test theories of consciousness, here I suggest to “ask not what neuroscience can do for consciousness but what consciousness can do for neuroscience.” “Big fish: Aren’t these waters fascinating and treacherous? Small fish: What waters?” – Anonymous Richard Feynman is notorious for his witty quotes, including that “philosophy of science is about as useful to scientists as ornithology is to birds.” Indeed, some neuroscientists would look perplexed in front of analytic accounts of their own practices, methods, and foundations. Starlings fly by flapping their feathered wings and yet, regardless of their individual skills and collective choreographies, they may be ignorant about how and why they do it. A tweet-long crash course in philosophy of science could suffice to realize that binary thinking (“Is it true or not?”) co...

Every so often, I conclude that life is not possible. It is not uncommon for me to walk out of a seminar about the pathways and dynamics of biochemical signaling or the structure of biological molecules to conclude that the complexities of life processes defy imagination. Our ability to maintain a sense of wonder about the mysteries of biological mechanisms is what drives us as scientists, as otherwise wresting new insights from the recalcitrant world of interacting pathways would be too frustrating. So all successful biologists must, paradoxically, see both the proverbial forest and their trees, and recognize both the elegant simplicity and the confounds characteristic of living organisms. That sense of mystery and wonder is somewhat at odds with our common sense. It is common sense that is now too often lost, as we grapple with new technologies and large datasets in our science. As scientists, today, we must balance our common sense with our growing reliance on big data to extract the new insights about...

Neuroscientists endeavor to unravel the mysteries of brain functions and dysfunctions. A common research strategy involves measuring specific parameters across various conditions. These measurements are then typically repeated, averaged, and used to infer general patterns or rules. The act of averaging data is an ancient practice; for instance, early astronomers in Babylonian, Chinese, and Indian cultures implicitly averaged observations of celestial phenomena to predict significant periods, such as those crucial for agriculture. Averaging is a sound approach when the process being studied follows to a mathematical function, represented as y = f(x), where f is a very general function. This is true even if the exact function is not known at the outset of the experiments. Implicit in this method is the assumption that any variations in measurements arise from imperfections in the recording process since a consistent mathematical rule suggests that identical inputs should always yield the same output. In ess...

The sensory system allows humans to not only explore the world but also to monitor their own bodies for injury and disease through the sensation of pain. After an injury, signals from the injured tissues travel along the nerves, entering the central nervous system through the spinal cord before going into the brain. In the acute stages, pain modulates behavior in ways that promote healing, including limiting mobility. In most cases, pain resolves as the injury heals, but, in some cases, pain persists and becomes chronic. Chronic pain is a massive issue, affecting up to 20% of Americans and leading to reduced quality of life for those affected. The factors leading to chronic pain are complex, and new approaches are needed to improve understanding of chronic pain and find effective treatments. In the current issue of eNeuro , Haroun et al. (2023) use a new approach to transiently silence sensory neurons in uninjured mice as well as mouse models of acute and chronic pain using a technique known as chemogenet...

Highlighted Research Paper: [[T. Moldwin, M. Kalmenson, and I. Segev, “Asymmetric voltage attenuation in dendrites can enable hierarchical heterosynaptic plasticity.” eNeuro (2023).][2]][2] []: /lookup/doi/10.1523/ENEURO.0014-23.2023

I am always marveled by the brain’s vast capabilities. Each discovery, each revelation, seems to open a door only to reveal myriad others yet unopened. The brain, with its vast intricacies, consistently reminds us that its complexity transcends the limits of our imagination. It is in this spirit that I wish to introduce “Brain Mysteries: Complexity Beyond Imagination” in eNeuro . All neuroscientists have been contributing for decades to the mapping of brain networks and to the unraveling of its codes. While every stride has been fruitful in terms …

Rhythms are a common feature of brain activity. Across different types of rhythms, the phase has been proposed to have functional consequences, thus requiring its accurate specification from noisy data. Phase is conventionally specified using techniques that presume a frequency band-limited rhythm. However, in practice, observed brain rhythms are typically nonsinusoidal and amplitude modulated. How these features impact methods to estimate phase remains unclear. To address this, we consider three phase estimation methods, each with different underlying assumptions about the rhythm. We apply these methods to rhythms simulated with different generative mechanisms and demonstrate inconsistency in phase estimates across the different methods. We propose two improvements to the practice of phase estimation: (1) estimating confidence in the phase estimate, and (2) examining the consistency of phase estimates between two (or more) methods.

Sympathetic preganglionic neurons (SPNs) are the final output neurons from the central arm of the autonomic nervous system. Therefore, SPNs represent a crucial component of the sympathetic nervous system for integrating several inputs before driving the postganglionic neurons (PGNs) in the periphery to control end organ function. The mechanisms which establish and regulate baseline sympathetic tone and overall excitability of SPNs and PGNs are poorly understood. The SPNs are also known as the autonomic motoneurons (MNs) as they arise from the same progenitor line as somatic MNs that innervate skeletal muscles. Previously our group has identified a rich repertoire of homeostatic plasticity (HP) mechanisms in somatic MNs of the embryonic chick following in vivo synaptic blockade. Here, using the same model system, we examined whether SPNs exhibit similar homeostatic capabilities to that of somatic MNs. Indeed, we found that after 2-d reduction of excitatory synaptic input, SPNs showed a significant increase ...