Updated March 24, 2020
Binaural Beats through the Auditory Pathway: From Brainstem to Connectivity Patterns
Binaural beats, an auditory illusion that happens when you present two slightly different sounds to each ear separately, have been claimed to enhance memory and attention, and regulate mood, thanks to their purported capacity to drive brain rhythms. Here the authors tested whether these sounds can entrain brain activity, whether they can regulate mood and whether they do so in a specific fashion. To do so, they compared the effects of binaural beats to that of a regular rhythmic sound, on the mood and electrical brain activity of sixteen participants. They found that rhythmic sounds synchronized the brain even more than binaural beats. Binaural beats did elicit complex brain connectivity patterns, but did not impact mood. Whether binaural beats have an impact on memory, attention, or mood remains an open question. The authors provide a controlled neuroscience paradigm enabling to investigate further.
Intra-infarct fibrotic repair occurs following acute ischemic stroke. Whether the intra-infarct fibrotic repair is beneficial or not for functional recovery has been controversial. In this study, the authors show that pericyte-mediated intra-infarct fibrotic repair via PDGFRβ promotes peri-infarct astrogliosis and oligodendrogenesis and correlates with post-stroke functional recovery. Promoting of intra-infarct repair is therapeutically relevant for post-stroke functional recovery.
Genetically Engineering the Nervous System with CRISPR-Cas
In this review, Sandoval, Elahi & Ploski discuss the rapidly accelerating field of CRISPR-mediated genome engineering with an overview of its canonical function, followed by a review of its many adaptations, with an emphasis on its applications for interrogation of brain function in physiological and pathological conditions.
Different layers of the cerebral cortex have been proposed to have different functions in the processing of sensory information. Using two-photon calcium imaging, O’Herron et al. show for the first time that the percentage of cortical neurons that respond to visual stimuli increases dramatically from superficial to deeper layer 2/3 and into layer 4. Moreover, the response amplitude increases and the selectivity for stimulus orientation decreases for individual neurons across this depth range. Thus, the depth of cortical neurons must be accounted for when analyzing or modeling population neural activity.
More than a Corepressor: The Role of CoREST Proteins in Neurodevelopment
The regulation of gene expression by transcription factors plays a significant role in normal brain development. Repressor element 1 (RE1) silencing transcription factor (REST) has been well characterized as a transcriptional regulator of neurogenesis through the formation of a complex with the REST corepressor (CoREST) proteins. Recently, the CoREST protein family has been shown to have important REST-independent functions in regulating neurodevelopment and are more than simply “REST corepressors.” This review summarizes the current understanding on the expression, target genes and roles of CoREST proteins in brain development.
Also of Interest
RatHat: A Self-Targeting Printable Brain Implant System
We demonstrate a new approach to rodent stereotaxic surgery. Rodent neurosurgery is a complex skill that requires expensive equipment for head stabilization and micromanipulators for localization. The RatHat is a 3D printable brain implant system that reduces costs and time using pre-mapped and printed surgical files. A surgical stencil allows for quick placement of drill holes, and a RatHat places components in the brain using atlas coordinates. The RatHat is an easily shared resource facilitating open science goals for replications and the archiving of specific experimental applications.
Biophysical Basis of Alpha Rhythm Disruption in Alzheimer’s Disease (AD)
Aggregation of amyloid-beta, modified expression of ion channels and alterations in calcium signaling are hallmarks of AD neurons. Separately, changes in the alpha rhythm is often an early observation in AD patients. We use a realistic computational model of the thalamus to elucidate the causal links between molecular changes in AD and their effect on alpha rhythm. Our model demonstrates that pathology of HCN, crucial for alpha generation, alters calcium signaling, modifies excitation-inhibition balance in the thalamus makes the network more sensitive to noise. Our model, when seen in conjunction with diverse experimental data, posits a causal relationship between the formation of amyloid-beta plaques, the down-regulation of HCN channels and aberrations in the occipital alpha rhythm.
Paired Associative Stimulation Fails to Induce Plasticity in Freely Behaving Intact Rats
Paired Associative Stimulation (PAS) can be applied non-invasively to modulate corticomotor plasticity in humans. However, our understanding of how we can use paired stimuli to produce the greatest beneficial reshaping of corticomotor connections in vivo is still rudimentary. We completed a systematic study varying inter-stimulus intervals between cortical and muscle stimulation in a freely-behaving rat PAS model, following the principles of spike-timing dependent plasticity (STDP). Crucially, our experiments have not demonstrated that the STDP model is effective in vivo using our PAS protocol. We discuss several other factors in addition to the inter-stimulus interval which may play a larger role in driving plasticity, and potential ways that the field can approach future work.
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