Temporal coherence shapes cortical responses to speech mixtures in a ferret cocktail party.

Perceptual segregation of complex sounds such as speech and music simultaneously emanating from multiple sources is a remarkable ability that is common in humans and other animals alike. Unlike animal physiological experiments with simplified sounds or human investigations with spatially broad imaging techniques, this study combines insights from animal single-unit recordings with segregation of speech-like sound mixtures. Ferrets are trained to attend to a female voice and detect a target word, both in presence and absence of a concurrent equally salient male voice.

Comparing the Memory Effects of 50-Hz Low-Frequency and 10-kHz High-Frequency Thoracic Spinal Cord Stimulation on Spinal Neural Network in a Myocardial Infarction Porcine Model.

Objective: This study evaluated the effects of cessation of both conventional low-frequency (50 Hz) and high-frequency (10 kHz) spinal cord stimulation (SCS) on the cardiospinal neural network activity in pigs with myocardial infarction (MI). The objective is to provide an insight into the memory effect of SCS.

Materials And Methods: In nine Yorkshire pigs, chronic MI was created by delivering microspheres to the left circumflex coronary artery.

Temporal Coherence Shapes Cortical Responses to Speech Mixtures in a Ferret Cocktail Party.

Segregation of complex sounds such as speech, music and animal vocalizations as they simultaneously emanate from multiple sources (referred to as the "cocktail party problem") is a remarkable ability that is common in humans and animals alike. The neural underpinnings of this process have been extensively studied behaviorally and physiologically in non-human animals primarily with simplified sounds (tones and noise sequences). In humans, segregation experiments utilizing more complex speech mixtures are common; but physiological experiments have relied on EEG/MEG/ECoG recordings that sample activity from thousands of neurons, often obscuring the detailed processes that give rise to the observed segregation.

Spinal neuromodulation mitigates myocardial ischemia-induced sympathoexcitation by suppressing the intermediolateral nucleus hyperactivity and spinal neural synchrony.

Introduction: Myocardial ischemia disrupts the cardio-spinal neural network that controls the cardiac sympathetic preganglionic neurons, leading to sympathoexcitation and ventricular tachyarrhythmias (VTs). Spinal cord stimulation (SCS) is capable of suppressing the sympathoexcitation caused by myocardial ischemia. However, how SCS modulates the spinal neural network is not fully known.

Is the MSB hypothesis (music as a coevolved system for social bonding) testable in the Popperian sense?

"Music As a Coevolved System for Social Bonding" (MSB) is a brilliant synthesis and appealing hypothesis offering insights into the evolution and social bonding of musicality, but is so broad and sweeping it will be challenging to test, prove or falsify in the Popperian sense (Popper, 1959). After general comments, I focus my critique on underlying neurobiological mechanisms, and offer some suggestions for experimental tests of MSB.

Breaking barriers and building bridges: Increasing community engagement in program evaluation.

Background: Between September 2015 and 2018, The Michigan Department of Health and Human Services (MDHHS) focused its Project PrIDE efforts on increasing PrEP awareness through a media campaign, and community engagement in. Wayne County, MI. A strained relationship between MDHHS and community has created barriers to sustained and effective community engagement.

Changes in membrane elasticity caused by the hydrophobic surfactant proteins correlate poorly with adsorption of lipid vesicles.

To establish how the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of lipids to an air/water interface, we used X-ray diffuse scattering (XDS) to determine an order parameter of the lipid chains (S) and the bending modulus of the lipid bilayers (K). Samples contained different amounts of the proteins with two sets of lipids. Dioleoylphosphatidylcholine (DOPC) provided a simple, well characterized model system.

Suppression of L/L Phase Coexistence in the Lipids of Pulmonary Surfactant.

To determine how different constituents of pulmonary surfactant affect its phase behavior, we measured wide-angle x-ray scattering (WAXS) from oriented bilayers. Samples contained the nonpolar and phospholipids (N&PL) obtained from calf lung surfactant extract (CLSE), which also contains the hydrophobic surfactant proteins SP-B and SP-C. Mixtures with different ratios of N&PL and CLSE provided the same set of lipids with different amounts of the proteins.

Location of the Hydrophobic Surfactant Proteins, SP-B and SP-C, in Fluid-Phase Bilayers.

The hydrophobic surfactant proteins, SP-B and SP-C, promote rapid adsorption by the surfactant lipids to the surface of the liquid that lines the alveolar air sacks of the lungs. To gain insights into the mechanisms of their function, we used X-ray diffuse scattering (XDS) and molecular dynamics (MD) simulations to determine the location of SP-B and SP-C within phospholipid bilayers. Initial samples contained the surfactant lipids from extracted calf surfactant with increasing doses of the proteins.

Dorsal prefrontal and premotor cortex of the ferret as defined by distinctive patterns of thalamo-cortical projections.

Recent studies of the neurobiology of the dorsal frontal cortex (FC) of the ferret have illuminated its key role in the attention network, top-down cognitive control of sensory processing, and goal directed behavior. To elucidate the neuroanatomical regions of the dorsal FC, and delineate the boundary between premotor cortex (PMC) and dorsal prefrontal cortex (dPFC), we placed retrograde tracers in adult ferret dorsal FC anterior to primary motor cortex and analyzed thalamo-cortical connectivity. Cyto- and myeloarchitectural differences across dorsal FC and the distinctive projection patterns from thalamic nuclei, especially from the subnuclei of the medial dorsal (MD) nucleus and the ventral thalamic nuclear group, make it possible to clearly differentiate three separate dorsal FC fields anterior to primary motor cortex: polar dPFC (dPFCpol), dPFC, and PMC.

Dynamics and Hierarchical Encoding of Non-compact Acoustic Categories in Auditory and Frontal Cortex.

Categorical perception is a fundamental cognitive function enabling animals to flexibly assign sounds into behaviorally relevant categories. This study investigates the nature of acoustic category representations, their emergence in an ascending series of ferret auditory and frontal cortical fields, and the dynamics of this representation during passive listening to task-relevant stimuli and during active retrieval from memory while engaging in learned categorization tasks. Ferrets were trained on two auditory Go-NoGo categorization tasks to discriminate two non-compact sound categories (composed of tones or amplitude-modulated noise).

What can animal communication teach us about human language?

Language has been considered by many to be uniquely human. Numerous theories for how it evolved have been proposed but rarely tested. The articles in this theme issue consider the extent to which aspects of language, such as vocal learning, phonology, syntax, semantics, intentionality, cognition and neurobiological adaptations, are shared with other animals.

Adaptive Efficient Coding of Correlated Acoustic Properties.

Natural sounds such as vocalizations often have covarying acoustic attributes, resulting in redundancy in neural coding. The efficient coding hypothesis proposes that sensory systems are able to detect such covariation and adapt to reduce redundancy, leading to more efficient neural coding. Recent psychoacoustic studies have shown the auditory system can rapidly adapt to efficiently encode two covarying dimensions as a single dimension, following passive exposure to sounds in which temporal and spectral attributes covaried in a correlated fashion.

Computational Neural Modeling of Auditory Cortical Receptive Fields.

Previous studies have shown that the auditory cortex can enhance the perception of behaviorally important sounds in the presence of background noise, but the mechanisms by which it does this are not yet elucidated. Rapid plasticity of spectrotemporal receptive fields (STRFs) in the primary (A1) cortical neurons is observed during behavioral tasks that require discrimination of particular sounds. This rapid task-related change is believed to be one of the processing strategies utilized by the auditory cortex to selectively attend to one stream of sound in the presence of mixed sounds.

Laminar profile of task-related plasticity in ferret primary auditory cortex.

Rapid task-related plasticity is a neural correlate of selective attention in primary auditory cortex (A1). Top-down feedback from higher-order cortex may drive task-related plasticity in A1, characterized by enhanced neural representation of behaviorally meaningful sounds during auditory task performance. Since intracortical connectivity is greater within A1 layers 2/3 (L2/3) than in layers 4-6 (L4-6), we hypothesized that enhanced representation of behaviorally meaningful sounds might be greater in A1 L2/3 than L4-6.

Getting pre-exposure prophylaxis to high-risk transgender women: lessons from Detroit, USA.

Unlabelled: Background Pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention strategy, but it is unclear how best to deliver PrEP to key populations. Drawing upon a cross-sectional survey of transgender women (TW) in Detroit, USA, and experience of a PrEP clinic that serves this population, this manuscript describes the following: (1) the risk profile of Detroit TW; (2) the proportion of TW with at least one PrEP indication; and (3) perceptions of and experiences with PrEP among TW in Detroit.

Methods: Between August 2017 and March 2018, 126 TW completed an online PrEP survey.

Implicit Memory for Complex Sounds in Higher Auditory Cortex of the Ferret.

Responses of auditory cortical neurons encode sound features of incoming acoustic stimuli and also are shaped by stimulus context and history. Previous studies of mammalian auditory cortex have reported a variable time course for such contextual effects ranging from milliseconds to minutes. However, in secondary auditory forebrain areas of songbirds, long-term stimulus-specific neuronal habituation to acoustic stimuli can persist for much longer periods of time, ranging from hours to days.

Go/No-Go task engagement enhances population representation of target stimuli in primary auditory cortex.

Primary sensory cortices are classically considered to extract and represent stimulus features, while association and higher-order areas are thought to carry information about stimulus meaning. Here we show that this information can in fact be found in the neuronal population code of the primary auditory cortex (A1). A1 activity was recorded in awake ferrets while they either passively listened or actively discriminated stimuli in a range of Go/No-Go paradigms, with different sounds and reinforcements.

Extracting neuronal functional network dynamics via adaptive Granger causality analysis.

Quantifying the functional relations between the nodes in a network based on local observations is a key challenge in studying complex systems. Most existing time series analysis techniques for this purpose provide static estimates of the network properties, pertain to stationary Gaussian data, or do not take into account the ubiquitous sparsity in the underlying functional networks. When applied to spike recordings from neuronal ensembles undergoing rapid task-dependent dynamics, they thus hinder a precise statistical characterization of the dynamic neuronal functional networks underlying adaptive behavior.

Orbitofrontal Cortex Neurons Respond to Sound and Activate Primary Auditory Cortex Neurons.

Sensory environments change over a wide dynamic range and sensory processing can change rapidly to facilitate stable perception. While rapid changes may occur throughout the sensory processing pathway, cortical changes are believed to profoundly influence perception. Prior stimulation studies showed that orbitofrontal cortex (OFC) can modify receptive fields and sensory coding in A1, but the engagement of OFC during listening and the pathways mediating OFC influences on A1 are unknown.

Temporal coherence structure rapidly shapes neuronal interactions.

Perception of segregated sources is essential in navigating cluttered acoustic environments. A basic mechanism to implement this process is the temporal coherence principle. It postulates that a signal is perceived as emitted from a single source only when all of its features are temporally modulated coherently, causing them to bind perceptually.