To understand how vowels are encoded by auditory nerve fibers, a number of representation schemes have been suggested that extract the vowel’s formant frequencies from auditory nerve-fiber spiking patterns. The current study aims to apply and compare these schemes for auditory nerve-fiber responses to naturally-spoken vowels in a speech-shaped background noise. Responses to three vowels were evaluated; based on behavioral experiments in the same species, two of these were perceptually difficult to discriminate from each other (/e/vs/i/) and one was perceptually easy to discriminate from the other two (/a:/). Single-unit auditory nerve fibers were recorded from ketamine/xylazine-anesthetized Mongolian gerbils of either sex (n = 8). First, single-unit discrimination between the three vowels was studied. Compared to the perceptually easy discriminations, the average spike timing-based discrimination values were significantly lower for the perceptually difficult vowel discrimination. This was not true for an ...

Bodily rhythms appear as novel scaffolding mechanisms orchestrating the spatio-temporal organization of spontaneous brain activity. Here, we follow up on the discovery of the gastric resting-state network (Rebollo et al, 2018), composed of brain regions in which the fMRI signal is phase-synchronized to the slow (0.05 Hz) electrical rhythm of the stomach. Using a larger sample size (n=63 human participants, both genders), we further characterize the anatomy and effect sizes of gastric-brain coupling across resting-state networks, a fine grained cortical parcellation, as well as along the main gradients of cortical organization. Most (67%) of the gastric network is included in the somato-motor-auditory (38%) and visual (29%) resting state networks. Gastric brain coupling also occurs in the granular insula and, to a lesser extent, in the piriform cortex. Thus, all sensory and motor cortices corresponding to both exteroceptive and interoceptive modalities are coupled to the gastric rhythm during rest. Converse...

Electrical stimulation of the peripheral nerves of human participants provides a unique opportunity to study the neural determinants of perceptual quality using a causal manipulation. A major challenge in the study of neural coding of touch has been to isolate the role of spike timing – at the scale of milliseconds or tens of milliseconds – in shaping the sensory experience. In the present study, we address this question by systematically varying the frequency (PF) of electrical stimulation pulse trains delivered to the peripheral nerves of seven participants with upper and lower extremity limb loss via chronically implanted neural interfaces. We find that increases in PF lead to systematic increases in perceived frequency, up to about 50 Hz, at which point further changes in PF have little to no impact on sensory quality. Above this transition frequency, ratings of perceived frequency level off, the ability to discriminate changes in PF is abolished, and verbal descriptors selected to characterize the sen...

Collaboration in neuroscience is impeded by the difficulty of sharing primary data, results, and software across labs. Here we introduce Neuroscience Data Interface (NDI), a platform-independent standard that allows an analyst to use and create software that functions independently from the format of the raw data or the manner in which the data is organized into files. The interface is rooted in a simple vocabulary that describes common apparatus and storage devices used in neuroscience experiments. Results of analyses – and analyses of analyses – are stored as documents in a scalable, queryable database that stores the relationships and history among the experiment elements and documents. The interface allows the development of an application ecosystem where applications can focus on calculation rather than data format or organization. This tool can be used by individual labs to exchange and analyze data, and it can serve to curate neuroscience data for searchable archives. Significance Statement Neuro...

Bulimia nervosa (BN) and binge eating disorder (BED) are characterized by episodes of eating large amounts of food whilst experiencing a loss of control. Recent studies suggest that the underlying causes of BN/BED consist of a complex system of environmental cues, atypical processing of food stimuli, altered behavioral responding, and structural/functional brain differences compared with healthy controls (HC). In this narrative review, we provide an integrative account of the brain networks associated with the three cognitive constructs most integral to BN and BED, namely increased reward sensitivity, decreased cognitive control, and altered negative affect and stress responding. We show altered activity in BED/BN within several brain networks, specifically in the striatum, insula, prefrontal and orbitofrontal cortex, and cingulate gyrus. Numerous key nodes in these networks also differ in volume and connectivity compared with HC. We provide suggestions for how this integration may guide future research in...

Postnatal CNS development is fine-tuned to drive the functional needs of succeeding life stages; accordingly, the emergence of sensory and motor functions, behavioral patterns and cognitive abilities relies on a complex interplay of signaling pathways. Strictly regulated Ca2+ signaling mediated by L-type channels (LTCCs) is crucial in neural circuit development and aberrant increases in neuronal LTCC activity are linked to neurodevelopmental and psychiatric disorders. In the amygdala, a brain region that integrates signals associated with aversive and rewarding stimuli, LTCCs contribute to NMDA-independent long-term potentiation (LTP) and are required for the consolidation and extinction of fear memory. In vitro studies have elucidated distinct electrophysiological and synaptic properties characterizing the transition from immature to functionally mature BLA principal neurons. Further, acute increase of LTCC activity selectively regulates excitability and spontaneous synaptic activity in immature BLA neu...

Hippocampal theta oscillations (HTO) during rapid eye movement (REM) sleep play an important role in mnemonic processes by coordinating hippocampal and cortical activities. However, it is not fully understood how HTO are modulated by subcortical regions, including the median raphe nucleus (MnR). The MnR is thought to suppress HTO through its serotonergic outputs. Here, our study on male mice revealed a more complex framework indicating roles of non-serotonergic MnR outputs in regulating HTO. We found that non-selective optogenetic activation of MnR neurons at theta frequency increased HTO amplitude. Granger causality analysis indicated that MnR theta oscillations during REM sleep influence HTO. By utilizing three transgenic mouse lines, we found that MnR serotonergic neurons exhibited little or no theta-correlated activity during HTO. Instead, most MnR GABAergic neurons and Vglut3 neurons respectively increased and decreased activities during HTO and exhibited hippocampal theta phase-locked activities. Alt...

Functional hemispheric lateralization is a basic principle of brain organization. In the auditory domain, the right auditory cortex (AC) determines the pitch direction of continuous auditory stimuli whereas the left AC discriminates gaps in these stimuli. The involved functional interactions between the two sides, mediated by commissural connections, are poorly understood. Here, we selectively disrupted the interhemispheric crosstalk from the left to the right primary AC and vice versa using chromophore-targeted laser-induced apoptosis of the respective projection neurons, which make up 6-17% of all AC neurons in layers III, V, and VI. Following photolysis, male gerbils were trained in a first experimental set to discriminate between rising and falling frequency-modulated tone (FM) sweeps. The acquisition of the task was significantly delayed in lesioned animals of either lesion direction. However, the final discrimination performance and hit rate was lowest for animals with left-side lesioned commissural ...

Consistent with current models of embodied emotions, this study investigates whether the somatosensory system shows reduced sensitivity to facial emotional expressions in autistic compared to neurotypical individuals, and if these differences are independent from between-group differences in visual processing of facial stimuli. To investigate the dynamics of somatosensory activity over and above visual carryover effects, we recorded EEG activity from two groups of Autism Spectrum Disorder (ASD) or Typically Developing (TD) humans (male and female), while they were performing a facial emotion discrimination task and a control gender task. To probe the state of the somatosensory system during face processing, in 50% of trials we evoked somatosensory activity by delivering task-irrelevant tactile taps on participants’ index finger, 105 ms after visual stimulus onset. Importantly, we isolated somatosensory from concurrent visual activity by subtracting visual responses from activity evoked by somatosensory and...

Duchenne muscular dystrophy (DMD), the most common form of childhood muscular dystrophy, is caused by mutations in the dystrophin gene. In addition to debilitating muscle degeneration, patients display a range of cognitive deficits thought to result from loss of dystrophin normally expressed in the brain. While the function of dystrophin in muscle tissue is well characterized, its role in the brain is still poorly understood. The highest expression of dystrophin in the mouse brain is in cerebellar Purkinje cells (PC), where it colocalizes with GABAA receptor clusters. Using ex vivo electrophysiological recordings from connected molecular layer interneuron (MLI)-PC pairs, we investigated changes in inhibitory synaptic transmission caused by dystrophin deficiency. In male mdx mice (which lack long-form dystrophin), we found that responses at MLI-PC pairs were reduced by ∼60%, due to both decreased quantal response amplitude and reduced number of functional vesicle release sites. Using electron microscopy, we...