Spatiotemporal Conversion of Auditory Information for Cochleotopic Mapping

2007 ◽  
Vol 19 (2) ◽  
pp. 351-370 ◽  
Author(s):  
Osamu Hoshino
Keyword(s):  
Action Potentials ◽  
Delay Line ◽  
Primary Auditory Cortex ◽  
Auditory Information ◽  
Latency Time ◽  
Delay Lines ◽  
Time Intervals ◽  
Communication Signals ◽  
Cortical Areas ◽  
The Brain

Auditory communication signals such as monkey calls are complex FM vocal sounds and in general induce action potentials in different timing in the primary auditory cortex. Delay line scheme is one of the effective ways for detecting such neuronal timing. However, the scheme is not straightforwardly applicable if the time intervals of signals are beyond the latency time of delay lines. In fact, monkey calls are often expressed in longer time intervals (hundreds of milliseconds to seconds) and are beyond the latency times observed in the brain (less than several hundreds of milliseconds). Here, we propose a cochleotopic map similar to that in vision known as a retinotopic map. We show that information about monkey calls could be mapped on a cochleotopic cortical network as spatiotemporal firing patterns of neurons, which can then be decomposed into simple (linearly sweeping) FM components and integrated into unified percepts by higher cortical networks. We suggest that the spatiotemporal conversion of auditory information may be essential for developing the cochleotopic map, which could serve as the foundation for later processing, or monkey call identification by higher cortical areas.

scholarly journals Speech-evoked brain activity is more robust to competing speech when it is spoken by someone familiar

2020 ◽  
Author(s):  
Emma Holmes ◽  
Ingrid S. Johnsrude
Keyword(s):  
Brain Activity ◽  
Primary Auditory Cortex ◽  
Target Sentence ◽  
Complex Signal ◽  
Middle Temporal ◽  
Cortical Areas ◽  
Novel Approach ◽  
Familiar Voice ◽  
Competing Speech ◽  
The Brain

AbstractPeople are much better at understanding speech when it is spoken by a familiar talker—such as a friend or partner—than when the interlocutor is unfamiliar. This provides an opportunity to examine the substrates of intelligibility and familiarity, independent of acoustics. Is the familiarity effect evident as early as primary auditory cortex, or only at later processing stages? Here, we presented sentences spoken by naturally familiar talkers (the participant’s friend or partner) and unfamiliar talkers (the friends or partners of other participants). We compared multivariate activity in speech-sensitive regions of cortex between conditions in which target sentences were presented alone and conditions in which the same target sentences were presented at the same time as a competing sentence. Using representational similarity analysis (RSA), we demonstrate that the pattern of activity evoked by a spoken sentence is less degraded by the presence of a competing sentence when it is spoken by a friend or partner than by someone unfamiliar; the results cannot be explained by acoustic differences since familiar and unfamiliar talkers were nearly identical across the group. This familiar-voice advantage is most prominent in nonprimary auditory cortical areas, along the posterior superior and middle temporal gyri. Across participants, the magnitude of the familiar-unfamiliar RSA difference correlates with the familiar-voice benefit to intelligibility. Overall, our results demonstrate that experience-driven improvements in intelligibility are associated with enhanced patterns of neural activity in nonprimary auditory cortical areas.Significance statementSpeech is a complex signal, and we do not yet fully understand how the content of a spoken sentence is encoded in cortex. Here, we used a novel approach based on analysing multivariate activity: we compared activity evoked by highly intelligible sentences presented alone and by the same sentences presented with a competing masker. The distributed pattern of activity in speech-sensitive regions of the brain was more similar between the alone and masker conditions when the target sentence was spoken by someone familiar—the participant’s friend or partner—than someone unfamiliar. This metric correlated with the intelligibility of the familiar voice. These results imply that the spatial pattern of activity in speech-sensitive regions reflects the intelligibility of a spoken sentence.

Alteration of Ambient GABA by Phasic and Tonic Neuronal Activation

2010 ◽  
Vol 22 (5) ◽  
pp. 1358-1382 ◽  
Author(s):  
Osamu Hoshino
Keyword(s):  
Action Potentials ◽  
Primary Auditory Cortex ◽  
Response Property ◽  
Optimal Timing ◽  
Auditory Information ◽  
Gabaergic Interneurons ◽  
Tone Frequency ◽  
Time Period ◽  
Ambient Gaba ◽  
Stimulation Period

Neurons of primary auditory cortex (AI) emit spikes (action potentials) in two distinct manners, responding to sounds in an onset or a sustained manner. The former AI neurons are called phasic cells and the latter tonic cells. The phasic cells generate spikes for a brief time period (less than hundreds of milliseconds) at the onset of an auditory stimulus (e.g., a tone frequency sound), and the tonic cells continuously generate spikes throughout the stimulation period. Simulating a neural network model of AI, we investigated whether and how the onset discharges influence the sustained discharges that are believed to play a central role in encoding auditory information. Onset discharges, triggered by a phasic input, briefly excited GABAergic interneurons and transiently increased the level of ambient GABA, which was immediately recognized by extrasynaptic GABAa receptors and provided inhibitory currents into neurons. The transient alteration of ambient GABA allowed tonic cells to respond selectively to a tonic input. The timing of phasic input relative to a tonic one had a great impact on the responsiveness of tonic cells. We found optimal timing for the best selective responsiveness: phasic input preceding tonic input by several tens of milliseconds. Offset discharges induced by a secondary input to phasic cells, applied at the end of the tonic input period, suddenly terminated the sustained discharges and allowed the network to return rapidly to the ongoing-spontaneous neuronal state. We suggest that the transporter-mediated alteration of ambient GABA, triggered by onset discharges, may improve the response property of AI neurons. Offset discharges may have a role in resetting AI neurons so that they can prepare for the next auditory input.

The Auditory Brainstem Implant

2019 ◽  
pp. 758-770
Author(s):  
Robert V. Shannon
Keyword(s):  
Surgical Technique ◽  
Cochlear Nucleus ◽  
Meta Analysis ◽  
Auditory Brainstem ◽  
Auditory Information ◽  
Speech Understanding ◽  
Auditory Neurons ◽  
Auditory Brainstem Implant ◽  
The Brain ◽  
Implanted Device

The auditory brainstem implant (ABI) is a surgically implanted device to electrically stimulate auditory neurons in the cochlear nucleus complex of the brainstem in humans to restore hearing sensations. The ABI is similar in function to a cochlear implant, but overall outcomes are poorer. However, recent applications of the ABI to new patient populations and improvements in surgical technique have led to significant improvements in outcomes. While the ABI provides hearing benefits to patients, the outcomes challenge our understanding of how the brain processes neural patterns of auditory information. The neural pattern of activation produced by an ABI is highly unnatural, yet some patients achieve high levels of speech understanding. Based on a meta-analysis of ABI surgeries and outcomes, a theory is proposed of a specialized sub-system of the cochlear nucleus that is critical for speech understanding.

scholarly journals Subcortical circuits mediate communication between primary sensory cortical areas in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Lohse ◽  
Johannes C. Dahmen ◽  
Victoria M. Bajo ◽  
Andrew J. King
Keyword(s):  
Cortical Neurons ◽  
Common Property ◽  
Primary Auditory Cortex ◽  
Facilitatory Effect ◽  
Thalamic Nuclei ◽  
Auditory Midbrain ◽  
Cortical Areas ◽  
Auditory Responses ◽  
Evoked Activity

AbstractIntegration of information across the senses is critical for perception and is a common property of neurons in the cerebral cortex, where it is thought to arise primarily from corticocortical connections. Much less is known about the role of subcortical circuits in shaping the multisensory properties of cortical neurons. We show that stimulation of the whiskers causes widespread suppression of sound-evoked activity in mouse primary auditory cortex (A1). This suppression depends on the primary somatosensory cortex (S1), and is implemented through a descending circuit that links S1, via the auditory midbrain, with thalamic neurons that project to A1. Furthermore, a direct pathway from S1 has a facilitatory effect on auditory responses in higher-order thalamic nuclei that project to other brain areas. Crossmodal corticofugal projections to the auditory midbrain and thalamus therefore play a pivotal role in integrating multisensory signals and in enabling communication between different sensory cortical areas.

scholarly journals Evaluation of the Lambs’ State of Consciousness Signs during Halal and Traditional Slaughtering

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 557
Author(s):  
Roberta Barrasso ◽  
Vincenzo Tufarelli ◽  
Edmondo Ceci ◽  
Francesco Luposella ◽  
Giancarlo Bozzo
Keyword(s):  
Electric Current ◽  
Brain Function ◽  
Traditional Method ◽  
Time Intervals ◽  
Corneal Reflex ◽  
Group A ◽  
Group B ◽  
The Brain

The aim of this study was to evaluate the persistence of two signs of consciousness (rhythmic breathing and corneal reflex) in lambs slaughtered according to the traditional method and Halal ritual rite. A total of 240 lambs were examined and divided into two equal groups (n = 120 each). Lambs of group A were subjected to the stunning phase by the action of an electric current on the brain, while lambs of group B were slaughtered according to the religious Halal method without prior stunning. Rhythmic breathing (RB) and corneal reflex (CR) were used as indicators of prolonged brain function, and their evaluation was carried out by the operators in three subsequent steps at 15 s, 30 s, and 90 s post-bleeding, respectively. The stunning of the lambs reduced the animal’s state of consciousness and, consequently, reduced suffering, pain, and distress. Indeed, the lambs of group B showed longer duration consciousness than the animals stunned by electrodes. The permanence of the reflexes in Halal slaughter could be reduced by introducing a reversible stunning method to make the animal temporarily unconscious. Moreover, given that our results revealed consciousness also after 90 s post-cut, the assessment of the animal’s state of consciousness in wider time intervals than those commonly used is recommended.

Ephaptic Coupling in Hybrid Neuronal Model

2021 ◽  
Author(s):  
Gabriel Moreno Cunha ◽  
Gilberto Corso ◽  
José Garcia Vivas Miranda ◽  
Gustavo Zampier Dos Santos Lima
Keyword(s):  
Electric Fields ◽  
Action Potentials ◽  
Population Vector ◽  
Input Stimulus ◽  
Circular Statistic ◽  
Coupling Behavior ◽  
The Impact ◽  
The Brain ◽  
Ephaptic Coupling ◽  
Phase Differences

Abstract In recent decades, there has been growing interest in the impact of electric fields generated in the brain. Transmembrane ionic currents originate electric fields in the extracellular space and are capable of affecting nearby neurons, a phenomenon called ephaptic neuronal communication. In the present work, the Quadratic Integrate-and-Trigger model (QIF-E) underwent an adjustment/improvement to include the ephaptic coupling behavior between neurons and their results are compared to the empirical results. In this way, the analysis tools are employed according to the neuronal activity regime: (i) for the subthreshold regime, the circular statistic is used to describe the phase differences between the input stimulus signal and the modeled membrane response; (ii) in the suprathreshold regime, the Population Vector and the Spike Field Coherence are employed to estimate phase preferences and the coupling intensity between the input stimulus and the Action Potentials. The results observed are i) in the subthreshold regime the values of the phase differences change with distinct frequencies of an input stimulus; ii) in the supra-threshold regime the preferential phase of Action Potentials changes for different frequencies. In addition, we explore other parameters of the model, such as noise and membrane characteristic-time, in order to understand different types of neurons and extracellular environment related to ephaptic communication. Such results are consistent with results observed in empirical experiments based on ephaptic coupling behavior. In addition, the QIF-E model allows further studies on the physiological importance of ephaptic coupling in the brain, and its simplicity can open a door to simulating ephaptic coupling in neuron networks and evaluating the impact of ephaptic communication in such scenarios.

scholarly journals Apical length governs computational diversity of L5 pyramidal neurons

2019 ◽  
Author(s):  
Alessandro R. Galloni ◽  
Aeron Laffere ◽  
Ede Rancz
Keyword(s):  
Action Potentials ◽  
Pyramidal Neurons ◽  
Apical Dendrite ◽  
Common Assumption ◽  
Dendritic Excitability ◽  
Visual Cortices ◽  
The Common ◽  
Channel Dependent ◽  
Apical Dendrites ◽  
The Brain

AbstractAnatomical similarity across the neocortex has led to the common assumption that the circuitry is modular and performs stereotyped computations. Layer 5 pyramidal neurons (L5PNs) in particular are thought to be central to cortical computation because of their extensive arborisation and nonlinear dendritic operations. Here, we demonstrate that computations associated with dendritic Ca2+ plateaus in L5PNs vary substantially between the primary and secondary visual cortices. L5PNs in the secondary visual cortex show reduced dendritic excitability and smaller propensity for burst firing. This reduced excitability is correlated with shorter apical dendrites. Using numerical modelling, we uncover a universal principle underlying the influence of apical length on dendritic backpropagation and excitability, based on a Na+ channel-dependent broadening of backpropagating action potentials. In summary, we provide new insights into the modulation of dendritic excitability by apical dendrite length and show that the operational repertoire of L5 neurons is not universal throughout the brain.

Hierarchical Dynamical Model for Multiple Cortical Neural Decoding

2021 ◽  
Vol 33 (5) ◽  
pp. 1372-1401
Author(s):  
Xi Liu ◽  
Xiang Shen ◽  
Shuhang Chen ◽  
Xiang Zhang ◽  
Yifan Huang ◽  
...  
Keyword(s):  
Hierarchical Structure ◽  
Primary Motor Cortex ◽  
Neural Pathway ◽  
Neural Recordings ◽  
Cortical Areas ◽  
The Hierarchical Structure ◽  
Brain States ◽  
Heavy Tailed ◽  
The Brain

Abstract Motor brain machine interfaces (BMIs) interpret neural activities from motor-related cortical areas in the brain into movement commands to control a prosthesis. As the subject adapts to control the neural prosthesis, the medial prefrontal cortex (mPFC), upstream of the primary motor cortex (M1), is heavily involved in reward-guided motor learning. Thus, considering mPFC and M1 functionality within a hierarchical structure could potentially improve the effectiveness of BMI decoding while subjects are learning. The commonly used Kalman decoding method with only one simple state model may not be able to represent the multiple brain states that evolve over time as well as along the neural pathway. In addition, the performance of Kalman decoders degenerates in heavy-tailed nongaussian noise, which is usually generated due to the nonlinear neural system or influences of movement-related noise in online neural recording. In this letter, we propose a hierarchical model to represent the brain states from multiple cortical areas that evolve along the neural pathway. We then introduce correntropy theory into the hierarchical structure to address the heavy-tailed noise existing in neural recordings. We test the proposed algorithm on in vivo recordings collected from the mPFC and M1 of two rats when the subjects were learning to perform a lever-pressing task. Compared with the classic Kalman filter, our results demonstrate better movement decoding performance due to the hierarchical structure that integrates the past failed trial information over multisite recording and the combination with correntropy criterion to deal with noisy heavy-tailed neural recordings.

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