Faculty Opinions recommendation of Functionally specific oscillatory activity correlates between visual and auditory cortex in the blind.

2012 ◽  
Author(s):  
Alfons Schnitzler ◽  
Bettina Pollok
Keyword(s):  
Auditory Cortex ◽  
Oscillatory Activity

scholarly journals Neural Modulation of the Primary Auditory Cortex by Intracortical Microstimulation with a Bio-Inspired Electronic System

2020 ◽  
Vol 7 (1) ◽  
pp. 23
Author(s):  
Maria Giovanna Bianco ◽  
Salvatore Andrea Pullano ◽  
Rita Citraro ◽  
Emilio Russo ◽  
Giovambattista De Sarro ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Primary Auditory Cortex ◽  
Electronic System ◽  
Ultrasonic Waves ◽  
Oscillatory Activity ◽  
Intracortical Microstimulation ◽  
Brain Functions ◽  
Neural Modulation ◽  
Gamma Rhythm ◽  
Electrical Stimuli

Nowadays, the majority of the progress in the development of implantable neuroprostheses has been achieved by improving the knowledge of brain functions so as to restore sensorial impairments. Intracortical microstimulation (ICMS) is a widely used technique to investigate site-specific cortical responses to electrical stimuli. Herein, we investigated the neural modulation induced in the primary auditory cortex (A1) by an acousto-electric transduction of ultrasonic signals using a bio-inspired intracortical microstimulator. The developed electronic system emulates the transduction of ultrasound signals in the cochlea, providing bio-inspired electrical stimuli. Firstly, we identified the receptive fields in the primary auditory cortex devoted to encoding ultrasonic waves at different frequencies, mapping each area with neurophysiological patterns. Subsequently, the activity elicited by bio-inspired ICMS in the previously identified areas, bypassing the sense organ, was investigated. The observed evoked response by microstimulation resulted as highly specific to the stimuli, and the spatiotemporal dynamics of neural oscillatory activity in the alpha, beta, and gamma waves were related to the stimuli preferred by the neurons at the stimulated site. The alpha waves modulated cortical excitability only during the activation of the specific tonotopic neuronal populations, inhibiting neural responses in unrelated areas. Greater neuronal activity in the posterior area of A1 was observed in the beta band, whereas a gamma rhythm was induced in the anterior A1. The results evidence that the proposed bio-inspired acousto-electric ICMS triggers high-frequency oscillations, encoding information about the stimulation sites and involving a large-scale integration in the brain.

scholarly journals Spatial Profile and Differential Recruitment of GABAB Modulate Oscillatory Activity in Auditory Cortex

2009 ◽  
Vol 29 (33) ◽  
pp. 10321-10334 ◽  
Author(s):  
A.-M. M. Oswald ◽  
B. Doiron ◽  
J. Rinzel ◽  
A. D. Reyes
Keyword(s):  
Auditory Cortex ◽  
Oscillatory Activity ◽  
Spatial Profile

scholarly journals Functionally specific oscillatory activity correlates between visual and auditory cortex in the blind

Brain ◽  
2012 ◽  
Vol 135 (3) ◽  
pp. 922-934 ◽  
Author(s):  
Inga M. Schepers ◽  
Joerg F. Hipp ◽  
Till R. Schneider ◽  
Brigitte Röder ◽  
Andreas K. Engel
Keyword(s):  
Auditory Cortex ◽  
Oscillatory Activity

scholarly journals Differential contributions of synaptic and intrinsic inhibitory currents to speech segmentation via flexible phase-locking in neural oscillators

2020 ◽  
Author(s):  
Benjamin R. Pittman-Polletta ◽  
Yangyang Wang ◽  
David A. Stanley ◽  
Charles E. Schroeder ◽  
Miles A. Whittington ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Speech Processing ◽  
Cortical Neurons ◽  
Phase Locking ◽  
Outward Current ◽  
Speech Segmentation ◽  
Oscillatory Activity ◽  
Acoustic Features ◽  
Neural Oscillators ◽  
Speech Stream

AbstractCurrent hypotheses suggest that speech segmentation – the initial division and grouping of the speech stream into candidate phrases, syllables, and phonemes for further linguistic processing – is executed by a hierarchy of oscillators in auditory cortex. Theta (~3-12 Hz) rhythms play a key role by phase-locking to recurring acoustic features marking syllable boundaries. Reliable synchronization to quasi-rhythmic inputs, whose variable frequency can dip below cortical theta frequencies (down to ~1 Hz), requires “flexible” theta oscillators whose underlying neuronal mechanisms remain unknown. Using biophysical computational models, we found that the flexibility of phase-locking in neural oscillators depended on the types of hyperpolarizing currents that paced them. Simulated cortical theta oscillators flexibly phase-locked to slow inputs when these inputs caused both (i) spiking and (ii) the subsequent buildup of outward current sufficient to delay further spiking until the next input. The greatest flexibility in phase-locking arose from a synergistic interaction between intrinsic currents that was not replicated by synaptic currents at similar timescales. Our results suggest that synaptic and intrinsic inhibition contribute to frequency-restricted and - flexible phase-locking in neural oscillators, respectively. Their differential deployment may enable neural oscillators to play diverse roles, from reliable internal clocking to adaptive segmentation of quasi-regular sensory inputs like speech.Author summaryOscillatory activity in auditory cortex is believed to play an important role in auditory and speech processing. One suggested function of these rhythms is to divide the speech stream into candidate phonemes, syllables, words, and phrases, to be matched with learned linguistic templates. This requires brain rhythms to flexibly phase-lock to regular acoustic features of the speech stream. How neuronal circuits implement this task remains unknown. In this study, we explored the contribution of inhibitory currents to flexible phase-locking in neuronal theta oscillators, believed to perform initial syllabic segmentation. We found that a combination of specific intrinsic inhibitory currents at multiple timescales, present in a large class of cortical neurons, enabled exceptionally flexible phase-locking, suggesting that the cells exhibiting these currents are a key component in the brain’s auditory and speech processing architecture.

scholarly journals Functional synchronization between hippocampal sEEG, parietal ECoG and scalp EEG during a verbal working memory task

2020 ◽  
Author(s):  
Vasileios Dimakopoulos ◽  
Ece Boran ◽  
Peter Hilfiker ◽  
Lennart Stieglitz ◽  
Thomas Grunwald ◽  
...  
Keyword(s):  
Working Memory ◽  
Auditory Cortex ◽  
Information Flow ◽  
Verbal Working Memory ◽  
Oscillatory Activity ◽  
Functional Coupling ◽  
Maintenance Period ◽  
Physiological Basis ◽  
Cortical Areas ◽  
Scalp Eeg

ABSTRACTBackgroundThe maintenance of items in working memory (WM) relies on a widespread network of brain areas where synchronization between electrophysiological recordings may reflect functional coupling. While the coupling from hippocampus to scalp EEG is well established, we provide here direct cortical recordings for a fine-grained analysis.MethodsA patient performed a WM task where a string of letters was presented all at once, thus separating the encoding period from the maintenance period. We recorded sEEG from the hippocampus, temporo-parietal ECoG from a 64-contact grid electrode, and scalp EEG.ResultsPower spectral density (PSD) showed a clear task dependence: PSD in the posterior parietal lobe (10 Hz) and in the hippocampus (20 Hz) peaked towards the end of the maintenance period.Inter-area synchronization was characterized by the phase locking value (PLV). WM maintenance enhanced PLV between hippocampal sEEG and scalp EEG specifically in the theta range [6 7] Hz.PLV from hippocampus to parietal cortex increased during maintenance in the [9 10] Hz alpha and the 20 Hz range.When analyzing the information flow to and from auditory cortex by Granger causality, the flow was from auditory cortex to hippocampus with a peak in the [8 18] Hz range while letters were presented, and this flow was subsequently reversed during maintenance, while letters were maintained in memory.ConclusionsThe increased functional interaction between hippocampus and cortex through synchronized oscillatory activity and the directed information flow provide physiological basis for reverberation of memory items during maintenance. This points to a network for working memory that is bound by coherent oscillations involving cortical areas and hippocampus.SIGNIFICANCE STATEMENTHippocampal activity is known for its role in cognitive tasks involving episodic memory or spatial navigation, but its role in working memory and its sensitivity to workload is still under debate. Here, we investigated hippocampal and cortical activity while a subject maintained sets of letters in verbal working memory for a few seconds to guide action.After confirming the coupling between hippocampal oscillations and oscillations on the scalp, we found during maintenance that hippocampal oscillations increased coupling differentially to several areas of cortex by recording directly from the cortex.. During encoding of the letters, information flow was from auditory cortex to hippocampus and subsequently reversed during maintenance, thus providing a physiological basis for memory encoding and maintenance.This demonstrates a network for working memory that is bound by coherent oscillations that underlie the functional connectivity between cortical areas and hippocampus.

Stereotactic electroencephalography in humans reveals multisensory signal in early visual and auditory cortices

2019 ◽  
Author(s):  
Stefania Ferraro ◽  
Markus J. Van Ackeren ◽  
Roberto Mai ◽  
Laura Tassi ◽  
Francesco Cardinale ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Auditory Cortex ◽  
Auditory Processing ◽  
Multisensory Processing ◽  
Low Frequency ◽  
Event Related Potentials ◽  
Stimulus Onset ◽  
Oscillatory Activity ◽  
Visual Responses ◽  
Related Potentials

AbstractUnequivocally demonstrating the presence of multisensory signals at the earliest stages of cortical processing remains challenging in humans. In our study, we relied on the unique spatio-temporal resolution provided by intracranial stereotactic electroencephalographic (SEEG) recordings in patients with drug-resistant epilepsy to characterize the signal extracted from early visual (calcarine and pericalcarine) and auditory (Heschl’s gyrus and planum temporale) regions during a simple audio-visual oddball task. We provide evidences that both cross-modal responses (visual responses in auditory cortex or the reverse) and multisensory processing (alteration of the unimodal responses during bimodal stimulation) can be observed in intracranial event-related potentials (iERPs) and in power modulations of oscillatory activity at different temporal scales within the first 150 ms after stimulus onset. The temporal profiles of the iERPs are compatible with the hypothesis that MSI occurs by means of direct pathways linking early visual and auditory regions. Our data indicate, moreover, that MSI mainly relies on modulations of the low-frequency bands (foremost the theta band in the auditory cortex and the alpha band in the visual cortex), suggesting the involvement of feedback pathways between the two sensory regions. Remarkably, we also observed high-gamma power modulations by sounds in the early visual cortex, thus suggesting the presence of neuronal populations involved in auditory processing in the calcarine and pericalcarine region in humans.

scholarly journals An Oscillatory Hierarchy Controlling Neuronal Excitability and Stimulus Processing in the Auditory Cortex

2005 ◽  
Vol 94 (3) ◽  
pp. 1904-1911 ◽  
Author(s):  
Peter Lakatos ◽  
Ankoor S. Shah ◽  
Kevin H. Knuth ◽  
Istvan Ulbert ◽  
George Karmos ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Neuronal Excitability ◽  
Spatial Scales ◽  
Current Source ◽  
Primary Auditory Cortex ◽  
Hierarchical Organization ◽  
Synaptic Activity ◽  
Oscillatory Activity ◽  
Theta Phase

EEG oscillations are hypothesized to reflect cyclical variations in the neuronal excitability, with particular frequency bands reflecting differing spatial scales of brain operation. However, despite decades of clinical and scientific investigation, there is no unifying theory of EEG organization, and the role of ongoing activity in sensory processing remains controversial. This study analyzed laminar profiles of synaptic activity [current source density CSD] and multiunit activity (MUA), both spontaneous and stimulus-driven, in primary auditory cortex of awake macaque monkeys. Our results reveal that the EEG is hierarchically organized; delta (1–4 Hz) phase modulates theta (4–10 Hz) amplitude, and theta phase modulates gamma (30–50 Hz) amplitude. This oscillatory hierarchy controls baseline excitability and thus stimulus-related responses in a neuronal ensemble. We propose that the hierarchical organization of ambient oscillatory activity allows auditory cortex to structure its temporal activity pattern so as to optimize the processing of rhythmic inputs.

scholarly journals Oscillatory activity in auditory cortex reflects the perceptual level of audio-tactile integration

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael Plöchl ◽  
Jeremy Gaston ◽  
Tim Mermagen ◽  
Peter König ◽  
W. David Hairston
Keyword(s):  
Auditory Cortex ◽  
Oscillatory Activity ◽  
Tactile Integration

scholarly journals Thalamocortical and intracortical contributions to stimulus-evoked and oscillatory activity in rodent primary auditory cortex

2021 ◽  
Author(s):  
Marcus Jeschke ◽  
Frank W. Ohl
Keyword(s):  
Auditory Cortex ◽  
Computational Models ◽  
Frequency Tuning ◽  
Current Source ◽  
Primary Auditory Cortex ◽  
Sensory Stimulation ◽  
Gamma Oscillations ◽  
Oscillatory Activity ◽  
Mongolian Gerbils ◽  
Horizontal Connections

Intracortical, horizontal connections seem ideally suited to contribute to cortical processing by spreading information across cortical space and coordinating activity between distant cortical sites. In sensory systems experiments have implicated horizontal connections in the generation of receptive fields and have in turn led to computational models of receptive field generation that rely on the contribution of horizontal connections. Testing the contribution of horizontal connections at the mesoscopic level has been difficult due to the lack of a suitable method to observe the activity of intracortical horizontal connections. Here, we develop such a method based on the analysis of the relative residues of the cortical laminar current source density reconstructions. In the auditory cortex of Mongolian gerbils, the method is then tested by manipulating the contribution of horizontal connections by surgical dissection. Our results indicate that intracortical horizontal connections contribute to the frequency-tuning of mesoscopic cortical patches. Futhermore, we dissociated a type of cortical gamma oscillation based on horizontal connections between mesoscopic patches from gamma oscillations locally generated within mesoscopic patches. The data further imply that global and local coordination of activity during sensory stimulation occur in a low and high gamma frequency band, respectively. Taken together the present data demonstrate that intracortical horizontal connections play an important role in generating cortical feature tuning and coordinate neuronal oscillations across cortex.

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