scholarly journals Adaptation of high-gamma responses in human auditory association cortex

2014 ◽  
Vol 112 (9) ◽  
pp. 2147-2163 ◽  
Author(s):  
Steven J. Eliades ◽  
Nathan E. Crone ◽  
William S. Anderson ◽  
Deepti Ramadoss ◽  
Frederick A. Lenz ◽  
...  
Keyword(s):  
Time Scales ◽  
Rapid Onset ◽  
Association Cortex ◽  
Complex Sounds ◽  
Time Frequency ◽  
Speech Stimuli ◽  
Stimulus Block ◽  
High Gamma ◽  
Frequent Response ◽  
Auditory Association Cortex

This study investigates adaptation of high-frequency cortical responses [>60 Hz; high-gamma (HG)] to simple and complex sounds in human nonprimary auditory cortex. We used intracranial electrocorticographic recordings to measure event-related changes in HG power as a function of stimulus probability. Tone and speech stimuli were presented in a series of traditional oddball and control paradigms. We hypothesized that HG power attenuates with stimulus repetition over multiple concurrent time scales in auditory association cortex. Time-frequency analyses were performed to identify auditory-responsive sites. Single-trial analyses and quantitative modeling were then used to measure trial-to-trial changes in HG power for high (frequent), low (infrequent), and equal (control) stimulus probabilities. Results show strong reduction of HG responses to frequently repeated tones and speech, with no differences in responses to infrequent and equal-probability stimuli. Adaptation of the HG frequent response, and not stimulus-acoustic differences or deviance-detection enhancement effects, accounted for the differential responses observed for frequent and infrequent sounds. Adaptation of HG responses showed a rapid onset (less than two trials) with slower adaptation between consecutive, repeated trials (2–10 s) and across trials in a stimulus block (∼7 min). The auditory-evoked N100 response also showed repetition-related adaptation, consistent with previous human scalp and animal single-unit recordings. These findings indicate that HG responses are highly sensitive to the regularities of simple and complex auditory events and show adaptation on multiple concurrent time scales in human auditory association cortex.

scholarly journals Comparison of Time–Frequency Responses and the Event-Related Potential to Auditory Speech Stimuli in Human Cortex

2009 ◽  
Vol 102 (1) ◽  
pp. 377-386 ◽  
Author(s):  
Erik Edwards ◽  
Maryam Soltani ◽  
Won Kim ◽  
Sarang S. Dalal ◽  
Srikantan S. Nagarajan ◽  
...  
Keyword(s):  
Inferior Frontal Gyrus ◽  
Tumor Resection ◽  
Superior Temporal Gyrus ◽  
Event Related Potential ◽  
Language Mapping ◽  
Mapping Procedure ◽  
Time Frequency ◽  
Speech Stimuli ◽  
Neurosurgical Patients ◽  
High Gamma

We recorded the electrocorticogram directly from the exposed cortical surface of awake neurosurgical patients during the presentation of auditory syllable stimuli. All patients were unanesthetized as part of a language-mapping procedure for subsequent left-hemisphere tumor resection. Time–frequency analyses showed significant high-gamma (γhigh: 70–160 Hz) responses from the left superior temporal gyrus, but no reliable response from the left inferior frontal gyrus. Alpha suppression (α: 7–14 Hz) and event-related potential responses exhibited a more widespread topography. Across electrodes, the α suppression from 200 to 450 ms correlated with the preceding (50–200 ms) γhigh increase. The results are discussed in terms of the different physiological origins of these electrocortical signals.

High Gamma Activity in Response to Deviant Auditory Stimuli Recorded Directly From Human Cortex

2005 ◽  
Vol 94 (6) ◽  
pp. 4269-4280 ◽  
Author(s):  
Erik Edwards ◽  
Maryam Soltani ◽  
Leon Y. Deouell ◽  
Mitchel S. Berger ◽  
Robert T. Knight
Keyword(s):  
Temporal Lobe ◽  
Temporal Cortex ◽  
Event Related Potentials ◽  
Gamma Oscillations ◽  
Auditory Stimuli ◽  
Association Cortex ◽  
Neurosurgical Patients ◽  
High Gamma ◽  
Related Potentials ◽  
Auditory Association Cortex

We recorded electrophysiological responses from the left frontal and temporal cortex of awake neurosurgical patients to both repetitive background and rare deviant auditory stimuli. Prominent sensory event-related potentials (ERPs) were recorded from auditory association cortex of the temporal lobe and adjacent regions surrounding the posterior Sylvian fissure. Deviant stimuli generated an additional longer latency mismatch response, maximal at more anterior temporal lobe sites. We found low gamma (30–60 Hz) in auditory association cortex, and we also show the existence of high-frequency oscillations above the traditional gamma range (high gamma, 60–250 Hz). Sensory and mismatch potentials were not reliably observed at frontal recording sites. We suggest that the high gamma oscillations are sensory-induced neocortical ripples, similar in physiological origin to the well-studied ripples of the hippocampus.

scholarly journals Nonlinearities of heart rate variability in animal models of impaired cardiac control: contribution of different time scales

2017 ◽  
Vol 123 (2) ◽  
pp. 344-351 ◽  
Author(s):  
Luiz Eduardo Virgilio Silva ◽  
Renata Maria Lataro ◽  
Jaci Airton Castania ◽  
Carlos Alberto Aguiar Silva ◽  
Helio Cesar Salgado ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Time Scales ◽  
Multiscale Entropy ◽  
Time Frequency ◽  
Cardiac Control ◽  
Long Time ◽  
Nonlinear Features ◽  
Short Time

Heart rate variability (HRV) has been extensively explored by traditional linear approaches (e.g., spectral analysis); however, several studies have pointed to the presence of nonlinear features in HRV, suggesting that linear tools might fail to account for the complexity of the HRV dynamics. Even though the prevalent notion is that HRV is nonlinear, the actual presence of nonlinear features is rarely verified. In this study, the presence of nonlinear dynamics was checked as a function of time scales in three experimental models of rats with different impairment of the cardiac control: namely, rats with heart failure (HF), spontaneously hypertensive rats (SHRs), and sinoaortic denervated (SAD) rats. Multiscale entropy (MSE) and refined MSE (RMSE) were chosen as the discriminating statistic for the surrogate test utilized to detect nonlinearity. Nonlinear dynamics is less present in HF animals at both short and long time scales compared with controls. A similar finding was found in SHR only at short time scales. SAD increased the presence of nonlinear dynamics exclusively at short time scales. Those findings suggest that a working baroreflex contributes to linearize HRV and to reduce the likelihood to observe nonlinear components of the cardiac control at short time scales. In addition, an increased sympathetic modulation seems to be a source of nonlinear dynamics at long time scales. Testing nonlinear dynamics as a function of the time scales can provide a characterization of the cardiac control complementary to more traditional markers in time, frequency, and information domains. NEW & NOTEWORTHY Although heart rate variability (HRV) dynamics is widely assumed to be nonlinear, nonlinearity tests are rarely used to check this hypothesis. By adopting multiscale entropy (MSE) and refined MSE (RMSE) as the discriminating statistic for the nonlinearity test, we show that nonlinear dynamics varies with time scale and the type of cardiac dysfunction. Moreover, as complexity metrics and nonlinearities provide complementary information, we strongly recommend using the test for nonlinearity as an additional index to characterize HRV.

Auditory-Somatosensory Multisensory Processing in Auditory Association Cortex: An fMRI Study

2002 ◽  
Vol 88 (1) ◽  
pp. 540-543 ◽  
Author(s):  
John J. Foxe ◽  
Glenn R. Wylie ◽  
Antigona Martinez ◽  
Charles E. Schroeder ◽  
Daniel C. Javitt ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Multisensory Integration ◽  
Multisensory Processing ◽  
Primary Auditory Cortex ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Association Cortex ◽  
Convergence Region ◽  
Auditory Cortices ◽  
Auditory Association Cortex

Using high-field (3 Tesla) functional magnetic resonance imaging (fMRI), we demonstrate that auditory and somatosensory inputs converge in a subregion of human auditory cortex along the superior temporal gyrus. Further, simultaneous stimulation in both sensory modalities resulted in activity exceeding that predicted by summing the responses to the unisensory inputs, thereby showing multisensory integration in this convergence region. Recently, intracranial recordings in macaque monkeys have shown similar auditory-somatosensory convergence in a subregion of auditory cortex directly caudomedial to primary auditory cortex (area CM). The multisensory region identified in the present investigation may be the human homologue of CM. Our finding of auditory-somatosensory convergence in early auditory cortices contributes to mounting evidence for multisensory integration early in the cortical processing hierarchy, in brain regions that were previously assumed to be unisensory.

Tonotopic organization of human auditory association cortex

1994 ◽  
Vol 663 (1) ◽  
pp. 38-50 ◽  
Author(s):  
Selene Cansino ◽  
Samuel J. Williamson ◽  
Daniel Karron
Keyword(s):  
Association Cortex ◽  
Tonotopic Organization ◽  
Auditory Association Cortex

scholarly journals Reduced Pyramidal Cell Somal Volume in Auditory Association Cortex of Subjects with Schizophrenia

2002 ◽  
Vol 28 (3) ◽  
pp. 599-609 ◽  
Author(s):  
Robert A Sweet ◽  
Joseph N Pierri ◽  
Sungyoung Auh ◽  
Allan R Sampson ◽  
David A Lewis
Keyword(s):  
Pyramidal Cell ◽  
Association Cortex ◽  
Auditory Association Cortex

Contribution of Human Prefrontal Cortex to Delay Performance

1998 ◽  
Vol 10 (2) ◽  
pp. 167-177 ◽  
Author(s):  
Linda L. Chao ◽  
Robert T. Knight
Keyword(s):  
Prefrontal Cortex ◽  
Neural Activity ◽  
Dorsolateral Prefrontal Cortex ◽  
Silent Period ◽  
Primary Auditory Cortex ◽  
Association Cortex ◽  
Focal Lesions ◽  
Delay Performance ◽  
Dorsolateral Prefrontal ◽  
Auditory Association Cortex

Neurological patients with focal lesions in the dorsolateral prefrontal cortex and age-matched control subjects were tested on an auditory version of the delayed-match-to-sample task employing environmental sounds. Subjects had to indicate whether a cue (S1) and a subsequent target sound (S2) were identical. On some trials, S1 and S2 were separated by a silent period of 5 sec. On other trials, the 5-sec delay between S1 and S2 was filled with irrelevant tone pips that served as distractors. Behaviorally, frontal patients were impaired by the presence of distractors. Electrophysiologically, patients generated enhanced primary auditory cortex-evoked responses to the tone pips, supporting a failure in inhibitory control of sensory processing after prefrontal damage. Intrahemispheric reductions of neural activity generated in the auditory association cortex and additional intrahemispheric reductions of attention-related frontal activity were also observed in the prefrontal patients. Together, these findings suggest that the dorsolateral prefrontal cortex is crucial for gating distracting information as well as maintaining distributed intrahemispheric neural activity during auditory working memory.

scholarly journals Top–down task effects overrule automatic multisensory responses to letter–sound pairs in auditory association cortex

NeuroImage ◽  
2007 ◽  
Vol 36 (4) ◽  
pp. 1345-1360 ◽  
Author(s):  
Nienke M. van Atteveldt ◽  
Elia Formisano ◽  
Rainer Goebel ◽  
Leo Blomert
Keyword(s):  
Association Cortex ◽  
Top Down ◽  
Task Effects ◽  
Auditory Association Cortex ◽  
Letter Sound

scholarly journals Frontal and motor cortex contributions to response inhibition: evidence from electrocorticography

2016 ◽  
Vol 115 (4) ◽  
pp. 2224-2236 ◽  
Author(s):  
Yvonne M. Fonken ◽  
Jochem W. Rieger ◽  
Elinor Tzvi ◽  
Nathan E. Crone ◽  
Edward Chang ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Response Inhibition ◽  
Motor Preparation ◽  
Relevant Information ◽  
Stop Signal ◽  
Response Preparation ◽  
Time Frequency ◽  
Beta Power ◽  
High Gamma ◽  
Stop Signal Reaction Time

Changes in the environment require rapid modification or inhibition of ongoing behavior. We used the stop-signal paradigm and intracranial recordings to investigate response preparation, inhibition, and monitoring of task-relevant information. Electrocorticographic data were recorded in eight patients with electrodes covering frontal, temporal, and parietal cortex, and time-frequency analysis was used to examine power differences in the beta (13–30 Hz) and high-gamma bands (60–180 Hz). Over motor cortex, beta power decreased, and high-gamma power increased during motor preparation for both go trials (Go) and unsuccessful stops (US). For successful stops (SS), beta increased, and high-gamma was reduced, indexing the cancellation of the prepared response. In the middle frontal gyrus (MFG), stop signals elicited a transient high-gamma increase. The MFG response occurred before the estimated stop-signal reaction time but did not distinguish between SS and US trials, likely signaling attention to the salient stop stimulus. A postresponse high-gamma increase in MFG was stronger for US compared with SS and absent in Go, supporting a role in behavior monitoring. These results provide evidence for differential contributions of frontal subregions to response inhibition, including motor preparation and inhibitory control in motor cortex and cognitive control and action evaluation in lateral prefrontal cortex.

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