02771nas a2200253 4500008004100000022001400041245014300055210006900198260001200267300000800279490000600287520196800293653002202261653003202283653001502315653002102330653001802351100001702369700002402386700002102410700001902431700001902450856004802469 2014 eng d a1662-516100aECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song.0 aECoG high gamma activity reveals distinct cortical representatio c10/2014 a7980 v83 a

Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

10aacoustic features10aelectrocorticography (ECoG)10ahigh gamma10amusic processing10anatural music1 aSturm, Irene1 aBlankertz, Benjamin1 aPotes, Cristhian1 aSchalk, Gerwin1 aCurio, Gabriel uhttp://www.ncbi.nlm.nih.gov/pubmed/2535279903446nas a2200253 4500008004100000245011700041210006900158260001200227300001100239490000700250520261100257653003402868653002402902653003202926653002802958653002202986653003403008100002103042700001903063700002003082700002303102700001903125856004803144 2014 eng d00aSpatial and temporal relationships of electrocorticographic alpha and gamma activity during auditory processing.0 aSpatial and temporal relationships of electrocorticographic alph c08/2014 a188-950 v973 aNeuroimaging approaches have implicated multiple brain sites in musical perception, including the posterior part of the superior temporal gyrus and adjacent perisylvian areas. However, the detailed spatial and temporal relationship of neural signals that support auditory processing is largely unknown. In this study, we applied a novel inter-subject analysis approach to electrophysiological signals recorded from the surface of the brain (electrocorticography (ECoG)) in ten human subjects. This approach allowed us to reliably identify those ECoG features that were related to the processing of a complex auditory stimulus (i.e., continuous piece of music) and to investigate their spatial, temporal, and causal relationships. Our results identified stimulus-related modulations in the alpha (8-12 Hz) and high gamma (70-110 Hz) bands at neuroanatomical locations implicated in auditory processing. Specifically, we identified stimulus-related ECoG modulations in the alpha band in areas adjacent to primary auditory cortex, which are known to receive afferent auditory projections from the thalamus (80 of a total of 15,107 tested sites). In contrast, we identified stimulus-related ECoG modulations in the high gamma band not only in areas close to primary auditory cortex but also in other perisylvian areas known to be involved in higher-order auditory processing, and in superior premotor cortex (412/15,107 sites). Across all implicated areas, modulations in the high gamma band preceded those in the alpha band by 280 ms, and activity in the high gamma band causally predicted alpha activity, but not vice versa (Granger causality, p<1e(-8)). Additionally, detailed analyses using Granger causality identified causal relationships of high gamma activity between distinct locations in early auditory pathways within superior temporal gyrus (STG) and posterior STG, between posterior STG and inferior frontal cortex, and between STG and premotor cortex. Evidence suggests that these relationships reflect direct cortico-cortical connections rather than common driving input from subcortical structures such as the thalamus. In summary, our inter-subject analyses defined the spatial and temporal relationships between music-related brain activity in the alpha and high gamma bands. They provide experimental evidence supporting current theories about the putative mechanisms of alpha and gamma activity, i.e., reflections of thalamo-cortical interactions and local cortical neural activity, respectively, and the results are also in agreement with existing functional models of auditory processing.10aalpha and high gamma activity10aauditory processing10aelectrocorticography (ECoG)10afunctional connectivity10agranger causality10athalamo-cortical interactions1 aPotes, Cristhian1 aBrunner, Peter1 aGunduz, Aysegul1 aKnight, Robert, T.1 aSchalk, Gerwin uhttp://www.ncbi.nlm.nih.gov/pubmed/2476893303280nas a2200229 4500008004100000022001400041245012300055210006900178260001200247300001000259490000700269520254700276653002402823653003202847653002402879653002002903100002102923700002002944700001902964700001902983856004803002 2012 eng d a1095-957200aDynamics of electrocorticographic (ECoG) activity in human temporal and frontal cortical areas during music listening.0 aDynamics of electrocorticographic ECoG activity in human tempora c07/2012 a841-80 v613 a

Previous studies demonstrated that brain signals encode information about specific features of simple auditory stimuli or of general aspects of natural auditory stimuli. How brain signals represent the time course of specific features in natural auditory stimuli is not well understood. In this study, we show in eight human subjects that signals recorded from the surface of the brain (electrocorticography (ECoG)) encode information about the sound intensity of music. ECoG activity in the high gamma band recorded from the posterior part of the superior temporal gyrus as well as from an isolated area in the precentral gyrus was observed to be highly correlated with the sound intensity of music. These results not only confirm the role of auditory cortices in auditory processing but also point to an important role of premotor and motor cortices. They also encourage the use of ECoG activity to study more complex acoustic features of simple or natural auditory stimuli.

10aauditory processing10aelectrocorticography (ECoG)10ahigh gamma activity10asound intensity1 aPotes, Cristhian1 aGunduz, Aysegul1 aBrunner, Peter1 aSchalk, Gerwin uhttp://www.ncbi.nlm.nih.gov/pubmed/22537600