Citation Context

...et trials and 380 standard non-target trials included in the analysis. For the three subjectswhoperformed the phoneme task, 215 and 270 trials were included, respectively. Data analysis All electrophysiological data were put into a common average reference to avoid spatial bias due to the choice of intracranial reference electrode (Boatman-Reich et al., 2010). All signals were analyzed in MATLAB® (R2009b, Natick, MA) using custom scripts. For ERSP and PAC figures (1, 3, 4, and 6) we corrected for multiple comparisons using a false discovery rate (FDR) method (fdr.m function in EEGLAB toolbox (Delorme and Makeig, 2004) in MATLAB). All analyses were done on an individual subject and electrode basis. Event-related spectral perturbations For ERSP analyses, the data for each channel was first filtered in multiple, logarithmically-spaced pass bands using a two-way, zero phase-lag, finite impulse response filter (eegfilt.m function in EEGLAB) to prevent phase distortion. The filter order is defined as 3r where r is the ratio of the sampling rate to the low-frequency cutoff of the filter, rounded down. Data were filtered in partially overlapping bands from 0.5 to 250 Hz. We seeded the first pass band such that fp(...

Citation Context

... rely on block design experiments and temporal concatenation at the cost of the sub-second temporal resolution afforded by electrophysiological recordings. Here we present a method for calculating event-related phase/ amplitude coupling (ERPAC) designed to capture the temporal evolution of task-related changes in PAC across events or between distant brain regions that is applicable to human or animal electromagnetic recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et...

Citation Context

... the cost of the sub-second temporal resolution afforded by electrophysiological recordings. Here we present a method for calculating event-related phase/ amplitude coupling (ERPAC) designed to capture the temporal evolution of task-related changes in PAC across events or between distant brain regions that is applicable to human or animal electromagnetic recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Vo...

Citation Context

...ot, for example, due to a possible spurious relationship induced by “sharp” artifacts (see Kramer et al., 2008b) or stimulus-induced. For normal ERPAC calculations, what is important is the trial-by-trial covariance between amplitude and phase. So for surrogate analyses we kept the actual analytic amplitude and phase values at each time point, but randomized the trial labels. This keeps the stimulus-evoked changes in amplitude or IPL intact while randomizing the relative trial structure between the two variables and is similar to methods used to calculate significance in e.g. phase synchrony (Lachaux et al., 1999). This was done 1000 times at each time point. If the observed ERPAC is caused by a spurious artifact then that value should not be improbable given the possible distribution of ERPAC values drawn from the permutation testing. In other words, at each time point we can Fig. 3. Event-related phase/amplitude coupling modulated by task demands. Trial-by-trial variance in low frequency phase explains a significant amount of the trial-by-trial variance in γ amplitude in visual cortex in response to (a) attended non-target standard and (b) attended target stimuli (data are from the same electrode as ...

Citation Context

...his requires researchers to rely on block design experiments and temporal concatenation at the cost of the sub-second temporal resolution afforded by electrophysiological recordings. Here we present a method for calculating event-related phase/ amplitude coupling (ERPAC) designed to capture the temporal evolution of task-related changes in PAC across events or between distant brain regions that is applicable to human or animal electromagnetic recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et...

Citation Context

...ynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi, 2012).k). rights reserved.Currently PAC calculation algorithms compute a value averaged across a semi-arbitrary time window (Canolty et al., 2006; Cohen and van Gaal, in press; Voytek et al., 2010a) (see Cohen, 2008; Penny et al., 2008; Tort et al., 2010 for methodological de...

Citation Context

...guhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). Fro...

Citation Context

... of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also ...

Citation Context

...d this target-specific ERPAC effect is not an artifact caused by stimulus-related changes in amplitude or phase (Figs. 4a–c). Importantly, this ERPAC method assesses coupling between distant brain regions (Fig. 5). For example, in a midline frontal electrode that demonstrates significant (~200–400 ms) γ amplitude increasesin response to targets we find that visual cortical θ phase correlates with frontal γ amplitude (Fig. 5). This technique might be useful for highlighting long-distance bottom-up and top-down interregional communication via neuronal synchrony (Engel et al., 2001; Fries, 2005; Womelsdorf and Fries, 2007). We assessed the trial-by-trial evolution of ERPAC by examining two electrodes over visual cortex that exhibit strong γ activity in response to attended targets. We observe complex intertrial evolution of early (100–200 ms) γ activity (Fig. 6). For example, across trials, at two neighboring electrodes, γ amplitude is anti-correlated (r=−0.26, p=0.005) such that one electrode exhibits strong a γ during the first 20–30 target trials, but this response decreases or attenuates with successive trials. In contrast, γ activity at the neighboring electrode shows the opposite pattern. Furthermore, usi...

Citation Context

...c recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale n...

Citation Context

...the sub-second temporal resolution afforded by electrophysiological recordings. Here we present a method for calculating event-related phase/ amplitude coupling (ERPAC) designed to capture the temporal evolution of task-related changes in PAC across events or between distant brain regions that is applicable to human or animal electromagnetic recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/pha...

Citation Context

...ct to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown...

Citation Context

...example black rectangles in a). In contrast to blocked PAC, which is calculated across time, ERPAC is calculated across trials separately at each time point. In this example (from the electrode shown in Fig. 1), trial-by-trial differences in α phase explain a significant amount of the inter-trial variability in broadband γ amplitude during a brief time window (50–250 ms) after stimulus onset. See Methods for full details. 419B. Voytek et al. / NeuroImage 64 (2013) 416–424recently been used to examine the relationship between scalp EEG θ phase and global field power during attention in humans (Busch and VanRullen, 2010). We can compare the significance of the difference between correlation coefficients ρ1 and ρ2 by first applying Fisher's z-transform to normalize correlation coefficients such that zrn 12 ln 1þρn1−ρn and calculating the difference Δρz=z(ρ1)−z(ρ2) and associated standard error σ ffiffiffiffiffiffiffiffiffi 1 n1−3 q þ 1n2−3. From this we can calculate the z-score z= Δρz/σ and associated p-value.Event-related phase/amplitude coupling (ERPAC) We introduce amethod for ERPACmaking use of either the circular– linear correlation above or itsmore generalized formof a circular–linear regression...

Citation Context

...r animal electromagnetic recording. © 2012 Elsevier Inc. All rights reserved.Introduction The mammalian neo- and archicortices generate electrophysiological oscillatory rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) ...

Citation Context

...; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi, 2012).k). rights reserved.Currently PAC calculation algorithms compute a value averaged across a semi-arbitrary time window (Canolty et al., 2006; Cohen and van Gaal, in press; Voytek et al., 2010a) (see Cohen, 2008; Penny et al., 2008; Tort et al., 2010 for methodological details). The minimum length of this timewindow is bounded by the frequency of the coupling phase, as at least one full cycle is needed to calculate the distribution of values of the coupling amplitude. However, the PAC metric is sensitive to noise, and recent simulations have made use of >200 cycles to get a reliable PAC estimate (Tort et al., 2010). This means, for example, that if one is investigating PAC between theta phase (4–8 Hz) and high gamma amplitude (80–150 Hz), the best temporal resolution one could achieve at 4 Hz would be 250 ms (one full cycle). However, 50 ...

Citation Context

...creasing γ activity across trials (green) also shows increasing α/γ ERPAC and the electrode that shows increasing γ across trials (orange) shows decreasing α/γ ERPAC.Phoneme repetition We extended the findings from our ECoG data in the visual target-detection task to the auditory modality and provide results from subjects with subdural ECoG performing a simple phoneme repetition task (see Methods). Similar to the visual attention data, subjects performing an auditory task also exhibit transient ERPAC. Consistent with previous reports of δ phase/γ amplitude relationships (Lakatos et al., 2008; Whittingstall and Logothetis, 2009), we show that the δ phase correlates with the γ amplitude in auditory cortical areas (Fig. 7). Notably one of the three subjects showed no significant δ phase/γ amplitude ERPAC effects. These findings illustrate that Fig. 7. Auditory cortex event-related phase/amplitude coupling in response to phonemes. In three separate subjects performing a phoneme repetition task, we observe significant, transient ERPAC between γ amplitude and δ phase (1–4 Hz) in auditory cortical regions for two subjects, illustrating the broad applicability of this method. Fig. 6. Relationship between phase/amplitude cou...

Citation Context

...uch that fL(n)=0.85(fH(n−1)) and fH(n)=1.1+(fH(n−1)− fL(n−1)) fL(n). We then applied a Hilbert transform to each of these time-series (hilbert.m function) resulting in a complex time-series, hx[n]=ax[n] exp(iϕx[n])where ax[n] andϕx[n] are the analytic amplitudes and phases, respectively, of a specific pass band fp(n). The phase time-series ϕxassumes values within (−π, π] radians with a cosine phase such that −/+π radians correspond to the troughs and 0 radians to the peak. The Hilbert phase and amplitude estimation method yields results equivalent to sliding window FFT and wavelet approaches (Bruns, 2004). From each trial the time-series of analytic amplitudes, ax (the absolute value, or modulus, of hx), was used to create an average eventrelated analytic amplitude (ERAA), an estimate of the band-specific signal energy. Each trial-specific epoch consisted of a 100-ms pre-stimulus period and a 1000 ms post-stimulus period. To calculate the significance of any event-related changes in analytic amplitude under a given experimental condition, we used a standard resampling technique (see Voytek et al., 2010b) to assess whether any event-related changes in analytic amplitude occurred relative to sti...

Citation Context

...across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi...

Citation Context

...t al., 2010a), use long trial windows at the cost of temporal resolution (Tort et al., 2009), or to concatenate time series across trials (Tort et al., 2009) which could introduce spurious PAC due to edge artifacts (see Kramer et al., 2008b). These limitations present a problem for analyzing subcomponents of a task such as encoding, delay, and retrieval periods during working memory. Here we demonstrate a novel approach for assessing time-resolved, event-related PAC (ERPAC). We provide results from subdural electrocorticographic (ECoG) data from three human subjects with implanted electrodes (Jacobs and Kahana, 2010) to demonstrate the utility of the ERPAC analysis procedure. We show that this method can be used to assess PAC both within local cortical regions as well as between distant sites. We observed couplings between multiple frequencies occurring at different time scales that evolved across trials 417B. Voytek et al. / NeuroImage 64 (2013) 416–424and were independent of evoked responses. ERPAC provides a method for assessing sub-second coupling dynamics supporting cortical processing. Methods Data collection We analyzed data from three patients with intractable epilepsywho were implanted with chron...

Citation Context

...Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi, 2012).k). rights reserved.Currently PAC calculation algorithms compute a value averaged across a semi-arbitrary time window (Canolty et al., 2006; Cohen and van Gaal, in press; Voytek et al., 2010a) (see Cohen, 2008; Penny et al., 2008; Tort et al., 2010 for methodological details). The minimum length of this timewindow is bounded by the frequency of the coupling phase, as at least one full cycle is needed to calculate the distribution of values of the coupling amplitude. However, the PAC metric is sensitive to noise, and recent simulations have made use of >200 cycles to get a reliable PAC estimate (Tort et al., 2010). This means, for example, that if one is investigating PAC between theta phase (4–8 Hz) and high gamma amplitude (80–150 Hz), the best temporal resolution one could achieve at 4 Hz would be 250 ms (one full c...

Citation Context

..., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi, 2012).k). rights reserved.Currently PAC calculation algorithms compute a value averaged across a semi-arbitrary time window (Canolty et al., 2006; Cohen and van Gaal, ...

Citation Context

...itude envelopes, and theta phase in electrode A predicts gamma amplitude in A, the theta phase from A will also predict gamma amplitude in B. Note that recent new methods provide a multivariate solution to a network of coupled oscillators the diminishes the solution space (Canolty et al., 2010). This technique provides a method for observing, quantifying, and statistically comparing ERPAC dynamics in a time-resolved and computationally tractable manner. Given that this method calculates PAC across trials at each time point it is likely capturing evoked (as opposed to induced) PAC effects (see David et al., 2006). This would provide complementary information to time-averaged PAC that would be better suited to capturing induced PAC. Here we use this method to analyze ECoG data from subdural recordings in humans, but the method can be applied to other forms of electromagnetic recordings in animals and man.Conflict of interest statement The authors declare no competing financial or other interests.Acknowledgments We thank Aurelie Bidet-Caulet, Maya Cano, Ryan Canolty, Adeen Flinker, John Long, Avgusta Shestyuk, Frederic Theunissen, Adriano Tort, and Jonathan Wallis for useful conversations about the manu...

Citation Context

...rhythms (Buzsáki and Draguhn, 2004; Engel et al., 2001) that interact to facilitate communication (Fries, 2005; Fröhlich and McCormick, 2010; Sirota et al., 2008). The amplitude and phase of these rhythms are typically assessed in an event-related manner across trials or subjects. There is emerging evidence that frequency-specific rhythms are often nested within other frequency bands (Kramer et al., 2008a; Roopun et al., 2008; Tort et al., 2009; see Canolty and Knight, 2010 for a review). There are multiple forms of coupling dynamics: phase/amplitude (Canolty et al., 2006; Cohen et al., 2009; Griesmayr et al., 2010; Lakatos et al., 2008; Miller et al., 2010; Osipova et al., 2008; Tort et al., 2009; Voytek et al., 2010a), phase/phase (Canolty et al., 2007; Darvas et al., 2009; Palva et al., 2005; Tass et al., 1998), and amplitude-to-amplitude (Bruns and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhat...

Citation Context

...field. For the phoneme repetition task, the three ECoG subjects listened to a stream of vowel phonemes (e.g., “oo” as in “book”, “ee” as in “eel”, etc.) with an average 3000-ms ISI and were asked to repeat each of them aloud. For the visual task, there were 117 target trials and 380 standard non-target trials included in the analysis. For the three subjectswhoperformed the phoneme task, 215 and 270 trials were included, respectively. Data analysis All electrophysiological data were put into a common average reference to avoid spatial bias due to the choice of intracranial reference electrode (Boatman-Reich et al., 2010). All signals were analyzed in MATLAB® (R2009b, Natick, MA) using custom scripts. For ERSP and PAC figures (1, 3, 4, and 6) we corrected for multiple comparisons using a false discovery rate (FDR) method (fdr.m function in EEGLAB toolbox (Delorme and Makeig, 2004) in MATLAB). All analyses were done on an individual subject and electrode basis. Event-related spectral perturbations For ERSP analyses, the data for each channel was first filtered in multiple, logarithmically-spaced pass bands using a two-way, zero phase-lag, finite impulse response filter (eegfilt.m function in EEGLAB) to prevent ...

Citation Context

... and Eckhorn, 2004; Voytek et al., 2010b). It is proposed that phase/amplitude coupling (PAC) reflects interactions between local microscale (Colgin et al., 2009; Quilichini et al., 2010) and systems-level macroscale neuronal ensembles (Canolty et al., 2010; Fries, 2005; Lisman and Idiart, 1995) that index cortical excitability and network interactions (Vanhatalo et al., 2004). From a behavioral viewpoint PAC has been shown to track learning and memory (Axmacher et al., 2010; Lisman and Idiart, 1995; Tort et al., 2009). PAC magnitude also fluctuates at an extremely low (b0.1 Hz) rate at rest (Foster and Parvizi, 2012).k). rights reserved.Currently PAC calculation algorithms compute a value averaged across a semi-arbitrary time window (Canolty et al., 2006; Cohen and van Gaal, in press; Voytek et al., 2010a) (see Cohen, 2008; Penny et al., 2008; Tort et al., 2010 for methodological details). The minimum length of this timewindow is bounded by the frequency of the coupling phase, as at least one full cycle is needed to calculate the distribution of values of the coupling amplitude. However, the PAC metric is sensitive to noise, and recent simulations have made use of >200 cycles to get a reliable PAC estimat...