Invariance of firing rate and field potential dynamics to stimulus modulation rate in human auditory cortex

The effect of stimulus modulation rate on the underlying neural activity in human auditory cortex is not clear. Human studies (using both invasive and noninvasive techniques) have demonstrated that at the population level, auditory cortex follows stimulus envelope. Here we examined the effect of stimulus modulation rate by using a rare opportunity to record both spiking activity and local field potentials (LFP) in auditory cortex of patients during repeated presentations of an audio‐visual movie clip presented at normal, double, and quadruple speeds. Mean firing rate during evoked activity remained the same across speeds and the temporal response profile of firing rate modulations at increased stimulus speeds was a linearly scaled version of the response during slower speeds. Additionally, stimulus induced power modulation of local field potentials in the high gamma band (64–128 Hz) exhibited similar temporal scaling as the neuronal firing rate modulations. Our data confirm and extend previous studies in humans and anesthetized animals, supporting a model in which both firing rate, and high‐gamma LFP power modulations in auditory cortex follow the temporal envelope of the stimulus across different modulation rates. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.     

GABA(A) alpha-1 subunit mediated desynchronization of elevated low frequency oscillations alleviates specific dysfunction in stroke – A case report

ObjectiveThe paradoxical effects of the hypnotic imidazopyridine zolpidem, widely reported in persistent vegetative state, have been replicated recently in brain-injured and cognitively impaired patients. However, the neuronal mechanisms underlying these benefits are yet to be demonstrated. We implemented contemporary neuroimaging methods to investigate sensorimotor and cognitive improvements, observed in stroke patient JP following zolpidem administration.MethodsWe used Magnetic-Resonance-Imaging (MRI) and Magnetic-Resonance-Spectroscopy (MRS) to anatomically and chemically characterize stroke damage. Single-photon-emission-computed-tomography (SPECT) and magnetoencephalography (MEG) were used to identify changes in cerebrovascular perfusion and neuronal network activity in response to sub-sedative doses of zolpidem, zopiclone and placebo. Cognitive improvements were measured using the WAIS-III and auditory-verbal tasks.ResultsMRI and MRS revealed a lesion with complete loss of neuronal viability in the left temporal–parietal region; whilst SPECT indicated improved perfusion in the affected hemisphere following zolpidem. MEG demonstrated high-amplitude theta (4–10 Hz) and beta (15–30 Hz) oscillations within the peri-infarct region, which reduced in power coincident with zolpidem uptake and improvements in cognitive and motor function.ConclusionsIn JP, functional deficits and pathological oscillations appear coincidentally reduced following administration of low-dose zolpidem.SignificanceGABA(A) alpha-1 sensitive desynchronisation of pathological oscillations may represent a biomarker and potential therapeutic target in brain injury.     

Transcranial alternating stimulation in a high gamma frequency range applied over V1 improves contrast perception but does not modulate spatial attention

Spatial visual attention enhances information processing within its focus. Vision at an attended location is faster, more accurate, of higher spatial resolution, and has an enhanced sensitivity for fine changes. Earlier hypotheses suggest that the neuronal mechanisms of these processes are based on the interactions among different neuronal groups by means of cortical oscillations in the gamma range. The aim of the current study was to modulate these oscillations externally, using a new technique called transcranial alternating current stimulation (tACS). We investigated the effect of covert spatial attention within and outside its focus by probing contrast sensitivity and contrast discrimination at high resolution across the visual field of 20 healthy human subjects. While applying 40, 60, and 80 Hz tAC stimulation over the primary visual cortex (V1), subjects' contrast-discrimination thresholds were obtained using two different conditions: in the first condition we presented a black disc as a peripheral cue that automatically attracted the subject's attention, whereas there was no cue in the second condition. We found that the spatial profile of contrast sensitivity was not affected by the stimulation. Contrast-discrimination thresholds on the other hand decreased significantly during 60 Hz tACS, whereas there was no effect of 40 and 80 Hz stimulation. These results suggest that attention plays an important role in contrast discrimination based on V1 activities that are influences by gamma range tACS stimulation.     

Interictal high-frequency oscillations (80-500 Hz) in the human epileptic brain: entorhinal cortex

Unique high-frequency oscillations of 250 to 500 Hz, termed fast ripples, have been identified in seizure-generating limbic areas in rats made epileptic by intrahippocampal injection of kainic acid, and in patients with mesial temporal lobe epilepsy. In the rat, fast ripples clearly are generated by a different neuronal population than normally occurring endogenous ripple oscillations (100-200 Hz), but this distinction has not been previously evaluated in humans. The characteristics of oscillations in the ripple and fast ripple frequency bands were compared in the entorhinal cortex of patients with mesial temporal lobe epilepsy using local field potential and unit recordings from chronically implanted bundles of eight microelectrodes with tips spaced 500 microm apart. The results showed that ripple oscillations possessed different voltage versus depth profiles compared with fast ripple oscillations. Fast ripple oscillations usually demonstrated a reversal of polarity in the middle layers of entorhinal cortex, whereas ripple oscillations rarely showed reversals across entorhinal cortex layers. There was no significant difference in the amplitude distributions of ripple and fast ripple oscillations. Furthermore, multiunit synchronization was significantly increased during fast ripple oscillations compared with ripple oscillations (p < 0.001). These data recorded from the mesial temporal lobe of epileptic patients suggest that the cellular networks underlying fast ripple generation are more localized than those involved in the generation of normally occurring ripple oscillations. Results from this study are consistent with previous studies in the intrahippocampal kainic acid rat model of chronic epilepsy that provide evidence supporting the view that fast ripples in the human brain reflect localized pathological events related to epileptogenesis.     

Spatio‐temporal dynamics of theta oscillations in hippocampal–entorhinal slices

Theta oscillations (4–12 Hz) are associated with learning and memory and are found in the hippocampus and the entorhinal cortex (EC). The spatio‐temporal organization of rhythmic activity in the hippocampal–EC complex was investigated in vitro. The voltage sensitive absorption dye NK3630 was used to record the changes in aggregated membrane voltage simultaneously from the neuronal networks involved. Oscillatory activity at 7.0 Hz (range, 5.8–8.2) was induced in the slice with the muscarinic agonist carbachol (75–100 μM) in the presence of bicuculline (5 μM). Time relations between all recording sites were analyzed using cross‐correlation functions which revealed systematic phase shifts in the theta oscillation recorded from the different entorhinal and hippocampal subregions. These phase shifts could be interpreted as propagation delays. The oscillation propagates over the slice in a characteristic spatio‐temporal sequence, where the entorhinal cortex leads, followed by the subiculum and then the dentate gyrus (DG), to finally reach the CA3 and the CA1 area. The delay from dentate gyrus to the CA3 area was 12.4 ± 1.1 ms (mean ± s.e.m.) and from the CA3 to the CA1 region it was 10.9 ± 1.9 ms. The propagation delays between the hippocampal subregions resemble the latencies of electrically evoked responses in the same subregions. Removing the entorhinal cortex from the slice changed the spatiotemporal pattern into a more clustered pattern with higher local synchrony. We conclude that in the slice, carbachol‐induced theta oscillations are initiated in the entorhinal cortex. The EC could serve to control the information flow through the neuronal network in the subregions of the hippocampus by synchronizing and/or entraining their responses to external inputs. © 2009 Wiley‐Liss, Inc.     

Spectral graph theory of brain oscillations

The relationship between the brain's structural wiring and the functional patterns of neural activity is of fundamental interest in computational neuroscience. We examine a hierarchical, linear graph spectral model of brain activity at mesoscopic and macroscopic scales. The model formulation yields an elegant closed‐form solution for the structure–function problem, specified by the graph spectrum of the structural connectome's Laplacian, with simple, universal rules of dynamics specified by a minimal set of global parameters. The resulting parsimonious and analytical solution stands in contrast to complex numerical simulations of high dimensional coupled nonlinear neural field models. This spectral graph model accurately predicts spatial and spectral features of neural oscillatory activity across the brain and was successful in simultaneously reproducing empirically observed spatial and spectral patterns of alpha‐band (8–12 Hz) and beta‐band (15–30 Hz) activity estimated from source localized magnetoencephalography (MEG). This spectral graph model demonstrates that certain brain oscillations are emergent properties of the graph structure of the structural connectome and provides important insights towards understanding the fundamental relationship between network topology and macroscopic whole‐brain dynamics. .     

Calcium activation of cortical neurons by continuous electrical stimulation: Frequency dependence,temporal fidelity,and activation density

Electrical stimulation of the brain has become a mainstay of fundamental neuroscience research and an increasingly prevalent clinical therapy. Despite decades of use in basic neuroscience research and the growing prevalence of neuromodulation therapies, gaps in knowledge regarding activation or inactivation of neural elements over time have limited its ability to adequately interpret evoked downstream responses or fine-tune stimulation parameters to focus on desired responses. In this work, in vivo two-photon microscopy was used to image neuronal calcium activity in layer 2/3 neurons of somatosensory cortex (S1) in male C57BL/6J-Tg(Thy1-GCaMP6s)GP4.3Dkim/J mice during 30 s of continuous electrical stimulation at varying frequencies. We show frequency–dependent differences in spatial and temporal somatic responses during continuous stimulation. Our results elucidate conflicting results from prior studies reporting either dense spherical activation of somas biased toward those near the electrode, or sparse activation of somas at a distance via axons near the electrode. These findings indicate that the neural element specific temporal response local to the stimulating electrode changes as a function of applied charge density and frequency. These temporal responses need to be considered to properly interpret downstream circuit responses or determining mechanisms of action in basic science experiments or clinical therapeutic applications.     

Fast oscillations display sharper orientation tuning than slower components of the same recordings in striate cortex of the awake monkey

We wanted to know whether fast oscillations ( approximately 30-80 Hz) in striate cortex of awake monkeys show sharper orientation selectivity than (i) slower components, including spike rate modulations, and (ii) broad-band signals of the same recordings. As fast oscillations are probably of cortical origin this may further clarify whether cortical network mechanisms are substantially involved in generating orientation selectivity. We recorded multi unit activity (MUA) and local field potentials (LFP, 1-140 Hz) by the same microelectrodes from upper layers of macaque striate cortex during visual stimulation with grating textures of different orientations. An orientation index (OI) was derived from the cortical responses in three frequency ranges (low, 0-11.7 Hz; medium, 11.7-31.3 Hz; and fast oscillations, 31.3-62.5 Hz) and for the broad-band LFP and MUA power. (i) Both LFP and MUA fast oscillations reveal a higher orientation index than signal components in the low and medium frequency ranges. (ii) For MUA the orientation index was significantly higher with fast oscillations than for the lower frequency ranges and the initial broad-band transient responses. (iii) LFPs show a significantly higher orientation index only for the fast oscillations during sustained activation compared with their broad-band power during the transient responses. Thus, our main result is the sharper orientation tuning of fast oscillations in spike activities of local populations compared with slower components of the same broad-band recordings. As fast oscillations occur synchronized in the awake monkey's striate cortex we assume that they have enhanced probability of activating successive stages of visual processing and hence contribute to the perception of orientation.     

Functional decoupling of BOLD and gamma-band amplitudes in human primary visual cortex

Although functional magnetic resonance imaging is an important tool for measuring brain activity, the hemodynamic blood oxygenation level dependent (BOLD) response is only an indirect measure of neuronal activity. Converging evidence obtained from simultaneous recording of hemodynamic and electrical measures suggest that the best correlate of the BOLD response in primary visual cortex is gamma-band oscillations ( approximately 40 Hz). Here, we examined the coupling between BOLD and gamma-band amplitudes measured with magntoencephalography (MEG) in human primary visual cortex in 10 participants. In Experiment A, participants were exposed to grating stimuli at two contrast levels and two spatial frequencies and in Experiment B square and sine wave stimuli at two spatial frequencies. The amplitudes of both gamma-band oscillations and BOLD showed tuning with stimulus contrast and stimulus type; however, gamma-band oscillations showed a 300% increase across two spatial frequencies, whereas BOLD exhibited no change. This functional decoupling demonstrates that increased amplitude of gamma-band oscillations as measured with MEG is not sufficient to drive the subsequent BOLD response.     

Uncovering phase‐coupled oscillatory networks in electrophysiological data

Phase consistent neuronal oscillations are ubiquitous in electrophysiological recordings, and they may reflect networks of phase‐coupled neuronal populations oscillating at different frequencies. Because neuronal oscillations may reflect rhythmic modulations of neuronal excitability, phase‐coupled oscillatory networks could be the functional building block for routing information through the brain. Current techniques are not suited for directly characterizing such networks. To be able to extract phase‐coupled oscillatory networks we developed a new method, which characterizes networks by phase coupling between sites. Importantly, this method respects the fact that neuronal oscillations have energy in a range of frequencies. As a consequence, we characterize these networks by between‐site phase relations that vary as a function of frequency, such as those that result from between‐site temporal delays. Using human electrocorticographic recordings we show that our method can uncover phase‐coupled oscillatory networks that show interesting patterns in their between‐site phase relations, such as travelling waves. We validate our method by demonstrating it can accurately recover simulated networks from a realistic noisy environment. By extracting phase‐coupled oscillatory networks and investigating patterns in their between‐site phase relations we can further elucidate the role of oscillations in neuronal communication. Hum Brain Mapp 36:2655–2680, 2015. © 2015 Wiley Periodicals, Inc.     

Consistent sequential activity across diverse forms of UP states under ketamine anesthesia

During slow‐wave sleep, the neocortex shows complex, self‐organized spontaneous activity. Similar slow‐wave oscillations are present under anesthesia where massive, persistent network activity (UP states) alternates with periods of generalized neural silence (DOWN states). To investigate the neuronal activity patterns occurring during UP states, we recorded simultaneously from populations of cells in neocortical layer V of ketamine/xylazine‐anesthetized rats. UP states formed a diverse class. In particular, simultaneous‐onset UP states were typically accompanied by sharp field potentials and 10–14 Hz modulation, and were often grouped in a 3 Hz (‘delta’) pattern. Longer, slow‐onset UP states did not exhibit 10–14 Hz modulation, and showed a slow propagation across recording electrodes (‘traveling waves’). Despite this diversity, the temporal patterns of spiking activity were similar across different UP state types. Analysis of cross‐correlograms revealed conserved temporal relationships among neurons, with each neuron having specific timing during UP states. As a group, putative interneurons were most active at the beginning of UP states and putative pyramidal cells were active uniformly throughout the duration of UP states. These results show that UP states under ketamine anesthesia have a stable, fine‐structured firing pattern despite a large variability in global structure.     

Oscillatory activity during maintenance of spatial and temporal information in working memory

Working memory (WM) processes help keep information in an active state so it can be used to guide future behavior. Although numerous studies have investigated brain activity associated with spatial WM in humans and monkeys, little research has focused on the neural mechanisms of WM for temporal order information, and how processing of temporal and spatial information might differ. Available evidence indicates that similar frontoparietal regions are recruited during temporal and spatial WM, although there are data suggesting that they are distinct processes. The mechanisms that allow for differential maintenance of these two types of information are unclear. One possibility is that neural oscillations may differentially contribute to temporal and spatial WM. In the present study, we used scalp electroencephalography (EEG) to compare patterns of oscillatory activity during maintenance of spatial and temporal information in WM. Time-frequency analysis of EEG data revealed enhanced left frontal theta (5–8 Hz), enhanced posterior alpha (9–12 Hz), and enhanced left posterior beta (14–28 Hz) power during the delay period of correct temporal order trials compared to correct spatial trials. In contrast, gamma (30–50 Hz) power at right lateral frontal sites was increased during the delay period of spatial WM trials, as compared to temporal WM trials. The present results are consistent with the idea that neural oscillatory patterns provide distinct mechanisms for the maintenance of temporal and spatial information in WM. Specifically, theta oscillations are most critical for the maintenance of temporal information in WM. Possible roles of higher frequency oscillations in temporal and spatial memory are also discussed.     

Spatial Memory Sequence Encoding and Replay During Modeled Theta and Ripple Oscillations

Spatial learning involves the storage and replay of temporally ordered spatial information. The hippocampus is a key brain structure involved in spatial learning in rats. Temporally ordered spatial memories are encoded and replayed by the firing rate and phase of hippocampal pyramidal cells and inhibitory interneurons with respect to ongoing network theta and ripple oscillations paced by intra- and extrahippocampal areas. Theta oscillations (4–7 Hz) may contribute to memory formation, whereas fast ripple oscillations to temporally compressed forward and reverse replay of previously stored memories. Different classes of CA1 excitatory and inhibitory neurons and medial septal inhibitory neurons have been shown to differentially phase their activities with respect to theta and ripples. Understanding how the different hippocampal and extrahippocampal areas and their neuronal classes interact during these network oscillations and how they facilitate the storage and replay of spatiotemporal memories is of great importance. A computational model of the hippocampal CA1 microcircuit that uses biophysical representations of the major cell types, including pyramidal cells and four types of inhibitory interneurons, is extended. Inputs to the network come from the entorhinal cortex (EC), the CA3 Schaffer collaterals and the medial septum. A biophysical mechanism of spike timing-dependent plasticity (STDP) is used for learning spatial memory patterns in the correct order. The model addresses two important issues: (1) How are the storage and replay (forward and reverse) of temporally ordered memory patterns controlled in the CA1 microcircuit during theta and ripples? (2) What roles do the various types of inhibitory interneurons play in these processes?     

Fast network oscillations in vitro exhibit a slow decay of temporal auto-correlations

Ongoing neuronal oscillations in vivo exhibit non-random amplitude fluctuations as reflected in a slow decay of temporal auto-correlations that persist for tens of seconds. Interestingly, the decay of auto-correlations is altered in several brain-related disorders, including epilepsy, depression and Alzheimer's disease, suggesting that the temporal structure of oscillations depends on intact neuronal networks in the brain. Whether structured amplitude modulation occurs only in the intact brain or whether isolated neuronal networks can also give rise to amplitude modulation with a slow decay is not known. Here, we examined the temporal structure of cholinergic fast network oscillations in acute hippocampal slices. For the first time, we show that a slow decay of temporal correlations can emerge from synchronized activity in isolated hippocampal networks from mice, and is maximal at intermediate concentrations of the cholinergic agonist carbachol. Using zolpidem, a positive allosteric modulator of GABA(A) receptor function, we found that increased inhibition leads to longer oscillation bursts and more persistent temporal correlations. In addition, we asked if these findings were unique for mouse hippocampus, and we therefore analysed cholinergic fast network oscillations in rat prefrontal cortex slices. We observed significant temporal correlations, which were similar in strength to those found in mouse hippocampus and human cortex. Taken together, our data indicate that fast network oscillations with temporal correlations can be induced in isolated networks in vitro in different species and brain areas, and therefore may serve as model systems to investigate how altered temporal correlations in disease may be rescued with pharmacology.     

Medial prefrontal theta phase coupling during spatial memory retrieval

Memory retrieval is believed to involve a disparate network of areas, including medial prefrontal and medial temporal cortices, but the mechanisms underlying their coordination remain elusive. One suggestion is that oscillatory coherence mediates inter‐regional communication, implicating theta phase and theta‐gamma phase‐amplitude coupling in mnemonic function across species. To examine this hypothesis, we used non‐invasive whole‐head magnetoencephalography (MEG) as participants retrieved the location of objects encountered within a virtual environment. We demonstrate that, when participants are cued with the image of an object whose location they must subsequently navigate to, there is a significant increase in 4–8 Hz theta power in medial prefrontal cortex (mPFC), and the phase of this oscillation is coupled both with ongoing theta phase in the medial temporal lobe (MTL) and perceptually induced 65–85 Hz gamma amplitude in medial parietal cortex. These results suggest that theta phase coupling between mPFC and MTL and theta‐gamma phase‐amplitude coupling between mPFC and neocortical regions may play a role in human spatial memory retrieval. © 2014 The Authors. Hippocampus Published by Wiley Periodicals, Inc.     

Synaptic activation of GABA(B) receptors regulates neuronal network activity and entrainment

In the mammalian central nervous system, GABA(B) receptors mediate slow pre- and postsynaptic inhibition. Using rat hippocampal slices we investigated the role of synaptic GABA(B) receptors in regulating kainate-induced subthreshold neuronal network oscillations in the gamma frequency range (25-80 Hz). The GABA(B) receptor agonist baclofen largely eliminated gamma oscillations. The GABA(B) receptor antagonist CGP55845 reversed this action of baclofen but alone did not alter the power or frequency of ongoing oscillations. To examine the role of synaptically released GABA on network activity, we electrically stimulated stratum radiatum of CA3 whilst recording gamma oscillations from stratum pyramidale. Single stimuli produced a pronounced transient (up to 1 s in duration) inhibition of gamma frequency oscillations. This stimulus-induced shutdown of network activity was enhanced by the GABA uptake inhibitor tiagabine and largely inhibited by CGP55845. Multiple stimuli delivered at frequencies of 1-3 Hz resulted in an activity-dependent fatigue of the inhibition of gamma activity, such that, after a number of stimuli, oscillations could be detected tens of milliseconds after the stimulus. Interestingly, this activity-dependent fatigue of inhibition uncovered a stimulus-dependent temporal entrainment of the gamma oscillations. Furthermore, the amount of repetitive synaptic input that was required to cause this entrainment was dramatically reduced by GABA(B) receptor antagonism such that it was evident within just a few stimuli. These data suggest that convergent afferent synaptic activity can alter the precise temporal arrangement of neuronal network activity. Furthermore, the flow of such information into a functioning neuronal network is highly regulated by GABA(B) receptor-mediated synaptic inhibition.     

Stimulus locking and feature selectivity prevail in complementary frequency ranges of V1 local field potentials

The local field potential (LFP) is a population measure of neuronal activity complementary to spike trains. Whereas the response properties of the spiking activity in the visual cortex have been characterized extensively, the responses of the LFP have not been well explored. No coherent picture exists about which frequency ranges exhibit feature tuning or show stimulus locked activity. Addressing this, we recorded LFP in the primary visual cortex of alert cats and calculated the tuning indices for orientation, spatial and temporal frequency. Furthermore, we quantified the locking of the power in different LFP frequency bands to the velocity profile of artificial and natural stimuli. We found that the LFP in alert animals is well tuned with similar specificity to orientation, spatial frequency and temporal frequency. Tuning to these features is most prominent in two frequency bands (8-23 Hz and 39-109 Hz). In two complementary frequency bands (23-39 Hz and above 109 Hz) the dynamics of the LFP power is locked tightly to the temporal structure of the stimulus. This locking is furthermore independent of the spatial structure of the stimulus. Together these four frequency bands cover the whole frequency range investigated. In contrast to previous studies, which often reported correlates of visual processing only in a limited frequency range of the LFP, the present results suggest that the entire frequency range of the LFP can be assigned a role in visual processing.     

Reorganization of the composition of brain oscillations and their temporal characteristics in opioid dependent patients

In the present study, we examined the composition of electroencephalographic (EEG) brain oscillations in broad frequency band (0.5–30 Hz) in 22 opioid-dependent patients and 14 healthy subjects during resting condition (closed eyes). The exact compositions of brain oscillations and their temporal behavior were assessed by the probability–classification analysis of short-term EEG spectral patterns. It was demonstrated that EEG of patients with opioid dependence was characterized by (a) significant reorganization of brain oscillations with increase in the percentage of beta- and mostly fast-alpha-rhythmic segments, (b) longer periods of temporal stabilization for alpha and beta brain oscillations and by shorter periods of temporal stabilization for theta and polyrhythmic activity when compared with control subjects, and (c) right-sided dominance (significantly larger relative presence of particular spectral patterns in EEG channels of the right hemisphere). These effects were widely distributed across the cortex with the maximum magnitude in the occipital, right parietal, temporal, and frontal areas. Taken together the present study suggested (a) an allostatic state with neuronal activation, and (b) high sensitivity of the right hemisphere to adverse opioid effects.     

Synchronization of neural oscillations as a possible mechanism underlying episodic memory: a study of theta rhythm in the hippocampus

Rat hippocampal cells exhibit characteristic phase-dependent firings when oscillation in frequency range around 8Hz is present. Based on the hypothesis that theta phase coding is generated by synchronization of neural activities, an autoassociative network model of the hippocampus and the entorhinal cortex was analyzed to explore mechanisms underlying episodic memory. Phase coding in theta rhythm enables instantaneous acquisition of experienced events including temporal and spatial contents. Further comparison with electrophysiological data from both rodents and primates suggests a possible role of theta oscillations in memory encoding and online processing of episodic events.     

Interactions between visual and motor areas during the recognition of plausible actions as revealed by magnetoencephalography

Several studies have shown activation of the mirror neuron system (MNS), comprising the temporal, posterior parietal, and sensorimotor areas when observing plausible actions, but far less is known on how these cortical areas interact during the recognition of a plausible action. Here, we recorded neural activity with magnetoencephalography while subjects viewed point‐light displays of biologically plausible and scrambled versions of actions. We were interested in modulations of oscillatory activity and, specifically, in coupling of oscillatory activity between visual and motor areas. Both plausible and scrambled actions elicited modulations of θ (5–7 Hz), α (7–13 Hz), β (13–35 Hz), and γ (55–100 Hz) power within visual and motor areas. When comparing between the two actions, we observed sequential and spatially distinct increases of γ (～65 Hz), β (～25 Hz), and α (～11 Hz) power between 0.5 and 1.3 s in parieto‐occipital, sensorimotor, and left temporal areas. In addition, significant clusters of γ (～65 Hz) and α/β (～15 Hz) power decrease were observed in right temporal and parieto‐occipital areas between 1.3 and 2.0 s. We found β‐power in sensorimotor areas to be positively correlated on a trial‐by‐trial basis with parieto‐occipital γ and left temporal α‐power for the plausible but not for the scrambled condition. These results provide new insights in the neuronal oscillatory activity of the areas involved in the recognition of plausible action movements and their interaction. The power correlations between specific areas underscore the importance of interactions between visual and motor areas of the MNS during the recognition of a plausible action. Hum Brain Mapp 35:581–592, 2014. © 2012 Wiley‐Periodicals, Inc.