Prestimulus alpha power signals attention to retrieval.

The human brain is in distinct processing modes at different times. Specifically, a distinction can be made between encoding and retrieval modes, which refer to the brain's state when it is storing new information or searching for old information, respectively. Recent research proposed the idea of a "ready-to-encode" mode, which describes a prestimulus effect in brain activity that signals (external) attention to encoding and predicts subsequent memory performance. Whether there is also a corresponding "ready-to-retrieve" mode in human brain activity is currently unclear. In this study, we examined whether prestimulus oscillations can be linked to (internal) attention to retrieval. We show that task cues to prepare for retrieval (or testing) in comparison with restudy of previously studied vocabulary word pairs led to a significant decrease of prestimulus alpha power just before the onset of word stimuli. Beamformer analysis localized this effect in the right secondary visual cortex (Brodmann area 18). Correlation analysis showed that the task cue-induced, prestimulus alpha power effect is positively related to stimulus-induced alpha/beta power, which in turn predicted participants' memory performance. The results are consistent with the idea that prestimulus alpha power signals internal attention to retrieval, which promotes the elaborative processing of episodic memories. Future research on brain-computer interfaces may find the findings interesting regarding the potential of using online measures of fluctuating alpha oscillations to trigger the presentation and sequencing of restudy and testing trials, ultimately enhancing instructional learning strategies.

Associations between spontaneous electroencephalogram oscillations and oxygen saturation across normobaric and hypobaric hypoxia.

High-altitude indoctrination (HAI) trains individuals to recognize symptoms of hypoxia by simulating high-altitude conditions using normobaric (NH) or hypobaric (HH) hypoxia. Previous studies suggest that despite equivalent inspired oxygen levels, physiological differences could exist between these conditions. In particular, differences in neurophysiological responses to these conditions are not clear. Our study aimed to investigate correlations between oxygen saturation (SpO2 ) and neural responses in NH and HH. We recorded 5-min of resting-state eyes-open electroencephalogram (EEG) and SpO2 during control, NH, and HH conditions from 13 participants. We applied a multivariate framework to characterize correlations between SpO2 and EEG measures (spectral power and multiscale entropy [MSE]), within each participant and at the group level. Participants were desaturating during the first 150 s of NH versus steadily desaturated in HH. We considered the entire time interval, first and second half intervals, separately. All the conditions were characterized by statistically significant participant-specific patterns of EEG-SpO2 correlations. However, at the group level, the desaturation period expressed a robust pattern of these correlations across frequencies and brain locations. Specifically, the first 150 s of NH during desaturation differed significantly from the other conditions with negative absolute alpha power-SpO2 correlations and positive MSE-SpO2 correlations. Once steadily desaturated, NH and HH had no significant differences in EEG-SpO2 correlations. Our findings indicate that the desaturating phase of hypoxia is a critical period in HAI courses, which would require developing strategies for mitigating the hypoxic stimulus in a real-world situation.

Action experience in infancy predicts visual-motor functional connectivity during action anticipation.

Despite substantial evidence indicating a close link between action production and perception in early child development, less is known about how action experience shapes the processes of perceiving and anticipating others' actions. Here, we developed a novel approach to capture functional connectivity specific to certain brain areas to investigate how action experience changes the networks involved in action perception and anticipation. Nine- and-12-month-old infants observed familiar (grasping) and novel (tool-use) actions while their brain activity was measured using EEG. Infants' motor competence of both actions was assessed. A link between action experience and connectivity patterns was found, particularly during the anticipation period. During action anticipation, greater motor competence in grasping predicted greater functional connectivity between visual (occipital alpha) and motor (central alpha) regions relative to global levels of whole-brain EEG connectivity. Furthermore, visual and motor regions tended to be more coordinated in response to familiar versus novel actions and for older than younger participants. Critically, these effects were not found in the control networks (frontal-central; frontal-occipital; parietal-central; parietal-occipital), suggesting a unique role of visual-motor networks on the link between motor skills and action encoding. HIGHLIGHTS: Infants' motor development predicted functional connectivity patterns during action anticipation. Faster graspers, and older infants, showed a stronger ratio of visual-motor neural coherence. Overall whole-brain connectivity was modulated by age and familiarity with the actions. Measuring inter-site relative to whole-brain connectivity can capture specific brain-behavior links. Measures of phase-based connectivity over time are sensitive to anticipatory action.

Multidimensional inhibitory signatures of sentential negation in behavioral variant frontotemporal dementia.

BACKGROUND: Processing of linguistic negation has been associated to inhibitory brain mechanisms. However, no study has tapped this link via multimodal measures in patients with core inhibitory alterations, a critical approach to reveal direct neural correlates and potential disease markers. METHODS: Here we examined oscillatory, neuroanatomical, and functional connectivity signatures of a recently reported Go/No-go negation task in healthy controls and behavioral variant frontotemporal dementia (bvFTD) patients, typified by primary and generalized inhibitory disruptions. To test for specificity, we also recruited persons with Alzheimer's disease (AD), a disease involving frequent but nonprimary inhibitory deficits. RESULTS: In controls, negative sentences in the No-go condition distinctly involved frontocentral delta (2-3 Hz) suppression, a canonical inhibitory marker. In bvFTD patients, this modulation was selectively abolished and significantly correlated with the volume and functional connectivity of regions supporting inhibition (e.g. precentral gyrus, caudate nucleus, and cerebellum). Such canonical delta suppression was preserved in the AD group and associated with widespread anatomo-functional patterns across non-inhibitory regions. DISCUSSION: These findings suggest that negation hinges on the integrity and interaction of spatiotemporal inhibitory mechanisms. Moreover, our results reveal potential neurocognitive markers of bvFTD, opening a new agenda at the crossing of cognitive neuroscience and behavioral neurology.

ECG Approximate Entropy in the Elderly during Cycling Exercise.

Approximate entropy (ApEn) is used as a nonlinear measure of heart-rate variability (HRV) in the analysis of ECG time-series recordings. Previous studies have reported that HRV can differentiate between frail and pre-frail people. In this study, EEGs and ECGs were recorded from 38 elderly adults while performing a three-stage cycling routine. Before and after cycling stages, 5-min resting-state EEGs (rs-EEGs) and ECGs were also recorded under the eyes-open condition. Applying the K-mean classifier to pre-exercise rs-ECG ApEn values and body weights revealed nine females with EEG power which was far higher than that of the other subjects in all cycling stages. The breathing of those females was more rapid than that of other subjects and their average heart rate was faster. Those females also presented higher degrees of asymmetry in the alpha and theta bands (stronger power levels in the right frontal electrode), indicating stressful responses during the experiment. It appears that EEG delta activity could be used in conjunction with a very low ECG frequency power as a predictor of bursts in the heart rate to facilitate the monitoring of elderly adults at risk of heart failure. A resting ECG ApEn index in conjunction with the subject's weight or BMI is recommended for screening high-risk candidates prior to exercise interventions.

Neural oscillations track the maintenance and proceduralization of novel instructions.

Humans are capable of flexibly converting symbolic instructions into novel behaviors. Previous evidence and theoretical models suggest that the implementation of a novel instruction requires the reformatting of its declarative content into an action-oriented code optimized for the execution of the instructed behavior. While neuroimaging research focused on identifying the brain areas involved in such a process, the temporal and electrophysiological mechanisms remain poorly understood. These mechanisms, however, can provide information about the specific cognitive processes that characterize the proceduralization of information. In the present study, we recorded EEG activity while we asked participants to either simply maintain declaratively the content of novel S-R mappings or to proactively prepare for their implementation. By means of time-frequency analyses, we isolated the oscillatory features specific to the proceduralization of instructions. Implementation of the instructed mappings elicited stronger theta activity over frontal electrodes and suppression in mu and beta activity over central electrodes. On the contrary, activity in the alpha band, which has been shown to track the attentional deployment to task-relevant items, showed no differences between tasks. Together, these results support the idea that proceduralization of information is characterized by specific component processes such as orchestrating complex task settings and configuring the motor system that are not observed when instructions are held in a declarative format.

Impact of sleep loss before learning on cortical dynamics during memory retrieval.

Evidence shows that sleep loss before learning decreases activation of the hippocampus during encoding and promotes forgetting. But it remains to be determined which neural systems are functionally affected during memory retrieval after one night of recovery sleep. To investigate this issue, we evaluated memory for pairs of famous people's faces with the same or different profession (i.e., semantically congruent or incongruent faces) after one night of undisturbed sleep in subjects who either underwent 4hours of acute sleep restriction (ASR, N=20) or who slept 8hours the pre-training night (controls, N=20). EEG recordings were collected during the recognition memory task in both groups, and the cortical sources generating this activity localized by applying a spatial beamforming filter in the frequency domain. Even though sleep restriction did not affect accuracy of memory performance, controls showed a much larger decrease of alpha power relative to a baseline period when compared to sleep-deprived subjects. These group differences affected a widespread frontotemporoparietal network involved in retrieval of episodic/semantic memories. Regression analyses further revealed that associative memory in the ASR group was negatively correlated with alpha power in the occipital regions, whereas the benefit of congruency in the same group was positively correlated with delta power in the left lateral prefrontal cortex. Retrieval-related decreases of alpha power have been associated with the reactivation of material-specific memory representations, whereas increases of delta power have been related to inhibition of interferences that may affect the performance of the task. We can therefore draw the conclusion that a few hours of sleep loss in the pre-training night, though insufficient to change the memory performance, is sufficient to alter the processes involved in retrieving and manipulating episodic and semantic information.

Brain electrical source imaging in manic and depressive episodes of bipolar disorder.

OBJECTIVE: Bipolar disorder (BD) electroencephalographic (EEG) studies have reported varying results. The present study compared EEG in BD during manic and depressive episodes, using brain electrical source imaging [standardized low-resolution electromagnetic tomography (sLORETA)] to assess the cortical spatial distribution of the sources of EEG oscillation frequencies. METHODS: Two independent datasets (a total of 95 patients with bipolar I disorder, of whom 59 were female) were analyzed. Dataset #1 comprised 14 patients in a manic as well as a depressive episode. Dataset #2 comprised 26 patients in a manic episode and 55 patients in a depressive episode. From the head surface-recorded EEG, sLORETA cortical activity was computed in eight EEG frequency bands, and compared between mood states in both datasets. The results from the two datasets were combined using conjunction analysis. RESULTS: Conjunction analysis yielded significant differences between mood states: In manic compared to depressive states, patients had lesser theta frequency band activity (right-hemispheric lateral lower prefrontal and anterior temporal, mainly Brodmann areas 13, 38, and 47), and greater beta-2 and beta-3 frequency band activity (extended bilateral prefrontal-to-parietal, mainly Brodmann area 6, and the cingulate). CONCLUSIONS: The spatial organization of the brain's electrical oscillations differed in patients with BD between manic and depressive mood states. The brain areas implementing the main functions that show opposing abnormalities during manic and depressive episodes were affected by unduly increased or decreased activity (beta or theta). The discussion considers that facilitating (beta) or inhibiting (theta) electrical activity can in either case result in behavioral facilitation or inhibition, depending on the function of the brain area.

Development of EEG alpha and theta oscillations in the maintenance stage of working memory.

Several studies have shown developmental changes in EEG oscillations during working memory tasks. Although the load-modulated theta and alpha activities in adults are well-documented, the findings are inconsistent if children possess the adult-like brain oscillations that are similarly modulated by memory load. The present study compares children's and adults' true theta and alpha EEG oscillations, separated from aperiodic components, in the maintenance stage of working memory. The EEG was recorded in 25 Chinese-speaking children (14 male, Mage = 9.4 yrs) and 31 adults (19 male, Mage = 20.8 yrs) in Hong Kong while they performed an n-back task that included four conditions differing in load (1- vs. 2-back) and stimulus type (Chinese character vs. visual pattern). The results show that aperiodic activities (i.e., broadband power and slope) during the maintenance stage in the n-back task were significantly higher in children than adults. The periodic theta and alpha oscillations also changed with age. More importantly, adults showed significant periodic theta increase with memory load, whereas such an effect was absent in children. Regardless of age, there was a significant alpha power decrease with load increase, and a significant theta power enhancement when maintaining visual patterns than Chinese characters. In adults, load-modulated alpha peak shift (towards higher frequency) was linked to higher behavioral efficiency in the n-back task. In children, higher load-modulated theta enhancement was linked to better behavioral efficiency. The findings suggest that the load-modulated theta power during working memory maintenance matures from childhood to adulthood.

Brain Functional Correlates of Resting Hypnosis and Hypnotizability: A Review.

This comprehensive review delves into the cognitive neuroscience of hypnosis and variations in hypnotizability by examining research employing functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and electroencephalography (EEG) methods. Key focus areas include functional brain imaging correlations in hypnosis, EEG band oscillations as indicators of hypnotic states, alterations in EEG functional connectivity during hypnosis and wakefulness, drawing critical conclusions, and suggesting future research directions. The reviewed functional connectivity findings support the notion that disruptions in the available integration between different components of the executive control network during hypnosis may correspond to altered subjective appraisals of the agency during the hypnotic response, as per dissociated and cold control theories of hypnosis. A promising exploration avenue involves investigating how frontal lobes' neurochemical and aperiodic components of the EEG activity at waking-rest are linked to individual differences in hypnotizability. Future studies investigating the effects of hypnosis on brain function should prioritize examining distinctive activation patterns across various neural networks.

Counterfactual imagination impairs memory for true actions: EEG and behavioural evidence.

Imagined events can be misremembered as experienced, leading to memory distortions. However, less is known regarding how imagining counterfactual versions of past events can impair existing memories. We addressed this issue, and used EEG to investigate the neurocognitive processes involved when retrieving memories of true events that are associated with a competing imagined event. Participants first performed simple actions with everyday objects (e.g., rolling dice). A week later, they were shown pictures of some of the objects and either imagined the same action they had originally performed, or imagined a counterfactual action (e.g., stacking the dice). Subsequent tests showed that memory for performed actions was reduced after counterfactual imagination when compared to both veridical imagination and a baseline condition that had not been imagined at all, providing novel evidence that counterfactual imagination impairs true memories beyond simple forgetting over time. ERPs and EEG oscillations showed evidence of separate processes associated with memory retrieval versus post-retrieval processes that were recruited to support recall of memories that were challenging to access. The findings show that counterfactual imagination can cause impairments to sensorimotor-rich event memories, and provide new evidence regarding the neurocognitive mechanisms that are recruited when people need to distinguish memories of imagined versus true events.

Transcranial Alternating Current Stimulation Alters Auditory Steady-State Oscillatory Rhythms and Their Cross-Frequency Couplings.

Auditory cortical plasticity deficits in schizophrenia are evidenced with electroencephalographic (EEG)-derived biomarkers, including the 40-Hz auditory steady-state response (ASSR). Aiming to understand the underlying oscillatory mechanisms contributing to the 40-Hz ASSR, we examined its response to transcranial alternating current stimulation (tACS) applied bilaterally to the temporal lobe of 23 healthy participants. Although not responding to gamma tACS, the 40-Hz ASSR was modulated by theta tACS (vs sham tACS), with reductions in gamma power and phase locking being accompanied by increases in theta-gamma phase-amplitude cross-frequency coupling. Results reveal that oscillatory changes induced by frequency-tuned tACS may be one approach for targeting and modulating auditory plasticity in normal and diseased brains.

Transcranial magnetic stimulation cortical oscillations and improve cognition in obstructive sleep apnea patients.

BACKGROUND: Transcranial magnetic stimulation (TMS) is a noninvasive tool to improve cognition. Relevant clinical studies are mainly focused on neurological and psychiatric diseases. However, cognition decline and psychiatric disorders are popular in obstructive sleep apnea (OSA) patients. We aimed to investigate the effect of TMS over the left dorsolateral prefrontal cortex (DLPFC) on cognition test performance and to compare the changes in quantitative electroencephalogram (EEG) before and after stimulation for OSA. METHODS: This study recruited 42 OSA patients diagnosed with polysomnography according to American Academy of Sleep Medicine guidelines. TMS (intermittent theta-burst stimulation paradigm; 2 s on, 8 s off, 600 pulses*3, intermittent 15 min) was performed on the DLPFC. Cambridge Automated Neuropsychological Test Battery was used to assess cognitive performance. EEG oscillations were computed via power spectral density with MATLAB software. RESULTS: Real-TMS group displayed a significant improvement in visual memory, sustain attention performance, as well as the outcome of working memory. However, the executive function of latency was changed in both groups. Furthermore, TMS resulted in a significant increase in the relative power spectral density of the theta band and beta band in the parietal, temporal, and anterior regions, respectively. CONCLUSIONS: In summary, our findings indicate that TMS can safely modulate cortical oscillations and improve cognition in OSA patients. In the future, TMS can be utilized as an alternative treatment option to improve cognition in OSA patients.

Tensor Decomposition Analysis of Longitudinal EEG Signals Reveals Differential Oscillatory Dynamics in Eyes-Closed and Eyes-Open Motor Imagery BCI: A Case Report.

Functional dissociation of brain neural activity induced by opening or closing the eyes has been well established. However, how the temporal dynamics of the underlying neuronal modulations differ between these eye conditions during movement-related behaviours is less known. Using a robotic-assisted motor imagery brain-computer interface (MI BCI), we measured neural activity over the motor regions with electroencephalography (EEG) in a stroke survivor during his longitudinal rehabilitation training. We investigated lateralized oscillatory sensorimotor rhythm modulations while the patient imagined moving his hemiplegic hand with closed and open eyes to control an external robotic splint. In order to precisely identify the main profiles of neural activation affected by MI with eyes-open (MIEO) and eyes-closed (MIEC), a data-driven approach based on parallel factor analysis (PARAFAC) tensor decomposition was employed. Using the proposed framework, a set of narrow-band, subject-specific sensorimotor rhythms was identified; each of them had its own spatial and time signature. When MIEC trials were compared with MIEO trials, three key narrow-band rhythms whose peak frequencies centred at ∼8.0 Hz, ∼11.5 Hz, and ∼15.5 Hz, were identified with differently modulated oscillatory dynamics during movement preparation, initiation, and completion time frames. Furthermore, we observed that lower and higher sensorimotor oscillations represent different functional mechanisms within the MI paradigm, reinforcing the hypothesis that rhythmic activity in the human sensorimotor system is dissociated. Leveraging PARAFAC, this study achieves remarkable precision in estimating latent sensorimotor neural substrates, aiding the investigation of the specific functional mechanisms involved in the MI process.

Task-Modulated Oscillation Differences in Auditory and Spoken Chinese-English Bilingual Processing: An Electroencephalography Study.

Neurophysiological research on the bilingual activity of interpretation or interpreting has been very fruitful in understanding the bilingual brain and has gained increasing popularity recently. Issues like word interpreting and the directionality of interpreting have been attended to by many researchers, mainly with localizing techniques. Brain structures such as the dorsolateral prefrontal cortex have been repeatedly identified during interpreting. However, little is known about the oscillation and synchronization features of interpreting, especially sentence-level overt interpreting. In this study we implemented a Chinese-English sentence-level overt interpreting experiment with electroencephalography on 43 Chinese-English bilinguals and compared the oscillation and synchronization features of interpreting with those of listening, speaking and shadowing. We found significant time-frequency power differences in the delta-theta (1-7 Hz) and gamma band (above 30 Hz) between motor and silent tasks. Further theta-gamma coupling analysis revealed different synchronization networks in between speaking, shadowing and interpreting, indicating an idea-formulation dependent mechanism. Moreover, interpreting incurred robust right frontotemporal gamma coactivation network compared with speaking and shadowing, which we think may reflect the language conversion process inherent in interpreting.

Resolving and characterizing the incidence of millihertz EEG modulation in critically ill children.

OBJECTIVE: We analyze a slow electrographic pattern, Macroperiodic Oscillations (MOs), in the EEG from a cohort of young critical care patients (n = 43) with continuous EEG monitoring. We construct novel quantitative methods to quantify and understand MOs. METHODS: We applied a nonparametric bilevel spectral analysis to identify MOs, a millihertz (0.004-0.01 Hz) modulation of 5-15 Hz activity in two separate ICU patient cohorts (n = 195 total). We also developed a rigorous measure to quantify MOs strength and spatial expression, which was validated against surrogate noise data. RESULTS: Strong or spatially widespread MOs appear in both high clinical suspicion and a general ICU population. In the former, patients with strong or spatially widespread MOs tended to have worse clinical outcomes. Intracranial pressure and heart rate data from one patient provide insight into a potential broader physiological mechanism for MOs. CONCLUSIONS: We quantified millihertz EEG modulation (MOs) in cohorts of critically ill pediatric patients. We demonstrated high incidence in two patient populations. In a high suspicion cohort, MOs are associated with poor outcome, suggesting future potential as a diagnostic and prognostic aid. SIGNIFICANCE: These results support the existence of EEG dynamics across disparate time-scales and may provide insight into brain injury physiology in young children.

Physics Clues on the Mind Substrate and Attributes.

The last decade has witnessed a remarkable progress in our understanding of the brain. This has mainly been based on the scrutiny and modeling of the transmission of activity among neurons across lively synapses. A main conclusion, thus far, is that essential features of the mind rely on collective phenomena that emerge from a willful interaction of many neurons that, mediating other cells, form a complex network whose details keep constantly adapting to their activity and surroundings. In parallel, theoretical and computational studies developed to understand many natural and artificial complex systems, which have truthfully explained their amazing emergent features and precise the role of the interaction dynamics and other conditions behind the different collective phenomena they happen to display. Focusing on promising ideas that arise when comparing these neurobiology and physics studies, the present perspective article shortly reviews such fascinating scenarios looking for clues about how high-level cognitive processes such as consciousness, intelligence, and identity can emerge. We, thus, show that basic concepts of physics, such as dynamical phases and non-equilibrium phase transitions, become quite relevant to the brain activity while determined by factors at the subcellular, cellular, and network levels. We also show how these transitions depend on details of the processing mechanism of stimuli in a noisy background and, most important, that one may detect them in familiar electroencephalogram (EEG) recordings. Thus, we associate the existence of such phases, which reveal a brain operating at (non-equilibrium) criticality, with the emergence of most interesting phenomena during memory tasks.

Clustering and switching in divergent thinking: Neurophysiological correlates underlying flexibility during idea generation.

EEG alpha synchronization, especially in posterior parietal cortical regions of the right hemisphere, is indicative of high internal processing demands that are typically involved in divergent thinking (DT). During the course of DT, as ideation proceeds, ideas tend to become more creative, being more likely to be drawn from new conceptual categories through the use of the cognitive mechanism of flexibility. The present study investigated whether EEG alpha synchronization can be modulated by flexibility in DT by comparing cortical activation patterns during the switch of category (switching) and the stay in the same category (clustering). Twenty participants were required to generate alternative uses of everyday objects during EEG recording. Differential results were specifically found in the lower alpha band (8-10 Hz): whereas clustering showed synchronization typically lateralized in the right posterior parietal areas, switching induced posterior parietal synchronization over both right and left hemispheres. These findings indicate that the two distinct cognitive mechanisms subsuming flexibility (switching and clustering) are associated with a different hemispheric modulation of lower alpha activity, as switching, in comparison to clustering, is related to higher power in the lower alpha band over the left hemisphere. Switching in comparison to clustering may thus require a larger investment of cognitive resources due to the exploratory process of moving from one semantic conceptual category to another in the course of creative ideation.

Aging reduces EEG markers of recognition despite intact performance: Implications for forensic memory detection.

ERP-based forensic memory detection is based on the logic that guilty suspects will hold incriminating knowledge about crimes they have committed, and therefore should show parietal ERP positivities related to recognition when presented with reminders of their crimes. We predicted that such forensic memory detection might however be inaccurate in older adults, because of changes to recognition-related brain activity that occurs with aging. We measured both ERPs and EEG oscillations associated with episodic old/new recognition and forensic memory detection in 30 younger (age < 30) and 30 older (age > 65) adults. EEG oscillations were included as a complementary measure which is less sensitive to temporal variability and component overlap than ERPs. In line with predictions, recognition-related parietal ERP positivities were significantly reduced in the older compared to younger group in both tasks, despite highly similar behavioural performance. We also observed aging-related reductions in oscillatory markers of recognition in the forensic memory detection test, while the oscillatory effects associated with episodic recognition were similar across age groups. This pattern of results suggests that while both forensic memory detection and episodic recognition are accompanied by aging-induced reductions in parietal ERP positivities, these reductions may be caused by non-overlapping mechanisms across the two tasks. Our findings suggest that EEG-based forensic memory detection tests are less valid in older than younger populations, limiting their practical applications.

Oscillatory Correlates of Intentional Forgetting: The Role of Theta and Alpha Power in Item-Method Directed Forgetting.

Results from item-method directed forgetting suggest that individuals are able to intentionally forget processed information. Most research suggests that either selective rehearsal of to-be-remembered or inhibitory control of to-be-forgotten information is accountable for the effects of intentional forgetting. Some research, however, hypothesized that the time to process information mediates the underlying mechanism. To test this hypothesis, the current study investigated associations between oscillatory power in theta (3-7.5 Hz) and alpha frequencies (8-13 Hz) and intentional forgetting in human participants and explored whether or not these mechanisms depended on processing time. Previously, theta power was shown to be associated with the creation of episodic memory traces and alpha power with inhibition. We therefore expected to find associations between these neural signatures and behavioral effects. Consistent with our hypotheses, we revealed increased theta power for to-be-remembered and increased alpha power for to-be-forgotten information and that the effects of activity in both frequency bands were influenced by the time individuals were given for processing the memory cue. These results suggest that not one but two mechanisms, rehearsal and inhibitory control, are accountable for item-method directed forgetting, both with different temporal profiles.