Brain Stimulation for Memory Enhancement During Sleep Cycles

Overseen By Andreina Hampton

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of California, Los Angeles

Disqualifiers: Neurological, psychiatric issues, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 1-2 weeks

150 Participants Needed

Trial Summary

What is the purpose of this trial?

The proposed project seeks to elucidate memory processes and consolidation during sleep by leveraging the unique capability of direct recordings from the human brain at multiple levels of resolution-single neurons, localized neuronal assemblies, intracranial local field potentials-during rich behavioral tasks with real-life narratives and extracting neural features that relate to different aspects of episodic experience. The investigators will further probe causal mechanisms of consolidation by application of auditory and electrical stimulations during sleep and its effect on modulating memory processes.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What data supports the effectiveness of the treatment Decoding and Selective Modulation of Human Memory During Awake/Sleep Cycles?

Research shows that using brain stimulation during sleep can improve memory by enhancing the brain's natural processes. For example, studies found that transcranial electrical stimulation (tES) during sleep can boost memory performance and increase the time spent in deep sleep stages, which are important for memory consolidation. ^{1 2 3 4 5}

Is brain stimulation during sleep safe for humans?

Research on brain stimulation during sleep, such as transcranial electrical stimulation (tES) and transcranial alternating current stimulation (tACS), has been conducted in healthy individuals and generally shows it can be safely applied. However, some studies suggest that while it can enhance certain sleep parameters, it may not always improve memory and could potentially impair it in some individuals with lower initial memory performance. ^{4 6 7 8 9}

How does the treatment of brain stimulation for memory enhancement during sleep cycles differ from other treatments?

This treatment is unique because it uses transcranial electrical stimulation (tES) during specific sleep stages to enhance memory consolidation, unlike other treatments that may not target sleep or use electrical stimulation. It specifically increases slow oscillations during non-rapid eye movement sleep, which is linked to improved memory performance. ^{2 3 4 5 8}

Eligibility Criteria

This trial is for epilepsy patients aged 18-65 undergoing depth electrode placement. They must be willing to consent and participate, as determined by the epilepsy surgery team after neuropsychological and psychiatric evaluation. Those with additional neurological or psychiatric conditions posing risks are excluded.

Inclusion Criteria

Eligibility is determined by the epilepsy surgery team (based on neuropsychological testing and on psychiatric evaluation)

Willing to provide informed consent and participate in the study

Exclusion Criteria

Unwilling to provide informed consent

I have no major mental or neurological issues, except for epilepsy.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants undergo memory tasks and receive auditory and electrical stimulations during sleep to modulate memory processes

1-2 weeks

In-hospital stay

Follow-up

Participants are monitored for memory performance and neural activity post-treatment

1-2 days

Treatment Details

Interventions

• Decoding and Selective Modulation of Human Memory During Awake/Sleep Cycles

Trial Overview The study aims to understand memory processes during sleep by recording brain activity in humans through various methods. It will also explore how auditory and electrical stimulations applied during sleep can affect memory consolidation.

Who Is Running the Clinical Trial?

University of California, Los Angeles

Lead Sponsor

Trials

1,594

Recruited

10,430,000+

National Institute of Neurological Disorders and Stroke (NINDS)

Collaborator

Trials

1,403

Recruited

655,000+

University of Iowa

Collaborator

Trials

486

Recruited

934,000+

Findings from Research

Real-time closed-loop deep brain stimulation during sleep, when synchronized with natural slow waves, significantly enhances sleep spindles and improves the coupling of brain activity, which is crucial for memory consolidation.

This synchronized stimulation not only boosts the accuracy of recognition memory but also shows a strong correlation between improved memory performance and enhanced brain electrophysiological activity, indicating a causal role in memory consolidation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Augmenting hippocampal-prefrontal neuronal synchrony during sleep enhances memory consolidation in humans. Geva-Sagiv, M., Mankin, EA., Eliashiv, D., et al.[2023]

In a study involving 26 elderly participants (average age 69.1 years), anodal transcranial direct current stimulation (tDCS) during early NREM sleep did not improve memory consolidation for either declarative or procedural tasks, contrasting with previous findings in younger adults.

The tDCS was associated with increased wakefulness and reduced deep sleep (NREM stage 3), suggesting that the stimulation may disrupt rather than enhance sleep-dependent memory processes in older individuals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

No effects of slow oscillatory transcranial direct current stimulation (tDCS) on sleep-dependent memory consolidation in healthy elderly subjects. Eggert, T., Dorn, H., Sauter, C., et al.[2016]

Transcranial electrical stimulation (tES) applied during sleep can enhance memory consolidation and improve metamemory sensitivity, which is our ability to judge the accuracy of our memories.

The study found that tES led to significant changes in brain network connectivity, particularly in the theta and spindle frequency bands, and these changes were linked to improvements in metamemory sensitivity, suggesting a mechanism for how tES can enhance memory processes during sleep.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Brain connectivity alterations during sleep by closed-loop transcranial neurostimulation predict metamemory sensitivity. Hubbard, RJ., Zadeh, I., Jones, AP., et al.[2021]

Short duration repetitive transcranial electrical stimulation (SDR-tES) during daytime naps significantly enhances declarative memory consolidation in healthy individuals, showing improved memory performance compared to sham stimulation both immediately after sleep and 48 hours later.

SDR-tES also increases the amount of time spent in deeper NREM sleep (NREM3) and boosts the rate of slow oscillations during NREM sleep, suggesting that the timing of stimulation during quiet brain activity may optimize its effects on memory consolidation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Short Duration Repetitive Transcranial Electrical Stimulation During Sleep Enhances Declarative Memory of Facts. Cellini, N., Shimizu, RE., Connolly, PM., et al.[2023]

Reactivating specific brain activity patterns during sleep can significantly improve memory performance the following day.

This finding suggests that sleep plays a crucial role in memory consolidation, highlighting the importance of sleep quality for learning and retention.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Let's replay. Rasch, B.[2020]

The study demonstrated that closed-loop transcranial Alternating Current Stimulation (tACS) during sleep can enhance memory consolidation, specifically improving the ability to generalize learned information, as shown by better performance on a target detection task in 21 participants.

An interesting finding was the inverted U-shaped dose effect of tACS on slow-wave oscillations, suggesting that the timing and intensity of stimulation are crucial for optimizing memory benefits, highlighting the potential of this method for both healthy individuals and those with neuropsychiatric conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dose-Dependent Effects of Closed-Loop tACS Delivered During Slow-Wave Oscillations on Memory Consolidation. Jones, AP., Choe, J., Bryant, NB., et al.[2020]

In a study involving 25 healthy participants, the effectiveness of anodal transcranial direct current stimulation (so-tDCS) on memory retention was linked to specific brain activity patterns during baseline sleep, particularly the coupling of slow spindles with slow oscillation (SO) troughs.

The steepness and direction of the SO slope during baseline sleep were also predictive of how well participants retained declarative memories after stimulation, highlighting the importance of sleep dynamics in memory consolidation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Spontaneous slow oscillation-slow spindle features predict induced overnight memory retention. Dehnavi, F., Koo-Poeggel, PC., Ghorbani, M., et al.[2021]

Transcranial direct current stimulation applied during slow-wave sleep in 18 healthy participants increased slow-wave density and improved the coupling of fast spindles and slow-waves, which are important for memory consolidation.

However, while the stimulation enhanced sleep parameters, it did not improve overall memory retention and even impaired memory consolidation in participants with below-average pre-sleep performance, suggesting that enhancing sleep may not benefit those who struggle with memory the most.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation. Ruch, S., Fehér, K., Homan, S., et al.[2021]

A new protocol using surface cortical electrical stimulation during slow wave sleep (SWS) in a non-human primate showed that this stimulation can enhance learning of a neuroprosthetic task, indicating a potential method to improve memory consolidation.

The study highlights the importance of delta oscillatory activity during SWS in coordinating brain regions involved in memory, suggesting that targeted stimulation during this sleep phase could help understand and leverage synaptic plasticity for better learning outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cycle-Triggered Cortical Stimulation during Slow Wave Sleep Facilitates Learning a BMI Task: A Case Report in a Non-Human Primate. Rembado, I., Zanos, S., Fetz, EE.[2020]

References

1. United States pubmed.ncbi.nlm.nih.gov

Augmenting hippocampal-prefrontal neuronal synchrony during sleep enhances memory consolidation in humans. [2023]

2. United States pubmed.ncbi.nlm.nih.gov

No effects of slow oscillatory transcranial direct current stimulation (tDCS) on sleep-dependent memory consolidation in healthy elderly subjects. [2016]

3. United States pubmed.ncbi.nlm.nih.gov

Brain connectivity alterations during sleep by closed-loop transcranial neurostimulation predict metamemory sensitivity. [2021]

4. Switzerland pubmed.ncbi.nlm.nih.gov

Short Duration Repetitive Transcranial Electrical Stimulation During Sleep Enhances Declarative Memory of Facts. [2023]

5. England pubmed.ncbi.nlm.nih.gov

Let's replay. [2020]

6. Switzerland pubmed.ncbi.nlm.nih.gov

Dose-Dependent Effects of Closed-Loop tACS Delivered During Slow-Wave Oscillations on Memory Consolidation. [2020]

7. United States pubmed.ncbi.nlm.nih.gov

Spontaneous slow oscillation-slow spindle features predict induced overnight memory retention. [2021]

8. Switzerland pubmed.ncbi.nlm.nih.gov

Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation. [2021]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Cycle-Triggered Cortical Stimulation during Slow Wave Sleep Facilitates Learning a BMI Task: A Case Report in a Non-Human Primate. [2020]