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Completed

NCT Number: NCT05809076

Effects of Gamma-tACS on EEG Periodic Activity

In this study on healthy subjects, the effect of transcranial alternating current stimulation (tACS) will be investigated. In particular, the distinction between periodic and aperiodic electroencephalogram (EEG) activity will be considered, as well as the state-dependency phenomenon. Participants will take part in two experimental sessions that will include tACS stimulation (one real, one control). Before, during, and after stimulation, subjects will have their EEG recorded during rest or during tasks.

The aim of this study is to investigate how the modulatory effects of gamma-tACS interact with intrinsic neural activity, measured in terms of periodic and aperiodic activity, as well as neurophysiological and behavioral modulation, taking into consideration the state-dependency phenomenon, which refers to the brain's activation state prior to stimulation.

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Key information

Conditions

Transcranial Alternating Current Stimulation

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

IRCCS San Camillo Hospital

Venice, Italy

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy adults

Exclusion criteria

  • Common exclusion criteria
  • Left-handedness (assessed through the Oldfield test)
  • Diagnosis of neurological or psychiatric disorders
  • Vision problems that prevent reading, not correctable with lenses
  • Diagnosis of substance dependence on drugs or alcohol
  • Presence of hearing aids/prostheses
  • Diagnosis of epilepsy or family history up to the second degree with it
  • Episodes of febrile convulsions or recurrent fainting
  • Head trauma
  • Presence of surgical clips or metal implants in the head
  • Diagnosis of heart disease
  • Presence of a cardiac pacemaker or artificial heart valve
  • Presence of hearing aids/prostheses
  • Hearing problems or tinnitus
  • Vision problems not corrected with lenses (such as color blindness)
  • Taking tricyclic antidepressant medications
  • Taking neuroleptic medications
  • Diagnosis of headache or migraine
  • Taking more than 3 alcoholic units in the last 24 hours
  • Taking 2 or more cups of coffee or caffeine from other sources in the last 2 hours

Treatment and study plan

Real tACS

Device

tACS is a non-invasive method to induce brain modulation. It will be applied at a frequency of 40 Hz (gamma-tACS) with a peak-to-peak intensity of 2 mA. During the real tACS condition, the alternating current will be administered for 20 minutes.

Sham tACS

Device

In the sham tACS condition, the current will be delivered only for the first 30 seconds and then stopped, in order to simulate the same somatosensory sensations as real tACS, but without inducing modulation.

Primary outcomes

  1. resting-state electroencephalography (EEG) signal

    Time frame: baseline

    The periodic and aperiodic activity of the EEG signal will be estimated through Brainstorm (i.e., EEG analysis software) and quantified in terms of numerical values representing the periodic/aperiodic component of the EEG signal. The periodic and aperiodic activity of the EEG signal will be assessed during three time frames: baseline, during the intervention, and immediately after the intervention (real or sham tACS)

  2. resting-state electroencephalography (EEG) signal

    Time frame: during the intervension

    The periodic and aperiodic activity of the EEG signal will be estimated through Brainstorm (i.e., EEG analysis software) and quantified in terms of numerical values representing the periodic/aperiodic component of the EEG signal. The periodic and aperiodic activity of the EEG signal will be assessed during three time frames: baseline, during the intervention, and immediately after the intervention (real or sham tACS)

  3. resting-state electroencephalography (EEG) signal

    Time frame: immediately after the intervention

    The periodic and aperiodic activity of the EEG signal will be estimated through Brainstorm (i.e., EEG analysis software) and quantified in terms of numerical values representing the periodic/aperiodic component of the EEG signal. The periodic and aperiodic activity of the EEG signal will be assessed during three time frames: baseline, during the intervention, and immediately after the intervention (real or sham tACS)

Secondary outcomes

  1. behavioral performance (response times)

    Time frame: baseline

    Participants' motor performance at a computerized task will be measured in terms of response times (how fast the participants press a computer button, according to the task's instructions). The participants' motor performance will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

  2. behavioral performance (response times)

    Time frame: immediately after the intervention

    Participants' motor performance at a computerized task will be measured in terms of response times (how fast the participants press a computer button, according to the task's instructions). The participants' motor performance will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

  3. behavioral performance (accuracy)

    Time frame: baseline

    Participants' motor performance at a computerized task will be measured in terms of accuracy (% of correct responses at the computerized task, according to the task's instructions). The participants' motor performance will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

  4. behavioral performance (accuracy)

    Time frame: immediately after the intervention

    Participants' motor performance at a computerized task will be measured in terms of accuracy (% of correct responses at the computerized task, according to the task's instructions). The participants' motor performance will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

  5. auditory steady state response (ASSR)

    Time frame: baseline

    The auditory steady state response will be measured via EEG during entrainment through exposure to amplitude-modulated 40Hz sounds (5 min, sequence of amplitude-modulated tones at 40 Hz, delivered via earplug binaurally). The auditory steady state response will be measured as power of the EEG gamma band. The auditory steady state response will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

  6. auditory steady state response (ASSR)

    Time frame: immediately after the intervention

    The auditory steady state response will be measured via EEG during entrainment through exposure to amplitude-modulated 40Hz sounds (5 min, sequence of amplitude-modulated tones at 40 Hz, delivered via earplug binaurally). The auditory steady state response will be measured as power of the EEG gamma band. The auditory steady state response will be assessed during two time frames: baseline and immediately after the intervention (real or sham tACS)

Sponsors and collaborators

Lead sponsor

IRCCS San Camillo, Venezia, Italy

Other

Registry information

Official study title

Evaluation of the Effects of Gamma-tACS on the Periodic Activity of Neural Signals as a Function of State-dependency

Acronym: GAMMAtACS

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Apr 12, 2023
Registry last updated
Apr 12, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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