Neuromodulation of Conscious Perception: Investigating Thalamic Roles Through Ultrasonic Stimulation

Not Applicable

Completed

Brief Summary: The purpose of this study is to evaluate the role that the thalamus (the egg-shaped structure in the middle of your brain) plays in perception using a low-intensity ultrasound pulsation (LIFUP) device. The researchers expect to observe differential changes in the perceptual outcomes based on the LIFUP stimulation of different thalamic areas

Recruitment & Eligibility

Inclusion Criteria

Must be right-handed.
Must have normal or corrected-to-normal vision (while wearing contact lenses). Please note: persons who need eyeglasses to achieve 20/20 vision cannot be included in this study as eyeglasses cannot be worn during the study visit.
Must not be on any medications for any neurological, psychological, or psychiatric conditions.
Must be English speaking.
Must be capable of giving written informed consent.

Exclusion Criteria

• Vision that is not 20/20, or vision that is not corrected to 20/20 while wearing contact lenses.

Please note: persons needing eyeglasses to achieve 20/20 vision cannot be included in this study as eyeglasses cannot be worn during the study visit.

History of significant head injury with loss of consciousness.
Learning disability or other developmental disorder.
Medication use for any neurological, psychological, or psychiatric conditions.
Any impairment (sensory or motor loss), activity, or situation that in the judgment of the study coordinator or Principal Investigators would prevent satisfactory completion of the study protocol.

Arm && Interventions

Group	Intervention	Description
LIFUP excitation	LIFUP excitation	Our study will involve the enrollment of 60 participants, who will be randomly assigned to two groups, with each group consisting of 30 participants. The participants will be divided based on the type of transcranial LIFUP they will receive, either excitation or inhibition, targeting four specific thalamic areas.
LIFUP inhibition	LIFUP inhibition	Our study will involve the enrollment of 60 participants, who will be randomly assigned to two groups, with each group consisting of 30 participants. The participants will be divided based on the type of transcranial LIFUP they will receive, either excitation or inhibition, targeting four specific thalamic areas.

Primary Outcome Measures

Name	Time	Method
Change in Sensitivity Derived From the Signal Detection Theory (SDT)	Up to 60 minutes after intervention	SDT was a means of measuring participants' ability to differentiate between information-bearing patterns and random patterns that distract from the information. Sensitivity measured a participant's ability to differentiate between real and scrambled images on a scale from 0.0 to 1.0, with higher scores indicating better accuracy in detecting a signal when it was present and lower scores indicating more missed signals. A score of 1.0 was perfect sensitivity (i.e., never missing a real signal).
Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT)	Up to 60 minutes after intervention	SDT was a means of measuring participants' ability to differentiate between information-bearing patterns and random patterns that distract from the information. Perceptual criterion measured a participant's tendency to say "yes" or "no" when the participant was unsure if a signal was present. Perceptual criterion was measured on a scale from -1.0 to 1.0, with a score of 0 indicating no bias towards "yes" or "no". Negative scores meant a bias towards "yes" (more likely to say a signal was present), while positive scores meant a bias towards "no" (more likely to say a signal was absent).

Secondary Outcome Measures