Thalamus
Conditions
Keywords
Perception
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
Interventions
DEVICELIFUP excitation
The experimental will consist of a 10-minute baseline period (LIFUP-OFF) followed by four 10-minute sessions of stimulating (LIFUP-ON-excitation) four thalamic areas. The order of thalamic area stimulation will be counterbalanced across participants and will include the ventral anterior (VA), dorsal anterior (DA), ventral posterior (VP), and dorsal posterior (DP) sections of the thalamus.
DEVICELIFUP inhibition
The experimental will consist of a 10-minute baseline period (LIFUP-OFF) followed by four 10-minute sessions of stimulating (LIFUP-ON-inhibition) four thalamic areas. The order of thalamic area stimulation will be counterbalanced across participants and will include the ventral anterior (VA), dorsal anterior (DA), ventral posterior (VP), and dorsal posterior (DP) sections of the thalamus.
Sponsors
University of Michigan
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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). |
Countries
United States
Participant flow
Pre-assignment details
61 participants were consented for this trial. 1 participant was excluded before randomization because of a scheduling conflict.
Participants by arm
| Arm | Count |
|---|---|
| LIFUP Excitation The 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 excitation: The experimental will consist of a 10-minute baseline period (LIFUP-OFF) followed by four 10-minute sessions of stimulating (LIFUP-ON-excitation) four thalamic areas. The order of thalamic area stimulation will be counterbalanced across participants and will include the ventral anterior (VA), dorsal anterior (DA), ventral posterior (VP), and dorsal posterior (DP) sections of the thalamus. | 30 |
| LIFUP Inhibition The 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: The experimental will consist of a 10-minute baseline period (LIFUP-OFF) followed by four 10-minute sessions of stimulating (LIFUP-ON-inhibition) four thalamic areas. The order of thalamic area stimulation will be counterbalanced across participants and will include the ventral anterior (VA), dorsal anterior (DA), ventral posterior (VP), and dorsal posterior (DP) sections of the thalamus. | 30 |
| Total | 60 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Insufficient baseline performance | 0 | 1 |
| Overall Study | Performed incorrect visual task | 1 | 0 |
| Overall Study | Technical issues with the interventional device | 2 | 2 |
Baseline characteristics
| Characteristic | LIFUP Excitation | LIFUP Inhibition | Total |
|---|---|---|---|
| Age, Continuous | 27.2 years STANDARD_DEVIATION 7 | 24.5 years STANDARD_DEVIATION 5.3 | 25.9 years STANDARD_DEVIATION 6.3 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants | 2 Participants | 3 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 29 Participants | 28 Participants | 57 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race/Ethnicity, Customized Asian | 7 Participants | 9 Participants | 16 Participants |
| Race/Ethnicity, Customized Black | 2 Participants | 2 Participants | 4 Participants |
| Race/Ethnicity, Customized Other | 1 Participants | 0 Participants | 1 Participants |
| Race/Ethnicity, Customized White | 20 Participants | 19 Participants | 39 Participants |
| Region of Enrollment United States | 30 Participants | 30 Participants | 60 Participants |
| Sex: Female, Male Female | 17 Participants | 21 Participants | 38 Participants |
| Sex: Female, Male Male | 13 Participants | 9 Participants | 22 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 30 | 0 / 30 |
| other Total, other adverse events | 4 / 30 | 3 / 30 |
| serious Total, serious adverse events | 0 / 30 | 0 / 30 |
Outcome results
Primary
Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT)
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).
Time frame: Up to 60 minutes after intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| LIFUP Excitation | Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT) | Baseline | 0.3008 units on a scale | Standard Deviation 0.2589 |
| LIFUP Excitation | Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT) | Following intervention | 0.3113 units on a scale | Standard Deviation 0.3 |
| LIFUP Inhibition | Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT) | Baseline | 0.2092 units on a scale | Standard Deviation 0.294 |
| LIFUP Inhibition | Change in Perceptual Criterion Derived From the Signal Detection Theory (SDT) | Following intervention | 0.2770 units on a scale | Standard Deviation 0.3322 |
p-value: 0.2Wilcoxon (Mann-Whitney)
Primary
Change in Sensitivity Derived From the Signal Detection Theory (SDT)
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).
Time frame: Up to 60 minutes after intervention
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| LIFUP Excitation | Change in Sensitivity Derived From the Signal Detection Theory (SDT) | Following intervention | 0.7520 units on a scale | Standard Deviation 0.1014 |
| LIFUP Excitation | Change in Sensitivity Derived From the Signal Detection Theory (SDT) | Baseline | 0.7452 units on a scale | Standard Deviation 0.1128 |
| LIFUP Inhibition | Change in Sensitivity Derived From the Signal Detection Theory (SDT) | Following intervention | 0.7120 units on a scale | Standard Deviation 0.1674 |
| LIFUP Inhibition | Change in Sensitivity Derived From the Signal Detection Theory (SDT) | Baseline | 0.7419 units on a scale | Standard Deviation 0.125 |
p-value: 0.02Wilcoxon (Mann-Whitney)