Subcortical Arousal in Perceptual Awareness

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

72 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-10-13

Study Completion Date

2030-12-31

Brief Summary

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The study is a multi-site study and will be conducted at up to 11 investigative sites in the United States. The study will investigate subcortical arousal circuits in visual perception using techniques with complementary strengths based on promising initial studies.

Detailed Description

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The study will investigate subcortical arousal circuits in visual perception using techniques with complementary strengths based on promising initial studies. This study is expected to shed important light on the precise relationship between transient increases in subcortical arousal and perceptual awareness, generalizable across the visual modality. This research will therefore provide important general potential benefits, including 1. Identification of subcortical arousal systems in perception, which can benefit treatment of many disorders where perceptual deficits are common, e.g. traumatic brain injury, Alzheimer's disease, stroke, developmental disorders, schizophrenia, epilepsy and others. 2. Understanding the role of specific subcortical arousal circuits in perception may help target improved treatments, including transient thalamic stimulation like that planned for the present investigations, or less invasive treatments (TMS, tDCS, designer drugs) to improve function of these circuits. 3. The planned no-report paradigms may detect perceptual awareness in severe brain damage and anesthesia, where people are unable to overtly respond.

The main hypotheses are that 1. the thalamic awareness potential (TAP) will be associated with visual perception independent of report, and 2. thalamic intralaminar stimulation at the time of stimulus presentation will augment the probability of perceptual awareness.

Conditions

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Epilepsy

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Thalamic Recording (Aim 1)

Participants will perform the visual behavioral task with intracranial electroencephalogram (EEG) brain recordings carried out in parallel with surface EEG recordings. For Aim 1, we will analyze thalamic event related potentials in perceived vs not perceived stimuli, classified as in perception of no report visual stimuli based on eye metrics.

Group Type EXPERIMENTAL

EEG

Intervention Type DEVICE

Participants will have scalp EEG recorded with the international 10-20 system sampled at 256Hz using EEG amplifiers for purposes of surface event related potential analysis

Eye Tracking

Intervention Type DEVICE

An eye-tracking device may be used during the perceptual awareness task. Pupillary and gaze location measurements are recorded using either a ViewPoint\~VoltagePro.EyeLink 1000 Plus system, or Argus Science ETVision system. If using the ViewPoint\~VoltagePro system or the Argus Science ETVision system, participants will be asked to wear an eye tracker during the perceptual awareness task (similar to wearing sunglasses). If using the EyeLink 1000 Plus system, participants may be asked to place their head inside of a padded head-chin rest to stabilize head position

Behavioral task

Intervention Type DEVICE

For the visual perceptual awareness task, the participant will be presented with barely perceptible visual stimuli. After a variable delay, the participant will be asked to report perception of each stimulus and identify its location.

Thalamic Stimulation (Aim 2)

We will test participants during the Visual Report Paradigm, while recording from the intralaminar thalamus with simultaneous scalp EEG as in Aim 1. Three thalamic stimulation conditions will be tested, randomized across trials: 1. No stimulation; 2. Stimulation Concurrent with visual stimuli; 3. Stimulation Delayed to 2s after visual stimuli. Stimulation will be a 100Hz train lasting 300ms, with biphasic square wave pulses 120μs per phase, current adjusted previously by clinicians to maximum tolerated level without side effects (typically \~3mA).

The electrical stimulation is being delivered for research purposes to understand the causal role of thalamus in regulating visual perception.

Group Type EXPERIMENTAL

EEG

Intervention Type DEVICE

Participants will have scalp EEG recorded with the international 10-20 system sampled at 256Hz using EEG amplifiers for purposes of surface event related potential analysis

Eye Tracking

Intervention Type DEVICE

An eye-tracking device may be used during the perceptual awareness task. Pupillary and gaze location measurements are recorded using either a ViewPoint\~VoltagePro.EyeLink 1000 Plus system, or Argus Science ETVision system. If using the ViewPoint\~VoltagePro system or the Argus Science ETVision system, participants will be asked to wear an eye tracker during the perceptual awareness task (similar to wearing sunglasses). If using the EyeLink 1000 Plus system, participants may be asked to place their head inside of a padded head-chin rest to stabilize head position

Behavioral task

Intervention Type DEVICE

For the visual perceptual awareness task, the participant will be presented with barely perceptible visual stimuli. After a variable delay, the participant will be asked to report perception of each stimulus and identify its location.

Interventions

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EEG

Participants will have scalp EEG recorded with the international 10-20 system sampled at 256Hz using EEG amplifiers for purposes of surface event related potential analysis

Intervention Type DEVICE

Eye Tracking

An eye-tracking device may be used during the perceptual awareness task. Pupillary and gaze location measurements are recorded using either a ViewPoint\~VoltagePro.EyeLink 1000 Plus system, or Argus Science ETVision system. If using the ViewPoint\~VoltagePro system or the Argus Science ETVision system, participants will be asked to wear an eye tracker during the perceptual awareness task (similar to wearing sunglasses). If using the EyeLink 1000 Plus system, participants may be asked to place their head inside of a padded head-chin rest to stabilize head position

Intervention Type DEVICE

Behavioral task

For the visual perceptual awareness task, the participant will be presented with barely perceptible visual stimuli. After a variable delay, the participant will be asked to report perception of each stimulus and identify its location.

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

* normal vision with or without the use of corrective lenses

* normal vision with or without the use of corrective lenses
* a female subject must have a negative pregnancy test and if sexually active, must be using a reliable form of birth control for the duration of the trial, be surgically sterile, or be at least two years post-menopausal.

Exclusion Criteria

* severe vision impairment even with correction preventing ability to see stimuli (prevents accurate pupil and eye gaze measurements)
* unable to perform the perception task due to cognitive impairment. All participants must be capable of consenting for themselves.

* severe vision impairment even with correction preventing ability to see stimuli (prevents accurate pupil and eye gaze measurements)
* unable to perform the perception task due to cognitive impairment. All participants must be capable of consenting for themselves.
* pregnancy

Minimum Eligible Age

13 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Hal Blumenfeld, MD, Phd

Role: PRINCIPAL_INVESTIGATOR

Yale University

Locations

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Yale School of Medicine

New Haven, Connecticut, United States

Site Status RECRUITING