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Preregistrations

 

Adaptive Optics Studies (with the Morgan Lab)

Psychophysics

Preregistrations

Single Cone Intrinsic Response

Preregistrations

Color Studies

SLC Project

This project compares measurements of simultaneous lightness contrast across a variety of contextual conditions.  The key manipuluation is that measurements obtained using real illuminated surfaces as stimuli are compared to measurements obtained using rendered computer graphics stimuli displayed on monitors. The broad goal is to understand the degree to which the graphics stimuli evoke the same performance as the real stimuli, and when there are deviations to understand what the critical differences between the graphics and real stimuli are.

Preregistrations

Illumination Discrimination

This project studies the ability of human subjects to make discriminations between changes in the illumination of scenes, with the goal of using these and related measurements to understand the nature and properties of the visual system's representation of illumination and object surfaces.  This project is collaborative with Anya Hurlbert's lab.  The work preregistered here is described in:

Preregistrations

Color-Material

This project studies how human subjects use object color and object material properties to identify and select objects.  The work preregistered in this section is described in the following:

  • Radonjić, A., Cottaris, N. P.,  Brainard D. H. (2018). Quantifying how humans trade off color and material in object identification. Proceedings of Electronic Imaging 2018, Burlingame, CA. Download PDF.
  • Brainard, D. H., Cottaris, N. P., Radonjić, A. (2018). The perception of color and material in natural tasks. Royal Society Interface Focus, 8(4), doi: 10.1098/rsfs.2018.0012Download PDF.
  • Radonjić, A., Cottaris, N. P.,  Brainard, D. H. (2018). The relative contribution of color and material in object selection. bioRxiv 393470, https://doi.org/10.1101/393470.

Preregistrations

Virtual World Psychophysics

Preregistrations

Cortical response to modulations in different color directions (with the Aguirre Lab)

Preregistrations

Melanopsin Studies (with the Aguirre Lab)

Perception

Control Population Stimulus Nulling Experiment 

This project studies the properties of melanopsin-directed spectral modulations, and asks how much cone contrast must be added to a nominally melanopsin-directed stimulus to minimize the visibility of that stimulus.  See:

  • Spitschan M, Datta R, Stern AM, Brainard DH, Aguirre GK (2016) Human visual cortex responses to rapid cone and melanopsin-directed  icker. Journal of Neuroscience 36(5):1471 1482.

Preregistrations

Perceptual Ratings of Light Flux, Cone-Directed and Melanopsin-Directed Light Pulses

This project records psychophysical ratings of light-flux, melanopsin and LMS directed stimuli. The goal is to determine if the different stimulus classes elicit different percepts. Data collected iunder this preregistration are described in:

  • Spitschan, M., Bock, A. S., Ryan, J., Frazzetta, G., Brainard, D. H., Aguirre, G. K. (2017). The human visual cortex response to melanopsin-directed stimulation is accompanied by a distinct perceptual experience. PNAS, 114(46), 1229112296, doi: 10.1073/pnas.1711522114. Download PDF.

Preregistrations

Quantifying light perception via perceptual and physiologic measures in response to melanopsin and cone stimulation in migraineurs with interictal photophobia and in headache-free control subjects

This project will determine if patients with light sensitivity due to migraine headache have increased sensitivity to cone stimulation, melanopsin stimulation, or both.

Preregistrations

Role of melanopsin in regulating visual sensitivity

This project investigates how changes in stimulation of melanopsin affects visual sensitivity.

Preregistrations

Pupillometry

Comparison of monochromatic and silent-substitution evoked pupil responses

This project compares pupillary responses to monochromatic blue and red pulses and silent-substitution melanopsin- and cone-directed pulses.  This work was presented in poster form but we judged the contrast of the silent substitution stimuli was not high enough for us to be confident about the results. The project was continued under "Comparison of monochromatic and silent-substitution melanopsin and LMS-directed evoked pupil responses" below.

Preregistrations

Pupillometry measures of melanopsin contrast - maximum melanopsin and LMS contrast pulses

This project studies pupil responses to high-contrast melanopsin- and cone-directed pulses. We did not pursue these measurements through to publication, but see pupillometry data collected along with fMRI measurements ("Max Mel fMRI" below) as well as "Comparison of monochromatic and silent-substitution melanopsin and LMS-directed evoked pupil responses". 

Preregistrations

Comparison of monochromatic and silent-substitution melanopsin and LMS-directed evoked pupil responses

In this experiment, we are comparing pupil responses evoked by monochromatic blue and red light pulses to those evoked by silent substitution LMS-directed and melanopsin-directed stimuli. The work preregistered here is described in:

  • McAdams, H., Igdalova, A., Spitschan, M., Brainard, D. H., Aguirre, G. K. (2018). Pulses of melanopsin-directed contrast produce highly reliable pupil responses that are insensitive to a change in background radiance. In press, IOVS. (Preprint available at https://doi.org/10.1101/365718.)

Preregistrations

MaxMelLMS Pupil (17 second protocol)

This project studies pupil responses to high-contrast melanopsin- and cone-directed pulses using a shortened stimulus protocol. We did not pursue these measurements through to publication.

Preregistrations

fMRI

Max Mel MRI

This project studies evoked brain responses to high-contrast melanopsin- and cone-directed pulses using BOLD fMRI. The work preregistered here is described in:

  • Spitschan, M., Bock, A. S., Ryan, J., Frazzetta, G., Brainard, D. H., Aguirre, G. K. (2017). The human visual cortex response to melanopsin-directed stimulation is accompanied by a distinct perceptual experience. PNAS, 114(46), 1229112296, doi: 10.1073/pnas.1711522114. Download PDF.

Preregistrations

MaxMel/LMS CRF

This project studies evoked brain responses to melanopsin- and cone-directed pulses using BOLD fMRI at various contrast levels. The work preregistered here is described in:

  • Spitschan, M., Bock, A. S., Ryan, J., Frazzetta, G., Brainard, D. H., Aguirre, G. K. (2017). The human visual cortex response to melanopsin-directed stimulation is accompanied by a distinct perceptual experience. PNAS, 114(46), 1229112296, doi: 10.1073/pnas.1711522114. Download PDF.

Preregistrations