fNIRS Information


KEY INFORMATION For Translating cognitive neuroscience to inform the use of behavioral assessments in child development:


We are asking you to choose whether or not to volunteer your child for a research study about what parts of the brain are involved as very young children develop and learn to perform common everyday behaviors, such as picking up a small object or recognizing named images.  This page is to give you key information to help you decide whether to participate with your child. The detailed consent form follows. Ask the research team questions that come to mind now.

Diagram showing light passing in a curved arc from a near-infrared light emitter through a cartoon human head and into a surface area of the brain and then back out to a near-infrared light detector

Diagram of how fNIRS works. Light is shined into the head from an emitter and then exits the head and is quantified by a detector.

What is the study about and how long will it last?  

By doing this study, we hope to learn more about which parts of the brain are involved in children’s development as they learn to complete important behavioral milestones. To do this, we use a non-invasive neuroimaging technique known as functional Near-Infrared Spectroscopy, or fNIRS. Light is able to penetrate up to several centimeters of biological tissue. For instance, when you shine a flashlight through your hand or finger, it appears to glow red, because reddish wavelengths pass most easily through tissue and bone. fNIRS exploits these wavelengths of light, employing sensitive instrumentation to precisely measure the amount of light that is transmitted. Changes in light transmission correspond to changes in hemoglobin concentration that occur when different parts of the brain are needed for performing activities. Many transmission measurements (hundreds or thousands) are performed in different locations on the head creating large datasets, which are then used to compute an image of the underlying brain activity. In short, fNIRS measures the relative activity of neurons in the brain tissue beneath the light emitters. Your child will wear a cap with light emitters and detectors while they sit on your lap and complete a task such as pointing to a picture. Your participation in this research will last about an hour.

What are key reasons you might choose to volunteer for this study?

Your participation in this study will help uncover which parts of the brain are active when children are learning to perform common behavioral tasks and help with our understanding of early childhood development. For a complete description of benefits, refer to the Informed Consent.

What are key reasons you might choose not to volunteer for this study?


fNIRS employs non-ionizing near-infrared light, so no cancerogeneous or genetic effects are possible. The light intensity is kept well below safety limits to avoid the risk of thermal damages. No cumulative harmful effects are known so that measurements can be applied repeatedly or in a continuous manner for monitoring purposes. The principal absorber in the near-infrared region in tissue is the pigment hemoglobin, which due to its confinement in the red cells, is highly concentrated in blood and therefore provides a strong optical contrast. This allows the sensitive imaging of local blood supply without additional contrast agents. fNIRS has been used with infants and very young children for many years because it is non-invasive and safe. The main inconvenience to you may be the time or travel commitment to visit our fNIRS lab. The main inconvenience to your child is that they may experience some discomfort from wearing the head cap that holds the light emitters and detectors against the head. If your child becomes fussy or too tired to participate, we can reschedule you for a second visit.  For a complete description of risks, refer to the Informed Consent.

The alternative to participating in this study is to not volunteer for the study or to withdraw from the study. For a complete description of alternatives to participating, refer to the Informed Consent.

Do you have to take part in the study?

If you decide to take part in the study, it should be because you really want to volunteer. You will not lose any services, benefits or rights you would normally have if you choose not to volunteer.

What if you have questions, suggestions or concerns?

The person in charge of the study is Ann M. Weber (annweber@unr.edu) of the School of Public Health, Department of Epidemiology.