The system sends near-infrared light into the scalp at multiple wavelengths and measures the returning light collected by scalp-mounted detectors. Because oxygenated and deoxygenated hemoglobin absorb these wavelengths differently, changes in detected light provide estimates of task-related changes in each form of hemoglobin. This wavelength-dependent absorption is the basis for relating optical measurements to cerebral oxygenation.
Light sources deliver near-infrared signals through the scalp, while detectors collect the light after it has traveled through the measured tissue. The recording system compares how absorption changes across wavelengths during a task, allowing it to estimate changes in oxygenated and deoxygenated hemoglobin. Mounting both components on the scalp supports measurements without relying on bulky fiber bundles.
The main distinction is how optical signals reach and leave the participant. Fiberless systems use scalp-mounted sources and detectors, whereas fiber-based arrangements rely on bulky fiber bundles that can tether participants. Reducing this tethering can provide greater mobility, making it more practical to examine movement, interaction, and other behaviors that are difficult to study under highly constrained laboratory conditions.
A behavioral task is performed while scalp-mounted sources emit near-infrared light and detectors collect the resulting signals. The recorded changes in light absorption are examined across wavelengths to estimate oxygenated and deoxygenated hemoglobin changes associated with the task. Researchers can then relate those cerebral oxygenation patterns to the participant’s attention, decision-making, movement, interaction, or other observed behavior.
Researchers would choose this approach when the study requires participants to move more freely or engage in interaction rather than remain tightly constrained. Its reduced cable burden supports naturalistic tasks and ecologically relevant settings, where behavior may include movement or social interaction. The resulting recordings can help investigate how cerebral oxygenation relates to attention, decisions, and social behavior.
Fiberless fNIRS recordings can be used to examine relationships between task-related cerebral oxygenation and several behavioral domains. Supported examples include attention, decision-making, movement, interaction, and social behavior. This makes the approach useful for extending neuroimaging beyond restricted laboratory tasks and for studying neural oxygenation during behaviors that more closely resemble natural activity.