An inverse model evaluates which hidden source configurations could account for the signals recorded at external sensors. It combines the measured data with a head or volume-conduction model that describes how activity may reach those sensors. Mathematical constraints then guide the estimation toward source patterns that are compatible with both the recordings and the model.
Regularization supplies mathematical constraints during inverse estimation. Because the recorded sensor patterns can be interpreted through a model rather than observed directly at their generators, these constraints help determine which source estimates are considered plausible within the analysis. The resulting activity maps therefore reflect both the measurements and the assumptions imposed by the reconstruction procedure.
A head or volume-conduction model represents how signals generated within the brain may be transmitted to external sensors. This information connects candidate neural activity with the EEG or MEG measurements used in the inverse model. Its inclusion helps give the reconstructed activity a spatial interpretation, while also making the result dependent on the model used.
Sensor recordings show signals measured outside the brain, whereas source reconstruction uses an inverse model to estimate the hidden generators that may have produced them. This can improve spatial interpretation and help relate activity to particular brain processes. However, the estimated locations and dynamics are model-dependent rather than direct observations of neural sources.
A typical analysis begins with EEG or MEG measurements, incorporates a head or volume-conduction model, and applies an inverse model with mathematical constraints such as regularization. The resulting source estimates can then be examined for their location and dynamics in relation to the behavioral process under study. Interpretation should account for the assumptions of the model.
The method can connect estimated neural activity with behavioral processes including perception, decision-making, learning, and motor responses. Researchers can examine when and where brain processes associated with these behaviors appear in the reconstructed results. This makes the approach useful when the scientific goal requires more spatial interpretation than external sensor measurements alone can provide.