A system for examining biological tissue of a subject includes a wireless optical probe, electronics and a processor. The wireless optical probe includes a light source connected to receive signals from a wireless receiver, and a light detector coupled to provide data to a wireless transmitter constructed to transfer data wirelessly. The wireless optical probe is powered by a battery. The light source is constructed and arranged to introduce optical radiation in the visible to infra-red range into the examined biological tissue of a subject, and the light detector is constructed and arranged to detect radiation that has migrated in the examined biological tissue of the subject. The electronics is constructed and arranged to communicate wirelessly with the optical probe, to store the transferred data, and to create optical data. The processor is constructed and arranged to evaluate the optical data. The system may also provide brain stimulation and evaluate the detected radiation to determine a brain cognitive function of the subject. One embodiment of the system can detect a brain disorder. Another embodiment of the system can detect “deceit.” In addition to the optical module, the system may include other optional modules such as an EEG module, an MEG module, a thermography module, a respiratory module, a skin conductivity module, and a blood pressure module.