1. Alternative Neuroimaging Techniques PET TMS SPECT EEG

2. Positron Emission Tomography (PET)
Relies on injection of a radioactive isotope to measure cerebral blood flow.
Whereas fMRI images rely on the interaction of multiple factors (different tissue proton densities, relaxation times, a combination of CBF, CBV, CRMO and CRMGl) PET relies only on only one factor for a given experiment (e.g., usually CBF – but can be CBV or CRMO)

3. Transcranial magnetic stimulation (TMS)
Typically an interruption of function – creating temporary lesions in the healthy brain.
Great for pinpointing regions involved in specific components of tasks or for mimicking neurological disorders.
Single vs. rapid-pulse TMS – inherent dangers in rapid-pulse TMS
Poor spatial resolution – vitamin E tablets and MRI help! (and magnetic dipole modeling as in VEPs)

4. Single Photon Emission Computed Tomography (SPECT)
PET
Less spatial resolution than PET – but far less expensive
Often used for early detection of dementias – evidenced by hypoperfusion in a given area

5. Electro-encephalogram (EEG)
Scalp potentials – EEG used clinically but from this we can get visually evoked potentials (VEPs) and the like.
Dipole modeling used to locate the source of the VEP
Requires many trials – poor spatial but great temporal resolution.
128 electrode array

6. Combinations fMRI and single cell in monkeys (Logothetis)
Non-pherous EEG recordings with fMRI in humans
TMS and PET (Paus, 1999; Desmurget et al. 1999)