Fourteen and six Hz positive spikes are best recorded with what type of reference?

The correct choice is the contralateral ear reference when recording fourteen and six Hz positive spikes, which are typically associated with certain types of EEG activity, such as spike-and-wave discharges. This reference is chosen because it allows for the best representation of focal activity in one hemisphere as compared to the overall electrical activity being picked up from the other side.

The contralateral ear reference provides a lateralized view of the brain activity since it compares the electrical potentials between the two ears. This is particularly useful in revealing features of spikes that may originate from a localized area in the brain, which may not be accurately captured when using midline references or those that could dilute the focal responses, such as frontal or occipital references.

Other references, like the frontal or occipital references, may not provide the same clarity for identifying these specific spikes, as they could be influenced by signals from various regions of the cerebral cortex, leading to less precise identification of focal points in the EEG. The vertex reference also has limitations in certain contexts as it may represent an average of potentials from both hemispheres, which may mask or diminish localized activity.