AJMONE-MARSAN 163The long-suspected limitations of scalp EEG were readily confirmed
by simultaneous recording from the various levels.^17 Convincing quan
titative and morphologic differences could be demonstrated between
the scalp and the cortical or subcortical levels regarding apparent site(s)
of origin of the epileptiform discharges. These differences could be quite
variable and unpredictable.^18
Monitoring of the (induced) clinical seizures (see page 162) was
performed using a single-frame camera adapted with an electric motor
to make it possible to shoot automatically up to 1 frame/s (in practice
it was enough to use 1 frame/2 s). The camera was furnished with a 50
foot capacity film magazine so that the entire seizure episode could be
photographed without interruption.^19 It is obvious that with this single-
frame method certain types of rapid movement were likely to be missed.
On the other hand, this method had the great advantage of easy and
faithful reproducibility of pictures for detailed analysis and high quality
publication, something not easily obtainable with either movie or video
techniques. A good correlation with the concomitant electrographic
events was facilitated by a simple, properly regulated electronic timer
with automatic control of the camera shutter and with a simultaneous
Figure 1. Schematic Outline of the Possible Pathways of the Spread of
Seizure Activity Originating in the Occipital Lobe
Donated to the Office of NIH History by Dr. Cosimo Ajmone-Marsan