| |
Abstract:
Binocular depth inversion (BDI) represents a well-known
illusionary perception. It results from a process of generating
hypotheses on the three-dimensional shape of objects by
interpreting the bottom-up signals using conceptual and perceptual
knowledge (top-down) as well as general rules of perception
(Gregory, 1998). Therefore, BDI is due to a domination of top-down
object knowledge over bottom-up signals. It has been suggested by
Gray and Rawlins (1986) that the hippocampus plays an important
role in the above processes of depth perception and inversion. We
therefore investigated BDI in 40 patients either suffering from
left or right temporal lobe epilepsy, each with defined unilocular
lesions and seizure-onset, and in 20 comparable healthy volunteers
as previously described (Leweke, 1999). BDI scores for ordinary
objects and face perception were significantly lower in left and
significantly elevated right temporal lesioned patients compared to
controls. Differences between mesial and other temporal lobe
lesions were statistically not significant. We conclude that
temporal lobe circuits play an important role in BDI, which may
represent an additional, non-invasive tool in localizing seizure
onset in temporal lobe epilepsy. Furthermore, we hypothesize a role
for temporal lobe functioning in schizophrenic disorders when BDI
is markedly disturbed.
|
