Anterior temporal lobe resection (ATLR) is a surgical procedure to treat
drug-resistant temporal lobe epilepsy (TLE). Resection may involve large
amounts of cortical tissue. Here, we examine the effects of this surgery on
cortical morphology measured in independent variables both near the resection
and remotely.
We studied 101 individuals with TLE (55 left, 46 right onset) who underwent
ATLR. For each individual we considered one pre-surgical MRI and one follow-up
MRI 2 to 13 months after surgery. We used our newly developed surface-based
method to locally compute traditional morphological variables (average cortical
thickness, exposed surface area, and total surface area), and the independent
measures K, I, and S, where K measures white matter tension, I
captures isometric scaling, and S contains the remaining information about
cortical shape. Data from 924 healthy controls was included to account for
healthy ageing effects occurring during scans. A SurfStat random field theory
clustering approach assessed changes across the cortex caused by ATLR.
Compared to preoperative data, surgery had marked effects on all
morphological measures. Ipsilateral effects were located in the orbitofrontal
and inferior frontal gyri, the pre- and postcentral gyri and supramarginal
gyrus, and the lateral occipital gyrus and lingual cortex. Contralateral
effects were in the lateral occipital gyrus, and inferior frontal gyrus and
frontal pole.
The restructuring following ATLR is reflected in widespread morphological
changes, mainly in regions near the resection, but also remotely in regions
that are structurally connected to the anterior temporal lobe. The causes could
include mechanical effects, Wallerian degeneration, or compensatory plasticity.
The study of independent measures revealed additional effects compared to
traditional measures
