That left open
the question of whether such improvements were due to
elevation of GM1 and its metabolic precursor (GD1a) or
elimination of the b-series gangliosides (GD1b and GT1b)
along with GD3, the latter having a prominent role
in apoptotic pathways, including Ab-induced cell death
[114]. (For more on the role of gangliosides in these and
other neurological disorders, see Schengrund, this issue
[3].)