There's been a contraversy for a while on whether or not tryptamines can be methylated with formaldehyde and sodium cyanoborohydride or other reducing agent. I found these patents on this type of reaction. Most use sodium cyanoborohydride.
Patent US5037845
column 8 line 54+
Patent US5298520
col. 23 l. 24+, col. 24 l. 57+
Patent US5317103
example 3 col. 20 NaBH4, ex. 37 col. 30
Patent US5852049
ex. 40 col. 31-32
Patent WO02079153
examples 27 and 32 formic acid
Patent US5300645
Pictet-Spengler