In the regional forums a few of us were discussing ride routes through West Virginia. I raised the point that in some ride environments -- typically, flat terrain twisties with an homogeneous view of green trees in front and to both sides with no horizon in view -- I tend to experience vertigo from time to time. For me, it is made worse if the sun is low and shining through the trees in way that creates something of a stroboscopic effect. I'm curious how many other riders experience the same phenomenon. If so, has anybody developed tricks or techniques to counteract or eliminate the problem? Years ago when I toured by motorcycle in the French, Swiss and Austrian Alps I experienced similar vertigo. I learned that keeping ones head vertical -- plane of eyes parallel with the horizon -- irrespective of the lean angle of the bike would virtually eliminate vertigo in the constant switch-back twisties of the Tyrol. I'd love to hear other rider's experiences related to vertigo while riding.