Wordnet 3.0
ADVERB (1)
1. 
 in a differential manner; 
- Example: "Hubel and Wiesel have found cells that respond differentially according to the direction in which a stimulus is moved across the retina"
The Collaborative International Dictionary of English v.0.48:
Differentially \Dif`fer*en"tial*ly\, adv.
   In the way of differentiation.
   [1913 Webster]
WordNet (r) 3.0 (2006):
differentially
    adv 1: in a differential manner; "Hubel and Wiesel have found
           cells that respond differentially according to the
           direction in which a stimulus is moved across the retina"