Jh. Mcauley et al., Common 3 and 10 Hz oscillations modulate human eye and finger movements while they simultaneously track a visual target, J PHYSL LON, 515(3), 1999, pp. 905-917
1. A 10 Hz range centrally originating oscillation has been found to modula
te slow finger movements and anticipatory smooth eye movements. To determin
e if an interaction or linkage occurs between these two central oscillation
s during combined visuo-manual tracking, frequency and coherence analysis w
ere performed on finger and eye movements while they simultaneously tracked
a visual target moving in intermittently visible sinusoidal patterns.
2. Two different frequencies of common or linked oscillation were found. Th
e first, at 2-3 Hz, was dependent on visual feedback of target and finger t
racking positions. The second, at around 10 Hz, still occurred when both ta
rget and finger positions were largely obscured, indicating that this commo
n oscillation was generated internally by the motor system independent of v
isual feedback. Both 3 and 10 Hz oscillation frequencies were also shared b
y the right and left fingers if subjects used these together to track a vis
ual target.
3. The linking of the 10 Hz range oscillations between the eyes and finger
was task specific; it never occurred when eye and finger movements were mad
e simultaneously and independently, but only when they moved simultaneously
and followed the target together. However, although specific for tracking
by the eyes and fingers together, the linking behaviour did not appear to b
e a prerequisite for such tracking, since significant coherence in the 10 H
z range was only present in a proportion of trials where these combined mov
ements were made.
4. The experiments show that common oscillations may modulate anatomically
very distinct structures, indicating that single central oscillations may h
ave a widespread distribution in the central nervous system. The task-speci
fic manifestation of the common oscillation in the eye and finger suggests
that such mechanisms may have a functional role in hand-eye co-ordination.