Tonic vibration reflexes and background force level.
On Earth, the functional stretch reflex is an important component in the maintenance of posture and muscle tone.  In parabolic flight experiments, we evaluated whether the functional stretch reflex, as reflected in the tonic vibration reflex, adjusts appropriately for changes in background gravitoinertial force level.  Virtually immediate alterations of appropriate sign occurred.
Lackner
J R
JR
Ashton Graybiel Spatial Orientation Laboratory, Brandeis University, Waltham, MA 02254-9110.
DiZio
P
P
Fisk
J
J
D005542:Forearm / Q000502:physiology*; D006112:Gravitation; D006801:Humans; D018471:Hypergravity; D009129:Muscle Tonus / Q000502:physiology*; D009132:Muscles / Q000502:physiology; D011187:Posture / Q000502:physiology; D011434:Proprioception / Q000502:physiology; D012026:Reflex, Stretch / Q000502:physiology*; D013026:Space Flight; D014732:Vibration; D014893:Weightlessness