Neurovestibular Illusions and Countermeasures 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Neurovestibular Illusions and Countermeasures
Space Illusions In weightlessness, down" cues from the inner ear otolith organs are absent. Astronauts are thought to rely more heavily on vision Many astronauts perceive a" subjective vertical. When it changes direction it can cause disorientation and motion sickness Inversion illusions Visual reorientation EVA acrophobia -sudden fear Common immediately illusions(VRIs)-surface of falling towards the Earth after reaching orbit below feet seems like floor 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Space Illusions • In weightlessness, “down” cues from the inner ear otolith organs are absent. Astronauts are thought to rely more heavily on vision. • Many astronauts perceive a “subjective vertical”. When it changes direction, it can cause disorientation and motion sickness. Inversion Illusions - Common immediately after reaching orbit Visual Reorientation Illusions (VRIs) - surface below feet seems like floor EVA acrophobia - sudden fear of falling towards the Earth
Neural Encoding of Orientation Studies have shown that animals construct internal neural representations of their spatial environment 257 “ Place cells" have a response component 106 related to the animals location in an environment ad Direction" cells discharge as a function of the animals head direction Copyright isi! The Aha y Pro+d in a horizontal plane independent of the animals place, behavior, or head pitch or roll (up to 90 deg) 16. 423 SBE(Neurovestibular Countermeasures
16.423 SBE (Neurovestibular Countermeasures Neural Encoding of Orientation • Studies have shown that animals construct internal neural representations of their spatial environment. – “Place cells” have a response component related to the animal’s location in an environment. – “Head Direction” cells discharge as a function of the animal’s head direction in a horizontal plane, independent of the animal’s place, behavior, or head pitch or roll (up to 90 deg)
HD cell responses in 0-G Prof. Jeff Taube, dartmouth college 0-G on ceiling Wall 0-G on floor. wall l.8-G Similar VRis occur with Place cell responses(McNaughton et al., 1999) 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) HD cell responses in 0-G 1-G 1.8-G 0-G on ceiling 0-G on floor, wall Floor Wall Ceiling Prof. Jeff Taube, Dartmouth College Similar VRIs occur with Place cell responses (McNaughton et al., 1999)
Neurovestibular risks of Spaceflight Impaired cognitive and/or physical performance Disorientation and inability to egress safely or perform other physical tasks Impaired neuromuscular coordination and/or strength Autonomic dysfunction Permanent impairment of orientation or balance function 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Neurovestibular Risks of Spaceflight • Impaired cognitive and/or physical performance • Disorientation and inability to egress safely or perform other physical tasks • Impaired neuromuscular coordination and/or strength • Autonomic dysfunction • Permanent impairment of orientation or balance function
Countermeasures using VR Experience in mockups, parabolic flight, and neutral buoyancy and vr simulators is anecdotally helpful 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Countermeasures using VR •Experience in mockups, parabolic flight, and neutral buoyancy and VR simulators is anecdotally helpful
Preflight Adaptation Training JSC, early 1990s · Device for Orientation and Motion Environments DOME apparatus · Tilt translation 子 Device (TtD)device 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Preflight Adaptation Training • JSC, early 1990’s • Device for Orientation and Motion Environments (DOME) apparatus • Tilt Translation Device (TTD) device
Visual clues to orientation Three types of visual information contribute to our sense of gravitational orientation Motion of the visual surroundings Roll rotation of a large field textured display induces an illusion of self-rotation(vection)and self-tilt Tilt of the visual frame Tilt can cause displacement of the visual or postural vertical Visual polarity Intrinsic polarity -Objects have a principle axis and perceptual top"and"bottom Extrinsic polarity -Spatial relationships between objects define principle axis and" top"or"bottom 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Visual Clues to Orientation • Three types of visual information contribute to our sense of gravitational orientation: – Motion of the visual surroundings • Roll rotation of a large field textured display induces an illusion of self-rotation (vection) and self-tilt. – Tilt of the visual frame • Tilt can cause displacement of the visual or postural vertical. – Visual polarity • Intrinsic polarity - Objects have a principle axis and perceptual “top” and “bottom”. • Extrinsic polarity - Spatial relationships between objects define principle axis and “top” or “bottom
Visual orientation in 0- ISS Experiments( C Oman, A Berthoz, et al Subjects indicate the subjective floor of the room 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Visual Orientation in 0-G ISS Experiments (C. Oman, A Berthoz, et al.) Subjects indicate the subjective floor of the room
Visual orientation in 0-G ISS Experiments( C Oman, A Berthoz, et al Perceived orientation will affect the perception of the shaded figure and ambiguous figure 16. 423 SBE(Neurovestibular Countermeasures)
16.423 SBE (Neurovestibular Countermeasures) Visual Orientation in 0-G ISS Experiments (C. Oman, A Berthoz, et al.) Perceived orientation will affect the perception of the shaded figure and ambiguous figure