Visuo-Vestibular Contributions to Vertical Self-motion Perception in - - PowerPoint PPT Presentation

MESROB July 8-10 2015 Nantes, France

Visuo-Vestibular Contributions to Vertical Self-motion Perception in Healthy Adults

• I. Giannopulu, P. Leboucher, G. Rautureau, I. Israël, R. Jouvent

IHU-A-ICM UPMC Prisme Virtual Reality

Global self-motion is defined with respect to the three body axes.

Z

Circular and/or linear

Sagittal backward Sagittal forward Vertical upward Vertical downward Lateral Right Lateral Left roll yaw pitch Vertical Upward & Downward vection onset

Self-motion Perception: Three perceptual steps

perception du mouvement de l'environnement visuel perception du mouvement de soi stimulation visuelle

v i t e s s e t e m p s Vo Va

délai de saturation délai de vection vection onset time vection saturation

t i m e v e l

• c

i t y

perception of visual environment self-motion perception visual stimulation

a) The subject perceives itself as stationary and the visual environment as mobile. b) After same onset time (self-motion onset time) the subject begins to perceive the mobile visual environment as moving slowly and itself as gradually moving in the opposite direction. c) The subject perceives self-motion only and the visual environment looks stationary (self-motion saturation).

from VNC to Basal Ganglia and Cortex

PFN: parafascicular nucleus; PPT: pedunculopontine tegmental nucleus SNc: substantia nigra pars compacta (Stiles and Smith, 2015)

Neural bases of self-motion perception

Deutschlander et al., 2004

Neural bases of self-motion perception

linear and circular self-motion perception

• ccipital, temporal

& parietal areas

Cardin & Smith, 2010

parietal areas

Self-motion Visuo-vestibular interaction/conflit Visual information self-mobility Vestibular information self-stationarity Modification of vestibular input ↓ Modification of visuo-vestibular interaction ↓ Facilitation of self-motion ↓ Reduction of self-motion onset time

Many characteristics of self-motion perception have been found to depend on the intensity of the conflict between visual and vestibular inputs.

• Patients with reduced vestibular sensitivity (Menière’s patients)

have traditionally shorter self-motion onset time than healthy control subjects (e.g Wong & Frost, 1978, 1981; Cheung et al., 1990).

• Vestibular healthy subjects have shorter self-motion perception
• nset time in microgravity than on earth gravity (e.g. Young &

Shelhamer, 1990).

horizontal movement X axis vertical movement Z axis

Upward Downward Self-motion Perception Onset Time 1st Hypothesis

Vertical axis (Z): Intra-axis Comparison

⟩ ⟨

Downward Saccular Sensibility Upward

⟨ ⟩

(p.e Howard, 1986; De Saedeleer et al. 2013; Pfeiffer et al., 2014)

saccular maculae ⟩

Utricular maculae

(e.g. Fernandez et al., 1972; Tomko et al., 1981)

• In healthy subjects, the otolith stimulation appears to modify

the cardiovascular activity measured by the heart rate (p.e. Olufsen et al., 2008)

• The heart rate is lower in patients (Meniere's patients)

suffering from bilateral vestibular disorder than in controls (p.e. Yates et al., 1999)

Z

Vertical upward Vertical downward

2nd Hypothesis Downward Saccular Sensibility Upward

⟨ ⟩

(p.e Howard, 1986; De Saedeleer et al. 2013; Pfeiffer et al., 2014)

Downward Cardio-vascular activity (bpm) Upward

⟨ ⟩

Vertical axis (Z): Relationship between vestibular and cardiovascular systems

Method

HMD

35/40 participants (17 males & 18 females) Mean Age: 26 years old without neurological, visuo-vestibular, cardiac and/or psychiatric disorders

HMD, SONY HMZ- T1 Cardiofrequence MIO key-bouton Electrodermal activity

Results

LRSM/s

2 4 6 8 10 s 2 3 s 3 5 s 6 s 2 4 s 3 9 s 1 5 s 3 7 s 7 s 1 8 s 2 1 s 3 3 s 1 9 s 3 s 2 5 s 2 s 2 7 s 3 s 9

Upward Downward

Onset time of reporting downward and upward self-motion Heart rate for downward and upward self-motion

heart rate (bpm)

55 65 75 85 95 105 Rest Upward Downward

Discussion

Evaluation of visual-vestibular interaction in the perception of angular self-motion (Zacharias & Young, 19981).

The existence of a reference signal visually generated. This signal corresponds to the vestibular dynamic that would be expected if the subject was really in motion within a stationary environment. In this context, the visuo-vestibular conflict corresponds to the difference between the current vestibular dynamic of the stationary subject and the expected vestibular dynamic (Zacharias & Young, 1981, Palmisano et al., 2000; Palmisano et al., 2003).

Z

Vertical upward Vertical downward

No asymmetry on onset time between

• pposite directions within vertical axis

Lepecq et al, (1999); Kano, 1994

HMD, SONY HMZ-T1

Asymmetry on onset time between

• pposite directions within vertical axis

Cardiovascular responses would be “vestibuloform”

1) Motion sickness development, i.e., vestibular

• ver-stimulation linked to self-motion

perception is accompanied by an increase in sympathetic activity (and an decrease in parasympathetic activity) (Grant et al., 1991) 2) Visually mediated illusory tilt associated to self-motion perception induces dissociation in the autonomous nervous system (increased heart rate) (Wood et al., 2007)

Yates, Holmes and JIAN (2000)

The intra-individual variability of the vestibular sensitivity on the vertical axes would explain the intra-individual variability

• f:
• 1. self-motion perception onset time
• 2. cardiovascular activity

Yates, Holmes and JIAN (2000)

Visuo-vestibular interaction could be considered as a minimalistic model for spatial navigation of humanoid robots. Most robots do not use a vestibular system but stabilise upright position by means of center of pressure control (COP). We suggest using a biologically inspired vestibular sensor (canal-otolith system) along with a human-inspired control mechanism. The idea is to simulate a vestibular sensor based on anthropomorphic measures and to implement it into the human-inspired stance control

• f robot.

Thank you for your attention