Activity of Ventroposterior Thalamus Neurons During Rotation and Translation in the Horizontal Plane in the Alert Squirrel Monkey

The firing behavior of 107 vestibular-sensitive neurons in the ventroposterior thalamus was studied in two alert squirrel monkeys during whole body rotation and translation in the horizontal plane. Vestibular-sensitive neurons were distributed primarily along the anterior and posterior borders of ventroposterior nuclei; three clusters of these neurons could be distinguished based on their location and inputs. Eighty-four neurons responded to rotation; 66 (78%) of them responded to rotation only and 18 (22%) to both rotation and translation. Forty-one neurons were sensitive to linear translation; 23 (56%) of them responded to translation only. The population rotational response to 0.5-Hz sinusoids with a peak velocity of 40°/s showed a gain of 0.23 ± 0.15 spike·s−1·deg−1·s−1 and phase lagging behind the angular velocity by −9.3 ± 34.1°. Although rotational response amplitude increased with the stimulus velocity across the range 4–100°/s, the rotational sensitivity decreased with and was inversely proportional to the stimulus velocity. The rotational response amplitude and sensitivity increased with the stimulus frequency across the range 0.2–4.0 Hz. The population response to sinusoidal translation at 0.5 Hz and 0.1 g amplitude had a gain of 111.3 ± 53.7 spikes·s−1· g−1 and lagged behind stimulus acceleration by −71.9 ± 42.6°. Translational sensitivity decreased as acceleration increased and this was inversely proportional to the square root of the acceleration. Results of this study imply that changes in the discharge rate of vestibular-sensitive thalamic neurons can be approximated using power functions of the angular and linear velocity of spatial motion.

Download Full-text

How to use body tilt for the simulation of linear self motion

Journal of Vestibular Research ◽

10.3233/ves-2004-14503 ◽

2004 ◽

Vol 14 (5) ◽

pp. 375-385 ◽

Cited By ~ 8

Author(s):

E.L. Groen ◽

W. Bles

Keyword(s):

Visual Motion ◽

Detection Threshold ◽

Stimulus Frequency ◽

Flight Simulation ◽

Body Tilt ◽

Whole Body ◽

Motion Percept ◽

Self Motion ◽

Rate Limit ◽

Pitch Tilt

We examined to what extent body tilt may augment the perception of visually simulated linear self acceleration. Fourteen subjects judged visual motion profiles of fore-aft motion at four different frequencies between 0.04âĂŞ0.33 Hz, and at three different acceleration amplitudes (0.44, 0.88 and 1.76 m / s 2 ). Simultaneously, subjects were tilted backward and forward about their pitch axis. The amplitude of pitch tilt was systematically varied. Using a two-alternative-forced-choice paradigm, psychometric curves were calculated in order to determine: 1) the minimum tilt amplitude required to generate a linear self-motion percept in more than 50% of the cases, and 2) the maximum tilt amplitude at which rotation remains sub-threshold in more than 50% of the cases. The results showed that the simulation of linear self motion became more realistic with the application of whole body tilt, as long as the tilt rate remained under the detection threshold of about 3 deg/s. This value is in close agreement with the empirical rate limit commonly used in flight simulation. The minimum required motion cue was inversely proportional to stimulus frequency, and increased with the amplitude of the visual displacement (rather than acceleration). As a consequence, the range of useful tilt stimuli became more critical with increasing stimulus frequency. We conclude that this psychophysical approach reveals valid parameters for motion driving algorithms used in motion base simulators.

Download Full-text

The perception threshold of the vestibular Coriolis illusion

Journal of Vestibular Research ◽

10.3233/ves-210073 ◽

2021 ◽

pp. 1-8

Author(s):

Mark M.J. Houben ◽

Arjan J.H. Meskers ◽

Eric L. Groen

Keyword(s):

Head Movement ◽

Generalized Linear Model ◽

Peak Velocity ◽

Head Rotation ◽

Velocity Model ◽

Whole Body ◽

Laboratory Studies ◽

Perception Threshold ◽

Spatial Disorientation ◽

S Peak

BACKGROUND: The vestibular Coriolis illusion is a disorienting sensation that results from a transient head rotation about one axis during sustained body rotation about another axis. Although often used in spatial disorientation training for pilots and laboratory studies on motion sickness, little is known about the minimum required rotation rate to produce the illusion. OBJECTIVE: This study determined the perception threshold associated with the Coriolis illusion. METHODS: Nineteen participants performed a standardized pitching head movement during continuous whole-body yaw rotation at rates varying between 5 to 50 deg/s. The participants reported their motion sensation in relation to three hypothesized perception thresholds: 1) any sense of motion, 2) a sense of rotation, and 3) a sense of rotation and its direction (i.e., the factual Coriolis illusion). The corresponding thresholds were estimated from curves fitted by a generalized linear model. RESULTS: On average threshold 1 was significantly lower (8 deg/s) than thresholds 2 and 3. The latter thresholds did not differ from each other and their pooled value was 10 deg/s. CONCLUSIONS: The Coriolis illusion is perceived at yaw rates exceeding 10 deg/s using a pitching head movement with 40 deg amplitude and 55 deg/s peak velocity. Model analysis shows that this corresponds to an internal rotation vector of 6 deg/s. With this vector the Coriolis perception threshold can be predicted for any other head movement.

Download Full-text

Spatial Alignment of Rotational and Static Tilt Responses of Vestibulospinal Neurons in the Cat

Journal of Neurophysiology ◽

10.1152/jn.1999.82.2.855 ◽

1999 ◽

Vol 82 (2) ◽

pp. 855-862 ◽

Cited By ~ 15

Author(s):

S. I. Perlmutter ◽

Y. Iwamoto ◽

J. F. Baker ◽

B. W. Peterson

Keyword(s):

Horizontal Plane ◽

Dimensional Space ◽

Body Position ◽

Three Dimensional ◽

Whole Body ◽

Angular Difference ◽

Spatial Alignment ◽

Minimum Sensitivity ◽

Alert Cats ◽

Vestibulospinal Neurons

The responses of vestibulospinal neurons to 0.5-Hz, whole-body rotations in three-dimensional space and static tilts of whole-body position were studied in decerebrate and alert cats. The neurons’ spatial properties for earth-vertical rotations were characterized by maximum and minimum sensitivity vectors ( R max and R min) in the cat’s horizontal plane. The orientation of a neuron’s R max was not consistently related to the orientation of its maximum sensitivity vector for static tilts ( T max). The angular difference between R max and T max was widely distributed between 0° and 150°, and R max and T max were aligned (i.e., within 45° of each other) for only 44% (14/32) of the neurons. The alignment of R max and T max was not correlated with the neuron’s sensitivity to earth-horizontal rotations, or to the orientation of R max in the horizontal plane. In addition, the extent to which a neuron exhibited spatiotemporal convergent (STC) behavior in response to vertical rotations was independent of the angular difference between R max and T max. This suggests that the high incidence of STC responses in our sample (56%) reflects not only canal-otolith convergence, but also the presence of static and dynamic otolith inputs with misaligned directionality. The responses of vestibulospinal neurons reflect a complex combination of static and dynamic vestibular inputs that may be required by postural reflexes that vary depending on head, trunk, and limb orientation, or on the frequency of stimulation.

Download Full-text

Perception of combined translation and rotation in the horizontal plane in humans

Journal of Neurophysiology ◽

10.1152/jn.00322.2016 ◽

2016 ◽

Vol 116 (3) ◽

pp. 1275-1285 ◽

Cited By ~ 2

Author(s):

Benjamin T. Crane

Keyword(s):

Motion Perception ◽

Horizontal Plane ◽

Peak Velocity ◽

Human Subjects ◽

Human Motion ◽

Subjective Equality ◽

The Right ◽

Biased Perception

Thresholds and biases of human motion perception were determined for yaw rotation and sway (left-right) and surge (fore-aft) translation, independently and in combination. Stimuli were 1 Hz sinusoid in acceleration with a peak velocity of 14°/s or cm/s. Test stimuli were adjusted based on prior responses, whereas the distracting stimulus was constant. Seventeen human subjects between the ages of 20 and 83 completed the experiments and were divided into 2 groups: younger and older than 50. Both sway and surge translation thresholds significantly increased when combined with yaw rotation. Rotation thresholds were not significantly increased by the presence of translation. The presence of a yaw distractor significantly biased perception of sway translation, such that during 14°/s leftward rotation, the point of subjective equality (PSE) occurred with sway of 3.2 ± 0.7 (mean ± SE) cm/s to the right. Likewise, during 14°/s rightward motion, the PSE was with sway of 2.9 ± 0.7 cm/s to the left. A sway distractor did not bias rotation perception. When subjects were asked to report the direction of translation while varying the axis of yaw rotation, the PSE at which translation was equally likely to be perceived in either direction was 29 ± 11 cm anterior to the midline. These results demonstrated that rotation biased translation perception, such that it is minimized when rotating about an axis anterior to the head. Since the combination of translation and rotation during ambulation is consistent with an axis anterior to the head, this may reflect a mechanism by which movements outside the pattern that occurs during ambulation are perceived.

Download Full-text

Swallow-evoked action potentials in vagal preganglionic efferents

Journal of Neurophysiology ◽

10.1152/jn.1984.52.6.1169 ◽

1984 ◽

Vol 52 (6) ◽

pp. 1169-1180 ◽

Cited By ~ 34

Author(s):

J. S. Gidda ◽

R. K. Goyal

Keyword(s):

Action Potentials ◽

Discharge Rate ◽

Stimulus Frequency ◽

Superior Laryngeal Nerve ◽

Bimodal Distribution ◽

Short Latency ◽

The Body ◽

Inhibitory Neurons ◽

Discharge Rates ◽

Long Latency

Swallow<evoked potentials in the preganglionic vagal fibers were studied using the single<fiber recording technique in anesthetized opossums. Swallows were evoked by tactile pharyngeal stimulation or electrical stimulation of the cut central end of the superior laryngeal nerve (SLN). Swallowing activity was recorded by the mylohyoid electromyogram and esophageal motility. Sixty<six fibers were studied in which swallowing evoked action potentials. The latencies (from the onset of mylohyoid activity) of evoked responses in different fibers varied from 100 ms to 5 s. The discharge rate of the evoked response was 3<8 action potentials per burst. Each burst lasted 1.1 +/- 0.02 (SE)s. The latencies of evoked spike bursts showed a bimodal distribution. In 34 fibers the latencies were less than 1 s, and in 32 fibers the latencies ranged between 1 and 5 s; these are the short- and long-latency fibers, respectively. Short-latency fibers could easily be distinguished from long-latency fibers based on the influence of SLN-stimulus frequency. Short-latency discharges had low thresholds of activation and were sensitive to changes in the frequency of SLN stimulation, since their latencies decreased and their discharge rate increased with increasing SLN-stimulus frequency. On the other hand, the latencies and discharge rates of long-latency discharges were not modified with changing SLN stimulus frequencies. The conduction velocities of 6 short- and 9 long-latency fibers were 5.64 +/- 0.12 and 5.78 +/- 0.12 (SE) m/s, respectively (P greater than 0.05). The relationship between the latencies of swallow-evoked discharges in the short- and long-latency fibers and the esophageal smooth muscle responses suggested that the short-latency discharges may correlate with the latency of initial inhibition, and the long-latency fibers may correlate with latencies of peristaltic contractions. Based on these temporal relationships, we speculate that vagal efferent fibers showing swallow-evoked, short-latency discharges make contact with intramural inhibitory neurons. They may mediate deglutitive inhibition in the body of the esophagus, relaxation of the lower esophageal sphincter, and receptive relaxation of the fundus of the stomach. The fibers showing late discharges make contact with intramural excitatory neurons and participate in their sequential activation. This dual pathway of activation may be responsible for physiological esophageal peristalsis.

Download Full-text

The spatial attributes of stimulus frequency and their role in monaural localization of sound in the horizontal plane

Perception & Psychophysics ◽

10.3758/bf03204889 ◽

1980 ◽

Vol 28 (5) ◽

pp. 449-457 ◽

Cited By ~ 30

Author(s):

Robert A. Butler ◽

Rosemary Flannery

Keyword(s):

Horizontal Plane ◽

Stimulus Frequency ◽

Spatial Attributes

Download Full-text

Gravity dependence of the effect of optokinetic stimulation on the subjective visual vertical

Journal of Neurophysiology ◽

10.1152/jn.00303.2016 ◽

2017 ◽

Vol 117 (5) ◽

pp. 1948-1958 ◽

Cited By ~ 11

Author(s):

Bryan K. Ward ◽

Christopher J. Bockisch ◽

Nicoletta Caramia ◽

Giovanni Bertolini ◽

Alexander Andrea Tarnutzer

Keyword(s):

Bayesian Theory ◽

Roll Angle ◽

Whole Body ◽

Optokinetic Stimulation ◽

Subjective Visual Vertical ◽

Vestibular Input ◽

Stimulus Velocity ◽

Visual Vertical ◽

Observer Model ◽

Roll Tilt

Accurate and precise estimates of direction of gravity are essential for spatial orientation. According to Bayesian theory, multisensory vestibular, visual, and proprioceptive input is centrally integrated in a weighted fashion based on the reliability of the component sensory signals. For otolithic input, a decreasing signal-to-noise ratio was demonstrated with increasing roll angle. We hypothesized that the weights of vestibular (otolithic) and extravestibular (visual/proprioceptive) sensors are roll-angle dependent and predicted an increased weight of extravestibular cues with increasing roll angle, potentially following the Bayesian hypothesis. To probe this concept, the subjective visual vertical (SVV) was assessed in different roll positions (≤ ± 120°, steps = 30°, n = 10) with/without presenting an optokinetic stimulus (velocity = ± 60°/s). The optokinetic stimulus biased the SVV toward the direction of stimulus rotation for roll angles ≥ ± 30° ( P < 0.005). Offsets grew from 3.9 ± 1.8° (upright) to 22.1 ± 11.8° (±120° roll tilt, P < 0.001). Trial-to-trial variability increased with roll angle, demonstrating a nonsignificant increase when providing optokinetic stimulation. Variability and optokinetic bias were correlated ( R2 = 0.71, slope = 0.71, 95% confidence interval = 0.57–0.86). An optimal-observer model combining an optokinetic bias with vestibular input reproduced measured errors closely. These findings support the hypothesis of a weighted multisensory integration when estimating direction of gravity with optokinetic stimulation. Visual input was weighted more when vestibular input became less reliable, i.e., at larger roll-tilt angles. However, according to Bayesian theory, the variability of combined cues is always lower than the variability of each source cue. If the observed increase in variability, although nonsignificant, is true, either it must depend on an additional source of variability, added after SVV computation, or it would conflict with the Bayesian hypothesis. NEW & NOTEWORTHY Applying a rotating optokinetic stimulus while recording the subjective visual vertical in different whole body roll angles, we noted the optokinetic-induced bias to correlate with the roll angle. These findings allow the hypothesis that the established optimal weighting of single-sensory cues depending on their reliability to estimate direction of gravity could be extended to a bias caused by visual self-motion stimuli.

Download Full-text

Quantitative Analyses of Dynamic Strain Sensitivity in Human Skin Mechanoreceptors

Journal of Neurophysiology ◽

10.1152/jn.00628.2004 ◽

2004 ◽

Vol 92 (6) ◽

pp. 3233-3243 ◽

Cited By ~ 74

Author(s):

Benoni B. Edin

Keyword(s):

Discharge Rate ◽

Receptive Fields ◽

Dynamic Strain ◽

Strain Sensitivity ◽

Power Functions ◽

Discharge Rates ◽

Response Onset ◽

Quantitative Analyses ◽

The Mean ◽

Skin Mechanoreceptors

Microneurographical recordings from 24 slowly adapting (SA) and 16 fast adapting (FA) cutaneous mechanoreceptor afferents were obtained in the human radial nerve. Most of the afferents innervated the hairy skin on the back of the hand. The afferents' receptive fields were subjected to controlled strains in a ramp-and-hold fashion with strain velocities from 1 to 64% · s−1, i.e., strain velocities within most of the physiological range. For all unit types, the mean variation in response onset approached 1 ms for strain velocities >8% · s−1. Except at the highest strain velocities, the first spike in a typical SAIII unit was evoked at strains <0.5% and a typical SAII unit began to discharge at <1% skin strain. Skin strain velocity had a profound effect on the discharge rates of all classes of afferents. The “typical” peak discharge rate at the highest strain velocity studied was 50–95 imp/s−1 depending on unit type. Excellent fits were obtained for both SA and FA units when their responses to ramp stretches were modeled by simple power functions ( r2 > 0.9 for 95% of the units). SAIII units grouped with SAII with respect to onset latency and onset variation but with SAI units with respect to dynamic strain sensitivity. Because both SA and FA skin afferents respond strongly, quickly, and accurately to skin strain changes, they all seem to be able to provide useful information about movement-related skin strain changes and therefore contribute to proprioception and kinesthesia.

Download Full-text