Pitch Tilt Research Articles

PHOTOISOMERISING EFFECTS IN NITROAZO FLEXOELECTRIC DIMERIC NEMATIC SYSTEMS

The photoisomerisation of a flexoelectric chiral nematic bimesogen system dyed with an azo dye has been investigated. The host material has a pitch and field dependent tilt angle that are temperature independent. Upon illumination by ultra violet, the azo dye molecules undergo a shape change from their trans to cis isomer. The effect of the shape change of the dye on the mixture is to decrease the I-N* transition temperatures, to increase the response times and to decrease the transmitted optical intensity. For the same reduced temperatures, the tilt angles, pitch and threshold voltages for the transition from focal conic to homeotropic textures are unchanged. The macroscopic parameters observed suggest that the orientational order parameter of the system is reduced by UV illumination. The cis isomers do not appear to separate from the host material or significantly change the flexoelectric coefficient.

Effects of gymnastics expertise on the perception of body orientation in the pitch dimension

The purpose of this study was to investigate how experts in motor skills requiring a fine postural control perceive their body orientation with few gravity based sensory cues. In Experiment 1, expert gymnasts and controls had to detect their body tilt when pitching at a velocity of 0.05 deg.s(-1), in two conditions of body restriction (strapped and body cast altering the somatosensory cues). Contrary to the experts, the controls exhibited a larger body tilt when totally restrained in the body cast. In Experiment 2, subjects had to estimate their Subjective Postural Vertical (SPV) starting from different angles of pitch tilt. The controls exhibited significant errors of SPV judgement whereas the experts were very precise. These results suggest that 1) somatosensory cues are more informative than otolithic cues for the perception of body orientation, and 2) the efficiency of otolithic and/or interoceptive inputs can be improved through a specific training to compensate for the lack of somatosensory cues.

Vestibulospinal and reticulospinal neuronal activity during locomotion in the intact cat. II. Walking on an inclined plane.

The experiments described in this report were designed to determine the contribution of vestibulospinal neurons (VSNs) in Deiters' nucleus and of reticulospinal neurons (RSNs) in the medullary reticular formation to the modifications of the walking pattern that are associated with locomotion on an inclined plane. Neuronal discharge patterns were recorded from 44 VSNs and 63 RSNs in cats trained to walk on a treadmill whose orientation was varied from +20 degrees (uphill) to -10 degrees (downhill), referred to as pitch tilt, and from 20 degrees roll tilt left to 20 degrees roll tilt right. During uphill locomotion, a majority of VSNs (25/44) and rhythmically active RSNs (24/39) showed an increase in peak discharge frequency, above that observed during locomotion on a level surface. VSNs, unlike some of the RSNs, exhibited no major deviations from the overall pattern of the activity recorded during level walking. The relative increase in discharge frequency of the RSNs (on average, 31.8%) was slightly more than twice that observed in the VSNs (on average, 14.4%), although the average absolute change in discharge frequency was similar (18.2 Hz in VSNs and 21.6 Hz in RSNs). Changes in discharge frequency during roll tilt were generally more modest and were more variable, than those observed during uphill locomotion as were the relative changes in the different limb muscle electromyograms that we recorded. In general, discharge frequency in VSNs was more frequently increased when the treadmill was rolled to the right (ear down contralateral to the recording site) than when it was rolled to the left. Most VSNs that showed significant linear relationships with treadmill orientation in the roll plane increased their activity during right roll and decreased activity during left roll. Discharge activity in phasically modulated RSNs was also modified by roll tilt of the treadmill. Modulation of activity in RSNs that discharged twice in each step cycle was frequently reciprocal in that one burst of activity would increase during left roll and the other during right roll. The overall results indicate that each system contributes to the changes in postural tone that are required to adapt the gait for modification on an inclined surface. The characteristics of the discharge activity of the VSNs suggest a role primarily in the overall control of the level of electromyographic activity, while the characteristics of the RSNs suggest an additional role in determining the relative level of different muscles, particularly when the pattern is asymmetric.

The human vertical optokinetic afternystagmus and the effect of gravity during pitch tilt

Background: Findings concerning human vertical optokinetic afternystagmus (VOKAN) are often not consistent and in some cases even contradictory. Method: VOKAN was studied in nine normal subjects using corneo-retinal potential technique and an infrared video camera detection apparatus (ISCAN). VOKAN responses were measured at three angles of pitch head (and body) tilt: 0° (upright), 90° (supine) and 135° (45° below horizontal). The optokinetic stimulus was stripe movement with a velocity of 60°/s. Results: Upward slow phase velocity (SP-Up) VOKAN was evoked in 6/9 subjects (67%) at 0° tilt and at 90° tilt, and in 4/9 (44%) at 135° tilt. Downward slow phase velocity (SP-Down) VOKAN was elicited in 3/9 subjects (33%) at 0° tilt; in 2/9 subjects (22%) at 90° tilt and in 0/9 subjects (0%) at 135° tilt. Conclusion: The pitch tilt, as a gravity effect, influences significantly on the appearance and the duration of VOKAN.

Three-dimensional analysis of eye movements induced by roll and pitch tilt

The torsional eye movements induced by the right and left ear-down position are known as "ocular counter-rolling" but the mechanism of the horizontal and vertical eye movements has not been clarified. The vertical eye movements induced by backward tilt are known as the "doll reflex", but clear eye movements are induced by forward tilt. The mechanism of horizontal and torsional eye movements are unclear. To detect 3D eye movements in the roll and pitch planes, we performed 3D analysis of eye movements by our video-oculographic method. During roll tilt, counter-torsional eye movements were clearly induced, but no definite, eye movements were observed in the horizontal and vertical components of eye movements. During pitch tilt, downward eye movements were observed following backward tilt, but no clear eye movements were observed following forward tilt. Moreover, no clear horizontal or torsional eye movements were observed during pitch tilt. These results suggest that the response to pitch tilt depends on the saccular input.

Development of hindlimb postural control during the first postnatal week in the rat

The development of the postural control of hindlimbs was investigated during the first postnatal week in the rat. The whole body was tilted in a vertical plane with the nose up. The proportion of animals producing a complete extension of both hindlimbs increased with age until the end of the first postnatal week. Motor responses were evoked by the pitch tilt already at birth with a slight extension of the hips, the knees and the ankles remaining bent in most cases. The extension produced at the ankle level increased gradually during the first postnatal week. This was correlated with a change in the EMG activity recorded from the triceps surae muscles (ankle extensors) during this postural reaction. There was a gradual acquisition of a tonic pattern. Characteristics of EMG responses changed significantly with age demonstrating an important increase in the use of triceps surae muscles in this postural task. These data demonstrate that the first postnatal week is a critical period for the development of postural reactions in the hindlimbs. They also suggest the existence of a proximo-distal gradient in the maturation of postural control. The mechanisms responsible for this reflex and for the maturation of posture are discussed.

A re-evaluation of relationships between fish size, acoustic frequency, and target strength

There are many measurements of dorsal aspect target strength of fish, but relatively few studies compare estimation methods or attempt to combine data from different studies into general relations between fish size, acoustic frequency and target strength (or acoustic cross-section). We edited and updated earlier summary regressions relating fish size, acoustic frequency and acoustic cross-section. Experimental measurements on marine fish were separated into swimbladder and non-swimbladder species, model results compared with experimental data, target strengths of marine, and freshwater fish were contrasted, and previous and new target strengths of commercial New Zealand fish species were placed in the context of the new regressions. Analysis of variance was used to show significant effects of species, freshwater vs. marine, swimbladder vs. non-swimbladder fish, model vs. experimental, and dead vs. alive fish on the relationship between maximum dorsal aspect target strength and fish length. For experimental results on gadoids we found significant species and live vs. dead (or stunned) fish effects on the target strength to length relationship. The quadratic dependence of target strength on fish length was also tested and found to be the exception rather than the rule. Existing pitch tilt angle data was compiled and a normal distribution with standard deviation of at least 15° was required to describe most distributions.

Shift of subjective reference and visual orientation during slow pitch tilt for the seated human subject

We examined the ability to assess subjective orientation and orientation of an external visual object during pitch titl. Subjects were seated, restrained, and in darkness in a simulator and estimated when they were 0°, 45°, and 90° forwards and backwards from upright during pitching at 1°/s. They temporarily stopped in these positions and set a 5 cm luminous cube, cockpit mounted at 60 cm from the nasium, to earth vertical. Estimates of subjective tilt were consistently greater than actual tilt. Overestimations were increased by preceding tilts in the opposite direction, particularly when tilting from forwards, where subjects sometimes estimated they were tilted backwards when the machine was tilted forwards. Subjects were surprised with their estimates, and reported disorientation. Regardless, settings of the visual vertical made “intuitively” were largely accurate. Subjective estimates could be construed as “accurate” if one assumes that the rostro-caudal axis of the head was referenced for estimates of upright and forwards and a trunk-leg axis for backwards. Because labyrinthine defective patients behaved as normal subjects, task performance must have been based on proprioception. The overestimation of tilt is exploited in fairground illusions and may account for the common experience when driving, that hills seem much steeper than they are.

両側前庭機能消失者における頭部立ち直り反射

This study investigated the mechanisms that help to stabilize the head during head tilt in normal subjects and in patients with absent labyrinthine function. Seven normal subjects and four patients were examined. They were seated in a gimbal with limbs and torso restrained and head free to move. The gimbal could be tilted from upright to pitch or roll about earth horizontal axes. Tilt stimuli were delivered under two conditions: i) while performing mental arithmetic with eyes closed. ii) while reading fixed N six test type. During tilt, position and acceleration of the trunk and head and neck EMGs were recorded simultaneously. Initial responses was similar for all subjects; following gimbal tilt, the had tended to lag behind the trunk because of intertial lag.. After that, movement of the head on the trunk varied widely with three broad types. i) Head held relatively fixed to trunk. This tactic was deployed by normal subjects and one patient. ii) Unstable head on trunk. This response was typical of patients with labyrinthine defect. iii) Effective compensatory head movement. Only normal subjects had effective compensatory movement. Regarding head stability in space, all subjects had superior stability during reading than mental arithmetic. All patients had significantly poorer stability than normal subjects during pitch tilt backwards. The stability of the two patients tested in roll tilt was at the upper limit of the normal range. The latency of the initial large burst of EMG varied depended on the mean rate of change in head acceleration (jolt). The pattern of the latency in proportion to jolt did not show a clear difference between normal subjects and patients. These results suggest that the short bursting of the neck muscles during sudden tilts is non-stretch and non-vestibular in origin and other candidates for the origin could exist.

Inertial representation of angular motion in the vestibular system of rhesus monkeys. I. Vestibuloocular reflex

1. The spatial organization of the vestibuloocular reflex (VOR) was studied in six rhesus monkeys by applying fast, short-lasting, passive head and body tilts immediately after constant-velocity rotation (+/- 90 degrees/s) about an earth-vertical axis. Two alternative hypotheses were investigated regarding the reference frame used for coding angular motion. 1) If the vestibular system is organized in head-centered coordinates, postrotatory eye velocity would decay invariably along the direction of applied head angular acceleration. 2) Alternatively, if the vestibular system codes angular motion in inertial, gravity-centered coordinates, postrotatory eye velocity would decay along the direction of gravity. 2. Horizontal VOR was studied with the monkeys upright. Pitch (roll) tilts away from upright elicited a transient vertical (torsional) VOR and shortened the time constant of the horizontal postrotatory slow phase velocity. In addition, an orthogonal torsional (after pitch tilts) or vertical (after roll tilts) response gradually built up. As a result, the eye velocity vector transiently deviated in the roll (pitch) plane and then gradually rotated in the same direction as gravity in the pitch (roll) head plane until the orthogonal component reached a peak value. Subsequently, the residual postrotatory eye velocity decayed along a line parallel to gravity. 3. The time constant of the horizontal postrotatory response was maximal in upright position (21.5 +/- 5.7 s, mean +/- SD) and minimal after tilts to prone (3.8 +/- 0.7 s), supine (4.5 +/- 1.2 s), and ear-down (5.2 +/- 1.6 s) positions. A similar dependence on head orientation relative to gravity characterized the dynamics of the resultant eye velocity vector in the pitch and roll planes. 4. Torsional VOR was studied with the monkeys in supine or prone position. Pitch (yaw) tilts from the supine or prone position toward upright (ear-down) position elicited a transient vertical (horizontal) VOR and shortened the time constant of the torsional postrotatory response while a horizontal (vertical) orthogonal component slowly built up. As a result the eye velocity vector gradually rotated in the pitch (yaw) plane until the orthogonal component reached a peak value. Subsequently residual postrotatory eye velocity decayed along a line parallel to gravity. 5. The time constant of the torsional postrotatory response in supine/prone positions was 16.5 +/- 6.8 s. After tilts from supine/prone positions toward upright position, time constants decreased and were minimal after tilts to upright position (2.7 +/- 0.7 s).(ABSTRACT TRUNCATED AT 400 WORDS)

Recovery of Head Postural Control Following Unilateral Vestibular Neurectomy in the Cat: Neck Muscle Activity and Neuronal Correlates in Deiters' Nuclei

Recovery of head postural control after unilateral vestibular neurectomy was investigated in the alert cat by chronically recording the spontaneous neck muscle EMG activity from splenius capitis on both sides and the vestibulocollic reflexes evoked during roll and pitch tilts. Neuronal correlates occurring within the lateral (Deiters) vestibular nuclei (LVN) were also recorded during the time-course of recovery. During the acute phase (1-2 weeks), the cats exhibited strong imbalance in spontaneous neck muscle activity, characterized by increased muscular tone in the ipsilateral splenius capitis muscle and hypoactivity in the contralateral one. At the same time, the mean resting activity of Deiters' neurons strongly decreased on the deafferented side, while a slight but significant decrease was observed on the intact side. Vestibulocollic reflexes were totally lacking during the acute phase, whatever the direction and the amplitude of tilt. Recovery developed in the following weeks, leading to complete rebalance of spontaneous EMG activity as well as near to normal static vestibulocollic reflexes 5 weeks after the lesion. However, compensation remained sub-normal during roll tilts while overcompensation was found during pitch tilts, suggesting that the intact labyrinth would play a leader role in the recovery process but that bilateral cooperation of the two labyrinths is required for proper head postural control. Five weeks are also needed for a partial rebalancing of resting activity between both LVN. These results indicate that changes in neck muscle activity observed in the acute cats and that recovery found in the compensated animals could result from modifications in neural networks controlling neck musculature, such as the LVN.

Vestibular control of swimming in lamprey. I. Responses of reticulospinal neurons to roll and pitch.

A method has been developed for recording the response of single neurons in the lamprey brainstem in vitro to natural stimulation of vestibular receptors. The brainstem dissected together with the intact vestibular apparatus could be rotated in space, in two perpendicular planes (transverse, the roll tilt, and sagittal, the pitch tilt), in one of them up to 360 degrees, and in the other one up to +/- 30 degrees. The responses of single reticulospinal (RS) neurons, in all four reticular nuclei of the brainstem, to roll and pitch were recorded extracellularly and, with small inclinations (up to +/- 45 degrees) also intracellularly. Two types of preparations were used, with and without the rostral part of the spinal cord. In the brainstem preparations, most RS neurons responded both to a definite brain orientation in space and to a change of the orientation (static and dynamic reactions). Responses to roll tilt were similar in all reticular nuclei: all cells were excited with roll tilt towards the contralateral side, this reaction was qualitatively preserved when the roll was performed in combination with different pitch inclinations. Responses to pitch tilt were less clearcut; some neurons were activated with nose-up deflection while others responded to nose-down tilt. In preparations including the spinal cord, responses of RS neurons to roll and pitch tilt differed from those in the isolated brainstem in that they were much less specific and stable. Roll and pitch tilts could trigger the spinal locomotor CPG, which, by sending "efference copy" signals back to the brainstem, produced modulation of RS neurons in relation to the locomotor rhythm.

Vestibular control of swimming in lamprey. II. Characteristics of spatial sensitivity of reticulospinal neurons.

1. Experiments were carried out on an in vitro preparation of the lamprey brainstem isolated together with intact labyrinths. Responses of reticulospinal neurons from different brainstem reticular nuclei (mesencephalic, MRN; anterior rhombencephalic, ARRN; middle rhombencephalic, MRRN; and posterior rhombencephalic, PRRN) to rotation of the preparation (0 degrees-360 degrees) either in the sagittal plane (pitch tilt, or nose up-down movement) or in the transverse plane (roll tilt, or left-right inclination) were recorded. 2. Responses to roll tilt were qualitatively similar in all nuclei: contralateral side down tilt (in relation to the location of the neuron in the brain) caused an activation of reticulospinal neurons. The angular thresholds for activation differed, however, between nuclei as well as the angle at which the maximal activity occurred. The maximal response for MRN was at 45 degrees, for MRRN and PRRN at 90 degrees, for ARRN at 180 degrees. Thus, the zones of spatial sensitivity differed in different nuclei, and they covered the whole range of possible inclinations in the transverse plane. 3. Responses to pitch tilt were not uniform in the different nuclei. MRN neurons responded preferentially in the range of 45 degrees-90 degrees nose-up inclinations, but a proportion of the cells responded in the range of 45 degrees-90 degrees nose-down inclinations. The ARRN neurons had their maximal response when the brain was turned to a dorsal side-down position (180 degrees). In the MRRN, three subgroups of neurons could be distinguished, the first responding at around 90 degrees nose-down, the second responding at around 90 degrees nose-up and the third responding in both zones. However, the activation in the nose-up zone was less robust: responses in this zone were present only in approximately one half of the experiments. Finally, the PRRN neurons were found to be very heterogeneous, with their zones of sensitivity being distributed throughout the whole space (0 degrees-360 degrees). Thus, also in the sagittal plane, the zones of spatial sensitivity in the different nuclei covered the whole range of possible inclinations. 4. Long-term recording of MRRN neurons having the zone of sensitivity around 90 degrees nose-up showed that this response was rather unstable. Its amplitude varied considerably and could disappear with time to reappear later. These results, together with the fact that in a part of the experiments the MRRN neurons responded only in the 90 degrees nose-down zone (see above), leads us to suggest that the system of spatial orientation can dynamically re-organize.(ABSTRACT TRUNCATED AT 400 WORDS)

Vestibular control of swimming in lamprey. III. Activity of vestibular afferents: convergence of vestibular inputs on reticulospinal neurons.

Experiments were carried out on the in vitro preparation of the lamprey brainstem isolated together with the labyrinths. The brain orientation in space could be changed in steps of 45 degrees by rotation (360 degrees) around the longitudinal axis (roll) or the transverse axis (pitch). Vestibular afferents in the VIII nerve, or reticulospinal (RS) neurons, were recorded extracellularly during roll and pitch. Two main types of afferents could be distinguished. Presumed otolith afferents responded both to a change of position and to a maintained new position. These afferents were classified in several groups according to the position of their zone of sensitivity. For roll, the largest group had their maximal sensitivity around 90 degrees tilt to the ipsilateral side, the next group in size responded at 180 degrees, and only a few afferents were activated by contralateral roll. For pitch, there are groups responding with maximal sensitivity at 90 degrees nose-up, 90 degrees nose-down and at 180 degrees. A minority of afferents were active when the brainstem was in a normal position, i.e. horizontal, with the dorsal side up. Another type of afferent responded only by a high-frequency burst to a change of brain orientation. They were classified as canal afferents in analogy with other species. All tested canal afferents responded to rotation towards ipsi-side down. Pitch tilt revealed two groups that responded to rotation towards either nose-up or nose-down. RS neurons from the anterior and middle rhombencephalic nuclei (ARRN and MRRN) were recorded before and after unilateral transection of the VIII nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Dielectric and Optical Measurements for Some Compounds Exhibiting an Is-Ch-SmC* Phase Transition Sequence

Abstract The Isotropic—Cholesteric—Chiral Smectic C—Crystal phase transition sequence for some terminal alkoxy derivatives of 2,2'-dihydroxybenzalazine has been studied. Dielectric and optical measurements for the compounds with n = 7, 8, 9 and 10 are reported. The low-frequency dielectric anisotropy is determined for the chiral meso-phases and the results are analysed as a function of the terminal chain length. The helical pitch values and tilt angles in the chiral smectic C phases are found to exhibit some peculiar characteristics which are qualitatively different from those of the materials undergoing the more fully studied smectic A—chiral smectic C phase transition.

New Chiral Polar Smectic C Liquid Crystals

Abstract Applicability of ferroelectric liquid crystals to large screens handling high density information has been demonstrated. High speed and bistable effect are the greater advantages of these materials. The chemical problems to be solved were to synthesize broad-band room temperature substances with high polarisation, negative dielectric anisotropy, large pitch and adequate tilt angle. A number of compounds having in their structure the R(-) 2 chloro propyl group have been synthesized. The smectic stability for these series has been examined. Some compounds exhibit the chiral smectic C phase. All of them can be used as chiral dopants in broad-band room temperature mixtures. Some examples of these mixtures will be presented.

Effects of lesion of the interstitial nucleus of Cajal on vestibular nuclear neurons activated by vertical vestibular stimulation.

Experiments were performed in cats anesthetized with nitrous oxide to study the effects of INC lesions on responses of vestibular nuclear neurons during sinusoidal rotations of the head in the vertical (pitch) plane. Responses of neurons in the INC region were recorded during pitch rotations at 0.15 Hz. A great majority of these neurons did not respond to static pitch tilts, and they seemed to respond either to anterior or to posterior semicircular canal inputs with a peak phase lag of 140 deg (re head acceleration). Responses of vestibular nuclei neurons in intact cats were recorded during pitch rotations at the same frequency (0.15 Hz). Neurons that seemed to respond to vertical semicircular canal inputs showed peak phase lags of 90 deg relative to head acceleration, whereas neurons that responded to static pitch tilts showed peak phase shifts near 0 deg. These results indicate that responses of neurons in the INC region lag those of vestibular neurons by about 50 deg, suggesting that the former neurons possess a phase-lagging (i.e. integrated) vestibular signal. Responses of vestibular neurons in cats that had received electrolytic lesions of bilateral INCs 1-2 weeks previously were recorded during pitch rotations at the same frequency (0.15 Hz). Neurons that presumably responded to vertical semicircular canal inputs showed a peak phase lag of 60 deg relative to head acceleration, a significant decrease of the phase lag compared to normal, whereas responses near 0 deg were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of Otolith Afferent Response Parameters Using Small Amplitude Sinusoidal Roll and Pitch Tilts

Previous investigations of the response properties of afferent neurons innervating the otolith organs of the inner ear have used experimental protocols which required the rotation of an animal through a full 3600 about its roll and pitch axes. These are difficult experiments since recordings from individual neurons must be maintained throughout the course of the rotations. This paper describes an alternative method which permits the calculation of otolith neuron response parameters from data collected during small amplitude sinusoidal roll and pitch tilts. The effectiveness of this technique is demonstrated by analyzing a variety of simulated afferent responses to sinusoidal tilts. This method facilitates the practical determination of otolith properties as well as simplifying the procedures prerequisite to the testing of otolith dynamic response characteristics.

Developments in the field of automatic guidance and control of rockets

Introduction T definitions are that navigation determines the vehicle's state for initial conditions as well as during flight; that selects the maneuvering sequence to get from the instantaneous state to a required state; and that executes the maneuvers called for by guidance. These definitions did not exist in the early development years. Navigation corrections were usually taken care of by flight time deviations, which were included in simple guidance functions. Fixed programs, such as flight-tilt programs and roll programs, to rotate the vehicle into its required flight plane have been considered control functions rather than guidance functions and have been exceptions to these definitions. The development of liquid fuel and oxidizer engines made it necessary to stabilize the rockets and to provide attitude control. This included a pitch tilt program, because these rockets with their low initial acceleration had to be launched in a vertical direction. In order to aim at a target the next requirements were to constrain the rocket to a predetermined flight plane and to provide a well-defined velocity vector at propulsion cutoff of the rocket engine. Related but less sophisticated requirements had existed for ship and airplane control. Inertial sensors, such as gimbal suspended gyroscopes and rate gyros, had been used for these systems. In 1912 Prof. Max Schuler had designed a threegyro, three-degree-of-freedom gyro compass for ship navigation, and two-degree-of-freedom gyros were used later as airplane orientation sensors. Schemes and components derived from these systems were applied to the first rocket attitude control systems. A somewhat more difficult task was to obtain guidance sensors, which did not exist yet. For many years inertial sensors were in competition with radio guidance devices, the latter being more promising in the early years to fulfill accuracy requirements. Accelerometers had to be used as inertial sensors for guidance. Velocity and displacement, as the information required, had to be derived; the first with normalized accuracy demands of at least 10~-10~ . The derived signals had to be obtained by the only available method, which was mechanical integration. In contrast to the inertial sensors, the radio sensors measured lateral displacements and forward (radial) velocities directly. Since the guidance systems had to be used for missiles an inertial system was preferable because it is self-contained and not subjected to external interference as radio guidance systems are. The radio guidance system became available and operational first. It yielded an accuracy in range that was about 10% better than the inertial system introduced afterward. Only a few test flights with a pure inertial system took place before the end of World War II. The cross-range impact errors were approximately twice as large as with the radio guidance system. Thus for some time it

Planar relationships of semicircular canals in the cat.

Planar relationships of semicircular canals in the cat.