Normal Upright Position Research Articles

Can three-year old children take spatial perspectives?: an approach with the 'face rotation task'

Spatial perspective taking ability of two-year-six-month to four-year-five-month old children was investigated, using a newly devised task named the 'Face Rotation Task.' In the task one of the two eyes in the face stimulus, which had been rotated 90, 180, or 270 degrees from the upright position, was highlighted and a buzzer sound was simultaneously presented. The subjects were asked to memorize the combination of the highlighted eye and the sound. When the face stimulus was set back to the normal upright position, the buzzer sound was presented and the subjects were asked to look or point at the position of the expected highlighting eye. Children over 3.5 years performed significantly better than chance expectation. The mental strategy employed by the children was also investigated using a modified Face Rotation Task. The result indicated that the mental strategy was perspective taking. The implications of these results were discussed in terms of the appropriate meaning of perspective taking ability.

Ocular counter-rolling after prolonged alteration in the direction of gravity

To investigate the dynamics of otolith and oculomotor function, we subjected volunteers to a lateral body tilt for a period of two hours and analyzed ocular counter-rolling. Six healthy adult volunteers were roll-tilted along the naso-occipital axis at a speed of 0 degree/sec. from the 0 degree earth vertical position to the 90 degrees lateral tilt position. After two hours, the volunteers were returned to the 0 degree earth vertical position. Ocular counter-rolling was recorded using an infrared CCD camera. The video recordings were made in the dark while the volunteers had their eyes open. Recordings were obtained (1) as the volunteers was moved from the 0 degree earth vertical position to the 90 degrees lateral position, (2) 5 minutes after reaching the lateral position, (3) during the roll-back from the 90 degrees lateral position to the 0 degree upright position, two hours after the lateral tilt loading, and (4) 5 minutes after reaching the final upright position. The occurrence of ocular counter-rolling between the 0 degree upright position and the 30 degrees tilt position was confirmed during both roll movements from 0 degree to 90 degrees and from 90 degrees to 0 degree. The counter-rolling was most noticeable between the 0 degree and the 30 degrees positions. No differences in ocular counter-rolling during the roll-tilt and the roll-back situations were observed. These results indicate that the two-hour lateral tilt position did not produce any functional changes in the hair cells and/or the otolith-oculomotor system. All of the subjects exhibited ocular counter-counter-rolling during the initial stage of their roll-back to a normal upright position. This phenomenon might result from the additional bending of the hairs by inertia during the initiation of the backward roll motion.

Plasma membrane NADH oxidase is gravi-responsive

NADH oxidase activities measured with intact tissue sections and with isolated plasma membrane vesicles from etiolated hypocotyls of soybean (Glycine max) respond to gravity and imposed centrifugal forces. The response is one of inhibition of activity with tissue sections lying flat for 20 min or less at 1 × g and one of stimulation with times of lying flat of 30 min or longer at 1 × g. Turning the tissue sections upside down resulted in stimulation of the activity with a lag of about 30 min. Returning the sections to the normal upright position resulted in a return to initial rates with a lag of less than 20 min. Both the stimulated and non-stimulated activities oscillate with a period of 24 min, precluding a more precise analyses of lag times. The activity was stimulated reversibly to a maximum of about 2-fold both in tissue sections and in isolated plasma membrane vesicles when subjected to centrifugal forces of 10 to 400 × g for 0.5 to 4 min duration. The findings are the first description of a gravi-responsive enzymatic activity related to the growth response in plants.

Disentangling gravitational, environmental, and egocentric reference frames in spatial neglect.

Previous studies in neglect patients using rotation of the body around the roll-axis revealed neglect of visual stimuli not only in the egocentric, body-centered left but also in the environmental left. The latter has been taken as evidence for a gravity-based environment-centered component of neglect occurring independently of the subject's actual body orientation. However, by using visual stimuli in a normally lightened room, the studies confounded the gravitational upright with the visible upright of the surround. Thus, it is possible that the visible upright of the environment may have served the role of the gravitational upright relative to which neglect occurred. The present experiment evaluated the influence of gravity on contralateral neglect when no visual information was presented. In complete darkness, neglect patients' exploratory eye movements were recorded in five experimental conditions: body in normal upright position, body titled 30 degrees to the left and 30 degrees to the right, and body pitched 30 degrees backward and 30 degrees forward. In the upright orientation, the patients with neglect showed a bias of ocular exploration to the ipsilesional right side. In egocentric body coordinates, we found no significant differences between the orientation of the biased search field in the different experimental conditions showing that the search field shifted with the orientation of the body. No significant decrease or enhancement of neglect was observed when body orientation was varied in the different conditions. In conclusion, the present results revealed that the modulation of gravitational forces has no significant influence on the exploratory bias of these patients. When visual information was excluded and only graviceptive information was available, the patients' failure to explore the contralesional part of space appeared purely body-centered. The results argue against a disturbed representation of space in neglect that encodes locations in a gravity-based reference system.

Mechanisms of cutaneous vasoconstriction during upright posture.

The cutaneous circulation is thought to participate in the neurocirculatory adjustments during orthostatic stress, but the underlying mechanisms mediating such reflex cutaneous vasoconstriction are poorly understood. The aim of this study was to assess the relative importance of baroreceptor (cardiopulmonary and arterial) and positional (vestibular, exercise, veno-arteriolar and myogenic) reflexes in triggering cutaneous vasoconstriction during upright posture. First, hypotensive lower body negative pressure (LBNP) was compared with actual postural changes to assess the relative contributions of baroreceptor reflexes and positional reflexes. Then changes in body position were compared with changes in limb position in the absence or presence of proximal (axillary) or distal (local cutaneous) nerve blocks, to assess the relative contributions of vestibular, exercise, veno-arteriolar and myogenic reflexes. Skin sympathetic nerve activity was determined by microneurography, and skin blood flow was determined by laser Doppler velocimetry. LBNP of -50 mm Hg cardiopulmonary + arterial baroreceptors) had no effect on skin sympathetic nerve activity or skin vascular resistance. In contrast, an upright posture with the arms dependent (baroreceptor + vestibular + exercise + veno-arteriolar reflexes) caused a two- to threefold increase in skin vascular resistance. In the supine position passive movement of the arm into a dependent position to activate veno-arteriolar reflexes alone evoked an increase in skin vascular resistance which approximated the response to normal upright posture. Blocking central sympathetic nerve impulses by application of an axillary blockade did not influence the cutaneous vasoconstrictor response to an upright posture or changes in limb position. In contrast, application of a distal nerve block by local cutaneous surface anaesthesia completely blocked vasoconstrictor responses evoked by these manoeuvres. In conclusion, these experiments in human subjects identify a primary role for veno-arteriolar reflexes in triggering vasoconstriction in the cutaneous circulation during upright posture.

Anomalous Differentiation in Chara Rhizoids: Effect of Gravity Vector

Chara corallina is a freshwater alga with a complex morphology having rhizoids and shoots. Shoots are comprised of multicellular nodal complexes separated by long internodal cells. Different nodal cell types can give rise to secondary development of either shoots or rhizoids. We describe here the morphology and development of rhizoids developed from nodes placed in a normal upright position and in an inverted position. We observed a change in cell type differentiation of the rhizoid when the parent node is inverted. A rhizoid-to-shoot "conversion" occurred in which some rhizoids later develop shootlike properties. Since this conversion was more likely in the inverted nodes, although it also occurred in some normal nodes, we designate this phenomenon gravimorphogenesis. If orientation was reversed after 7 d, the subsequent development of rhizoids was like the final, not the initial, orientation, implying that the morphogenetic process was reversible before that time. If orientation was reversed after 11 d, nodes that had been normal but were now inverted showed development characteristic of inverted nodes, while nodes that were returned to normal from an inverted orientation continued to develop as though inverted. Thus the initiation of the conversion process could occur at different times, but, once initiated, the process tended not to revert. We also describe the effect of culture conditions on statolith formation. Rhizoids that formed in aqueous culture had fewer statoliths than those cultured on agar, and their gravitropic responses were slower.

The influence of an inverted face on the McGurk effect

The McGurk effect is a situation in which the perception of the speech signal is influenced by watching a talker’s face articulate a conflicting speech utterance. For example, observers typically report the syllable /da/ when the auditory syllable /ba/ is presented in synchrony with a videotape of the talker saying the syllable /ga/. It is well-known that inverted faces are much more difficult to recognize than faces presented in a normal, upright orientation. The current study investigated whether inverting the talker’s face would also influence the McGurk effect. Two groups of subjects were presented with a videotape consisting of conflicting auditory and visual syllables designed to produce the typical McGurk effect. The first group viewed the test tape on a video monitor set in its normal upright position. This group showed a typical, robust McGurk effect. The second group viewed the videotape on the monitor set in an inverted position. This group showed a significantly weaker McGurk effect. Thus inverting the face and the corresponding articulatory movements impacts on the integration of phonetic information from the auditory and visual modalities. [Work supported by NIH.]

Ocular torsion and tilt of subjective visual vertical are sensitive brainstem signs

Deviations of the position of the eye in the roll plane, ocular torsion (OT), and the subjective visual vertical (SVV) were systematically studied in 111 patients with acute vascular brainstem lesions. Of the 111 patients, 104 (94%) showed a direction-specific pathological tilt of the static SVV in our series. Seventy-one (83%) of 86 patients exhibited pathological static OT of one (47%) or both (36%) eyes. OT and SVV tilts are therefore sensitive signs in acute unilateral brainstem disorders. Measurements of SVV and OT may prove to be useful components of the neuro-ophthalmological evaluation. With respect to the directions of pathological tilt, SVV and OT are generally in the same direction. Based on neuroimaging, we conclude that all unilateral brainstem lesions caudal to the upper pons cause ipsiversive OT of one or both eyes, with concurrent ipsiversive tilts of SVV adjustments; all lesions rostral to this pontine level cause contraversive tilts of OT and SVV. Evidence is presented that pathological tilts of OT and SVV are secondary to a dysfunction of the tonic bilateral vestibular inputs that stabilize the eyes and head in normal upright position in the roll plane and dominate our perception of verticality.

Stability of the head in pitch (neck flexion-extension): studies in normal subjects and patients with axial rigidity.

The dynamic stability of the head in pitch during normal upright posture has been studied in normal subjects and patients with neurological disease affecting neck muscle tone by examining angular head acceleration responses to unpredictable linear motion of the trunk in the direction of surge. Within the frequency range of natural head movements the transfer function between head and trunk for both normal subjects and patients approximated a second-order linear differential equation involving inertia and coefficients of viscosity and elasticity. The degree of neck rigidity was determined by the damping ratio (viscosity:elasticity), which averaged .35 for normal subjects and ranged from 0.6 to 0.96 for patients with rigid syndromes. A patient with absent labyrinthine function and a "floppy" head had a damping ratio 0.18. The technique gives a numerical measurement of neck rigidity, which could be of value in characterising severity of disorder and response to therapy.

Reaction Time to Normal and Reflected Letter-Strings in Different Orientations

Reaction times for discriminating between normal and reflected (mirror-image) letter-strings in six different orientations were measured in six men and six women. The letter-strings were the word FROG, the reverse word GORF, and the nonword GFRO. Analysis showed that reaction time increased in relation to the deviation from standard upright orientation of the normal letter-strings in a way similar to what Cooper and Shepard found for single letters. With reflected letter-strings, however, reaction time decreased slightly when the strings departed from a normal upright position, but otherwise changed irregularly in relation to the angle of orientation.

On physiological edema in man's lower extremity.

To examine whether the so-called musculovenous pump counteracts the development of interstitial edema in the lower extremities of man in the upright position, the volume changes in the calf which occurred during twenty minutes of rhythmic muscular exercise were measured in twenty-three subjects by impedance-plethysmography. The results were compared with the volume increase found during quiet relaxed standing for the same length of time. Contrary to the hypothesis, and edema-protective effect of the musculovenous pump could only be shown in about half the number of the subjects. In the others, muscular exercise led to increases in calf volume which were higher than those measured in the normal upright position. These results show that the calf muscle pump does not generally have a edema-protective effect but rather that muscle contractions also activate mechanisms which stimulate the extravasation of fluid. In a second test-series with twenty subjects, changes in calf volume were measured during the course of the day. In nearly all cases, the calf volume was greater in the evening than in the morning. It could be shown that the volume increases in the evening are caused by an increase in extravascular fluid. Compared to the increase in extravascular volume occurring during twenty minutes, in a normal upright position, the accumulation of extravascular fluid during the day is, however, remarkably low. Although it is still unknown how interstitial edema in man's lower extremities is prevented during the day, these findings lead to the hypothesis that the edema-preventing mechanisms, for instance the muscle-lymphpump, do not become maximally effective until a certain volume has accumulated in the interstitial space.

The response of theOctopus angular acceleration receptor system to sinusoidal stimulation

The nine crista/cupula sections (C1–C9) that form the angular acceleration receptor system ofOctopus vulgaris can be divided into two subsystems on the basis of cupula size. Electrophysiological recordings were made from representatives (C1 and C2) of these two sub-systems to determine their functional response characteristics. 1. With the statocyst stationary in the normal upright position, 62% of the afferent units from erista section C2, which has a large cupula, displayed a resting level of activity. None of the afferent units from erista section C1, which has a small cupula, showed resting activity. 2. The dynamic responses of the C1 and C2 units were examined during sinusoidal oscillations of the statocyst in the pitch plane at stimulus frequencies between 0.01 and 1.6 Hz, and with amplitudes between 3° and 35°. Both the C1 and C2 units showed linear increases in their responses with increasing stimulus amplitudes (Fig. 5). The threshold frequency at which a unit first responded was found to be an order of magnitude lower for the C2 units in comparison to the C1 units (Fig. 9). At a stimulus frequency of 1.6 Hz, 40% of the C2 units showed a saturation in their responses. None of the C1 units showed signs of response saturation at this frequency. 3. The gain values of the C1 and C2 units decreased with increasing stimulus frequency; the C1 values were higher than the C2 values (Fig. 7). The phase lag values, with respect to peak angular acceleration, were lower for C2 units compared with C1 units (Fig. 8). The phase lag values of both types of unit increased with increasing stimulus frequency but, in the middle frequency range, showed a plateau level at 100° for the C1 units and between 80° and 90° for the C2 units (Fig. 8). This indicates that in the middle frequency range the units code angular velocity. Both phase and gain values were affected by changes in the orientation of the statocyst with respect to gravity (Fig. 12). 4. All of the units analysed in this report originated from ventrally polarized receptor cells. However, during large amplitude oscillations, responses from dorsally polarized receptor units were also observed (Fig. 13). 5. These results demonstrate that the octopus angular acceleration receptor system is divided into two sub-systems of differing sensitivities and that the dynamic response characteristics of the system show close parallels with those of the vertebrate semicircular canal system.

The auditory subjective vertical as a function of body tilt.

A loudspeaker is moved from a position beside the subject to a position vertically above the subject's head. The subject's head is either in the normal upright position (= 0 degrees) or the head (and body) is tilted 30 degrees or 60 degrees to the left. The subject estimates the sound as vertical (=auditory subjective vertical, ASV) before it reaches the true above-head position. This results in differences between the ASV obtained from clockwise or counterclockwise movement (Fig. 1). The ASV changes with experimental time (Fig. 2). The data are discussed with respect to findings about the visually perceived SV.

Effects of m‐Xylene on Human Equilibrium Measured with a Quantitative Method

Swaying during normal upright posture in 17 young males and the effects of m-xylene exposure on the body sway of six of the 17 has been studied by a quantitative Romberg test, conducted with an equipment consisting of a strain gauge transducer platform and of an electronic unit. The exposures were conducted in a dynamic exposure chamber. The sway of the 17 subjects was larger when their eyes were closed than when they were open (P less than 0.001) indicating the importance of vision in the control of body balance. Exposure to a time-weighted average (TWA) concentration of 100 p.p.m. (4.1 mumol/l) of xylene with 200 p.p.m. (8.2 mumol/l) peaks had no observable effect on the body balance of the six subjects. Exposure to a TWA concentration of 200 p.p.m. of xylene with 400 p.p.m. (16.4 mumol/l) peaks--the corresponding mean concentration of xylene in venous blood being 29.1 +/- 3.2 mumol/l--clearly impaired the body balance of the six subjects. The impairment was most pronounced with the eyes closed (P = 0.016). The results suggest that human equilibrium is rather sensitive to effects of exposure to xylene.

Hemispheric differences in the mode of information processing (author's transl)

To examine hemispheric differences in the mode of information processing, 24 normal right-handed subjects were required to make same or different responses to a set of letters varying in number from two to four which were all identical or contained one letter differing from the rest. When letters were presented in the normal upright position, the left hemisphere showed serial processing wherein reaction times increased as a function of number of letters. The right hemisphere, however, showed no increase of reaction times, i.e. parallel processing. When letters were presented in the inverted upside-down position, the left hemisphere showed partial serial processing, despite letters being analyzed physically. The results suggest that visuopatial analysis doesn't always force parallel processing in the left hemisphere.

Role of prior knowledge on naming and lexical decisions with good and poor stimulus information.

To what extent does prior knowledge of a superordinate category facilitate recognition of an instance of that category? In Experiment 1, observers named good and poor exemplars of categories with and without prior presentation of the category name. The test words were either printed in a normal upright position, or the words were rotated 180°. Prior priming with the category name shortened naming times, but only when the test stimulus was rotated. The prime facilitated recognition to a greater degree for the good exemplars than for the poor exemplars. To ensure that lexical access was not bypassed in the first experiment, the study was replicated in a lexical decision task. Nonwords were identical to the test words except that they were misspelled by one letter. Identical results were found in the lexical decision task. These experiments and other recent studies make apparent the trade-off between the facilitating effects of prior knowledge and stimulus information in word recognition.

Normal postural stability and steadiness

A force platform was utilized to provide a new and sensitive means to measure postural steadiness and stability. Normal standards are presented for the center of pressure of the vertical supportive force during standing and sustained weight-shifting of normal men in three age groups. Two distinguishing characteristics were seen for normal upright posture: (1) a large area of stability over which weight can be safely shifted and maintained, and (2) steadiness such that the center of pressure fluctuates incessantly, traversing large total excursions, while remaining remarkably close to the mean point. The youngest age group showed the greatest steadiness and stability and the oldest group showed the least.

THE BASIS OF THE DIFFERENTIAL PHYTOTOXICITY OF 4‐HYDROXY‐3,5‐DI‐IODOBENZONITRILE*

Summary. Retention of the spray solution was shown to be a major factor in the selectivity of ioxynil. Retention was high on mustard plants with or without surfactant(Tween 20). Very little ioxynil was retained by barley and pea plants when no surfactant was included in the spray hut inclusion of 0.1 or 1.0% Tween 20 increased retention. With 1.0% the retention on pea plants approached that on mustard, and there was then little differential toxicity. With no surfactant in the spray, mustard plants retained twenty‐six times more ioxynil than barley plants. Addition of 01 or 1.0% surfactant increased retention by barley and reduced the differential to eleven times and eight times respectively. By varying the angle of barley leaves to the spray it was shown that the normal upright position results in reduced interception of a vertical spray and reflection of the drops without surfactant. It was concluded that for a given species growth reduction by ioxynil is largely conditioned by the amount retained and that apart from influencing retention, Tween 20 has no major independent action.At equivalent retention levels barley was much less susceptible than mustard or pea. Plants of mustard, pea and barley were treated either on the leaves only or over the whole exposed surface of the plant lo assess the influence of morphology on the response to ioxynil. There was no difference in the response of barley, but treatment by dipping aerial shoots of mustard and pea produced an effect twice that from treatment of the leaves alone at the same level of retention. The increased response of mustard and pea to whole shoot treatment is considered to be due primarily to the exposed stem and bud tissues of these species.Les bases de la toxicilé différentielle du 4‐hydroxy‐3,5‐di‐iodobenzomtrite I. Infiuence de la rétention de la bouillie et de la morphologie de la plante

Social Behavior of a South American Leaf Fish, Polycentrus schomburgkii, with an Account of Recurring Pseudofemale Behavior

This account of social behavior is restricted to hostile, sexual, and parental behavior. The major color patterns can be characterized as banded juvenile, nonbreeding brown adult, territorial black g', spawning pale 9, and parental black g. A glossary is given of the motor patterns characterizing hostile behavior. An abstracted typical sequence of motor patterns is described as are details of orientation and of appeasement behavior. Mature g'' hold territories which may be unusually small in aquaria. The most striking feature of the aggressive behavior is the near absence of damaging attacks. Much of the sexual behavior of the g involves motor patterns seen in hostile behavior. The g responds aggressively to the approach of the 9 . After entering his lair she capsizes and places her vent at the ceiling where the eggs are deposited. The g remains below the 9 in a normal upright position, washing the sperm up to the eggs. Commonly during such a spawning, subordinate g' g in the aquarium approach while the manifesting color patterns typical of the spawning 9 9 . If the dominant g attacks, these pseudo9 9 may skim although in an upright position. Evidently the pseudo9 is attempting to steal a fertilization. The parental g' fans the eggs or larvae, but sporadically. He removes intruders such as snails, but he does not retrieve the progeny. Remarkably the adults, breeding or nonbreeding, were never seen to eat any of their own young; this is doubtless an adaptation necessary to the perpetuation of such an effective piscivore.

RESULTS OF THE VESTIBULAR EXAMINATION IN CASES OF MENIERE'S DISEASE WITH THE STEPPING TEST COMBINED WITH CHANGES IN HEAD POSITION

After the stepping test with eyes covered had been done according to the original method, i. e. with the head in normal upright position, the same procedure of stepping was repeated with the head prone, supine, inclined to the left and inclined to the right respectively.As exemplified by representative cases shown in figures, the majority of cases of Meniere's disease showed marked deviation in stepping in a certain constant direction and this phenomenon was apt to be especially marked when the head was inclined to the side of the impaired ear verified with tinnitus and difficulty of hearing. In cases which had positional vertigo subjectively but no manifest positional nystagmus objectively, the stepping test revealed the fact that the angle of deviation was largest and ataxia was seen during stepping when the head took such a position as could induce positional vertigo.By means of this new test, latent abnormality of the labyrinthine function in cases of Meniere's disease was manifested in higher incidence than the usual tests of vestibulo-spinal reaction.