Nonvisual Control Research Articles

Comparison of gnostic and balancing capabilities in different sport disciplines

Background: The quality of proprioception, which we classify as Gnostic functions, affects a person's physical performance. Sports performance requires a good perception of one's own body, a sufficient ability to control one's body and keep it as stable as possible in space. The purpose: The purpose of the research was to compare the state of Gnostic and balance abilities between different sports disciplines, in comparison with the control group. Methods: 80 probands of both genders, aged 18-30 years, were divided into 7 groups of 10, according to sports discipline. The last control group consisted of 10 probands who did not perform any sport. Active athletes were selected for the research, involved in the highest competition of their discipline from various sports: sprint, athletic walking, throws, long jumps, judo, basketball and ice hockey. For the diagnosis of gnostic functions, tests were chosen to examine the modalities of kinesthesia, somatognosis and stereognosis. To test the equilibrium functions, 6 tests using BOSU with both, visual and non-visual control were used. Results: Results at the level of statistical significance at the level of p = 0.05 were demonstrated between the groups of jumpers and basketball players in the kinesthesia test and in the somatognosis test between all athletes and the control group. The stereognosis test showed significant differences between all groups except the sprinter and basketball players. In the equilibrium tests, a statistically significant difference was shown only in the test of standing on both lower limbs without visual control, between the groups of sprinters and the control group, sprinters and basketball players and between the control group and all athletes together. Conclusions: Based on the results, we can say that there are significant differences in some proprioceptive and equilibrium modalities in different sports. We assume that the type of sport can have an impact on the quality of these functionsDOI: https://doi.org/10.24040/sjss.2020.6.2.4-14

Dose-dependent effect of donepezil administration on long-term enhancement of visually evoked potentials and cholinergic receptor overexpression in rat visual cortex

Stimulation of the cholinergic system tightly coupled with periods of visual stimulation boosts the processing of specific visual stimuli via muscarinic and nicotinic receptors in terms of intensity, priority and long-term effect. However, it is not known whether more diffuse pharmacological stimulation with donepezil, a cholinesterase inhibitor, is an efficient tool for enhancing visual processing and perception. The goal of the present study was to potentiate cholinergic transmission with donepezil treatment (0.5 and 1mg/kg) during a 2-week visual training to examine the effect on visually evoked potentials and to profile the expression of cholinergic receptor subtypes. The visual training was performed daily, 10min a day, for 2weeks. One week after the last training session, visual evoked potentials were recorded, or the mRNA expression level of muscarinic (M1-5) and nicotinic (α/β) receptors subunits was determined by quantitative RT-PCR. The visual stimulation coupled with any of the two doses of donepezil produced significant amplitude enhancement of cortical evoked potentials compared to pre-training values. The enhancement induced by the 1mg/kg dose of donepezil was spread to neighboring spatial frequencies, suggesting a better sensitivity near the visual detection threshold. The M3, M4, M5 and α7 receptors mRNA were upregulated in the visual cortex for the higher dose of donepezil but not the lower one, and the receptors expression was stable in the somatosensory (non-visual control) cortex. Therefore, higher levels of acetylcholine within the cortex sustain the increased intensity of the cortical response and trigger the upregulation of cholinergic receptors.

On the Open-Loop and Feedback Processes That Underlie the Formation of Trajectories During Visual and Nonvisual Locomotion in Humans

We investigated the nature of the control mechanisms at work during goal-oriented locomotion. In particular, we tested the effects of vision, locomotor speed, and the presence of via points on the geometric and kinematic properties of locomotor trajectories. We first observed that the average trajectories recorded in visual and nonvisual locomotion were highly comparable, suggesting the existence of vision-independent processes underlying the formation of locomotor trajectories. Then by analyzing and comparing the variability around the average trajectories across different experimental conditions, we were able to demonstrate the existence of on-line feedback control in both visual and nonvisual locomotion and to clarify the relations between visual and nonvisual control strategies. Based on these insights, we designed a model in which maximum-smoothness and optimal feedback control principles account, respectively, for the open-loop and feedback processes. Taken together, the experimental and modeling findings provide a novel understanding of the nature of the motor, sensory, and "navigational" processes underlying goal-oriented locomotion.

Velocity-dependent changes of rotational axes in the non-visual control of unconstrained 3D arm motions

We examined the roles of inertial (e3), shoulder-centre of mass (SH-CM) and shoulder-elbow articular (SH-EL) rotation axes in the non-visual control of unconstrained 3D arm rotations. Subjects rotated the arm in elbow configurations that yielded either a constant or variable separation between these axes. We hypothesized that increasing the motion frequency and the task complexity would result in the limbs' rotational axis to correspond to e3 in order to minimize rotational resistances. Results showed two velocity-dependent profiles wherein the rotation axis coincided with the SH-EL axis for S and I velocities and then in the F velocity shifted to either a SH-CM/e3 trade-off axis for one profile, or to no preferential axis for the other. A third profile was velocity-independent, with the SH-CM/e3 trade-off axis being adopted. Our results are the first to provide evidence that the rotational axis of a multi-articulated limb may change from a geometrical axis of rotation to a mass or inertia based axis as motion frequency increases. These findings are discussed within the framework of the minimum inertia tensor model (MIT), which shows that rotations about e3 reduce the amount of joint muscle torque that must be produced by employing the interaction torque to assist movement.

Axes of rotation in the non-visual control of unconstrained 3D multijoint movements

The objective of this work was to increase our understanding of the mechanical parameters organising the non-visual control of unconstrained 3D arm motion and the adaptation mechanisms carried out ...

Postural Stability after Vestibular Schwannoma Surgery

Factors related to postural stability and the course of recovery after vestibular schwannoma surgery were analyzed in a retrospective study of 177 patients and in a prospective study of 44 patients. Before surgery, 7 of the 44 patients in the prospective group complained of postural instability. The body sway velocity was measured. In the retrospective study, the sway velocity was abnormal under nonvisual control in 63% of the patients and under visual control in 34%. The sway velocity correlated with tumor size, smooth pursuit deficit, and postoperative work history. We compared patients with abnormal postural control to those with normal postural control, and found that the former relied to a greater extent on visual information and the latter on proprioceptive information. In the prospective study, the sway velocity increased after the operation, and 1 year after surgery it had not returned to preoperative values. In the logistic regression analysis, a translabyrinthine approach, rehabilitation, the patient's age, and preserved function of the facial nerve predicted a good outcome of postural stability. The retrosigmoid approach and depression were the most significant risk factors for postoperative gait difficulties. Vestibular rehabilitation increased the reliance on proprioception for maintenance of postural control and improved postural stability.

Circadian Modulation of c-Fos Expression Occurs only in the SCN and not in Other Visual Projection Areas in the Rat

Brief photic stimuli at different circadian times induce differential expression of c-Fos in the suprachiasmatic nuclei (SCN). Whether circadian modulation of light-induced c-Fos expression occurs in other visual projection areas is not known. We addressed this question by estimating the immunohistochemical expression of c-Fos induced by 60 min light pulses at three different circadian times. The areas studied were the SCN, the ventral lateral geniculate nucleus, the intergeniculate leaflet, the ventral tegmental area, the superior colliculus and a non-visual control, the paraventricular thalamic nucleus (PVT). Light pulses induced an increase in the number of c-Fos immunoreactive cells in the SCN as a function of the circadian time. Remaining visual structures showed a light-induced increase in c-Fos expression but this was not dependent on the circadian time. The non-visual control area (PVT) did not respond to light pulses. Since no circadian modulation was found in the intergeniculate leaflet, which rec eives collateral projections from the same retinal ganglion cells that project to the SCN, nor in other primary visual projection areas, the present findings suggest that the circadian modulation of light-induced c-Fos expression in the SCN depends mainly on the functional properties of its intrinsic neurons.

Emmetropization and optical development of the eye of the barn owl (Tyto alba)

1. We have studied the development of the refractive state in young barn owls (Tyto alba pratincola). Strikingly, the eyes had severe refractive errors shortly after lid opening (which occurred around day 14 after hatching; average from 6 owls: 13.83 ± 1.47 days). Refractive errors vanished in the subsequent one or two weeks (Fig. 1, Fig. 2). 2. Refractive errors did not differ by more than 1 diopter (D) in both eyes of an individual (Fig. 2). Thus, non-visual control of eye growth was sufficient to produce non-random refractions. However, visual input was finally required to adjust the optical system to emmetropia. 3. Using in-vivo A-scan ultrasonography of ocular dimensions (Fig. 4A), photokeratometric measurements of corneal radius of curvature (Fig. 4B), and frozen sections of excised eyes (Fig. 3), we developed paraxial schematic eye models which described age-dependent changes in ocular parameters and were applicable through the ages from lid opening to fledging (Table 1). A schematic eye for the adult barn owl (European subspecies: Tyto alba alba) is also provided. Eye sizes in an adult owl of the American (Tyto alba pratincola) and the European subspecies (T. alba alba) were similar despite of different body weights (500 g and 350 g, respectively). 4. The schematic eyes were used to test which ocular parameters might have caused the recovery from refractive errors. However, none of the ocular dimensions measured underwent obvious changes in their growth curves as visual input became available. Apparently, coordinated growth of several ocular components produced emmetropia. 5. From the schematic eye model, the developmental changes in image brightness and image magnification were calculated (Fig. 5). In barn owl eyes, image size was not quite as extreme as in the tawny owl or the great horned owl. However, the image was larger and the f/number was lower than in diurnal birds of comparable weight (pigeon, chicken). The observation supports a conclusion that image size is maximised in owls to permit a higher degree of photoreceptor convergence for higher light sensitivity at dusk while spatial acuity remains comparable to diurnal birds with smaller eyes.

What is needed for a theory of mobility: Direct perceptions and cognitive maps—lessons from the blind.

A theory of mobility using nonvisual stimuli and cognitive control process is proposed to augment Gibson's (1958, 1979) explanations of visual guidance. Nonvisual processes are clearly important to the totally blind, who often manage considerable independent mobility in the absence of vision, but are also important to the sighted. Mobility can be directed by visual control stimuli in the ambient optic array, by nonvisual control stimuli, as well as by processes of spatial learning, including stimulus-response (S-R) rote learning, motor plans, schemas, and cognitive maps. The selection of processes and strategies depends on the availability of particular information or on task demands. Attentional processes select stimuli for locomotor control within any particular modality and select between perceptual and cognitive processes. The skill of traveling through the spatial environment, avoiding obstacles, and traveling directly or indirectly toward goals, is a general characteristic of animal behavior and is described here by the term mobility. Although this term has a special connotation within blindness rehabilitation (Welsh & Blasch. 1980), it is used here to describe the overall processes of guidance by which both blind and sighted travelers move through space. The study of mobility encompasses several more traditional research concerns, such as space perception, motor control, and spatial cognition. Until recently there has been little research related to general psychological theory of mobility. A comparison may be made with the study of reading, where considerable research has taken place on component tasks such as letter extraction, word recognition, and eye movements, but where there has been comparatively little interest until recently in the general rules of the process (see Haber, 1978).

Imitation of a passive avoidance response in the rat

Rats learned a candle-flame avoidance task following observation of a demonstrator rat (1) learning to avoid the flame, with flame contacts by the demonstrator visible to the observer (experimental group), (2) learning to avoid the flame, with flame contacts by the demonstrator concealed (nonvisual control group), or (3) unable to make contact with the flame (noncontact control group). Experimental observers learned faster than nonvisual and noncontact controls, and the control groups learned faster than the two avoidance-trained demonstrator groups. The results suggest that facilitated learning by the experimental group was due to true imitation, and not to an increase in fear or general arousal produced by nonspecific demonstrator-provided auditory, olfactory, or visual “alarm signals.”

Competition within the left hemisphere between speaking and unimanual tasks performed without visual guidance

It is known that speaking interferes selectively with right hand performance of some unimanual motor tasks. Using tasks from Lomas and Kimura (1976), the effect of varying visual feedback (present or absent) on this lateralized interference phenomenon was investigated. The results demonstrated that speaking competed selectively with right hand performance only when the tasks were apparently directed by a system for the non-visual control of limb movement. This was taken to suggest (a) cognitive-manual interference effects cannot be attributed simply to processing within the same hemisphere, they must occur in functionally overlapping systems within that hemisphere, and (b) the left hemisphere contains a system specialized for the control of movement transitions made with minimal visual guidance, and that this system is significantly involved in the control of speech.

Voluntary, Non-Visual Control of The Human Vestibulo-Ocular Reflex

Voluntary control of the human vestibulo-ocular reflex with and without visual targets was investigated. Subjects were rotated sinusoidally from 0.1 to 1.0 Hz using d.c. electro-oculography to record eye position. The ratio of eye to head movement, or gain, of the vestibulo-ocular reflex was measured. When subjects were rotated in the dark at 0.3 Hz whilst performing mental arithmetic the gain was 0.65. When subjects were asked to fixate imaginary targets in the dark that were stationary in space, the gain rose to 0.95. When they imagined targets rotating with them on the chair, the gain dropped to 0.35. Our results indicate that the ability to modulate the gain of the vestibulo-ocular reflex does not depend entirely on the smooth pursuit system. Higher centers must modulate eye velocity so that it is appropriate to the subject's choice of a frame of reference, whether or not vision is available.

Dimensional analysis of motion: IX. Comparison of visual and nonvisual control of component movements.

Dimensional analysis of motion: IX. Comparison of visual and nonvisual control of component movements.