Visual Sensory Information Research Articles

Sensory modulation and behavioral choice during feeding in the Australian frog, Cyclorana novaehollandiae.

This study investigates how visual and tactile sensory information, as well as biomechanical effects due to differences in physical characteristics of the prey, influence feeding behavior in the frog Cyclorana novaehollandiae. Video motion analysis was used to quantify movement patterns produced when feeding on five prey types (termites, waxworms, crickets, mice and earthworms). Twelve kinematic variables differed significantly among prey types, and twelve variables were correlated with prey characteristics (including mass, length, height and velocity of movement). Results indicate that C. novaehollandiae uses a different strategy to capture each prey type. Visual assessment of prey characteristics appeared to be more important in modulating feeding behavior that tactile cues or biomechanical effects. We propose a hierarchical hypothesis of behavioral choice, in which decisions are based primarily on visual analysis of prey characteristics. In this model, the frogs first choose between jaw prehension and tongue prehension based on prey size. If they have chosen jaw prehension, they next choose between upward or downward head rotation based on length and height of the prey. If they have chosen tongue prehension, they next choose between behavior for fast and slow prey. Final decisions may be the result of behavioral fine tuning based on tactile feedback.

Optomotor Behaviour in Xenopus Laevis Tadpoles as a Measure of the Effect of Gravity on Visual and Vestibular Neural Integration

The ability of aquatic vertebrates to maintain their position requires integration of visual and vestibular sensory information. To understand better how aquatic animals integrate such information, we measured the optomotor behaviour of Xenopus laevis tadpoles raised in growth chambers in microgravity (< 10(-3)g), normal gravity (1 g), hypergravity (3 g) and on a slowly rotating clinostat (simulated microgravity). The goal of this research was to determine how development in an altered gravitational force field affects the visual- and vestibular-dependent behaviour of tadpoles. This research represents the first time that the optomotor behaviour of an organism raised from fertilization in microgravity has been tested. Significant differences were observed in the optomotor behaviour among the four gravity treatments. When first exposed to normal gravity, the microgravity-raised tadpoles exhibited the strongest (or most positive) optomotor behaviour, while the 3 g centrifuge tadpoles showed no optomotor response. Some abnormal behaviours (such as erratic swimming, lying motionless and abnormal swimming posture) were observed in the tadpoles raised in altered gravity on the initial day of testing. One day later, the tadpoles raised in hypergravity did not differ significantly in their optomotor behaviour from control tadpoles raised in normal gravity. However, tadpoles raised in microgravity still displayed an exaggerated optomotor response. One week after the tadpoles had been introduced to normal gravity, there was no longer a significant difference in optomotor behaviour among the different gravity treatments. This convergence of optomotor behaviour by tadpoles from the different treatment reflects the acclimation of their vestibular systems to normal gravity.

Dynamics of behavior: Theory and applications for autonomous robot architectures

Abstract Limitations both for the further development as well as for the actual technical application of autonomous robots arise from the lack of a unifying theoretical language. We propose three concepts for such a language: (1) Behaviors are represented by variables, specific constant values of which correspond to task demands; (2) Behaviors are generated as attractors of dynamical systems; (3) Neural field dynamics lift these dynamic principles to the representation of information. We show how these concepts can be used to design autonomous robots. Because behaviors are generated from attractor states of dynamical systems, design of a robot architecture addresses control-theoretic stability. Moreover, flexibility of the robot arises from bifurcations in the behavioral dynamics. Therefore techniques from the qualitative theory of dynamical systems can be used to design and tune autonomous robot architectures. We demonstrate these ideas in two implementations. In one case, visual sensory information is integrated to achieve target acquisition and obstacle avoidance in an autonomous vehicle minimizing the known problem of spurious states. In a second implementation of the same behavior, a neural dynamic field endows the system with a form of obstacle memory. A critical discussion of the approach highlights strengths and weaknesses and compares to other efforts in this direction.

Dynamic Platform Sway Measurement in Menière'S Disease

Fourteen patients in the latent phase of Menière's disease and 14 control subjects were tested on a moving platform apparatus as part of a protocol of investigations for Menière's disease. Subjects were tested under 3 different visual conditions (eyes open, eyes closed, sway feedback) and 2 proprioceptive conditions (fixed platform and ankle stabilization). There was a significant interaction between subject group and visual condition, Menière's patients had a larger RMS sway amplitude than controls with their eyes open and closed, but this difference was abolished by sway feedback. Loss of either visual or proprioceptive sensory information increased sway amplitude, indicating that both cues influence postural control, and in different ways, but patients were able to use these cues to maintain upright posture almost as effectively as controls. More patients than controls lost balance with ankles stabilized and eyes closed, but the difference was not statistically significant (P = 0.0516). There was no detectable relationship between clinical ratings of disease severity and sway scores. The dynamic platform tests described in this report are more suitable for tests involving comparisons between groups of subjects rather than for diagnostic testing of individuals.

Convergence of somatic and visual afferent impulses in the Wulst of pigeon.

In 79 pigeons, unit discharges of Wulst neurons responding to bilateral stimulation of N. radialis and N. sciaticus and to bilateral light flashes were recorded. Of 178 such neurons, 55 showed multisensory convergence of various types: 40 of these were somatic convergent neurons, characterized as 3 types; three were binocular convergent cells; and twelve were bimodal (visual-somatosensory) convergent neurons. Of these neurons, the convergent action was either inhibitory or excitatory. These results suggest that the Wulst may function as an important centre for integrating visual and somatic sensory information.

Walking while using a sensory tactile feedback system: potential use with a functional electrical stimulation orthosis

A major limitation in the utilization of a functional electrical stimulation (FES) orthosis for routine, daily standing and walking of the spinal-cord-injured person is that visual monitoring is required to maintain balance and the walking pace. For standing and walking to be continuous and automatic with such an orthosis, a closed-loop sensory feedback system is proposed and evaluated; it provides vibrotactile feedback as a substitute to one's own visual sensation. Eight blindfolded experimental subjects were utilized as ‘imitators’ to interpret the footfalls of a second person (the pace setter). The experimental objective was to test the hypothesis that sufficient information could be transferred by way of the sensory (tactile) feedback system to the ‘imitator’ and to determine effectively foot position and anticipate the next step of the pacesetter. Quantitative analysis evaluated the effect of three different levels of training, under two different levels of cognitive load. The results disclosed a significant improvement in subject performance at the higher training levels compared with the ‘no training’ level ( P = 0.01). Neither the cognitive load nor the interaction of training and cognitive load altered significantly the effect of training on subject performance. The experimental hypothesis is therefore satisfied that sufficient information was indeed transferred using the apparatus described. Such information (when utilized in conjunction with a thorough training programme) could be used in a practical sense by a paraplegic individual to interpret his own foot steps. Through continued use and training, it is likely that this information could become subconscious and automatic. Therefore, the spinal-cord-injured person would walk with an FES orthosis in various environments and minimize or remove their reliance on visual sensory information.

Structure of receptive fields of hyppocampal visually-sensitive neurons in the cat

We studied the structure of receptive fields (RF) in the visually sensitive CA1 and CA3 fields of the dorsal hippocampus in alert cats subjected to pretrigeminal section of the brain stem. Scanning with moving stimuli and mapping the whole RF area with point by point application of a stationary stimulus, we studied 76 RF neurons. We found no significant differences in the response characteristics of neurons of fields CA1 and CA3. Our data are a basis for classifying the neurons in the following groups: homogeneous RF structure of the RF (54%) and nonhomogeneous structure (28%) and weak reaction to the standard stimulus, but a strong reaction to movement (18%). The results showed that responses of some of the hippocampal neurons exhibit high specificity. Thus, 9% of the neurons with nonhomogeneous RF structure disclosed with static stimuli reacted variously to a change in contrast and contours of moving stimuli. The data presented indicate that visually sensitive neurons of the hippocamus have a relatively well-developed mechanism for processing visual sensory information and this obviously ensures participation of the limbic system in visually controlled behavior of the animal.

An Auxiliary Instrument for Automobiles Using Tactile Sense

Human beings depend mostly on visual sensory information to recognize their environment. There are many devices which provide vibration to the skin but a few use vibration for practical application. In this study, the vibration pattern is produced by a 16x6 array of small vibrator (PZT) reeds (50 Hz) and the entire array fits on the thumb. This apparatus can be used by the driver who can recognize the correct order of the characters from the motion of the vibrator points.

Advances in the design of autonomous dextrous hands

Intelligent robots, with multifingered end-effectors and control relying on real-time processing of huge amounts of visual and tactile sensory information, belong, no doubt, to the class of large dynamical systems. The essential feature of such systems is the multilevel organization of control. Due to the great amount of data processing in large systems, the state space approach, which id efficient in less complex problems, does not always provide the most efficient solution. Rather, a mixture of numerical and non-numerical control methods leads in many instances to an optimal solution in terms of the response of the large system. This paper describes advances in the design of autonomous dextrous hands.

触覚を利用した自動車用補助計器

Human beings depend mostly on visual sensory information to recognize their environment. There are many devices which provide vibratory sensation to the skin but a few use vibratory sensation for practical application. In this study, the vibration pattern is produced by a 16x6 array of small vibrator(PZT) reeds(50 Hz) and the entire array fits on thumb. This apparatus can be used by the driver who can recognize the correct order of the characters from the motion of the vibrator points.

Morphology of descending statocyst interneurons in the crayfish Procambarus clarkii Girard

The morphological features of descending interneurons that responded to the artificial bending of statolith hairs were assessed with intracellular recording and staining techniques. Seven statocyst interneurons were identified on the basis of their structure and response characteristics and designated as interneurons S1 to S7. All seven identified interneurons project to the optic lobe, where the optic nerve also projects, and to the dorsal part of the tritocerebrum, where the eyestalk motoneurons originate. All except interneuron S6 also extend their major branches to other neuropilar regions. S2 projects to the dorsal part of the deutocerebrum, where the statocyst nerve terminates, and S3 to the dorsal part of deutocerebrum and the antennal lobe. Four other interneurons (S1, S4, S5, S7) also extend their branches to the parolfactory lobe to which the statocyst nerve projects as well as to the deutocerebrum and antennal lobe. The extensive dendritic projections of S1–S7 suggest that they are complex multimodal interneurons rather than simple relay interneurons, receiving at least visual and statocyst sensory information. The function of the antennal lobe branches, however, has yet to be determined since the functional role of antennal input in equilibrium control is unknown.

The effects of long-term benzodiazepine treatment and graded withdrawal on psychometric performance.

Twelve patients were assessed prior to and during 4 weeks' graded withdrawal from long-term benzodiazepine treatment. A control group of ten healthy drug-free individuals were assessed over the same period. Psychometric measures included Four Choice Reaction Time--Decision (FCRT-D), Four Choice Reaction Time--Movement (FCRT-M), Sensory Threshold Detection (STD) and Key Tapping Rate (KTR). Patients anxiety level was monitored using the Hamilton Rating Scale (HAM) and a Visual Analogue Self-Report Measure (VASR). There was no evidence of psychometric practice effects and no significant changes in patients anxiety ratings. Prior to withdrawal the patient group showed significantly impaired performance compared to the control group on FCRT-D and STD, tasks primarily involving visual sensory information processing, but there were no differences between the two groups on FCRT-M and KTR, tasks primarily involving motor speed. During withdrawal the patient group showed significant improvements compared to the control group on FCRT-D and STD.

Interactions between normal ewes and newly born lambs deprived of visual, olfactory and tactile sensory information

Fifty-seven Merino and crossbred ewes were observed with their lambs for 1 h after birth to establish whether visual, olfactory or tactile sensory stimulation is the more important for teat location and sucking. The main observations made were, for the lamb, standing, nosing of the ewe and sites nosed, and sucking; for the ewe they were licking of the lamb and sites licked. A group of 12 ewe/lamb pairs in which each lamb was blindfolded at birth showed that these lambs failed to approach the ewe and some did not stand, although all approached the udder and sucked very quickly after the blindfold was removed. Eleven lambs fitted with a control blindfold with holes cut for the eyes did not differ from untreated controls. A group of 11 in which the lambs' nasal passages were sprayed with 10% aerosol xylocaine differed from the 11 controls in that fewer treated lambs sucked within the test period. The behaviour of 12 lambs whose upper lips were anaesthetised with xylocaine differed from controls in time to first touch on the udder and in sucking. Results are discussed in terms of the importance of visual stimulation in the lamb's initial approach to the ewe, and also of the role of the lamb in eliciting maternal attentiveness and differences between the maternal behaviour of Merino and crossbred ewes, part of which may be imputed in the present work to the vigour of the lambs.

Organization of subcortical pathways for sensory projections to the limbic cortex. I. Subcortical projections to the medial limbic cortex in the rat.

Subcortical afferent projections to the medial limbic cortex were examined in the rat by the use of retrograde axonal transport of horseradish peroxidase. Small iontophoretic injections of horseradish peroxidase were placed at various locations within the dorsal and ventral cingulate areas, the dorsal agranular and ventral granular divisions of the retrosplenial cortex and the presubiculum. Somata of afferent neurons in the thalamus and basal forebrain were identified by retrograde labeling. Each of the anterior thalamic nuclei was found to project to several limbic cortical areas, although not with equal density. The anterior dorsal nucleus projects primarily to the presubiculum and ventral retrosplenial cortex; the anterior ventral nucleus projects to the retrosplenial cortex and the presubiculum with apparently similar densities; and the anterior medial nucleus projects primarily to the cingulate areas. The projections from the lateral dorsal nucleus to these limbic cortical areas are organized in a loose topographic fashion. The projection to the presubiculum originates in the most dorsal portion of the lateral dorsal nucleus. The projection to the ventral retrosplenial cortex originates in rostral and medial portions of the nucleus, whereas afferents to the dorsal retrosplenial cortex originate in caudal portions of the lateral dorsal nucleus. The projection to the cingulate originates in the ventral portion of the lateral dorsal nucleus. Other projections from the thalamus originate in the intralaminar and midline nuclei, including the central lateral, central dorsal, central medial, paracentral, reuniens, and paraventricular nuclei, and the ventral medial and ventral anterior nuclei. In addition, projections to the medial limbic cortex from the basal forebrain originate in cells of the nucleus of the diagonal band. Projections to the presubiculum also originate in the medial septum. These results are discussed in regard to convergence of sensory and nonsensory information projecting to the limbic cortex and the types of visual and other sensory information that may be relayed to the limbic cortex by these projections.

A three‐phase psychoacoustic assessment of learning disabled subjects

A three‐phase assessment paradigm was implemented to evaluate areas of auditory and visual perceptual integration and processing by a heterogeneous group of 35 learning disabled subjects ranging in age from 4 to 37 years. Phase I involved testing peripheral auditory acuity, phase II tested central auditory processing, and phase III evaluated cognitive integration of auditory and visual sensory information. Subtest analysis was performed to identify the test material most sensitive to identification of perceptual impairment. Several diagnostic profiles emerged from the test data, and will be discussed in regard to relevance in selecting the assessment battery most appropriate for testing auditory and visual sensory perception of the learning disabled.

Diagnostic profiles obtained from a psychoacoustic assessment procedure with mathematically impaired subjects

A three‐phase assessment paradigm was implemented to identify possible areas of dysfunction in auditory visual perception and processing by mathematically impaired subjects. Phase I involved assessing peripheral auditory acuity, Phase II tested central auditory processing, and Phase III evaluated cortical integration of auditory and visual sensory information. Several diagnostically significant profiles emerged from the test data, and will be discussed in regard to relevance in designing successful mathematical training programs for the mathematically impaired population. The profiles will be presented and discussed as to clinical and educational repercussions.

Analysis of conduction of visual, somatic, and audiovibratory sensory information to the hippocamapal cortex in lizards

Acute electrophysiological experiments on lizards (Ophisaurus apodus) showed that electrical stimulation of the anterior dorsolateral thalamic nucleus and medial forebrain bundle evokes short-latency responses in the hippocampal (mediodorsal) cortex which coincides in distribution and configuration with responses in the same cortical area to sensory stimulation. Extensive destruction of these structures inhibits, or even completely blocks, the conduction of sensory (visual, somatic, audiovibratory) and tactile impulses to the hippocampal cortex. It is concluded that the anterior dorsolateral thalamic nucleus and medial forebrain bundle constitutes, if not the only, at least the principal pathway for transmission of these sensory impulses to the hippocampal cortex in lizards.

Models for bimodal signal detection: a reply to Fidell.

Fidell (1982)has raised questions about the validity of our conclusions regarding performance in a bimodal detection task (Mulligan & Shaw, 1980). This reply explains why his critique is in error. Our paper is concerned with how subjects combine auditory and visual sensory information to decide whether either an auditory or a visual signal is present. Under conditions of continuous auditory and visual noise, subjects were presented with four types of stimuli: (1) auditory signal, (2) visual signal, (3) auditory plus visual signal, and (4) neither auditory nor visual signal. The subject's task was to decide whether at least one signal (visual or auditory) was presented. We presented and tested the predictions of two decision models. According to the independent decisions model, a subject makes a separate, covert, binary (yes-no) decision for each modality by comparing a measure of signal strength in that modality to the relevant decision criterion. The total number of covert yes decisions is then used to make an overt final decision: yes if one or more covert yes decisions have been made and no otherwise. In contrast, according to the integration model, a singledecision variable is formed by taking a weighted sum of the signal strength measures from the separate modalities. If this decision variable exceeds its criterion, the subject responds yes. The data from our experiment supported a version of the independent decisions model and rejected the integration model. In his critique, Fidell emphasizes a formulation of the integration model in which ad' value for bimodal detection is predicted from two separate d' values estimated from unimodal detection data. He shows that our data conform quite well to this prediction, and from this he infers that our conclusion favoring the independent decisions model is erroneous; indeed, he suggests that it must be based exclusivelyon aesthetic preference. We claim that this inference is faulty.' We will substantiate our position below by arguing that a prediction in terms of d' is not appropriate for discriminating between the two models, and that the predictions we use provide a better and more general test of the models. Earlier comparisons of independent-decisions integration models (cf. Green & Swets, 1973) have been restricted to a threshold (i.e., two-state) independentdecisions model with a nonzero probability of a detect state given noise (hence low threshold). In our paper, we consider an independent-decisions model in which sensory strength measures are treated as continuous random variables, and the internal strength measure of each modality is compared with its own criterion. The criteria selected for the auditory and visual modalities are independently adjustable, and can differ between unimodal and bimodal tasks. A consequence of these two properties is that the continuous independent decisions model can produce hit and false alarm rates that mimic the hit and false alarm rates of the integration model. This means that these models are not identifiable on the basis of the relation between bimodal and unimodal d' values. Thus, Fidell's observation that our data conform to the integration model predictions for d' is meaningless-because this conformity also applies to predictions from the independent decisions model, given appropriate choices of criteria. In our paper, we do not rely exclusively on the prediction of one model to discriminate the two theoretical alternatives. Instead, we derive predictions from each model in terms of the same statistic (probability of a no response), and these two predictions are pitted against each other. (See Green & Swets, 1973, and Sternberg, 1963, for a discussion.) A separate analysis (Shaw, 1980) shows that these and the other predictions we use differ enough between the models to provide reliable discrimination. The data we collected clearly reject the integration model and support the independent decisions model. Only if it can be argued that thereliable discrimination of one model from another confers a certain beauty on that model can we agree with Fidell that our choice of the independent decisions model is aesthetic. We claim that our tests of these models are more general in several ways than the test proposed by Fidell (and others; cf. Green & Swets, 1973). First, our predictionsapply to both threshold and continuousstate variants of the independent-decisions model (see Shaw, in press). Second, for none of the models we considered do the critical predictions depend upon subjects' maintaining fixed criteria from unimodal to bimodal detection tasks. Third, for none of our critical predictions is it required that attentional demands be invariant between unimodal and bimodal

Perceptual and Oculomotor Reactions to Interacting Visual and Vestibular Stimulation

Abstract : Six men received repeated vestibular stimulation under several conditions of visual stimulation. Nystagmus, suppressed during brief room illumination, recovered almost completely in a following period of darkness; the subjective response remained suppressed. A small light (or large fixation field) inhibited nystagmus but did not suppress the subjective response. Apparently any visual still fixation field suppressess nystagmus, but the subjective response depends upon visual sensory information denying relative motion between the fixation field and the earth; intellectual information alone is ineffective. Nystagmic and subjective reactions diminish with repeated rotation. Only the subjective reaction recovered after a 9-day rest. (Author)