The influence of visual information on habituation of the electrodermal and the visual orienting reaction.

In this study the influence of the information value of visual stimuli on habituation of the visual orienting reaction (VOR) and the skin conductance reaction (SCR) was investigated. 28 subjects received two blocks of 14 trials. Half the subjects received the higher information condition first and then the lower information, the other half received the conditions in the reversed order. Subjects fixated the stimuli with the higher information value longer than the stimuli with the lower information value during the 14 trials and habituated slower. This effect of information was absent in the second block and VOR habituation was also faster in this block. There was no difference in SCR amplitudes nor in SCR habituation scores between the two information conditions, neither in block 1 nor in block 2. The results of this study are discussed in relation with a two-stage model of the OR.     

Effects of task relevance on habituation of visual single-trial ERPs and the skin conductance orienting response

Single-trial event-related potentials were recorded at Oz, Pz, Cz, and Fz, concurrently with skin conductance reactions and fixation behavior in a habituation paradigm. A total of 48 subjects received 16 identical visual stimuli; 24 of them were instructed to pay attention, whereas the other half were given a neutral instruction. Two early negative components (N1 and N2), as well as a late positive component (P3) were identified. N1 and skin conductance reaction (SCR) showed fast decrement over trials, whereas N2 and P3 habituated slowly. Habituation of N1 and SCR was delayed by task instructions; N2 was hardly seen at all in the neutral condition. The task effects on N1 and N2 were observed only at Oz. It is concluded that the processing of relevant stimuli differs structurally from the processing of neutral stimuli; this difference may be observed even at a latency of 100 ms. The N1 appears to be related to the SCR, whereas this does not hold for P3; the N2 is related to selection negativities reported by other authors.     

Effect of propranolol and phenothiazines on electrodermal orienting and habituation in schizophrenia

Bilateral electrodermal orienting responses were measured to repeated auditory stimuli in schizophrenic patients and controls. In 3 studies phasic activity to moderate intensity sounds of patients on no drugs or phenothiazines was predominantly hyper- or hypo-responsive. Controls showed moderate or slow habituation. Propranolol was found to facilitate habituation in slow habituators and to reinstate responses in half of non-responders, especially when given as the sole drug. The effects seldom had a counterpart in changes in non-specific responses or levels of skin conductance. Modulatory influences on stimulus and response processing and on lateral asymmetries in responses may underlie propranolol's efficacy in treating schizophrenia.     

The effects of uncertainty and task-relevance on habituation and recovery of the electrodermal and visual orienting reaction

Habituation and recovery of the skin conductance reaction (SCR) and visual orienting reaction (VOR) were investigated. Half the subjects (total N = 48) were instructed to memorize a complex visual stimulus (TR), while the other half received a non task-relevant instruction (NTR). All subjects were exposed to two series of 16 identical stimuli. At trial 17 the location of the stimulus changed. Half the subjects in both groups received a priori information about the stimuli, the other half did not. Task-relevance led to slower SCR habituation and longer VORs. In the TR condition the VOR latency time rapidly decreased, indicating the development of a set. In terms of SCR frequency, but not in terms of SCR magnitude OR recovery was stronger in the task-relevant condition. However, all subjects oriented visually to the stimulus change. No habituation of the VOR was found using a drift-free technique for measuring eye-movements. It is concluded that the SCR and the VOR latency data supply evidence for a structural difference between task-relevant and task-irrelevant ORs.     

The influence of task relevance and stimulus information on habituation of the visual and the skin conductance orienting reaction

This study investigated the hypothesis that task-relevant stimuli induce orienting reactions (ORs) that are stronger and more resistant to habituation when their information content is high than when it is low. Task-relevance was given to the stimuli by rewarding the subjects for correct recognition at the end of the experiment. The dependent variables in this study were the visual orienting reaction (VOR), the skin conductance reaction (SCR), their habituation scores and the number of spontaneous fluctuations in skin conductance (SFs). 28 subjects received two blocks of 14 trials. Half the subjects received the higher information condition first and then the lower information condition, while the other half received the reversed order. The VOR habituated quickly and was not significantly influenced by information value. SCR amplitudes were larger and SCR-habituation slower to stimuli containing more information. The results were interpreted as supporting the hypothesis that the SCR is associated with a secondary phase of the orienting process.     

Effects of social anxiety and facial expression on habituation of the electrodermal orienting response.

The present research examined electrodermal orienting to happy and angry faces as a function of social anxiety and threat of shock. A preliminary study using 569 undergraduate participants developed an adequate set of normative data of social anxiety for the Willoughby questionnaire (WQ) for use in subject selection. Electrodermal activity was measured in both high and low socially anxious subjects (N = 85) during exposure to 10 presentations of an angry face intermixed with 10 presentations of a happy face. Threat of shock (no-shock, shock work-up only, and shock work-up plus threat) was also manipulated. Skin conductance responses (SCRs) which occurred within 1-4 s of stimulus onset and trials-to-habituation constituted the data of primary interest. Although trials-to-habituation did not differ between angry and happy facial expressions, SCRs were larger to the angry face than to the happy face in both high and low socially anxious subjects. No differences in SCR magnitude were found as a function of threat of shock. The implications of these results for Ohman's functional-evolutionary model of social phobia are discussed, and alternative explanations in terms of prepotency and prior learning are examined.     

Developmental changes in visual orienting behavior to featural versus structural information in the human infant

Ten male infants, 3–4 months old, and 10 male infants, 6–7 months old, were habituated to a visual stimulus composed of both specific featural and structural information. After habituation, orienting magnitude (dishabituation) to changes in feature with structure controlled versus changes in structure with feature controlled was used as a means of measuring the infant's processing capacity. Results indicate that younger and older infants were habituated over the habituation trials but that younger and older infants differed significantly in dishabituation to changes in structure and feature information. The present findings support the hypothesis that feature and structure information are both independently important to visual processing in the human infant.     

Duration of early visual experience and visual cliff behavior of chicks.

Visual cliff behavior was studied in 120 chicks as a function of 22, 46, 70, 94, or 118 hr of rearing in a deep or shallow environment. Preference for the deep side of the visual cliff increased directly with duration of depth-rearing but was uninfluenced at any duration of shallow-rearing. Although qualitative differences existed in the behaviors of those shallow- and deep-reared chicks which crossed the cliff, the loss of depth avoidance by the latter group appeared to be specific to the rearing and testing apparatus.     

Effects of stimulus information and stimulus duration on amplitude and habituation of the electrodermal orienting response

This study was designed to investigate the effects of stimulus information and stimulus duration on the skin conductance response (SCR) component of the orienting response (OR). Three levels of stimulus information were combined with two levels of stimulus duration in a 3 × 2 independent groups factorial design (N = 90). On the basis of Sokolov's (1966) theory, it was hypothesized that: (a) high information stimuli would elicit larger initial SCRs than would stimuli of low information, (b) high-information stimuli would evoke more SCRs throughout a habituation series than would low-information stimuli, and (c) high-information stimuli would require more presentations to reach a habituation criterion than would stimuli of low information. It was also hypothesized that (d) long-duration stimuli would require fewer presentations to reach a habituation criterion and result in a faster rate of habituation than would stimuli of short duration. The stimuli consisted of black and white chequered patterns containing 12, 26 or 60 bits of information. Stimulus duration was either 0.5 or 4.5 sec, and each subject received 20 presentations at randomly ordered intervals of 20, 25, 30 and 35 sec. The results provided support for hypotheses (b), (c) and (d), but not for hypothesis (a). These results support the view that OR habituation can be conceptualized as a process of information extraction.     

Coordination of the eyes and head during visual orienting

Changing the direction of the line of sight is essential for the visual exploration of our environment. When the head does not move, re-orientation of the visual axis is accomplished with high velocity, conjugate movements of the eyes known as saccades. Our understanding of the neural mechanisms that control saccadic eye movements has advanced rapidly as specific hypotheses have been developed, evaluated and sometimes rejected on the basis of new observations. Constraints on new hypotheses and new tests of existing models have often arisen from the careful assessment of behavioral observations. The definition of the set of features (or rules) of saccadic eye movements was critical in the development of hypotheses of their neural control. When the head is free to move, changes in the direction of the line of sight can involve simultaneous saccadic eye movements and movements of the head. When the head moves in conjunction with the eyes to accomplish these shifts in gaze direction, the rules that helped define head-restrained saccadic eye movements are altered. For example, the slope relationship between duration and amplitude for saccadic eye movements is reversed (the slope is negative) during gaze shifts of similar amplitude initiated with the eyes in different orbital positions. Modifications to the hypotheses developed in head-restrained subjects may be needed to account for these new observations. This review briefly recounts features of head-restrained saccadic eye movements, and then describes some of the characteristics of coordinated eye–head movements that have led to development of new hypotheses describing the mechanisms of gaze shift control.     

Effects of instructions on habituation of the orienting response: another perspective on the study by Gruzelier and Eves

A recent study by Gruzelier and Eves (1987, Int. J. Psychophysiol., 4: 289-291) purported to test the hypothesis of Iacono and Lykken (1979, Schizophrenia Bull., 5: 11-14), that instructions to subjects that clarify task demands facilitate habituation. However, the Gruzelier and Eves study did not provide an adequate test of this hypothesis. Moreover, contrary to the assertions of Gruzelier and Eves, the data presented in their paper are consistent with the predictions of Iacono and Lykken.     

Effect of varying the duration of pre-test cage habituation on oxytocin induction of short-latency maternal behavior

Intracerebroventricular (ICV) infusion of the peptide hormone oxytocin has been previously reported to induce the performance of short-latency maternal behavior (less than one hour of exposure to foster pups required) in estrogen-treated, ovariectomized virgin rats. Tests for the effect of ICV oxytocin in maternal behavior latency have included transfer of animals from their home cage to a larger test cage one to two hours before oxytocin infusion. The importance of this test feature on peptide-induced short-latency maternal behavior was evaluated by varying the duration of the pre-test cage habituation. The responses of ovariectomized, estrogen-primed Zivic-Miller Sprague-Dawley rats housed in the test cages one week, two hours, or 0 hours before oxytocin or saline infusion were compared. It was found that only the rats given two hours of pre-test cage habituation responded to ICV oxytocin treatment with short-latency maternal behavior. This result is discussed with regard to the failure of other investigators to elicit short-latency maternal behavior with oxytocin. Possible neuroendocrine mechanisms for the interaction of degree of environment novelty with oxytocin-induced behavior are considered.     

Gaze orienting in dynamic visual double steps

Visual stimuli are initially represented in a retinotopic reference frame. To maintain spatial accuracy of gaze (i.e., eye in space) despite intervening eye and head movements, the visual input could be combined with dynamic feedback about ongoing gaze shifts. Alternatively, target coordinates could be updated in advance by using the preprogrammed gaze-motor command ("predictive remapping"). So far, previous experiments have not dissociated these possibilities. Here we study whether the visuomotor system accounts for saccadic eye-head movements that occur during target presentation. In this case, the system has to deal with fast dynamic changes of the retinal input and with highly variable changes in relative eye and head movements that cannot be preprogrammed by the gaze control system. We performed visual-visual double-step experiments in which a brief (50-ms) stimulus was presented during a saccadic eye-head gaze shift toward a previously flashed visual target. Our results show that gaze shifts remain accurate under these dynamic conditions, even for stimuli presented near saccade onset, and that eyes and head are driven in oculocentric and craniocentric coordinates, respectively. These results cannot be explained by a predictive remapping scheme. We propose that the visuomotor system adequately processes dynamic changes in visual input that result from self-initiated gaze shifts, to construct a stable representation of visual targets in an absolute, supraretinal (e.g., world) reference frame. Predictive remapping may subserve transsaccadic integration, thus enabling perception of a stable visual scene despite eye movements, whereas dynamic feedback ensures accurate actions (e.g., eye-head orienting) to a selected goal.     

Head movement trajectory in three-dimensional space during orienting behavior toward visual targets in rhesus monkeys

Head movement trajectories in three-dimensional space were studied in two monkeys with their heads free during natural and spontaneous orienting behavior toward objects of interest displayed in a horizontal plane. The main interest of this study lies in understanding the process responsible for behaviorial variability during the execution of head movements, with special reference to units of movement. The head movements were recorded by an optoelectronic movement analyzer working with passive markers. Algorithms have been designed to reconstruct the three-dimensional trajectories of the center of gravity of the head. Simultaneously, electromyographic activity in the four pairs of suboccipital muscles was studied. A quantitative evaluation of the involvement of the head in orienting behavior toward visual targets shows that the gaze shift is always produced by eye movements in combination with head movements, even with target eccentricities of less than 10°. On the basis of 80 trials performed by the two monkeys, head trajectories and recruitment patterns of the four pairs of suboccipital muscles have been analyzed. We have been able to identify four elementary kinematic units which can be described as a rightward or leftward turning associated with a contralateral or ipsilateral bending. Each of these four elementary units are underlain by a precise fixed recruitment pattern in the four pairs of suboccipital muscles. These four sets of motor strategies can be combined in order to offer a certain amount of plasticity from which the animal builds its own head trajectory.     

Cardiac orienting and habituation to auditory and vibrotactile stimuli in the infant decerebrate rat

Phasic changes in heart rate were used to evaluate sensory reactivity and habituation in 5- and 12-day-old normal and decerebrate rats. Twenty-four and forty-eight hours after thalamic transection, temporally paired auditory or vibrotactile stimuli were repeatedly presented in a sensory disparity paradigm. While tone stimuli failed to evoke consistent cardiac change, vibrotactile stimuli produced cardiac decelerations, characteristic of the orienting response, in all subject groups. The magnitude of this response was comparable in both normal and decerebrate subjects at 5 days of age, but demonstrated a more notable increase with age in the normal subjects. Habituation of the cardiac response was apparent in all groups, and was not significantly different in the normal and decerebrate subjects. No consistent responses were apparent in any group to the unexpected omission of the second stimulus of the pair. Results indicate that orienting and habituation processes can persist in the absence of the cerebral hemispheres and support the view that lower levels of the neuraxis are capable of mediating a range of adaptive functions.     

Effect of psychotropic drugs on orienting and investigative behavior after fright induced by acoustic stimulation

After frightening acoustic stimulation a state of alertness and anxiety arises and leads to weakening of attention to the new situation and intensification of the orienting reaction toward the source of sound. Defensive motivation arising under these conditions does not change with an increase in loudness of the sound. The tranquilizers diazepam (Seduxen), benactyzine, and chlordiazepoxide (Librium), the antidepressants amitriptuline and imipramine, and the neuroleptics trifluoperazine and haloperidol, in small doses, prevent these disturbances. Pentobarbital, chlorpromazine, and also trifluoperazine and haloperidol in large doses, do not prevent these consequences of emotional excitation.Institute of Pharmacology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academioian of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 11, pp. 579–582, November, 1977.