Can brain electrical activity associated with the Craik–Cornsweet–O’Brien effect (CCOB) be identified in humans? Opposing luminance gradients met in the middle of a square image to create a luminance contrast-defined vertical border. The resulting rectangles on each side of the border were otherwise equiluminant, but appeared to differ in brightness, the CCOB effect. When the contrast gradients were swapped, the participants perceived darker and lighter rectangles trading places. This dynamic CCOB stimulus was reversed 1/s to elicit visual evoked potentials. The CCOB effect was absent in two control conditions. In one, the immediate contrast border, where the gradients met, was replaced by a dark vertical stripe; in the other, the outer segments of both rectangles, where the illusion would otherwise occur, were replaced by dark rectangles, leaving only the contrast-reversing gradients. Visual evoked potential components P1 and N2 were present for the CCOB stimuli, but not the control stimuli. Results are consistent with functional MRI and single unit evidence, suggesting that the brightness of the CCOB effect becomes dissociated from the luminance falling on the eye early in visual processing. These results favor explanations of brightness induction invoking rapid, early amplification of very low spatial-frequency information in the image to approximate natural scenes as opposed to a sluggish brightness adjustment spreading from the contrast border.

Diagnostic and therapeutic approaches are reviewed for the management of peripheral visual field loss in those with acquired brain injury. Differentiation of field loss from visual neglect (aka visual unilateral spatial inattention) is a key component in diagnosis and treatment. Since the emphasis is on compensation, visual field loss requires less vision rehabilitation, although modest visual field recovery is a relatively common finding. Visual neglect requires considerably more rehabilitation, but it is more likely than visual field loss to be remediable.

Spatial vision in adults is thought to be mediated by multiple bandpass spatial frequency-tuned (SF-tuned) channels with inhibitory interactions. Existing preferential looking data imply that young infants lack these channels (Banks, Stephens, & Hartmann, 1985), instead, processing spatial information with multiple lowpass channels, or a single "channel". Further, questions have been raised as to whether inhibitory systems are in place to mediate spatial vision in the infant (e.g. Morrone & Burr, 1986). Previously, we have used a SF adaptation paradigm (Blakemore & Campbell, 1969) combined with visual evoked potentials (VEPs) to demonstrate the bandpass and inhibitory nature of SF channels in adults (Suter, Armstrong, Suter, & Powers, 1991). SF adaptation decreased VEP amplitude in a bandpass manner near the adapting SF, and increased VEP responding at SFs removed from the adapting SF. Increased contrast sensitivity thresholds, reduced cortical response, and reduction of VEP amplitude after adaptation may be due to neuronal fatigue or adjustment of a local contrast gain mechanism within the adapted channel (Ohzawa, Sclar, & Freeman 1985). Following adaptation, lower contrast sensitivity thresholds at SFs removed from the adapting SF have been explained by release of inhibition on neighboring channels when SF adaptation reduced responding of the adapted channel (De Valois, 1977). The research summarized here uses the VEP with the SF adaptation paradigm to demonstrate the existence of multiple, bandpass, co-inhibitory SF-tuned channels in 3, 6, and 12 week-old infants.

ABSTRACT This report refers to a body of investigations directed toward the examination of autonomic nervous system responses to motion sickness. Heart rate, respiration rate, finger pulse volume, and basal skin resistance were measured on 127 men and women before, during, and after exposure to a nauseogenic rotating chair test. Significant changes in all autonomic responses were observed across the tests ( p <.05). Significant differences in autonomic responses among groups divided according to motion sickness susceptibility were also observed ( p <.05). Results suggest that the examination of autonomic responses as an objective indicator of motion sickness malaise is warranted and may contribute to the overall understanding of the syndrome.

Three studies are reported that, in general, fail to replicate an earlier investigation by this laboratory ( Suter & Loughry - Machado , 1981) in which impressive self-regulation of skin temperature by children was obtained. Mediation of skin temperature biofeedback effects is discussed. It is concluded that biofeedback self-regulation cannot be understood independently of the interpersonal, attitudinal, and cognitive context in which it occurs.

Bilateral EEG alpha (alpha) was measured during several cognitive tasks in two experiments. EEG alpha was suppressed relative to baseline in both hemispheres during every drawing and writing task. In addition, there were task-related EEG alpha asymmetries. Differences in left-hemisphere, but not right-hemisphere EEG alpha activity, were responsible for EEG alpha asymmetry differences between writing and drawing tasks. There was no difference in bilateral EEG alpha during drawing an upright versus an inverted drawing stimulus; failing to support Edward's (1977, 1979) 'cognitive shift' approach to drawing instruction.

ABSTRACT Studies of the pre‐lingually deaf may help clarify the role of language experience in the development of cerebral lateralization. Bilateral EEG alpha (α) was recorded for three groups: Deaf, normal‐hearing Controls, and Interpreters for the deaf, during five tasks. The tasks were: 1) Baseline (eyes open); 2) Letter Writing; 3) Oral Story, a story presented orally to every participant; 4) Signed Story, a story presented to every participant in American Sign Language (AMSLAN) by an interpreter; and 5) Block Design. Consistent with earlier studies, both of the hearing groups showed relatively greater cortical activation of the left hemisphere as compared to the right hemisphere during Letter Writing as compared to Block Design. For the Interpreters, but not for the Controls, there was relatively greater left‐hemisphere activation during the Signed Story as compared to Baseline, indicating left hemisphere involvement in comprehension of a gestural language. There were no task‐related EEG asymmetries for the Deaf, suggesting that auditory language experience contributes to, and is necessary for, full development of cerebral lateralization.

Integrated EEG alpha was recorded from T 3 and T 4 . Larger Rα/Lα ratios were defined as right asymmetry, relatively smaller ratios as left asymmetry. In different phases of the study, participants attempted to identify the presence of the EEG asymmetries and to produce the EEG asymmetries during auditory biofeedback, and were tested on hemisphere-specialized cognitive tasks while attempting to produce the EEG asymmetries. Experiential descriptions of the EEG asymmetries were obtained throughout using a set of bipolar scales. Some participants were able to identify the presence of the EEG asymmetries (p<.05). As a group there was numerically small but significant (p<.05) biofeedback control of the EEG asymmetries, but no improvement across sessions of training. There were marked individual differences in the ability to control the EEG asymmetries and in Lα and Rα during control. During baselines Lα and Rα were strongly positively correlated across time. Experiential descriptions were not consistent across participants. Effects of EEG asymmetries on performance of hemisphere-specialized tasks were demonstrated for one participant.

Skin temperature biofeedback performance was studied in 38 children, ages 6 to 10, and 38 of their parents, across two sessions of audio biofeedback segments in which the participants alternately attempted hand-warming and hand-cooling. Skin temperature from each hand was monitored throughout, but only one hand at a time was in the feedback loop. The major finding was that children were superior to adults in controlling skin temperature in the presence of biofeedback (p < .001). Adults showed no skin temperature control. For children, temperature changes were greater for the hand in the feedback loop as compared to the contralateral hand (p < .001). Children were equally successful in increasing and decreasing skin temperature. The results are consistent with earlier studies and suggest that children have considerable potential for neuropsychological self-regulation.

Greenstadt, Cchurnan, and Shapiro (1978) compared monaural left vs right ear audio feedback in a heart-rate-increase biofeedback task and found an unexpected superiority of the right ear. Their rationale was based on the demonstrated specialized function of the cerebral hemispheres, in particular recent evidence of specialization of the right hemisphere for emotion (Schwarcz, Davidson, & Maer, 1975) and the predominance of contralateral projections in the auditory system (Peronnet, Echallier, & Girod, 1974) . The present study searched for similar effects in the vascular system and esplored whether asymmetries in vascular responses (Diekhoff, et al., 1978) might be reflected in biofeedback control of finger temperature. The 32 participants, 18 females and 14 males between the ages of 14 and 35 yr., were right-handed. Thermistors from a BFT Model 301 feedback thermometer were taped to each index finger. A variablypitched tone proportional to skin temperature was delivered to either ear via headphones. Following a 5-min. temperature stabilization period there were eight biofeedback segments during which the participant attempted to raise or lower the temperarure of the lefc or right finger via feedback to the lefc or right ear. Order of the eight conditions was counterbalanced. An analysis of variance was performed in which the factors were gender, direction, hand, and ear. There was over-all self-regulation of finger temperature with means of 93.2" F during warming vs 92.6" F during cooling ( F 3 . 8 0 = 8.96, p < .01). However, no effects involving ear or hand were significant. Across participants temperature changes during warming and cooling were negatively correlated (530 = .53), suggesting a common mechanism for regulation skin temperature warming and cooling. The results of Greenstadt, et al. (1978) may be linked to the asymmetrical innervation of the heart or to the complex interplay of sympathetic and parasympathetic activiry in regulating heart rate, in contrast to vascular tone which is regulated only by sympathetic activity.

Understanding individual differences in biofeedback performance may help elucidate the mechanisms of biofeedback and aid in identifying the treatment of choice in clinical settings. Although many studies have attempted to relate biofeedback performance and personality measures (e.g., Ray, 1974). one fundamental problem has received little attention, namely, the extent to which an individual's success in biofeedback is task-specific vs consistent across physiological responses. The present study examined biofeedback performance across three biofeedback tasks. The 36 participants, 18 males and 18 females, ages 13 to 59 yr., received three biofeedback sessions, one each for electromyogram (EMG) reduction, bi-directional EEG alpha control, and bi-directional skin resistance control, with the order of the sessions counterbalanced. For EMG, a BIT Model 401 device measured frontalis EMG and provided audio feedback. After a 5-min. baseline the participants attempted to reduce EMG for 24 min. For EEG alpha, BFT Model 115 and 215c devices measured integrated EEG alpha from 01 referenced to A1 and provided audio feedback. After a 5-min. baseline, the participant attempted successively to increase and decrease EEG alpha across two 12-min. segments. The procedure was identical for skin resistance. A BFT Model 701 device monitored skin resistance from finger electrodes on the dominant hand and provided pitch-proportional audio feedback. There was significant reduction of EMG from the first one-half of training, 24.4 pV (peak-tepeak), to the second, 19.4 pV (F1.a = 46.40, p < .001). There was no significant self-regulation of skin resistance over-all, with means of 20.0 KQ during resistance increase vs 19.9 KR during resistance decrease (F < 1.00). There was self-regulation of EEG alpha with means of 5.33 pV during EEG alpha increase vs 4.83 pV during EEG alpha decrease (FI.~, = 7.25, 9 < .01). There were no significant correlations across participants between biofeedback performance measures for the three biofeedback tasks. These results complement findings (e.g., Suter, 1977) that biofeedback effects tend to be limited to the physiological response in the feedback loop and suggest that brief periods of different types of biofeedback training do not each produce phys~ological changes along a unitary cortical-somatic dimension of activation-inhibition.

Skin resistance and EEG alpha were recorded concurrently during alpha biofeedback, in which the participant attempted to control alpha, and during skin resistance biofeedback, in which the participant attempted to control skin resistance. Alpha production changed significantly (p<0.001) during alpha biofeedback, indicating successful self-regulation of alpha, but did not change significantly during skin resistance biofeedback. Similarly, skin resistance changed significantly (p<.001) during skin resistance biofeedback but did not change significantly during alpha biofeedback. The results show independent control of alpha and skin resistance, and may reflect independent self-regulation of cognitive and somatic tension-relaxation systems.

Two experiments were performed to explore the effect of illumination on rat vocalizations to shock and to repeat a previous experiment in which the presence of a CS significantly reduced squealing to shock. The first experiment replicated the suppressive effect of a CS on vocalizations and indicated the effect may be obtained using onset or offset of illumination as the CS. Reduced squealing due to illumination alone was found in Experiment I using an independent group design but not found in Experiment II using a repeated measures design. A marked increase in vocalizations over trials was observed in both experiments.

Two studies are reported using rat vocalization to electric shock as the behavioral measure. Study 1 used a classical conditioning procedure with an auditory CS for one group while presenting only the UCS to a second group. The second study investigated the same phenomenon but used a within- instead of a between-groups design. In both studies, Ss given CS-UCS pairings vocalized significantly less to UCS than when the UCS was given alone. Both studies also produced gradual UCR curves but no detectable vocalizations to the CS occurred.

Human Ss preferred warned shock to unwarned shock when the warning signal contained 2 bits of information (25% shock) but not when it was redundant, i.e., 0 bits (100% shock). Rated strength of preference was also related to the information contained in the warning.

Rat vocalization to electric shock was studied using a classical conditioning procedure for one group and presenting only the UCS to a second group. Ss given CS-UCS pairings vocalized significantly less to the UCS than Ss given only the UCS. Results were discussed and predicted from an information-preparation framework. Unexpected gradual OCR curves were obtained but no vocalization to the CS occurred.