Presentation Of Visual Stimuli Research Articles

Long-term memory of haptic and visual information in older adults

ABSTRACT The present study examined haptic and visual memory capacity for familiar objects through the application of an intentional free-recall task with three-time intervals in a sample of 78 healthy older adults without cognitive impairment. A wooden box and a turntable were used for the presentation of haptic and visual stimuli, respectively. The procedure consisted of two phases, a study phase that consisted of the presentation of stimuli, and a test phase (free-recall task) performed after one hour, one day or one week. The analysis of covariance (ANCOVA) indicated that there was a main effect only for the time intervals (F (2,71) = 12.511, p = .001, η2 = 0.261), with a lower recall index for the interval of one week compared to the other intervals. We concluded that the memory capacity between the systems (haptic and visual) is similar for long retrieval intervals (hours to days).

Взаимоотношения монокулярного и бинокулярного механизмов пространственного восприятия до и после функционального лечения у детей с послеоперационной остаточной микродевиацией

Purpose. Of this work is to study the relationship of monocular and binocular mechanisms of spatial perception before and after functional treatment in children with postoperative residual microdeviation. Material and methods. The study included 30 children aged 8 to 16 years (average 12.5 years) with postoperative residual microdeviation (RM) and 44 children of the same age (average 10.6 years) in the control group. Along with the usual ophthalmic examination, Bagolini test, Lang test and Fly test were used to evaluate binocular functions in all children. To study the stereokinetic effect (SE), a ring image with a diameter of 20 cm with an eccentricity (the ratio of the displacement of the central element of the ring image from the center of rotation to the radius of the image) of 0.4 rotating on a laptop screen at the speed of 60 rpm was presented using a computer program developed by M.V. Zhmurov was used. The distance from the eyes to the image was 3 m. A child was asked to evaluate the illusory size of the virtual cone or the virtual funnel in binocular and monocular viewing conditions. Seven reference paper cones with a base diameter of 20 cm and a height of 5.10, 15, 20, 25, 30 and 35 cm were used to facilitate estimates of the SE value. The child pointed the paper cone closest in size to the virtual cone or virtual funnel. We also noted the time of dominance of the virtual cone and the virtual funnel during their alternation (in seconds per 1 min) and then calculated the average time of domination of both variants of the virtual figure. The study of visual functions and SE in children with RM was carried out before and after the course of functional treatment, providing presenting of stereostimules in the alternation mode using a computer program developed by M.V. Zhmurov. Three modes of alternative presentation of stimuli were used: 1) with consecutive monocular presentation of visual stimuli corresponding to the right and left eye; 2) with the presence of an empty interval between monocular phases; 3) with the presence of a binocular phase between monocular phases. Results. In all children with RM, the results of the stereovision study with Lang-test, Fly-test were negative before treatment. After functional treatment, 24 children showed stable binocular character of vision, the results of the study with Fly-test after treatment were positive in 20 children, and in five children with Lang-test. Orthotropy was achieved in 24 children. As a result of treatment, the visual acuity of the amblyopic eye increased from 0.74±0.03 to 0.91±0.01. The number of children with RM perceiving SE in the form of alternating virtual figures (cone and funnel) increases from 50% to 83.3% as a result of treatment. The dominance time of the virtual cone in children with RM significantly decreased (p<0.01) after treatment both in monocular conditions (average from 2.9±0.2 to 2.3±0.1 s) and in binocular conditions (average from 3.6 ±0.2 to 3±0.1 s), reaching the values of the control group. As a result of treatment of children with RM, the average size of the virtual cone for binocular conditions decreased from 21.3±1.2 to 16.8±0.9 cm and was significantly lower (p<0.001) compared with both the mean values before treatment and with the average values in the control group. After treatment, the average value of the virtual funnel for binocular conditions decreased from 19±1.1 cm to 13.1±0.7 cm and was significantly lower compared with the values obtained before treatment (p<0.001) and in the control group (p<0.05). Conclusion. Using alternating presentation of stereoimages in functional treatment of children with RM leads to positive changes: a reduction or elimination of residual deviation, improved visual acuity of amblyopic eye, increasing of the number of patients with stable bifoveal fusion and appearance of a stereo vision in them. The number of children with RM perceiving SE in the form of alternating virtual figures (cone and funnel) increases as a result of treatment. The dominance time of the virtual cone in children with RM significantly decreases after treatment, reaching the values in the control group. The average value of the virtual cone size for binocular conditions in children with RM significantly decreases after treatment to values smaller than in the control group, and for monocular observation conditions – increases to values comparable with the results in the control group. The average value of the virtual funnel size for binocular conditions in children with RM significantly decreases after treatment in comparison both with the values obtained before treatment and with the values obtained in the control group. Changes in the relationship between monocular and binocular mechanisms of spatial perception can serve as additional criteria for assessing the effectiveness of functional treatment of patients with RM.

Forgotten but not gone: FMRI evidence of implicit memory for negative stimuli 24 hours after the initial study episode

Endel Tulving conducted pioneering work on the explicit and implicit memory systems and demonstrated that priming effects can be long-lasting. It is also well-established that emotion can amplify explicit and implicit memory. Prior work has utilized repetition suppression (RS) of the fMRI-BOLD signal—a reduction in the magnitude of activity over repeated presentations of stimuli—to index implicit memory. Using an explicit recognition memory paradigm, we examined emotional modulation of long-term implicit memory effects as revealed by repetition suppression (i.e., comparing second-exposure forgotten items to first-exposure correct rejections). Forty-seven participants incidentally encoded line-drawings of negative, positive, and neutral scenes followed by the full color image. Twenty-four hours later, participants underwent fMRI during a recognition memory test in which old and new line-drawings were presented. Implicit and explicit memory effects were defined by the contrasts of New-Correct Rejections > Old-Misses and Old-Hits > New-Correct Rejections, respectively. Wide-spread Negative RS was found in frontal and occipito-temporal cortex that was greater than Neutral RS in the right orbito-frontal cortex and inferior frontal gyri. Valence-specific Negative RS, compared to Positive RS, was observed in the left inferior occipital gyrus. There was no strong evidence for emotional modulation of amygdala RS, but functional connectivity analyses revealed valence-specificity: Negative and positive valence were associated with repetition suppression and repetition enhancement of amygdala-occipital connectivity, respectively. Negative implicit memory patterns in most frontal regions—but not occipital areas—overlapped with explicit memory effects. Thus, implicit memory effects for a single visual stimulus presentation are modulated by emotional valence, can be observed 24hours after initial exposure, and show some overlap with explicit memory.

Результаты использования альтернирующего предъявления различных стереостимулов для исследования способности к стереовосприятию у детей с послеоперационной остаточной микродевиацией

Purpose. To study abilities to stereo-perception in children with postoperative residual micro-deviation via alternating presentation of different stereo stimuli. Material and methods. The study included 30 children aged 8 to 16 years (average 12.5 years) with operated strabismus who have postoperative residual micro-deviation (mean 6.8±0.4 pr.D) at the time of the observation. Residual esotropia was observed in 21 children (5 of them had also a vertical micro-deviation), exotropia – 9 children. Along with the usual ophthalmic examination and evaluation of stereovision by means of classical Lang-test and Fly-test we used our own stereo-tests developed on the basis of stereo images created by J. Ninio. Our stereo-tests included stimuli: 1) with a central location of vertical or horizontal stripes with a successful fusion and an ability to stereo perception of tilt relative to the horizontal axis (vertical strip) or turn around the vertical axis (horizontal strip); 2) with a peripheral location of vertical or horizontal stripes creating respectively the effect of tilt or reversal turn; 3) randomly-point stereo-grams, creating the impression of a successful fusion of vertical or horizont al cylinder. The subject observed the images shown on the monitor screen from a distance of 50 cm from the eyes through the red-blue light filters in conditions of full prismatic compensation of the angle of strabismus and optimal spectacle or contact correction of ametropia. The stimuli were presented both in the static version and in the modes of alternation via a computer pr ogram developed by M. V. Zhmurov. Three modes of alternative presentation of stimuli were used: 1) the mode with a consecutive monocular presentation of visual stimuli corresponding to the right and left eyes 2) the mode with the presence of an empty interval between monocular phases; 3) the mode with the presence of a binocular phase between monocular phases. Results. In all patients, the results of the study of stereovision with Lang-test, Fly-test and static version of our stereo-tests used in this work were negative. In eight children of the general group, the stereo effect appears only with stereo-images with a peripheral arrangement of vertical or horizontal stripes in all three modes of the alternating presentation. In 22 children, the stereo effect appears with stimuli both with peripheral and with the central location of the stripes in all three modes of their alternating presentation. The volume effect with random-dot stereo-stimuli occurred in only nine children, with a stable bifoveal fusion, and only in the mode of alternating presentation with an empty interval between monocular phases. Thus, in this mode of alternating presentation it was possible to perceive not only linear, but also random-dot stereo-images. Comparing the maximum durations of monocular phases for different images in this mode, a significant difference was found between the mean values for stimuli with peripheral vertical stripes (57±2.3 ms) and with central vertical stripes (43.2±2.6 ms; p<0.001), as well as between the mean values for stimuli with peripheral horizontal stripes (56±2.1 ms) and central horizontal stripes (43.6±3.4 ms; p<0.002). The maximum duration of monocular phases for random-dot stereo-images producing the effect of a vertical cylinder (32.2±5.8 ms) and a horizontal cylinder (31.1±6.7 ms) was significantly lower than the maximum duration for stimuli with peripheral vertical and horizontal stripes (p<0.001). The same regularities were observed for the maximum dur ation of the empty i nterval. Conclusion. The stereo-perception is possible in children with residual postoperative micro-deviation. At the same time, the most effective of the images we used are stimuli with a peripheral arrangement of elements that create a stereo effect in condition of a successful fusion. The mode of alternating presentation of stimuli with the presence of an empty interval between monocular phases creates more favorable conditions for the appearance of a stereo effect in comparison with the mode of alternating presentation of stimuli with the presence of a binocular phase between monocular phases and in comparison with the mode of alternating monocular phases. Stereovision with random-dot stereograms causes serious difficulties in most children with postoperative microdeviation, however, it is possible in some cases in the mode of alternating presentation of stimuli with the presence of an empty i nterval between monocular phases.

Tri-modal speech: Audio-visual-tactile integration in speech perception

Speech perception is a multi-sensory experience. Visual information enhances [Sumby and Pollack (1954). J. Acoust. Soc. Am. 25, 212-215] and interferes [McGurk and MacDonald (1976). Nature 264, 746-748] with speech perception. Similarly, tactile information, transmitted by puffs of air arriving at the skin and aligned with speech audio, alters [Gick and Derrick (2009). Nature 462, 502-504] auditory speech perception in noise. It has also been shown that aero-tactile information influences visual speech perception when an auditory signal is absent [Derrick, Bicevskis, and Gick (2019a). Front. Commun. Lang. Sci. 3(61), 1-11]. However, researchers have not yet identified the combined influence of aero-tactile, visual, and auditory information on speech perception. The effects of matching and mismatching visual and tactile speech on two-way forced-choice auditory syllable-in-noise classification tasks were tested. The results showed that both visual and tactile information altered the signal-to-noise threshold for accurate identification of auditory signals. Similar to previous studies, the visual component has a strong influence on auditory syllable-in-noise identification, as evidenced by a 28.04 dB improvement in SNR between matching and mismatching visual stimulus presentations. In comparison, the tactile component had a small influence resulting in a 1.58 dB SNR match-mismatch range. The effects of both the audio and tactile information were shown to be additive.

Working memory in Cantonese and German speaking dyslexic children

BackgroundThe performance of visual and auditory working memory together with different automated central executive functions was investigated on the basis of four computerized, adaptive task sets with measurement of accuracy and reaction time.Participants and procedureEighty-six children selected from 192 dyslexic and nondyslexic children (mean age = 10.29 years) in Hong Kong and Leipzig were matched on intelligence by using the Culture Fair test (CFT 20) and age. The used reading and writing tests were language specific but scientifically similar. Four task sets with visual material (dot and line patterns) and auditory material (tone sequences) were adapted and randomly presented by a computer. Mean and maximum accuracy and speed parameters were measured. The hypotheses of dyslexia deficits and Chinese superiority in working memory performance on nonverbal material were examined.ResultsThe Cantonese speaking children were found to have a working memory advantage in the speed measure on all four task sets with visual and auditory stimulus presentation, and in the accuracy measure on the auditory tasks only. Dyslexia deficits were only found in the Chinese sample for the maximum performance parameters and one auditory task set. In the German sample, the dyslexia deficits were found to be more generalized in the auditory matching and reproduction task sets concerning mean and maximum accuracy and speed parameters.ConclusionsThe novel approach in this study concerns the new paradigm of adaptive, time efficient testing of working memory functions with nonverbal, auditory and visual material.

New characteristics of neurophysiological changes in neurocognitive disorders in HIV-infected patients in Uzbekistan

We aim to study the features of electroencephalographic indices taking into account Р300 in the formation of early neurocognitive disorders. EEG registration was provided out in 20 patients (11 women and 9 men) at rest and with functional tests, the cognitive evoked potentials of the brain P300 upon presentation of visual and auditory stimuli, measured the time of complex sensory-motor responses upon presentation of visual and auditory stimuli, were recorded visual evoked potentials during pattern stimulation. The average age of patients was 35.2 ± 8.8 years. The number of CD4 lymphocytes in blood plasma ranged from 230 to 859 cells / μl, the average was 451 ± 55 cells/μl. Of the 18 patients in whom local changes on the EEG were recorded, involvement of the temporal areas was noted in 94% of cases, the frontal-central areas - in 66% of cases, parietal-occipital - in 50% of cases. When registering visual evoked potentials in 75% of cases, an increase in the latent period of the P300 component was observed on average from 10 to 30% with a decrease in the amplitude of the P300 component and signs of desynchronization of excitation in the visual cortex. For men, the average latent period of P100 was 117.9 ± 7.7 ms, for women - 111.2 ± 7.0 ms (normative data: 102.3 ± 3.2 ms). The obtained results indicate that the presence of diffuse changes, which were characterized mainly by local irritative and epileptiform changes, can serve as electrophysiological criteria for HIV infection.

Результаты использования альтернирующего предъявления стимулов в ортоптическом лечении у детей

Purpose. To evaluate the results in the use of different modes for alternating presentation of stimuli in the orthoptic treatment of strabismus in children. Material and methods. The study included 41 patients with a nonparalytic strabismus (30 children with esotropy and 11 children with exotropy) aged from 7 to 16 years. For additional studies of binocular functions, we used a modified Bagolini test and our own stereo-test created for the conditions of anaglyph separation of visual fields. During the first examination the results with all the used stereo-tests (the Flytest, the Lang-test, and the stereo image that we created) were negative. Besides to the static presentation of test images, three different modes of alternating presentation of stimuli were used: 1) with consecutive monocular presentation of visual stimuli corresponding to the right and left eye; 2) with the presence of an empty interval between monocular phases; 3) with the presence of a binocular phase between monocular phases. The duration of the monocular and binocular phases, as well as the empty interval, was regulated by the researcher. Depending on the results of the examination, an optimal mode of alternative presentation of stimuli for the orthoptic tr eatment was selected individually. Results. In the duration of the monocular phase 50 ms in combination with the duration of an empty interval 50 ms, the majority of children (32 of 41) with strabismus were able to have stereovision. As a result of orthoptic exercises, the number of patients capable of bifoveal fusion increased from 24.4% to 48.8%. Stereovision appeared in 39% of children according to the Fly-test and in some cases according to the Lang-test. In all children with moderate amblyopia the visual acuity increased on average from 0.23±0.01 to 0.52±0.05 (p<0.001), in children with mild amblyopia the visual acuity increased on average from 0.66±0.02 to 0.93±0.01 (p<0.001). A reduction of the strabismus angle or an elimination of postsurgical microdeviation occur in one-third of children. Conclusion. The proposed method for the study of binocular functions in patients with strabismus allows to evaluate the ability to the bifoveal fusion and stereo perception not only with static presentation of visual stimuli, but also with the use of different modes of their alternating presentation. The most favorable mode for the elimination of functional inhibition is the mode of alternating presentation of stimuli with the presence of an empty interval not less than 50 ms between the monocular phases, which are also not less than 50 ms. This mode with the combination of monocular phase duration and empty interval duration in the range from 30 to 60 ms creates the most favorable conditions for the appearance of the stereo effect in the majority of the patients. The use of optimal individually chosen regime of alternating presentation of the stimuli allows to improve significantly the binocular functions, to increase the visual acuity, and in some cases to reduce the angle of strabismus or to eliminate postsurgical microdeviations.

Promoting Young Children’s Understanding of the Situations and Prosocial Responses Related to Jealousy

The present study investigated the effects of two emotion trainings on young children’s knowledge about jealousy. Participants were 53 kindergarten and first-grade children who were assigned to one of two experimental conditions or a control condition. Children in the first experimental condition (video condition) received discussions about the components of jealousy paired with the presentation of dynamic visual stimuli (i.e., animated video clips). Children in the second experimental condition (video and role-play condition) received role-play exercises along with the discussions and video clips. Children in the control condition participated in their typical school curriculum. After receiving three emotion-training sessions of 15 min each, children in both experimental conditions made significant gains in their knowledge of the situations and prosocial cognitive/behavioral responses related to jealousy when compared to children in the control condition. The two experimental conditions made similar gains, showing that both trainings were equally effective at helping children improve their knowledge about jealousy. Implications for supporting young children’s understanding of emotions are discussed.

True contextuality in a psychophysical experiment

Recent crowdsourcing experiments have shown that true contextuality of the kind found in quantum mechanics can also be present in human behavior. In these experiments simple human choices were aggregated over large numbers of respondents, with each respondent dealing with a single context (set of questions asked). In this paper we present experimental evidence of contextuality in individual human behavior, in a psychophysical experiment with repeated presentations of visual stimuli in randomly varying conteXts (arrangements of stimuli). The analysis is based on the Contextuality-by-Default (CbD) theory whose relevant aspects are reviewed in the paper. CbD allows one to detect contextuality in the presence of direct influences, i.e., when responses to the same stimuli have different distributions in different contexts. The experiment presented is also the first one in which contextuality is demonstrated for responses that are not dichotomous, with five options to choose among. CbD requires that random variables representing such responses be dichotomized before they are subjected to contextuality analysis. A theorem says that a system consisting of all possible dichotomizations of responses has to be contextual if these responses violate a certain condition, called nominal dominance. In our experiment nominal dominance was violated in all data sets, with very high statistical reliability established by bootstrapping.

Area V1 responses to illusory corner-folds in Vasarely's nested squares and the Alternating Brightness Star illusions.

Vasarely’s nested squares illusion shows that the corners of concentric squares, arranged in a gradient of increasing or decreasing luminance, generate illusory “corner-folds,” which appear more salient (either brighter or darker) than the adjacent flat (non- corner) regions of each individual square. The Alternating Brightness Star (ABS) illusion, based on Vasarely’s classic nested squares, further shows that the strength of these corner-folds depends on corner angle. Previous psychophysical studies showed the relationship between corner angle and perceived contrast in the ABS illusion to be linear, with sharp angles looking higher in contrast, and shallow angles lower in contrast. Center-surround difference-of-Gaussians (DOG) modeling did not replicate this linear relationship, however, suggesting that a full neural explanation of the nested squares and ABS illusions might be found in the visual cortex, rather than at subcortical stages. Here we recorded the responses from single area V1 neurons in the awake primate, during the presentation of visual stimuli containing illusory corner-folds of various angles. Our results showed stronger neural responses for illusory corner-folds made from sharper than from shallower corners, consistent with predictions from the previous psychophysical work. The relationship between corner angle and strength of the neuronal responses, albeit parametric, was apparently non-linear. This finding was in line with the previous DOG data, but not with the psychophysical data. Our combined results suggest that, whereas corner-fold illusions likely originate from center-surround retinogeniculate processes, their complete neural explanation may be found in extrastriate visual cortical areas.

P300 in detecting concealed information and deception: A review.

Studies using the P300 ERP in detection of concealed information are reviewed. An overview of the initial findings, methodological issues, and use of bootstrapping methods for data analysis are considered, with various protocols explicated. Applications to forensic issues, employee screening, cognitive deficit malingering, and facial recognition in lineups are outlined. Countermeasures to the original P300-based tests are described, and a possible approach to this problem using a new complex-trial protocol is offered. Applications of this protocol to forensic and antiterror scenarios are then presented, along with its first independent replication. Studies of visual versus auditory stimulus presentation in the complex-trial protocol are evaluated. Findings from attempted voluntary suppression of P300 as a recognition signal are presented, and the effects of motivational manipulations on the P300-based complex-trial protocol are summarized. Limitations of the research are reviewed, and, based on this review, future directions of P300 methods for detection of concealed information and deception are suggested that may guide the development of more precision and reliability of this promising tool.

Motor expertise modulates unconscious rather than conscious executive control.

BackgroundExecutive control, the ability to regulate the execution of a goal-directed task, is an important element in an athlete’s skill set. Although previous studies have shown that executive control in athletes is better than that in non-athletes, those studies were mainly confined to conscious executive control. Many recent studies have suggested that executive control can be triggered by the presentation of visual stimuli without participant’s conscious awareness. However, few studies have examined unconscious executive control in sports. Thus, the present study investigated whether, similar to conscious executive control, unconscious executive control in table tennis athletes is superior to that in non-athletes.MethodsIn total, 42 age-matched undergraduate students were recruited for this study; 22 nonathletic students lacking practical athletic experience comprised one group, and 20 table tennis athletes with many years of training in this sport comprised a second group. Each participant first completed an unconscious response priming task, the unconscious processing of visual-spatial information, and then completed a conscious version of this same response priming task.ResultsTable tennis athletes showed a significant response priming effect, whereas non-athletes did not, when participants were unable to consciously perceive the visual-spatial priming stimuli. In addition, the number of years the table tennis athletes had trained in this sport (a measure of their motor expertise) was positively correlated with the strength of the unconscious response priming effect. However, both table tennis athletes and non-athletes showed a response priming effect when the primes were unmasked and the participants were able to consciously perceive the visual-spatial priming stimuli.ConclusionOur results suggest that motor expertise modulates unconscious, rather than conscious, executive control and that motor expertise is positively correlated with unconscious executive control in table tennis athletes.

Unimodal and crossmodal extinction of nociceptive stimuli in healthy volunteers

Nociception, the physiological mechanisms specifically processing information about noxious and potentially painful stimuli, has the double function to warn about potential body damages (interoception) and about the cause of such potential damages (exteroception). The exteroceptive function is thought to rely on multisensory integration between somatic and extra-somatic stimuli, provided that extra-somatic stimuli occur near the stimulated body area. To corroborate this hypothesis, we succeeded to show in healthy volunteers that the perception of nociceptive stimuli applied on one hand can be extinguished, as compared to single presentation, by the simultaneous application of nociceptive stimuli on the opposite hand, as well as by the presentation of visual stimuli near the opposite hand. On the contrary, visual stimuli presented near the same stimulated hand facilitated the perception of nociceptive stimuli. This nociceptive extinction phenomenon indicates that the perception of noxious events does not merely rely on the specific activation of the nociceptive system, but also depends on other sensory experiences about the body and the space around it.

Validation of Kinesthetic Illusion by Ball-Rotation System Which Present Visual and Haptic Stimuli

Validation of Kinesthetic Illusion by Ball-Rotation System Which Present Visual and Haptic Stimuli

Systematic Integration of Structural and Functional Data into Multi-Scale Models of Mouse Primary Visual Cortex

Structural rules underlying functional properties of cortical circuits are poorly understood. To explore these rules systematically, we integrated information from extensive literature curation and large-scale experimental surveys into data-driven, biologically realistic models of the mouse primary visual cortex. The models were constructed at two levels of granularity, using either biophysically-detailed or point-neuron models, with identical network connectivity. Both models were compared to each other and to experimental recordings of neural activity during presentation of visual stimuli to awake mice. Three specific predictions emerge from model construction and simulations: about connectivity between excitatory and parvalbumin-negative inhibitory neurons, functional specialization of connections between excitatory neurons, and the impact of the cortical retinotopic map on structure-function relationships. Finally, despite their vastly different neuronal levels of granularity, both models perform similarly at the level of firing rate distributions. All data and models are freely available as a resource for the community.

Detection and analysis of spatiotemporal patterns in brain activity.

There is growing evidence that population-level brain activity is often organized into propagating waves that are structured in both space and time. Such spatiotemporal patterns have been linked to brain function and observed across multiple recording methodologies and scales. The ability to detect and analyze these patterns is thus essential for understanding the working mechanisms of neural circuits. Here we present a mathematical and computational framework for the identification and analysis of multiple classes of wave patterns in neural population-level recordings. By drawing a conceptual link between spatiotemporal patterns found in the brain and coherent structures such as vortices found in turbulent flows, we introduce velocity vector fields to characterize neural population activity. These vector fields are calculated for both phase and amplitude of oscillatory neural signals by adapting optical flow estimation methods from the field of computer vision. Based on these velocity vector fields, we then introduce order parameters and critical point analysis to detect and characterize a diverse range of propagating wave patterns, including planar waves, sources, sinks, spiral waves, and saddle patterns. We also introduce a novel vector field decomposition method that extracts the dominant spatiotemporal structures in a recording. This enables neural data to be represented by the activity of a small number of independent spatiotemporal modes, providing an alternative to existing dimensionality reduction techniques which separate space and time components. We demonstrate the capabilities of the framework and toolbox with simulated data, local field potentials from marmoset visual cortex and optical voltage recordings from whole mouse cortex, and we show that pattern dynamics are non-random and are modulated by the presence of visual stimuli. These methods are implemented in a MATLAB toolbox, which is freely available under an open-source licensing agreement.

An Exploratory Study on the Central Nervous Correlates of Sexual Excitation and Sexual Inhibition

The Sexual Inhibition/Sexual Excitation Scales (SIS/SES) measure sexual excitation and sexual inhibition proneness. We used SIS and SES scores of 62 heterosexual teleiophilic men (Mage 34.3, SD = 9.9) to predict brain activation levels during the presentation of male and female visual sexual stimuli in a magnetic resonance imaging (MRI) scanner. Statistical analyses revealed significant correlations. SES and SIS1 scores were positively associated with brain activation in various brain regions during the presentation of both male and female stimuli. SIS2 turned out to be a weaker predictor of brain activation, still revealing one significant correlation in the right lateral orbitofrontal cortex. Significant regions for SES and SIS1 were, among others, primary and supplementary motor areas, the caudate nucleus, the dorsal anterior cingulate cortex, anterior insula, and prefrontal areas. Our study can be seen as an exploratory investigation of SIS and SES with means of functional brain imaging. The results provide a promising contribution to the assertion of neurophysiological systems of sexual inhibition and excitation proneness.

Conserved behavioral circuits govern high-speed decision-making in wild fish shoals

To evade their predators, animals must quickly detect potential threats, gauge risk, and mount a response. Putative neural circuits responsible for these tasks have been isolated in laboratory studies. However, it is unclear whether and how these circuits combine to generate the flexible, dynamic sequences of evasion behavior exhibited by wild, freely moving animals. Here, we report that evasion behavior of wild fish on a coral reef is generated through a sequence of well-defined decision rules that convert visual sensory input into behavioral actions. Using an automated system to present visual threat stimuli to fish in situ, we show that individuals initiate escape maneuvers in response to the perceived size and expansion rate of an oncoming threat using a decision rule that matches dynamics of known loom-sensitive neural circuits. After initiating an evasion maneuver, fish adjust their trajectories using a control rule based on visual feedback to steer away from the threat and toward shelter. These decision rules accurately describe evasion behavior of fish from phylogenetically distant families, illustrating the conserved nature of escape decision-making. Our results reveal how the flexible behavioral responses required for survival can emerge from relatively simple, conserved decision-making mechanisms.

Effects of the Simultaneous Presentation of Corresponding Auditory and Visual Stimuli on Size Variance Perception.

To overcome limitations in perceptual bandwidth, humans condense various features of the environment into summary statistics. Variance constitutes indices that represent diversity within categories and also the reliability of the information regarding that diversity. Studies have shown that humans can efficiently perceive variance for visual stimuli; however, to enhance perception of environments, information about the external world can be obtained from multisensory modalities and integrated. Consequently, this study investigates, through two experiments, whether the precision of variance perception improves when visual information (size) and corresponding auditory information (pitch) are integrated. In Experiment 1, we measured the correspondence between visual size and auditory pitch for each participant by using adjustment measurements. The results showed a linear relationship between size and pitch—that is, the higher the pitch, the smaller the corresponding circle. In Experiment 2, sequences of visual stimuli were presented both with and without linked auditory tones, and the precision of perceived variance in size was measured. We consequently found that synchronized presentation of audio and visual stimuli that have the same variance improves the precision of perceived variance in size when compared with visual-only presentation. This suggests that audiovisual information may be automatically integrated in variance perception.