Evaluation of Free-operant Preference Assessment: Outcomes of Varying Session Duration and Problem Behavior

Previous researchers have found brief versions of preference assessments correspond to outcomes of longer preference assessments, and that varying levels of problem behavior occur in different preference assessments. Researchers conducted two studies to examine 1-, 2-, and 5-min duration outcomes of the free-operant preference assessment and evaluated the correspondence between the shorter and longer session durations and to identify frequency of problem behavior at each duration. Researchers also assessed relative reinforcing efficacy of the highest preferred stimulus from the shortest duration sessions. Moderate to high correlations were found between the 1- and 2-min sessions and 1- and 5-min sessions across six of eight participants diagnosed with autism spectrum disorder in Study 1 and two of three participants in Study 2. Furthermore, all highest preference stimuli identified in the shortest duration assessment served as reinforcers. Researchers found problem behavior generally occurred more in longer duration sessions.

Eye Preference for Emotional Stimuli in Sichuan Snub-Nosed Monkeys

This study presents the first evidence of effects of applying both positive and negative stimuli simultaneously on visual laterality in Old World monkeys. Thirteen captive individuals of Sichuan snub-nosed monkeys (<i>Rhinopithecus roxellana</i>) were chosen as focal subjects in the monocular box task. In total, 4 emotional categories (the preferred, the novel, the neutral, and the fearful) of visual stimuli were applied, and eye preference was recorded when individuals looked at each stimulus through an observation hole in the box. We found evidence of visual laterality at the individual level, but not at the group level for each stimulus. For the preferred stimulus, 9 individuals showed significant right-eye preference while 4 individuals showed significant left-eye preference. For the other 3 stimuli, 7 individuals displayed significant right-eye preference while 6 individuals displayed significant left-eye preference. Totally, 11 of 13 individuals showed consistency in the visual laterality direction (7 right-eye preference and 4 left-eye preference) across the 4 stimuli. The remaining 2 individuals displayed right-eye preference for the preferred stimulus while they showed left-eye preference for the other 3 stimuli. There was no significant difference among various stimuli regarding the direction of visual laterality. However, there was a significant difference in the strength of visual laterality among various stimulus categories. The strength of visual laterality for the preferred stimulus was significantly lower than that for the other 3 stimuli. The strength of visual laterality for the fearful stimulus was significantly higher than that for the novel stimulus and the neutral stimulus. Furthermore, the looking duration for the preferred stimulus was significantly higher than that for the other 3 stimuli. The looking duration for the novel stimulus was significantly higher than that for the neutral stimulus and the fearful stimulus. The looking duration for the neutral stimulus was significantly higher than that for the fearful stimulus. Our findings indicate emotional valence of stimuli significantly influence eye looking duration and the strength of visual laterality but not for the direction of visual laterality in this species. Taken together, emotional valence of stimuli plays an important role in the eye use of <i>R. roxellana</i>.

Tolerance Training with Adolescents in a Residential Juvenile Facility

For individuals receiving treatment in residential juvenile facilities, the inability to tolerate typical but unpleasant stimulus events may manifest in aggressive behavior toward staff or other residents. Such behaviors can lead to loss of privileges, interfere with other treatments, and contribute to negative staff-student relationships. As a procedure, tolerance training (TT) involves systematically increasing the duration of exposure to an undesired stimulus event or situation. The current study evaluated the effects of a procedure to increase tolerance of aversive situations for four adolescents who were receiving treatment for sexual offenses in a residential detention facility. Results from single-subject experimental designs indicate that TT increased all four adolescents’ ability to tolerate a non-preferred stimulus event. We briefly discuss the clinical implications of the use of behavior-analytic procedures to improve skill sets for adolescents in residential treatment facilities.

Evaluating Preference and Performance in Accumulated versus Distributed Response–Reinforcer Arrangements

To determine the effects of response–reinforcer arrangements on task performance and preference, participants completed tasks on accumulated and distributed response–reinforcer arrangements. Three males diagnosed with an autism spectrum disorder completed tasks before receiving 5-min or 30-seconds access to a preferred stimulus. To enhance discrimination between the two arrangements, color-coded token boards were used to represent each arrangement. Responding was evaluated within a multielement design to compare the response rate across conditions for each participant. A preference assessment was conducted after the comparison to determine whether a preference for one of the arrangements emerged. All participants produced a higher rate of responding in the accumulated schedule of reinforcement.

Diversity of Feature Selectivity in Macaque Visual Cortex Arising from a Limited Number of Broadly Tuned Input Channels

Spike (action potential) responses of most primary visual cortical cells in the macaque are sharply tuned for the orientation of a line or an edge, and neurons preferring similar orientations are clustered together in cortical columns. The preferred stimulus orientation of these columns span the full range of orientations, as observed in recordings of spikes and in classical optical imaging of intrinsic signals. However, when we imaged the putative thalamic input to striate cortical cells that can be seen in imaging of intrinsic signals when they are analyzed on a larger spatial scale, we found that the orientation domain map of the primary visual cortex did not show the same diversity of orientations. This map was dominated by just the one orientation that is most commonly preferred by neurons in the retina and the lateral geniculate nucleus. This supports cortical feature selectivity and columnar architecture being built upon feed-forward signals transmitted from the thalamus in a very limited number of broadly tuned input channels.

Diversity of feature selectivity in macaque visual cortex arising from limited number of broadly-tuned input channels

Spikes (action potential) responses of most primary visual cortical cells in the macaque are sharply tuned for the orientation of a line or an edge and neurons preferring similar orientations are clustered together in cortical columns. The preferred stimulus orientation of these columns span the full range of orientations, as observed in recordings of spikes, which represent the outputs of cortical neurons. However, when we imaged also the thalamic input to these cells that occur on a larger spatial scale, we found that the orientation domain map of the primary visual cortex did not show the diversity of orientations exhibited by signals representing outputs of the cells. This map was dominated by just the one orientation that is most commonly represented in subcortical responses. This supports cortical feature selectivity and columnar architecture being built upon feed-forward signals transmitted from the thalamus in a very limited number of broadly-tuned input channels.

Stimulus Preference and Mental Imagery: Influencing the Way Sexual Stimuli are Viewed and the Intensity of Subjective Sexual Arousal

Background: The connection between mental imagery and feelings of presence within a film has not yet been investigated in sex research in relation to observational stance (imagining oneself as either a spectator or participant while viewing a film). Several studies have shown that people who take a participant stance when viewing a sexual film are more likely to report greater subjective sexual arousal (SSA). Research on observational stance has also found that viewing a preferred stimulus is predictive of taking a participant stance. Despite this, very few studies have allowed participants to select their own stimuli. Methodology: Sexual films that were researcher-selected or participant-selected will be presented to women and men, while continuously measuring their SSA. Information will be collected about observational stance and vividness of mental imagery via questionnaires. Expected Results: 1. Greater mental imagery ability will be associated with adopting a participant stance. 2. The relationship between mental imagery ability and taking a participant stance will be stronger for participant-selected sexual stimuli than for researcher-selected sexual stimuli. 3. Taking a participant stance will be associated with greater SSA. 4. The relationship between taking a participant stance and SSA will be stronger for participant-selected sexual stimuli than for researcher-selected stimuli. Conclusions: This project is the first to examine the relationship between mental imagery and observational stance for sexual stimuli, and is among the first to allow participants to self-select stimuli. Results of this project will encourage the development of standardized procedures for providing participants with optimal sexual stimulation.

Dendrites Enable a Robust Mechanism for Neuronal Stimulus Selectivity

Hearing, vision, touch: underlying all of these senses is stimulus selectivity, a robust information processing operation in which cortical neurons respond more to some stimuli than to others. Previous models assume that these neurons receive the highest weighted input from an ensemble encoding the preferred stimulus, but dendrites enable other possibilities. Nonlinear dendritic processing can produce stimulus selectivity based on the spatial distribution of synapses, even if the total preferred stimulus weight does not exceed that of nonpreferred stimuli. Using a multi-subunit nonlinear model, we demonstrate that stimulus selectivity can arise from the spatial distribution of synapses. We propose this as a general mechanism for information processing by neurons possessing dendritic trees. Moreover, we show that this implementation of stimulus selectivity increases the neuron's robustness to synaptic and dendritic failure. Importantly, our model can maintain stimulus selectivity for a larger range of loss of synapses or dendrites than an equivalent linear model. We then use a layer 2/3 biophysical neuron model to show that our implementation is consistent with two recent experimental observations: (1) one can observe a mixture of selectivities in dendrites that can differ from the somatic selectivity, and (2) hyperpolarization can broaden somatic tuning without affecting dendritic tuning. Our model predicts that an initially nonselective neuron can become selective when depolarized. In addition to motivating new experiments, the model's increased robustness to synapses and dendrites loss provides a starting point for fault-resistant neuromorphic chip development.

Local processing of visual information in neurites of VGluT3-expressing amacrine cells

Synaptic inputs to neurons are distributed across extensive neurite arborizations. To what extent arbors process inputs locally or integrate them globally is, for most neurons, unknown. This question is particularly relevant for amacrine cells, a diverse class of retinal interneurons, which receive input and provide output through the same neurites. Here, we used two-photon Ca2+ imaging to analyze visual processing in VGluT3-expressing amacrine cells (VG3-ACs), an important component of object motion sensitive circuits in the retina. VG3-AC neurites differed in their preferred stimulus contrast (ON vs. OFF); and ON and OFF responses varied in transience and preferred stimulus size. Contrast preference changed predictably with the laminar position of neurites in the inner plexiform layer. Yet, neurites at all depths were strongly activated by local but not by global image motion. Thus, VG3-AC neurites process visual information locally, exhibiting diverse responses to contrast steps, but uniform object motion selectivity.