Stimulus Objects Research Articles

Visual Attention to Competing Social and Object Images by Preschool Children with Autism Spectrum Disorder

Eye tracking studies of young children with autism spectrum disorder (ASD) report a reduction in social attention and an increase in visual attention to non-social stimuli, including objects related to circumscribed interests (CI) (e.g., trains). In the current study, fifteen preschoolers with ASD and 15 typically developing controls matched on gender and age (range 24-62 months) were eye tracked while viewing a paired preference task of face and object stimuli. While co-varying verbal and nonverbal developmental quotients, preschoolers with ASD were similar to controls in their visual attention to faces presented with objects unrelated to CI, but attended significantly less than controls to faces presented with CI-related objects. This was consistent across three metrics: preference, prioritization and duration. Social attention in preschoolers with ASD therefore appears modulated by salience of competing non-social stimuli, which may affect the development of both social and non-social characteristics of the disorder.

People-selectivity, audiovisual integration and heteromodality in the superior temporal sulcus

The functional role of the superior temporal sulcus (STS) has been implicated in a number of studies, including those investigating face perception, voice perception, and face–voice integration. However, the nature of the STS preference for these ‘social stimuli’ remains unclear, as does the location within the STS for specific types of information processing. The aim of this study was to directly examine properties of the STS in terms of selective response to social stimuli. We used functional magnetic resonance imaging (fMRI) to scan participants whilst they were presented with auditory, visual, or audiovisual stimuli of people or objects, with the intention of localising areas preferring both faces and voices (i.e., ‘people-selective’ regions) and audiovisual regions designed to specifically integrate person-related information. Results highlighted a ‘people-selective, heteromodal’ region in the trunk of the right STS which was activated by both faces and voices, and a restricted portion of the right posterior STS (pSTS) with an integrative preference for information from people, as compared to objects. These results point towards the dedicated role of the STS as a ‘social-information processing’ centre.

PERCEPTION, ATTENTION AND WORDS: AN INTERVEHAVIORAL ACCOUNT

Perception is still a controversial topic in psychology and in the history of science. Historically, it has been studied using non-existent entities that are responsible for the way organisms interact with the world perceived. A naturalistic approach developed by Kantor (1924, 1926, 1977; Kantor & Smith, 1975) is presented as to alternative of traditional explanations. The concepts of sensation, attention and perception are explained as fundamental parts of the total response system. Perceptual functions are described as historical and context dependent; they define how the organism will respond to a stimulus object. As any other function, perceptual functions can also be substitutable; this possibility is developed further while considering non-linguistic perceptual functions of words. It is concluded that perceptual reactions are fundamental for any further interaction of the organism with its environment; therefore it should not be left outside of the study of scientific psychology.

Comparable mechanisms of working memory interference by auditory and visual motion in youth and aging

Intrasensory interference during visual working memory (WM) maintenance by object stimuli (such as faces and scenes), has been shown to negatively impact WM performance, with greater detrimental impacts of interference observed in aging. Here we assessed age-related impacts by intrasensory WM interference from lower-level stimulus features such as visual and auditory motion stimuli. We consistently found that interference in the form of ignored distractions and secondary task interruptions presented during a WM maintenance period, degraded memory accuracy in both the visual and auditory domain. However, in contrast to prior studies assessing WM for visual object stimuli, feature-based interference effects were not observed to be significantly greater in older adults. Analyses of neural oscillations in the alpha frequency band further revealed preserved mechanisms of interference processing in terms of post-stimulus alpha suppression, which was observed maximally for secondary task interruptions in visual and auditory modalities in both younger and older adults. These results suggest that age-related sensitivity of WM to interference may be limited to complex object stimuli, at least at low WM loads.

Repetition Probability Does Not Affect fMRI Repetition Suppression for Objects

Previously several functional magnetic resonance imaging (fMRI) studies point toward the role of perceptual expectations in determining adaptation or repetition suppression (RS) in humans. These studies showed that the probability of repetitions of faces within a block influences the magnitude of adaptation in face-related areas of the human brain (Summerfield et al., 2008). However, a current macaque single-cell/local field potential (LFP) recording study using objects as stimuli found no evidence for the modulation of the neural response by the repetition probability in the inferior temporal cortex (Kaliukhovich and Vogels, 2010). Here we examined whether stimulus repetition probability affects fMRI repetition suppression for nonface object stimuli in the human brain. Subjects were exposed to either two identical [repetition trials (RTs)] or two different [alternation trials (ATs)] object stimuli. Both types of trials were presented blocks consisting of either 75% [repetition blocks (RBs)] or 25% [alternation blocks (ABs)] of RTs. We found strong RS, i.e., a lower signal for RTs compared to ATs, in the object sensitive lateral occipital cortex as well as in the face-sensitive occipital and fusiform face areas. More importantly, however, there was no significant difference in the magnitude of RS between RBs and ABs in each of the areas. This is in agreement with the previous monkey single-unit/LFP findings and suggests that RS in the case of nonface visual objects is not modulated by the repetition probability in humans. Our results imply that perceptual expectation effects vary for different visual stimulus categories.

Will the most informative object stand? Determining the impact of structural context on informativeness judgements

A fundamental unsolved problem in the cognitive sciences concerns why, how, and to what extent humans judge object stimuli as conveying different amounts of information. Central to this problem is how the notion of informativeness is conceptualised by humans in the first place. In this paper, we investigate this question from the standpoint of how the structure of categories of objects influences informativeness judgements about their members. Results from our two experiments show that the structural or relational context surrounding single-object cues from a categorical stimulus largely determines such informativeness judgements. Moreover, we found that object cues elicit absolute magnitude judgements about their associated concept that are not consistent with the prototype interpretation of the concept. We were able to account for over 90% of the variance in the data from our two judgement experiments with a general theory and measure of information referred to as Representational Information.

The role of histamine receptors in the consolidation of object recognition memory

Findings have shown that histamine receptors in the hippocampus modulate the acquisition and extinction of fear motivated learning. In order to determine the role of hippocampal histaminergic receptors on recognition memory, adult male Wistar rats with indwelling infusion cannulae stereotaxically placed in the CA1 region of dorsal hippocampus were trained in an object recognition learning task involving exposure to two different stimulus objects in an enclosed environment. In the test session, one of the objects presented during training was replaced by a novel one. Recognition memory retention was assessed 24h after training by comparing the time spent in exploration (sniffing and touching) of the known object with that of the novel one. When infused in the CA1 region immediately, 30, 120 or 360min posttraining, the H1-receptor antagonist, pyrilamine, the H2-receptor antagonist, ranitidine, and the H3-receptor agonist, imetit, blocked long-term memory retention in a time dependent manner (30–120min) without affecting general exploratory behavior, anxiety state or hippocampal function. Our data indicate that histaminergic system modulates consolidation of object recognition memory through H1, H2 and H3 receptors.

Altered automatic face processing in individuals with high-functioning autism spectrum disorders: Evidence from visual evoked potentials

Individuals with autism spectrum disorders (ASDs) have different automatic responses to faces than typically developing (TD) individuals. We recorded visual evoked potentials (VEPs) in 10 individuals with high-functioning ASD (HFASD) and 10 TD individuals. Visual stimuli consisted of upright and inverted faces (fearful and neutral) and objects presented subliminally in a backward-masking paradigm. In all participants, the occipital N1 (about 100ms) and P1 (about 120ms) peaks were major components of the evoked response. We calculated “subliminal face effect (SFE)” scores by subtracting the N1/P1 amplitudes and latencies of the object stimuli from those of the face stimuli. In the TD group, the SFE score for the N1 amplitude was significantly higher for upright fearful faces but not neutral faces, and this score was insignificant when the stimuli were inverted. In contrast, the N1 amplitude of the HFASD subjects did not show this SFE in the upright orientation. There were no significant group differences in SFE scores for P1 amplitude, latency, or N1 latency. Our findings suggest that individuals with HFASD have altered automatic visual processing for emotional faces within the lower level of the visual cortex. This impairment could be a neural component of the disrupted social cognition observed in individuals with HFASD.

Object discrimination and reversal learning in infant and juvenile non‐human primates in a non‐clinical laboratory

Biopharmaceutical development necessitates use of non-human primates in toxicology, leading to adoption of non-traditional methods including cognitive function assessment. A two-object discrimination and reversal test in cynomolgus monkeys (Macaca fascicularis) was performed using a Wisconsin General Testing Apparatus (WGTA). Non-clinical study design and regulatory considerations dictate that infants are raised by their biological mothers until weaning at 6 months. Thirty-four animals (6-21 months of age) were trained to discriminate between two randomly selected stimulus objects to retrieve a reward. Following training, days to first reversal after interchanging the reward were measured. Both sexes acquired visual discrimination skills at similar rates. Trends in learning and reversals completed were uniform across age groups. Completing training early in some subjects had no impact on subsequent testing phases. Weaned cynomolgus monkey infants can be successfully tested for cognitive abilities using the WGTA in a non-clinical laboratory setting.

Palinopsia Induced by Topiramate and Zonisamide in a Patient With Migraine

Palinopsia is an illusory visual phenomenon consisting in the persistence or recurrence of visual images after the exciting stimulus object has been removed. It has been reported in association with parietal and occipital lobe lesions, migraine auras, and related to the use of several drugs and illicit drugs. Here, we report the case of a 23-year-old woman with a 4-year history of episodic migraine with aura who developed palinopsia during sequential prophylactic therapies with topiramate and zonisamide. Although the exact physiopathology of this phenomenon remains unknown, topiramate- and zonisamide-induced palinopsia support an increase on serotonergic activity as a possible mechanism for this visual disorder.

Parietal and frontal contributions to episodic encoding of location

Specific contributions of frontal and parietal regions to visuospatial encoding and attention remain controversial. This study used fMRI to examine associative encoding of sequentially-presented spatial cues and object stimuli. The cue preceded the centrally-displayed object by a jittered-delay-interval to better isolate attempt and success in episodically integrating pure location information with separately presented objects. Superior parietal response was modulated by attempted location binding, while superior/middle frontal response was predictive of successful location binding.

Syntactic prominence in Icelandic Experiencer arguments: quirky subjects vs. dative objects

AbstractAs has often been demonstrated, Icelandic Quirky Subjects largely behave like canonical nominative subjects and unlike topicalized objects. Among verbs selecting for Quirky Subjects, experiential predicates with a dative Experiencer subject and a nominative Stimulus object are the most common type. Recently, several studies have proposed a sub-class within this group of dat-nom-verbs, characterized by an alternation in their argument mapping. Here, both the dative Experiencer and the nominative Stimulus can occur as either the syntactic subject or object.This paper empirically investigates this class as well as the extent to which its alternation is determined by semantic and pragmatic factors.

FMRI Investigation of Monocular Pattern Rivalry

In monocular pattern rivalry, a composite image is shown to both eyes. The patient experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. We used fMRI at 3T to image brain activity while participants perceived monocular rivalry passively or indicated their percepts with a task. The stimulus patterns were left/right oblique gratings, face/house composites, or a nonrivalrous control stimulus that did not support the perception of transparency or image segmentation. All stimuli were matched for luminance, contrast, and color. Compared with the control stimulus, the cortical activation for passive viewing of grating rivalry included dorsal and ventral extrastriate cortex, superior and inferior parietal regions, and multiple sites in frontal cortex. When the BOLD signal for the object rivalry task was compared with the grating rivalry task, a similar whole-brain network was engaged, but with significantly greater activity in extrastriate regions, including V3, V3A, fusiform face area (FFA), and parahippocampal place area (PPA). In addition, for the object rivalry task, FFA activity was significantly greater during face-dominant periods whereas parahippocampal place area activity was greater during house-dominant periods. Our results demonstrate that slight stimulus changes that trigger monocular rivalry recruit a large whole-brain network, as previously identified for other forms of bistability. Moreover, the results indicate that rivalry for complex object stimuli preferentially engages extrastriate cortex. We also establish that even with natural viewing conditions, endogenous attentional fluctuations in monocular pattern rivalry will differentially drive object-category-specific cortex, similar to binocular rivalry, but without complete suppression of the nondominant image.

Sensory determinants of agonistic interactions in the red-backed salamander, Plethodon cinereus

Many animals use and react to multimodal signals — signals that occur in more than one sensory modality. This study focused on the respective roles of vision, chemoreception, and their possible interaction in determining agonistic responses of the red-backed salamander, Plethodon cinereus. The use of a computer display allowed separate or combined presentation of visual and chemical cues. A cue isolation experiment using adult male and juvenile salamanders showed that both visual and chemical cues from unfamiliar male conspecifics could increase aggressive displays. Submissive displays were only increased in juveniles, and specifically by the visual cue. The rate of chemoinvestigation of the substrate was increased only by chemical cues in adults, whereas both chemical and visual cues increased this behaviour in juveniles. Chemoinvestigation appears, thus, more dependent on sensory input in juvenile salamanders. A follow-up experiment comparing responses to visual cues of different animals (conspecific salamander, heterospecific salamander and earthworm) or an inanimate object (wood stick) showed that exploratory behaviour was higher in the presence of the inanimate object stimulus. The heterospecific salamander stimulus produced strong submissive and escape responses, while the conspecific salamander stimulus promoted aggressive displays. Finally, the earthworm stimulus increased both aggressive and submissive behaviours at intermediate levels when compared to salamander cues. These specific combinations of agonistic and exploratory responses to each stimulus suggest that salamanders could discriminate the cues visually. This study sheds some light on how information from different sensory modalities guides social behaviour at different life stages in a salamander.

A response to ‘Regarding “Syrnyk, C. and Meints, K., 2012, Fishy fishes: the typicality of object stimuli used to assess children's language in the Reynell Development Language Scales – III

We appreciate Edwards, Letts, and Sinka’s desire to respond to our work and take the opportunity to reply to their concerns and to reaffirm the intent and nature of this particular study.

Regarding “Syrnyk, C. and Meints, K., 2012, Fishy fishes: the typicality of object stimuli used to assess children's language in the Reynell Development Language Scales – III

Letter to the Editor The item referred to here is a 'Letter to the Editor', regarding a paper published in the July-August issue of the International Journal of Language and Communication Disorders (vol. 47, 4, pages 437-450): “Syrnyk, C. and Meints, K., 2012, Fishy fishes: the typicality of object stimuli used to assess children’s language in the Reynell Developmental Language Scales – III.” The letter identifies concerns with the aims and conclusions drawn in Syrnyk and Meints' study and responds to the observations and comments the authors make about the Reynell Developmental Language Scalees III (a language test co-authored by Edwards, Letts and Sinka).

Solid shape discrimination from vision and haptics: natural objects (Capsicum annuum) and Gibson’s “feelies”

A set of three experiments evaluated 96 participants' ability to visually and haptically discriminate solid object shape. In the past, some researchers have found haptic shape discrimination to be substantially inferior to visual shape discrimination, while other researchers have found haptics and vision to be essentially equivalent. A primary goal of the present study was to understand these discrepant past findings and to determine the true capabilities of the haptic system. All experiments used the same task (same vs. different shape discrimination) and stimulus objects (James Gibson's "feelies" and a set of naturally shaped objects--bell peppers). However, the methodology varied across experiments. Experiment 1 used random 3-dimensional (3-D) orientations of the stimulus objects, and the conditions were full-cue (active manipulation of objects and rotation of the visual objects in depth). Experiment 2 restricted the 3-D orientations of the stimulus objects and limited the haptic and visual information available to the participants. Experiment 3 compared restricted and full-cue conditions using random 3-D orientations. We replicated both previous findings in the current study. When we restricted visual and haptic information (and placed the stimulus objects in the same orientation on every trial), the participants' visual performance was superior to that obtained for haptics (replicating the earlier findings of Davidson et al. in Percept Psychophys 15(3):539-543, 1974). When the circumstances resembled those of ordinary life (e.g., participants able to actively manipulate objects and see them from a variety of perspectives), we found no significant difference between visual and haptic solid shape discrimination.

Familiarity and recollection produce distinct eye movement, pupil and medial temporal lobe responses when memory strength is matched

Two experiments explored eye measures (fixations and pupil response patterns) and brain responses (BOLD) accompanying the recognition of visual object stimuli based on familiarity and recollection. In both experiments, the use of a modified remember/know procedure led to high confidence and matched accuracy levels characterising strong familiarity (F3) and recollection (R) responses. In Experiment 1, visual scanning behaviour at retrieval distinguished familiarity-based from recollection-based recognition. Recollection, relative to strength-matched familiarity, involved significantly larger pupil dilations and more dispersed fixation patterns. In Experiment 2, the hippocampus was selectively activated for recollected stimuli, while no evidence of activation was observed in the hippocampus for strong familiarity of matched accuracy. Recollection also activated the parahippocampal cortex (PHC), while the adjacent perirhinal cortex (PRC) was actively engaged in response to strong familiarity (than to recollection). Activity in prefrontal and parietal areas differentiated familiarity and recollection in both the extent and the magnitude of activity they exhibited, while the dorsomedial thalamus showed selective familiarity-related activity, and the ventrolateral and anterior thalamus selective recollection-related activity. These findings are consistent with the view that the hippocampus and PRC play contrasting roles in supporting recollection and familiarity and that these differences are not a result of differences in memory strength. Overall, the combined pupil dilation, eye movement and fMRI data suggest the operation of recognition mechanisms drawing differentially on familiarity and recollection, whose neural bases are distinct within the MTL.

Can complex visual discrimination deficits in amnesia be attributed to the medial temporal lobe? An investigation into the effects of medial temporal lobe damage on brain connectivity

It has been suggested that complex visual discrimination deficits in patients with medial temporal lobe (MTL) damage may be explained by damage or dysfunction beyond the MTL. We examined the resting functional networks and white matter connectivity of two amnesic patients who have consistently demonstrated discrimination impairments for complex object and/or spatial stimuli across a number of studies. Although exploratory analyses revealed some significant differences in comparison with neurologically healthy controls (more specifically in the patient with a larger MTL lesion), there were no obvious findings involving posterior occipital or posterior temporal regions, which can account entirely for their discrimination deficits. These findings converge with previous work to support the suggestion that the MTL does not subserve long-term declarative memory exclusively. © 2012 Wiley Periodicals, Inc.

Sharpening and formation: two distinct neuronal mechanisms of repetition priming

The repetition of an object stimulus results in faster and better recognition of this object (repetition priming). This phenomenon is neuronally associated with a reduced firing rate of neurons (repetition suppression). It has been interpreted as a sharpening mechanism within the cell assembly representing the object. In the case of an unfamiliar stimulus for which no object representation exists, the repetition of the stimulus results in an increase in the firing rate (repetition enhancement).It has been hypothesized that this increase reflects the formation of a cortical object representation. We aimed to investigate cortical object representations as well as repetition suppression and enhancement by means of the steady-state visual evoked potential (SSVEP) in the healthy human brain. To that end, we used a repetition paradigm with familiar and unfamiliar objects, each presented with 12-Hz flicker, producing an oscillatory brain response at the same frequency (i.e. an SSVEP). Results showed significantly smaller SSVEP amplitudes for repeated familiar objects compared to their first presentation (repetition suppression). For unfamiliar objects, SSVEP amplitudes increased with stimulus repetition (repetition enhancement). Source reconstruction revealed inferior temporal regions as generators for the repetition suppression effect, probably reflecting a sharpening mechanism within the cortical representations of the constituting features of an object. In contrast, repetition enhancement was localised in the superior parietal lobe, possibly reflecting the formation of a structural object representation. Thus, the mechanisms underlying repetition priming (i.e. sharpening and formation) depend on the semantic content of the incoming information.