Validation of a mobile game-based assessment of cognitive control among children and adolescents

Cognitive control is the most fundamental psychological function that underlies the execution of many other psychological functions. A mobile game application could be a useful strategy to evaluate cognitive control in the groups of children and adolescents. Although a serious game that is based on gamification would be an optimal platform for the administration of behavioral and clinical assessments of children and adolescents, most studies on gamification have been conducted among adults and older adults than among children and adolescents. This study aimed to assess cognitive control using a mobile game that used gamification and compared the results to those from traditional neuropsychological tests for children and adolescents. In order to address this objective, this study used a serious game, namely, “CoCon,” which was developed to assess cognitive control in children and adolescents. This study included 100 participants from a community sample (mean age = 11.75 years, ranged from 9 to 16 years, SD = 1.40 years; Male = 59(59%), Female = 41(41%)). The analyses interrogated the relationships among various game behaviors scores of CoCon, the standardized neuropsychological tests (K-WISC-IV, CTT, and Stroop), and self-reporting executive function difficulty questionnaire. As results, a mobile game application-based assessment proved to be a reliable and valid measure of the cognitive control in children and adolescents. The index scores from the CoCon were significantly related to various cognitive control functions and differentiated between the high and low cognitive control groups. Specifically, even though the participants completed the mobile game ‘CoCon’ in their natural habitats, the CoCon scores were comparable to the measures from standard neuropsychological tests. In conclusion, the present findings suggest that mobile games that use advanced technology and sophisticated psychological strategies can serve as a new and expanded platform for the administration of psychological assessments.

The effect of attention on repetition suppression and multivoxel pattern similarity

Fundamental to our understanding of learning is the role of attention. We investigated how attention affects two fMRI measures of stimulus-specific memory: repetition suppression (RS) and pattern similarity (PS). RS refers to the decreased fMRI signal when a stimulus is repeated, and it is sensitive to manipulations of attention and task demands. In PS, region-wide voxel-level patterns of responses are evaluated for their similarity across repeated presentations of a stimulus. More similarity across presentations is related to better learning, but the role of attention on PS is not known. Here, we directly compared these measures during the visual repetition of scenes while manipulating attention. Consistent with previous findings, we observed RS in the scene-sensitive parahippocampal place area only when a scene was attended both at initial presentation and upon repetition in subsequent trials, indicating that attention is important for RS. Likewise, we observed greater PS in response to repeated pairs of scenes when both instances of the scene were attended than when either or both were ignored. However, RS and PS did not correlate on either a scene-by-scene or subject-by-subject basis, and PS measures revealed above-chance similarity even when stimuli were ignored. Thus, attention has different effects on RS and PS measures of perceptual repetition.

Out of mind, out of sight: perceptual consequences of memory suppression

In the present study, the effect of memory suppression on subsequent perceptual processing of visual objects was examined within a modified think/no-think paradigm. Suppressing memories of visual objects significantly impaired subsequent perceptual identification of those objects when they were briefly encountered (Experiment 1) and when they were presented in noise (Experiment 2), relative to performance on baseline items for which participants did not undergo suppression training. However, in Experiment 3, when perceptual identification was performed on mirror-reversed images of to-be-suppressed objects, no impairment was observed. These findings, analogous to those showing forgetting of suppressed words in long-term memory, suggest that suppressing memories of visual objects might be mediated by direct inhibition of perceptual representations, which, in turn, impairs later perception of them. This study provides strong support for the role of inhibitory mechanisms in memory control and suggests a tight link between higher-order cognitive operations and perceptual processing.

Placebo effects on analgesia related to testosterone and premotor activation

Using functional magnetic resonance imaging, we tested whether graded placebo conditions could modulate the degree of placebo effect and brain activation patterns in study participants and whether the placebo effect could be influenced by hormones. Each participant was investigated under three conditions: the control (no placebo) condition, the low-placebo condition, and the high-placebo condition (HPC). Activations of the premotor areas, anterior cingulate cortex, and prefrontal cortex were stronger in the HPC compared with those in the control and low placebo conditions. The premotor areas were activated by increased testosterone levels under the HPC. These results suggest that testosterone may affect the brain activation and response to pain during a high-placebo response, with the data supported by brain imaging.

When a thought equals a look: refreshing enhances perceptual memory

Cognition constantly involves retrieving and maintaining information that is not perceptually available in the current environment. Studies on visual imagery and working memory suggest that such high-level cognition might, in part, be mediated by the revival of perceptual representations in the inferior temporal cortex. Here, we provide new support for this hypothesis, showing that reflectively accessed information can have similar consequences for subsequent perception as actual perceptual input. Participants were presented with pairs of frames in which a scene could appear, and were required to make a category judgment on the second frame. In the critical condition, a scene was presented in the first frame, but the second frame was blank. Thus, it was necessary to refresh the scene from the first frame in order to make the category judgment. Scenes were then repeated in subsequent trials to measure the effect of refreshing on functional magnetic resonance imaging repetition attenuation -- a neural index of memory -- in a scene-selective region of the visual cortex. Surprisingly, the refreshed scenes produced equal attenuation as scenes that had been presented twice during encoding, and more attenuation than scenes that had been presented once during encoding, but that were not refreshed. Thus, the top-down revival of a percept had a similar effect on memory as actually seeing the stimulus again. These findings indicate that high-level cognition can activate stimulus-specific representations in the ventral visual cortex, and that such top-down activation, like that from sensory stimulation, produces memorial changes that affect perceptual processing during a later encounter with the stimulus.

Beyond the edges of a view: boundary extension in human scene-selective visual cortex

To allow perception of a continuous world, cortical mechanisms extrapolate missing information with highly constrained predictions about the environment just beyond the edges of a view. Here, we report functional magnetic resonance imaging evidence for extrapolation of scene layout information beyond what was physically presented, an illusion known as boundary extension. Consistent with behavioral reports, we observed boundary extension for scene-selective attenuation in the parahippocampal place area (PPA) and retrosplenial cortex (RSC), but no such extrapolation of object representations in the lateral occipital complex (LOC). These results demonstrate that scene layout representations are extrapolated beyond the confines of the perceptual input. Such extrapolation may facilitate perception of a continuous world from discontinuous views.

Linking Implicit and Explicit Memory: Common Encoding Factors and Shared Representations

Dissociations between implicit and explicit memory have featured prominently in theories of human memory. However, similarities between the two forms of memory have been less studied. One open question concerns whether implicit and explicit memory share encoding resources. To explore this question, we employed a subsequent memory design in which several novel scenes were repeated once during an fMRI session and explicit memory for the scenes was unexpectedly tested afterward. Subsequently remembered scenes produced more behavioral priming and neural attenuation-two conventional measures of implicit memory-than did subsequently forgotten scenes. Moreover, brain-behavior correlations between these two implicit measures were mediated by subsequent memory. Finally, tonic activity, possibly reflecting the natural time course of attention, was predictive of subsequent memory. These results suggest that implicit and explicit memory are subject to the same encoding factors and can rely on similar perceptual processes and representations.

Shape-specific perceptual learning in a figure-ground segregation task

What does perceptual experience contribute to figure-ground segregation? To study this question, we trained observers to search for symmetric dot patterns embedded in random dot backgrounds. Training improved shape segmentation, but learning did not completely transfer either to untrained locations or to untrained shapes. Such partial specificity persisted for a month after training. Interestingly, training on shapes in empty backgrounds did not help segmentation of the trained shapes in noisy backgrounds. Our results suggest that perceptual training increases the involvement of early sensory neurons in the segmentation of trained shapes, and that successful segmentation requires perceptual skills beyond shape recognition alone.

Attentional modulation of repetition attenuation is anatomically dissociable for scenes and faces

Repeating a stimulus generally leads to a decreased response in neural activity compared to that for novel items. This neural attenuation provides a marker for stimulus-specific perceptual encoding and memory that can be detected using functional magnetic resonance imaging (fMRI). Although previously assumed to occur automatically whenever a stimulus is repeated, recent studies have begun to show that the repetition attenuation effect is task-specific and modulated by attention. Here, we demonstrate that attention is crucial for obtaining neural attenuation even after extensive stimulus repetitions. Furthermore, the effect of attention on attenuation is anatomically dissociable for stimuli that have relatively segregated neural representations in high-level perceptual cortex. To manipulate attention, we used overlapping scene and face images, and asked subjects to attend to either category. In a scene-sensitive cortical region known as the parahippocampal place area (PPA), significant attenuation in the fMRI BOLD signal was observed for the attended repeated scenes (relative to attended novel scenes), while no attenuation was observed for ignored repeated scenes or attended repeated faces against their respective novel image baselines. Conversely, in the face-sensitive region known as the fusiform face area (FFA), significant attenuation was observed for attended repeated faces, but not for ignored repeated faces or attended repeated scenes. An additional control experiment ruled out alternative explanations based on global signal level reductions due to inattention. Thus, attention actively governed when neuronal activity was attenuated to repeated perceptual input, and such attenuation was specific to the cortical regions that actively represent the attended category of stimuli.

Attentional modulation of learning-related repetition attenuation effects in human parahippocampal cortex

Two of the most fundamental processes in biological vision are attention and learning. Attention actively selects and enhances visual information that is most relevant to behavior. Learning enables the visual system to benefit from perceptual experience. The amount of visual information to learn is infinite; however, top-down control mechanisms must somehow regulate learning to achieve an adaptive balance between plasticity and stability in neural circuitry. Functional magnetic resonance imaging (fMRI) can measure learning-related changes in neural activity to previously viewed perceptual stimuli. Described variably as the repetition suppression or adaptation effect, the attenuation in neural activity to repeated stimuli versus novel stimuli provides a marker for stimuli-specific perceptual processing and memory. One important issue concerns whether repetition attenuation is automatic or not, and recent work has begun to show that it is sensitive to task demands. Accordingly, the present study further examined how attention controls the attenuated response to repeated stimuli, specifically testing whether attention is important for initial encoding, for the expression of memory traces, or for both encoding and expression. To manipulate attention, we used overlapping scene and face images and asked subjects to attend to either category. fMRI revealed significant attenuation in the parahippocampal place area for only the repeated scenes that were attended both during the initial presentation and during repetition. Thus, attention actively governs when neuronal activity is attenuated to repeated perceptual input, and such attention is important during both initial encoding and subsequent expression of the learned information.

Neural fate of ignored stimuli: dissociable effects of perceptual and working memory load

Observers commonly experience functional blindness to unattended visual events, and this problem has fuelled an intense debate concerning the fate of unattended visual information in neural processing. Here we used functional magnetic resonance imaging (fMRI) to demonstrate that the type of task that a human subject engages in determines the way in which ignored visual background stimuli are processed in parahippocampal cortex. Increasing the perceptual difficulty of a foveal target task attenuated processing of task-irrelevant background scenes, whereas increasing the number of objects held in working memory did not have this effect. These dissociable effects of perceptual and working memory load clarify how task-irrelevant, unattended stimuli are processed in category-selective areas in human ventral visual cortex.

The neural fate of consciously perceived and missed events in the attentional blink

Cognitive models of attention propose that visual perception is a product of two stages of visual processing: early operations permit rapid initial categorization of the visual world, while later attention-demanding capacity-limited stages are necessary for the conscious report of the stimuli. Here we used the attentional blink paradigm and fMRI to neurally distinguish these two stages of vision. Subjects detected a face target and a scene target presented rapidly among distractors at fixation. Although the second, scene target frequently went undetected by the subjects, it nonetheless activated regions of the medial temporal cortex involved in high-level scene representations, the parahippocampal place area (PPA). This PPA activation was amplified when the stimulus was consciously perceived. By contrast, the frontal cortex was activated only when scenes were successfully reported. These results suggest that medial temporal cortex permits rapid categorization of the visual input, while the frontal cortex is part of a capacity-limited attentional bottleneck to conscious report.

Inhibition of return to occluded objects

Since many visual objects are vulnerable to occlusion, an active process that tracks objects behind occluders confers considerable ecological validity to the visual system. We studied this possibility by testing whether inhibition of return can be observed with occluded objects. In our experiments, two moving objects disappeared or reappeared behind occluders while a cue and a probe were presented. Contrary to the results of a previous study (Tipper, Weaver, Jerreat, & Burak, 1994), responses were consistently delayed for the cued object that was occluded when it was cued (Experiment 1), when it was probed (Experiment 2), or both (Experiment 3). These results suggest that attention can select occluded objects that are out of view. Our findings are in line with prior studies that have demonstrated similar perceptual/attentional effects for occluded objects, as well as for visible objects.