Spontaneous perception: a framework for task-free, self-paced perception.

Flipping through social media feeds, viewing exhibitions in a museum, or walking through the botanical gardens, people consistently choose to engage with and disengage from visual content. Yet, in most laboratory settings, the visual stimuli, their presentation duration, and the task at hand are all controlled by the researcher. Such settings largely overlook the spontaneous nature of human visual experience, in which perception takes place independently from specific task constraints and its time course is determined by the observer as a self-governing agent. Currently, much remains unknown about how spontaneous perceptual experiences unfold in the brain. Are all perceptual categories extracted during spontaneous perception? Does spontaneous perception inherently involve volition? Is spontaneous perception segmented into discrete episodes? How do different neural networks interact over time during spontaneous perception? These questions are imperative to understand our conscious visual experience in daily life. In this article we propose a framework for spontaneous perception. We first define spontaneous perception as a task-free and self-paced experience. We propose that spontaneous perception is guided by four organizing principles that grant it temporal and spatial structures. These principles include coarse-to-fine processing, continuity and segmentation, agency and volition, and associative processing. We provide key suggestions illustrating how these principles may interact with one another in guiding the multifaceted experience of spontaneous perception. We point to testable predictions derived from this framework, including (but not limited to) the roles of the default-mode network and slow cortical potentials in underlying spontaneous perception. We conclude by suggesting several outstanding questions for future research, extending the relevance of this framework to consciousness and spontaneous brain activity. In conclusion, the spontaneous perception framework proposed herein integrates components in human perception and cognition, which have been traditionally studied in isolation, and opens the door to understand how visual perception unfolds in its most natural context.

Hierarchical syntactic processing is beyond mere associating: Functional magnetic resonance imaging evidence from a novel artificial grammar.

Grammar is central to any natural language. In the past decades, the artificial grammar of the An Bn type in which a pair of associated elements can be nested in the other pair was considered as a desirable model to mimic human language syntax without semantic interference. However, such a grammar relies on mere associating mechanisms, thus insufficient to reflect the hierarchical nature of human syntax. Here, we test how the brain imposes syntactic hierarchies according to the category relations on linearized sequences by designing a novel artificial "Hierarchical syntactic structure-building Grammar" (HG), and compare this to the An Bn grammar as a "Nested associating Grammar" (NG) based on multilevel associations. Thirty-six healthy German native speakers were randomly assigned to one of the two grammars. Both groups performed a grammaticality judgment task on auditorily presented word sequences generated by the corresponding grammar in the scanner after a successful explicit behavioral learning session. Compared to the NG group, we found that the HG group showed a (a) significantly higher involvement of Brodmann area (BA) 44 in Broca's area and the posterior superior temporal gyrus (pSTG); and (b) qualitatively distinct connectivity between the two regions. Thus, the present study demonstrates that the build-up process of syntactic hierarchies on the basis of category relations critically relies on a distinctive left-hemispheric syntactic network involving BA 44 and pSTG. This indicates that our novel artificial grammar can constitute a suitable experimental tool to investigate syntax-specific processes in the human brain.

Novel Mathematical Model of Breast Cancer Diagnostics Using an Associative Pattern Classification.

Breast cancer is a disease that has emerged as the second leading cause of cancer deaths in women worldwide. The annual mortality rate is estimated to continue growing. Cancer detection at an early stage could significantly reduce breast cancer death rates long-term. Many investigators have studied different breast diagnostic approaches, such as mammography, magnetic resonance imaging, ultrasound, computerized tomography, positron emission tomography and biopsy. However, these techniques have limitations, such as being expensive, time consuming and not suitable for women of all ages. Proposing techniques that support the effective medical diagnosis of this disease has undoubtedly become a priority for the government, for health institutions and for civil society in general. In this paper, an associative pattern classifier (APC) was used for the diagnosis of breast cancer. The rate of efficiency obtained on the Wisconsin breast cancer database was 97.31%. The APC's performance was compared with the performance of a support vector machine (SVM) model, back-propagation neural networks, C4.5, naive Bayes, k-nearest neighbor (k-NN) and minimum distance classifiers. According to our results, the APC performed best. The algorithm of the APC was written and executed in a JAVA platform, as well as the experimental and comparativeness between algorithms.

Novel associative processing and aging: effect on creative production.

Creative production has been reported to decline with age. This study investigated age-related differences in creative verbal production. Participants were 30 younger and 30 older adults. Study testing included language and cognitive assessments and the experimental task wherein participants created short stories incorporating words that are not commonly related, semantically or associatively. The resulting stories were rated by independent blinded judges for originality, cohesion, appropriateness, and organization. Younger adults' stories were rated as being significantly more original and more appropriate. Integrating unrelated words to create original stories requires activating widely distributed lexical-semantic networks to develop novel associations. Potential decreased neural network connectivity due to white matter degradation, commonly seen in normal aging, as well as decrements in front-executive disengagement may have affected older adults' performance on this story creation task. Future research using neuroimaging may elucidate possible neuroanatomic correlates of age-related changes in associative creative production..

Relating movements in aesthetic spaces: Immersing, distancing, and remembering.

According to Aby Warburg, the aesthetic experience is informed by a pendulum-like movement of the observer's mind that allows him to immerse as well as to take distance from the artwork's composing elements. To account for Warburg's definition, we are proposing embodied simulation and associative processing as constitutive mechanisms of this pendulum-like movement within the aesthetic experience that enable the observer to relate to the displayed artistic material within aesthetic spaces. Furthermore, we suggest that associative processing elicits constructive memory processes that permit the development of a knowledge within which the objects of art become part of memory networks, potentially informing future ways of thinking, feeling, and behaving in real-world situations, as an individual or collectively.

Associative false consumer memory: effects of need for cognition and encoding task.

Two experiments investigated the effects of product-attribute associations on false consumer memory. In both experiments, subjects were presented with sets of related product attributes under incidental encoding conditions. Later, recognition memory was tested with studied attributes, non-studied but associated attributes (critical lures) and non-studied unrelated attributes. In Experiment 1, the effect of Need for Cognition (NFC) was assessed. It was found that individuals high in NFC recognised more presented attributes and falsely recognised more associative critical lures. The increase in both true and associative false memory was accompanied by a greater number of responses that index the retrieval of detailed episodic-like information. Experiment 2, replicated the main findings through an experimental manipulation of the encoding task that required subjects to consider purchase likelihood. Explanations for these findings are considered from the perspective of activation processes and knowledge structures in the form of gist-based representations.

Impairment in active navigation from trauma and Post-Traumatic Stress Disorder.

The study investigated the impact of trauma exposure and of Post-Traumatic Stress Disorder (PTSD) on spatial processing and active navigation in a sample (n=138) comprising civilians (n=91), police officers (n=22) and veterans (n=27). Individuals with previous trauma exposure exhibited significantly poorer hippocampal-dependent (allocentric) navigation performance on active navigation in a virtual environment (the Alternative Route task) regardless of whether or not they had PTSD (scoring above 20 on the PTSD Diagnostic Scale). No effect of trauma exposure was found in static perspective taking (the Four Mountains task). Moreover, an associative information processing bias in those with PTSD interfered with ability to use hippocampal-dependent processing in active navigation. This study provides new evidence of impaired active navigation in individuals with trauma exposure and highlights the importance of considering the relationship between trauma and spatial processing in clinical and occupational settings.

Associative hallucinations result from stimulating left ventromedial temporal cortex.

Visual recognition requires connecting perceptual information with contextual information and existing knowledge. The ventromedial temporal cortex (VTC), including the medial fusiform, has been linked with object recognition, paired associate learning, contextual processing, and episodic memory, suggesting that this area may be critical in connecting visual processing, context, knowledge and experience. However, evidence for the link between associative processing, episodic memory, and visual recognition in VTC is currently lacking. Using electrocorticography (ECoG) in a single human patient, medial regions of the left VTC were found to be sensitive to the contextual associations of objects. Electrical brain stimulation (EBS) of this part of the left VTC of the patient, functionally defined as sensitive to associative processing, caused memory related, associative experiential visual phenomena. This provides evidence of a relationship between visual recognition, associative processing, and episodic memory. These results suggest a potential role for abnormalities of these processes as part of a mechanism that gives rise to some visual hallucinations.

The Influences of Pre-testing Reviews and Delays on Differentialassociative Processing versus A Condition in which Students chose their Learning Strategy.

Recent studies show that a new strategy called differential-associative processing is effective for learning related concepts. However our knowledge about differential-associative processing is still limited. Therefore the goals of the present study are to assess the duration of knowledge that is acquired from using differential-associative processing, to determine whether the efficacy of differential-associative processing changes with the addition of a 10-minute pre-testing review, and to compare differential-associate processing to two conditions in which students select their own learning strategy. The results revealed that differential-associative processing was a better strategy for learning related concepts than were either of the two comparison conditions. They also revealed that a 10-minute pre-testing review had a positive additive influence on differential-associative processing. Finally, although the knowledge acquired from using differential-associative processing declined with an increase in delay between learning and testing, this decline was equivalent to the decline observed in both comparison conditions.

Predictive feedback and conscious visual experience.

The human brain continuously generates predictions about the environment based on learned regularities in the world. These predictions actively and efficiently facilitate the interpretation of incoming sensory information. We review evidence that, as a result of this facilitation, predictions directly influence conscious experience. Specifically, we propose that predictions enable rapid generation of conscious percepts and bias the contents of awareness in situations of uncertainty. The possible neural mechanisms underlying this facilitation are discussed.