Abstract: The role of the basal ganglia in cognition is still uncertain. This case study investigates the partial neuropsychological profile of a 20-year-old patient with a perinatal left putaminal lesion. This pathology is relatively rare and little is known of its cognitive effects. The focuses of our neuropsychological assessment were working memory, executive functions, analysis of spontaneous speech and implicit skill learning. The patient's executive functions did not attain the normal range, and working memory was also partially impaired. In addition, the temporal features of her speech revealed an increased pause/signal time ratio. Finally, in an implicit skill learning task, the patient showed general motor skill learning, but no sequence specific learning. Together these findings suggest that the frontal/subcortical circuit between the putamen and frontal motor areas plays a role in higher cognitive processing such as executive functions, working memory, as well as in first-order sequence learning.

Abstract: Perceptual organization (PO) impairments have been repeatedly demonstrated in schizophrenia. The extent to which these impairments can be reduced or eliminated, however, has received less attention, and evidence on this issue has not been previously reviewed. The literature suggests that whether normal experience-dependent change in perceptual organization occurs in schizophrenia depends on factors such as: stimulus grouping strength, extent of practice, type of cues upon which top-down feedback can be generated, and patient characteristics (trait and state). Therefore, the purpose of this paper is to review and synthesize the available evidence on plasticity and other forms of change in PO in schizophrenia, and to relate it to current data and theories on plasticity, including perceptual learning (PL) in healthy people. This can clarify the computational and neural mechanisms involved in experience-dependent and state-related aspects of PO in schizophrenia, and also contribute to a greater under...

Abstract: The majority of individuals with dyslexia and additional learning difficulties (D-LDs) also perform poorly on many simple auditory discrimination tasks. We now trained a group of D-LD teenagers on a series of auditory tasks and assessed their pattern of auditory improvement as well as their generalization to reading related tasks. We found that the performance of most D-LD participants quickly improved and reached the level of the general age matched population. Moreover, their pattern of learning specificity (e.g. no transfer from frequency to duration discriminations) was also similar to that previously observed in the general population. When assessed with a battery of verbal tasks that they initially performed poorly, a pattern of specific transfer was observed. Performance on verbal memory tasks improved to peer level, whereas performance on reading and non-verbal cognitive tasks did not. These findings suggest that D-LDs’ mechanisms of long-term learning are adequate. Moreover, perceptual learning can be used as a tool for improving general working memory skills, whose underlying mechanisms seem to be shared by simple tones and complex speech sounds.

Abstract: This paper attempts to apply the reverse hierarchy theory (RHT) of visual perceptual learning to auditory perceptual learning, and to extend it to account for how the differences in architecture of the two systems may affect the learning process. I would like to propose that rather than a singular learning process as described by RHT two types of auditory learning are occurring concurrently and in opposing directions: selection and enhancement of task-relevant information which proceeds in reverse through the processing hierarchies, starting at high levels and cascading to low levels as training progresses, and filtering of task-irrelevant information which proceeds forward through the processing hierarchy. Transfer of learning is likewise a twofold phenomenon: either a by-product of the enhancement process benefitting from processing at high levels where there is less specificity in neuronal representations, or the result of a failure to filter out and suppress processing information extraneous ...

Abstract: Practicing sensory tasks could result in two main perceptual outcomes. The first, and more widely documented, is perceptual learning referring to long-lasting improvement of perceptual thresholds. The second is perceptual deterioration, which is observed when the number of trials is increased within a training session or between closely spaced sessions. Recent results with visual texture discrimination show that these two processes inversely affect each other: decremental effects interfere with further learning, while efficient short practice results in a long-term learning effect in which performance decrements are practically eliminated. Further results show that sleep is necessary to preserve learning effects following short training and facilitates the decay of deterioration that normally results from extensive training. We suggest a theoretical link between perceptual deterioration and learning, assuming a system with saturating connectivity. Training strengthens task related connections, wi...

Abstract: I propose that perceptual learning of tasks to detect targets among uniform background items involves changing intra-cortical interactions in the primary visual cortex (V1). This is the case for tasks that rely mainly on bottom-up saliency to guide attention to the task relevant locations quickly, and rely less on top-down knowledge of the stimuli or on other strategies. In particular, suppression between V1 neurons responding to background, rather than target, visual items is predicted to increase over the course of such learning. Various other predictions are derived from this proposal, based on the theory that V1 creates a bottom-up saliency map to guide attention. Different tasks depend to different degrees on attention driven by bottom-up saliency; this leads to differences among findings from various studies of perceptual learning of pop out or detection tasks.

Abstract: The Weather Prediction (WP) Task is one of the most widely used tasks in probabilistic category learning research. Earlier studies mainly tested adults on similarly structured but different versions of the WP task, mostly without specific focus given to the differences between these tasks. The current paper focuses on the effects of stimulus organization on learning, manipulating two variables: 1) transparency of cues and outcomes and 2) combination of cues into features of a single image vs presenting them as distinct cues. Results show that different variables affect probabilistic categorization differently; cue-based (as opposed to holistic) presentation leads to better performance, and transparency also helps categorization in the early phases of the task, but this advantage turns into a disadvantage later. In general, adults’ probabilistic categorization abilities surpass children's categorization, but the pattern of performance was similar regardless of age.

Abstract: The impact of state/trait anxiety and worry on decision-making was investigated applying a computerized gambling task (Iowa Gambling Task). Besides, using two measures of knowledge about the task-contingencies, we examined the role of declarative knowledge in successful performance on the task and we tested whether the amount of declarative knowledge is related to anxiety. Results showed that trait anxiety has a negative impact, while state anxiety and worry have a positive impact on performance on the Iowa Gambling Task. Furthermore, responses on post-experiment survey suggest that those who perform better on the Iowa Gambling Task are more likely to form and report correct declarative knowledge about the task-rules. This ability, however, was not associated with anxiety.

Abstract: In the present review we discuss an extension of classical perceptual learning called the observational learning paradigm. We propose that studying the process how humans develop internal representation of their environment requires modifications of the original perceptual learning paradigm which lead to observational learning. We relate observational learning to other types of learning, mention some recent developments that enabled its emergence, and summarize the main empirical and modeling findings that observational learning studies obtained. We conclude by suggesting that observational learning studies have the potential of providing a unified framework to merge human statistical learning, chunk learning and rule learning.

Abstract: How does the brain determine what to learn and what not to learn? Previous studies showed that a feature or stimulus on which subjects performed a task was learned, while the features or stimuli that were irrelevant to the task were not learned. This led some researchers to conclude that attention to a stimulus was necessary for the stimulus to be learned. This thought was challenged by the discovery of a task-irrelevant perceptual learning, in which learning occurred by mere exposure to the unattended and subthreshold stimulus. However, this exposure-based learning does not necessarily indicate that all presented stimuli are learned. Rather, recent studies showed that the occurrence of this learning was very selective for the following new findings: unattended stimulus learning occurred only (1) when the unattended stimulus was associated temporally with the processing of an attended target, (2) when the unattended stimulus was synchronously presented with reinforcers, such as internal or external rewards, and (3) when the unattended stimulus had subliminal properties. These selectivities suggest some degrees of similarity between task-relevant and task-irrelevant perceptual learning, which has been the motivation for making a united model in which both task-relevant and task-irrelevant learning are formed with similar or same mechanisms.

Abstract: Most theories of perception assume a rigid relationship between objects of the physical world and the corresponding mental representations. We show by a priori reasoning that this assumption is not fulfilled. We claim instead that all object-representation correspondences have to be learned. However, we cannot learn to perceive all objects that there are in the world. We arrive at these conclusions by a combinatory analysis of a fictive stimulus world and the way to cope with its complexity, which is perceptual learning. We show that successful perceptual learning requires changes in the representational states of the brain that are not derived directly from the constitution of the physical world. The mind constitutes itself through perceptual learning.

Abstract: The processing of any noisy stimuli requires extra means from the nervous system. Several electrophysiological studies have proved that the processing of noise starts approximately 150–200 milliseconds after stimulus onset. This is suggested by the fact that the amplitude of the face-selective N170 component has been reduced and its latency prolonged by adding Gaussian noise to a face stimulus while the earlier P100 component is not influenced by added noise. While previous studies tested the electrophysiological correlates of noisy face perception in humans, the nature of added noise has not been studied yet in relation to face processing. Our goal was to distinguish the effects of added phase-noise from that of another irrelevant, overlapping non-face object (a car) on the electrophysiological correlates of human face processing. Subjects performed a two-alternative gender discrimination task with seven levels of difficulty, equalised between the phase-noise and overlapping object conditions. W...

Abstract: In our everyday interactions we encounter a plethora of novel experiences in different contexts that require prompt decisions for successful actions and social interactions. Despite the seeming ease with which we perform these interactions, extracting the key information from the highly complex input of the natural world and deciding how to interpret it is a computationally demanding task for the visual system. Accumulating evidence suggests that the brain solves this problem by combining sensory information and previous knowledge about the environment. Here, we review the neural mechanisms that mediate experience-based plasticity and shape perceptual decisions. We propose that learning plays an important role in the adaptive optimization of visual functions that translate sensory experiences to decisions by shaping neural representations across cortical circuits in the primate brain.

Abstract: Perceptual learning is often considered one of the simplest and basic forms of learning in general. Accordingly, it is usually modeled with simple and basic neural networks which show good results in grasping the empirical data. Simple meets simple. Complex forms of perception and learning are, then, thought to rely on these simple networks. Here, we will argue that the simplicity is in fact the Achilles heel of models of perceptual learning. We propose, instead, that perceptual learning of simple stimuli cannot be modeled with simple networks. We will review some of the empirical results yielding to this conclusion

Abstract: Recent research has focused on the role of emotion in decision-making. This study sought to build upon such work by examining whether individual differences in cognitive and emotional processes predict decision-making task performance. Thirty five participants (15 male; 20 female) completed the Iowa Gambling Task (IGT) and the Balloon Analogue Risk Task (BART), and the following questionnaires: Beck Depression Inventory (BDI), Need for Cognition (NFC), Need for Affect (NAQ). Although participants generally demonstrated learning over time, F(4,136) = 11.98, p <.001, with differences (p <.005) between scores on Block 1 and the other Blocks, 28% scored in the impaired range (net score < 10) on the IGT. Participants within the moderately/severely depressed range on the BDI were poorer on the IGT (p <.05) and the BART (p <.05) than those not in this range. Psychological distress was associated with poorer decision-making on the IGT. Furthermore, individual difference variables were related to decision...

Abstract: The aim of the study was to investigate the influence of approach and avoidance motivation (evoked by particular bodily states) on the breadth of attentional scope. It was hypothesized that the enactment of approach behavior (induced by arm flexion) would broaden, whereas the enactment of avoidance behavior (induced by arm extension) would narrow attentional scope. Both conditions were also compared with neutral condition (with no additional action). Under these conditions subjects performed an attentional task — they had to respond to the dot appearing in one of the 5 positions on the screen (one central and four peripheral, situated on the horizontal line). Longer Reaction Times for the central dot position were observed. Such pattern of results can be caused by an inhibition of return-like (IOR) effect, evoked by the centrally situated fixation cross, disappearing before the exposition of the dot. To rule out this possibility a second study was conducted, using another type of fixation point. ...

Abstract: Perceptual learning is the improvement in perceptual task performance with practice or training. The observation of specificity in perceptual learning has been widely associated with plasticity in early visual cortex representations. Here, we review the evidence supporting the plastic reweighting of readout from stable sensory representations, originally proposed by Dosher & Lu (1998), as an alternative explanation of perceptual learning. A task-analysis that identifies circumstances in which specificity supports representation enhancement and those in which it implies reweighting provides a framework for evaluating the literature; reweighting is broadly consistent with the behavioral results and almost all of the physiological reports. We also consider the evidence that the primary mode of perceptual learning is through augmented Hebbian learning of the reweighted associations, which has implications for the role and importance of feedback. Feedback is not necessary for perceptual learning, but can improve it in some circumstances, and in some cases block feedback is also helpful - all effects that are generally compatible with an augmented Hebbian model (Petrov, Dosher, & Lu, 2005). The two principles of perceptual learning through reweighting evidence from stable sensory representations and of augmented Hebbian learning provide a theoretical structure for the consideration of issues such as task difficulty, task roving, and cuing in perceptual learning.