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In non-human primates, at the junction of the prefrontal with the premotor cortex, there is a sector designated as frontal eye field (FEF), involved in controlling oculomotor behavior and spatial attention. Evidence for at least two FEFs in humans is at the basis of the still open issue of the possible homologies between the macaque and the human frontal oculomotor system. In this review article we address this issue suggesting a new view solidly grounded on evidence from the last decade showing that, in macaques, the FEF is at the core of an oculomotor domain in which several distinct areas, including areas 45A and 45B, provide the substrate for parallel processing of different aspects of oculomotor behavior. Based on comparative considerations, we will propose a correspondence between some of the macaque and the human oculomotor fields, thus suggesting sharing of neural substrate for oculomotor control, gaze processing, and orienting attention in space. Accordingly, this article could contribute to settle some aspects of the so-called "enigma" of the human FEF anatomy.

Companion robots should perceive speech, recognize objects in the real world, and further react with speech utterances and nonverbal communicative cues. Robots should also remember the interaction history and accumulate knowledge from external text sources: news, blogs, and e-mails. We have designed a conceptual representation system for a companion robot, able to support this list of interactive tasks. The system includes a speech processing component and operates with semantic representations: sets of semantic markers, assigned to valencies within sentence predications. The reaction support system inherits a classic production architecture and consists of scripts, sensitive to rational or emotional stimuli. The general architecture is based on parallel processing of scripts, it may trigger several behavioral reactions in response to a stimulus, and after that it combines speech output and nonverbal reactions of these scripts on the robot, thus, constructing compound and rich behavior. Semantic representations and scripts are also used to index incoming utterances in a memory base.

A general problem of sensory systems is how to simultaneously encode prevailing input as well as deviations from this baseline. A new study shows how the fly visual system has solved this by using parallel processing.

Reading research has long endorsed the view that words are processed strictly one by one. The primary empirical test of this notion is the search for effects from upcoming words on readers' eye movements during sentence reading. Here we argue that no conclusions can be drawn from the absence of such effects, and that the serial versus parallel processing debate cannot be resolved without treading beyond the methodological scope of tracking eye movements. Recent considerations of how the brain organizes linguistic input have sparked key predictions in- and outside the realm of text reading, with ensuing research revealing phenomena that complicate the serial processing perspective. A case is made for parallelism, along with new methods to infer the cognitive architecture driving reading.

A fundamental function of the visual system is detecting motion, yet visual perception is poorly understood. Current research has determined that the retina and ganglion cells elicit responses for motion detection; however, the underlying mechanism for this is incompletely understood. Previously we proposed that retinogeniculo-cortical oscillations and photoreceptors work in parallel to process vision. Here we propose that motion could also be processed within the retina, and not in the brain as current theory suggests. In this paper, we discuss: 1) internal neural space formation; 2) primary, secondary, and tertiary roles of vision; 3) gamma as the secondary role; and 4) synchronization and coherence. Movement within the external field is instantly detected by primary processing within the space formed by the retina, providing a unified view of the world from an internal point of view. Our new theory begins to answer questions about: 1) perception of space, erect images, and motion, 2) purpose of lateral inhibition, 3) speed of visual perception, and 4) how peripheral color vision occurs without a large population of cones located peripherally in the retina. We explain that strong oscillatory activity influences on brain activity and is necessary for: 1) visual processing, and 2) formation of the internal visuospatial area necessary for visual consciousness, which could allow rods to receive precise visual and visuospatial information, while retinal waves could link the lateral geniculate body with the cortex to form a neural space formed by membrane potential-based oscillations and photoreceptors. We propose that vision is tripartite, with three components that allow a person to make sense of the world, terming them “primary, secondary, and tertiary roles” of vision. Finally, we propose that Gamma waves that are higher in strength and volume allow communication among the retina, thalamus, and various areas of the cortex, and synchronization brings cortical faculties to the retina, while the thalamus is the link that couples the retina to the rest of the brain through activity by gamma oscillations. This novel theory lays groundwork for further research by providing a theoretical understanding that expands upon the functions of the retina, photoreceptors, and retinal plexus to include parallel processing needed to form the internal visual space that we perceive as the external world.

Prior research suggests an egocentric bias in the ability to adopt a third-person perspective in sarcastic statements. However, it remains unclear whether (1) this bias is genuinely due to egocentric anchoring or to the cost of the activation of the sarcastic interpretation; (2) context-based, allocentric processing of sarcasm can be by-passed by cheaper strategies, such as prosody processing. To settle the first question, two sarcastic conditions were compared: one, ‘egocentric’, where the favored interpretation was sarcastic only from the participant's perspective, and another, ‘allocentric’, where the sarcastic interpretation was salient from both the addressee's and the participant's perspectives. To address the second question, performance in the egocentric and allocentric conditions were compared when salient prosodic cues were added. To show direct evidence for serial adjustment and to minimize the possibility of parallel processing of prosodic and contextual cues, we compare two experiments: In the first experiment, French-speaking participants had no time limit to respond, while time pressure was added in the second experiment. Results confirm that perspective-shifting is egocentrically anchored (i.e. slower reaction times and poorer accuracy for egocentric condition than allocentric one); furthermore, this egocentric bias is already evident in early stages of processing (within 3 s). We also show that perspectival assessment of contextual cues is not triggered in the presence of salient prosodic cues. Since perspective-taking is time consuming, using the non-contextual, prosodic cue is an efficient strategy to make an accurate judgment with the least processing effort.

When partaking of any food or beverage, we actually perceive its flavour, which is the combined effect of aroma and taste. This parallel processing of signals from our nose and tongue is possible due to the presence of large and complex biological neural networks in our brain. Artificial perception of odor and taste is attempted by the scientists using similar techniques, and is implemented with an array of sensors and an array of electrodes known as electronic nose and tongue, respectively. Fusion of electronic nose and tongue at various levels provides improved results for various applications This review article discusses different techniques of fusing electronic nose and tongue information as well as applications of the combined system in different fields.

Reading relies on the recognition of units larger than single letters and smaller than whole words. Previous research has linked sublexical structures in reading to properties of the visual system, specifically on the parallel processing of letters that the visual system enables. But whether the visual system is essential for this to happen, or whether the recognition of sublexical structures may emerge by other means, is an open question. To address this question, we investigate braille, a writing system that relies exclusively on the tactile rather than the visual modality. We provide experimental evidence demonstrating that adult readers of (English) braille are sensitive to sublexical units. Contrary to prior assumptions in the braille research literature, we find strong evidence that braille readers do indeed access sublexical structure, namely the processing of multi-cell contractions as single orthographic units and the recognition of morphemes within morphologically-complex words. Therefore, we conclude that the recognition of sublexical structure is not exclusively tied to the visual system. However, our findings also suggest that there are aspects of morphological processing on which braille and print readers differ, and that these differences may, crucially, be related to reading using the tactile rather than the visual sensory modality.

Machine sensing has progressed through innovative breakthroughs. Perhaps the most significant advancements have been in the field of machine vision through the advent of the charge-coupled-device (CCD) chip and the development of artificial neural networks. This is evident in the range of sophisticated behaviors that have been replicated including facial recognition and object tracking. Due to parallel processing of large amounts of temporally evolving data, these systems can rapidly learn, adapt and predict in changing environments. While there have been significant advances in chemically diverse sensor arrays that mimic the mammalian olfactory system under well-defined conditions, relatively little work has been done to understand the temporal response of these systems and to develop neural architectures that will enable machines to become chemically aware of their surroundings. In this work, the temporal response behavior for sensors is investigated, demonstrating that both the response evolution and steady-state provide useful information about the chemical environment under dynamic conditions and that neural networks are ideally suited to combine this information in unsupervised learning to perceive odors in a dynamic environment.

In primates, the refinement of motor behaviors, in particular hand use, is associated with the establishment of more direct projections from primary motor cortex (M1) onto cervical motoneurons [1, 2] and the appearance of additional premotor and sensory cortical areas [3]. All of these areas have reciprocal connections with M1 [4-7]. Thus, during the evolution of the sensorimotor network, the number of interlocutors with which M1 interacts has tremendously increased. It is not clear how these additional interconnections are organized in relation to one another within the hand representation of M1. This is important because the organization of connections between M1 and phylogenetically newer and specialized cortical areas is likely to be key to the increased repertoire of hand movements in primates. In cebus monkeys, we used injections of retrograde tracers into the hand representation of different cortical areas of the sensorimotor network (ventral and dorsal premotor areas [PMv and PMd], supplementary motor area [SMA], and posterior parietal cortex [area 5]), and we analyzed the pattern of labeled neurons within the hand representation of M1. Instead of being uniformly dispersed across M1, neurons sending projections to each distant cortical area were largely segregated in different subregions of M1. These data support the view that primates split the cortical real estate of M1 into modules, each preferentially interconnected with a particular cortical area within the sensorimotor network. This modular organization could sustain parallel processing of interactions with multiple specialized cortical areas to increase the behavioral repertoire of the hand.

Image quality assessment is an indispensable in computer vision applications, such as image classification, image parsing. With the development of Internet, image data acquisition becomes more conveniently. However, image distortion is inevitable due to imperfect image acquisition system, image transmission medium and image recording equipment. Traditional image quality assessment algorithms only focus on low-level visual features such as color or texture, which could not encode high-level features effectively. CNN-based methods have shown satisfactory results in image quality assessment. However, existing methods have problems such as incomplete feature extraction, partial image block distortion, and inability to determine scores. So in this paper, we propose a novel framework for image quality assessment based on deep learning. We incorporate both low-level visual features and high-level semantic features to better describe images. And image quality is analyzed in a parallel processing mode. Experiments are conducted on LIVE and TID2008 datasets demonstrate the proposed model can predict the quality of the distorted image well, and both SROCC and PLCC can reach 0.92 or higher.

Mental memory system has sensory memory, short-term memory, working memory, and long-term memory. Working memory "keeps things in mind in parallel" when performing complex tasks. Similar aspects can be found for immunological memory. However, there exists another one, the memory of the fatty acid system. This article shows sensory memory of the fatty acid system, which is the perception apparatus of small intestine enterocytes (CD36, SR-B1, FATP4, FABP1, FABP2) and hepatocytes. In these cells, the fatty acid short-term memory is located, consisting of a cytoplasmic lipid droplet cycle. Similar like a working memory in the brain, the short-term memory of enterocytes and hepatocytes use parallel processing and recourse to long-term fatty acid memory. The fatty acid long-term memory is far away from these primary points of uptake. It is located in the adipocyte and in cellular membranes. The process of building a fatty acid memory is described with constructs like sensing environmental material, encoding, consolidation, long-term storage, retrieval, re-encoding, re-consolidation, and renewed long-term storage. The article illustrates the dynamics of building a fatty acid memory, the information content of fatty acids including the code, the roles of fatty acids in the body, and a new understanding of the expression "you are what you eat". The memory of the fatty acid system, plays a decisive role in integrating environmental signals over time (diet and microbiome).

Two experiments examined underlying cognitive processes that may explain why it is harder to learn to read in English than in more transparent orthographies such as German and Dutch. Participants were English and Dutch readers from Grades 3 and 4. Experiment 1 probed the transition from serial to more parallel processing, as measured by the word length effect for words and pseudowords. English children took longer to make the transition to more parallel reading strategies for words than Dutch children. In contrast, Dutch children continued to use more serial reading strategies for pseudowords. Experiment 2 investigated children’s sensitivity to the orthographic overlap between words, as measured by the size of orthographic neighborhood effects for words and pseudowords. Children reading Dutch showed greater sensitivity to the overlap between both words and pseudowords than English children. Cross-linguistic differences in the transition from serial to parallel reading strategies are discussed within the framework offered by the self-teaching hypothesis and the orthographic depth hypothesis. Finally, it is argued that differences between the two languages in the effect of orthographic neighborhood size are a result of cross-linguistic differences in orthographic density and not cross-linguistic differences in orthographic transparency.

Background complexity is a main reason that results in false detection in cat-eye target recognition. Human vision has selective attention property which can help search the salient target from complex unknown scenes quickly and precisely. In the paper, we propose a novel cat-eye effect target recognition method named Multi-channel Saliency Processing before Fusion (MSPF). This method combines traditional cat-eye target recognition with the selective characters of visual attention. Furthermore, parallel processing enables it to achieve fast recognition. Experimental results show that the proposed method performs better in accuracy, robustness and speed compared to other methods.

Dual systems theories play an important role in the conceptual foundations of behavioural economics, such as distinguishing between ‘fast’ and ‘slow’ responses to stimuli. After considering how behavioural economists use these dualities to legitimize policy interventions, I critically reflect their empirical validity in the light of recent research in psychology and the neurosciences. I argue that their major flaw is the inadequate treatment of reflection. I introduce the distinction between ‘reflectivity’ and ‘reflexivity’, arguing that most action preparation involves complex brain connectivities that integrate the two systems, as understood traditionally. G.H. Mead’s duality of ‘I’ and ‘me’ seems to be a promising alternative to existing dualities, which combines with a parallel processing or selectionist model of action generation. I conclude that this approach helps to resolve the current tension between dualistic approaches in behavioural economics and unitary views in neuroeconomics that aim at reducing the economic model of choice, thus introducing the notion of a ‘social neuroeconomics’.

When two concurrent sensorimotor tasks have to be performed at a short time interval, the second response is generally delayed at a central decision stage. However, in patients who have undergone full or partial transection of forebrain fibers connecting the two hemispheres (split-brain), independent structures subserving all processing stages should reside in each disconnected hemisphere, thus predicting parallel processing of dual tasks. Surprisingly, this prediction is usually not verified behaviorally. We reasoned that brain imaging with high-density recordings of event-related potentials (ERPs) could clarify the extent and limits of parallel processing in callosal patients. We studied a patient (AC) with posterior callosal section in a lateralized number-comparison task. Behaviorally, the split-brain patient showed robust dual-task interference, superficially similar to the psychological refractory period (PRP) effect in the control group of 14 healthy subjects, but significantly different in important aspects such as slowing of response times in the first task. Analysis of ERPs revealed that the parietal P3 component became split into distinct contralateral components in the patient, and was dramatically reduced for targets in his left visual field. In contrast to the control group, P3 latencies showed minimal to nonexistent postponement related to dual-task processing in the patient. In summary, our findings suggest that the left and right hemisphere networks normally involved in a single distributed "global neuronal workspace" that underlies the generation of the P3 component and serial processing, became strongly decoupled after a posterior callosal lesion.

Introduction Kernicterus is a serious but easily preventable disease in newborns that is not well-known even by some health care professionals. This study evaluated a parent guide and poster on kernicterus awareness and prevention generated by the Centers for Disease Control and Prevention. The Extended Parallel Processing Model was used as a framework for creating the interview protocol and analyzing the results. Method In-depth interviews were conducted with four parents and six health care personnel of different ethnicities to evaluate the materials. Content for the parent guide and poster was held constant, but photos were varied according to the ethnicity of the baby (white, African American, or Hispanic) and the language in which the interviews were conducted (English and Spanish). Results The parent guide was evaluated positively, but reactions to the poster were varied. The consensus was that the poster drew more attention than the pocket guide but lacked sufficient information about what jaundice is or how to treat it, while the pocket guide provided information, especially with regard to efficacy. The Extended Parallel Processing Model claims that when efficacy is equal to or higher than perceived threat, respondents should engage in recommended responses, which was the general finding from these interviews. Discussion Recommendations for improvements of the materials are presented. The focus on different ethnicities in the materials was perceived as unnecessary and potentially counter-productive. Both parents and health care professionals mentioned the lack of information regarding treatment. Providing information on the length and effectiveness of treatment for jaundice and kernicterus might increase efficacy in averting the threat in both conditions.

article i nfo Flexible response adaptation and the control of conflicting information play a pivotal role in daily life. Yet, little is known about the neuronal mechanisms mediating parallel control of these processes. We examined these mechanisms using a multi-methodological approach that integrated data from event-related potentials (ERPs) with structural MRI data and source localisation using sLORETA. Moreover, we calculated evoked wave- let oscillations. We applied this multi-methodological approach in healthy subjects and patients in a prodromal phase of a major basal ganglia disorder (i.e., Huntington's disease), to directly focus on fronto-striatal networks. Behavioural data indicated, especially the parallel execution of conflict monitoring and flexible response adap- tation was modulated across the examined cohorts. When both processes do not co-incide a high integrity of fronto-striatal loops seems to be dispensable. The neurophysiological data suggests that conflict monitoring (reflected by the N2 ERP) and working memory processes (reflected by the P3 ERP) differentially contribute to this pattern of results. Flexible response adaptation under the constraint of high conflict processing affected the N2 and P3 ERP, as well as their delta frequency band oscillations. Yet, modulatory effects were strongest for the N2 ERP and evoked wavelet oscillations in this time range. The N2 ERPs were localized in the anterior cingulate cortex (BA32, BA24). Modulations of the P3 ERP were localized in parietal areas (BA7). In addition, MRI-determined caudate head volume predicted modulations in conflict monitoring, but not working memory processes. The results show how parallel conflict monitoring and flexible adaptation of action is mediated via fronto- striatal networks. While both, response monitoring and working memory processes seem to play a role, especially response selection processes and ACC-basal ganglia networks seem to be the driving force in mediating parallel conflict monitoring and flexible adaptation of actions.

In the brain, numbers are thought to be represented in a spatially organised fashion on what is known as the Mental Number Line (MNL). The SNARC (Spatial-Numerical Association of Response Codes) effect refers to the faster responses to digits when the reaction side is congruent with the digit position on the MNL (e.g. a left-handed response to a small magnitude) and the slowing down of responses (inhibition) in the case of incongruity. We examined the electrophysiological correlates of conflict, which are linked to that of inhibition, to shed light on the relationship between the SNARC effect and executive attention. Event-related potentials (ERPs) were recorded from twenty-nine participants during a parity-judgment task. The participants responded more quickly on congruent than on incongruent trials. The congruency effect was reflected in early sensory (N1, N2) components above parieto-occipital and frontal regions, as well as in the later P3 component above centro-parietal areas. Moreover, both the N1 amplitude and N2 latency were greater with high than low magnitude digit targets. P3 amplitude modulation implies that the SNARC effect is the result of first evoking the parallel processing of digit magnitude categorisation (in the occipital and central areas) and numeric conflict detection (in the parieto-occipital and frontal areas) and secondly conflict monitoring and resolution localised in the centro-parietal and frontal sites. These results also suggest that the left hemisphere specialises in conflict processing of high magnitude digit targets, while the right hemisphere of low digit magnitudes.

Highlights ► We develop a parallel reading model that includes a visual processing component. ► We examine whether the model can account for “serial” effects found in normal reading. ► The length by lexicality interaction is an emergent property of parallel models with visual processing. ► “Serial” effects in reading can be produced by parallel models. ► Visual processing may be the key to understanding “serial” effects in normal reading., There is now considerable evidence showing that the time to read a word out loud is influenced by an interaction between orthographic length and lexicality. Given that length effects are interpreted by advocates of dual-route models as evidence of serial processing this would seem to pose a serious challenge to models of single word reading which postulate a common parallel processing mechanism for reading both words and nonwords (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Rastle, Havelka, Wydell, Coltheart, & Besner, 2009). However, an alternative explanation of these data is that visual processes outside the scope of existing parallel models are responsible for generating the word-length related phenomena (Seidenberg & Plaut, 1998). Here we demonstrate that a parallel model of single word reading can account for the differential word-length effects found in the naming latencies of words and nonwords, provided that it includes a mapping from visual to orthographic representations, and that the nature of those orthographic representations are not preconstrained. The model can also simulate other supposedly “serial” effects. The overall findings were consistent with the view that visual processing contributes substantially to the word-length effects in normal reading and provided evidence to support the single-route theory which assumes words and nonwords are processed in parallel by a common mechanism.

The results of two experiments provide the first direct demonstration that subjects can process a word lexically despite concurrently being engaged in decoding a task cue telling them which of two tasks to perform. These results, taken together with others, point to qualitative differences between the mind's ability to engage in lexical versus sublexical processing during the time they are engaged with other tasks. The emerging picture is one in which some form of resource(s) plays little role during lexical processing whereas the need for some form of resource(s) during sublexical processing serves to bottleneck performance.

Neuroscience has increasingly explored the neural mechanisms underlying our sense of self. Recent studies have demonstrated the recruitment of regions like the ventral tegmental area, ventromedial prefrontal cortex, and the ventral striatum to self-specific stimuli-regions typically associated with reward-related processing. This raises the question of whether there is a relationship between self and reward and, if so, how these different fields can be linked. Three relationship models that aim to explore the relationship between self and reward are discussed here: integration, segregation, and parallel processing. Their pros and cons are reviewed in light of the most recent findings. The conclusion is that both the fields of self and reward may benefit from increased interaction. This interaction may help to fill in some of the missing pieces regarding reward-related processing, as well as illuminate how brain function can bring forward the philosophical concept and psychological reality of self.

We report the performance of a group of adult dyslexics and matched controls in an array-matching task where two strings of either consonants or symbols are presented side by side and have to be judged to be the same or different. The arrays may differ either in the order or identity of two adjacent characters. This task does not require naming - which has been argued to be the cause of dyslexics' difficulty in processing visual arrays - but, instead, has a strong serial component as demonstrated by the fact that, in both groups, Reaction times (RTs) increase monotonically with position of a mismatch. The dyslexics are clearly impaired in all conditions and performance in the identity conditions predicts performance across orthographic tasks even after age, performance IQ and phonology are partialled out. Moreover, the shapes of serial position curves are revealing of the underlying impairment. In the dyslexics, RTs increase with position at the same rate as in the controls (lines are parallel) ruling out reduced processing speed or difficulties in shifting attention. Instead, error rates show a catastrophic increase for positions which are either searched later or more subject to interference. These results are consistent with a reduction in the attentional capacity needed in a serial task to bind together identity and positional information. This capacity is best seen as a reduction in the number of spotlights into which attention can be split to process information at different locations rather than as a more generic reduction of resources which would also affect processing the details of single objects.

Human adaptive behaviour to potential threats involves specialized brain responses allowing rapid and reflexive processing of the sensory input and a more directed processing for later evaluation of the nature of the threat. The amygdalae are known to play a key role in emotion processing. It is suggested that the amygdalae process threat-related information through a fast subcortical route and slower cortical feedback. Evidence from human data supporting this hypothesis is lacking. The present study investigated event-related neural responses during processing of facial emotions in the unattended hemifield using magnetoencephalography (MEG) and found activations of the amygdala and anterior cingulate cortex to fear as early as 100 ms. The right amygdala exhibited temporally dissociated activations to input from different visual fields, suggesting early subcortical versus later cortical processing of fear. We also observed asymmetrical fusiform activity related to lateralized feed-forward processing of the faces in the visual-ventral stream. Results demonstrate fast, automatic, and parallel processing of unattended emotional faces, providing important insights into the specific and dissociated neural pathways in emotion and face perception.

Attempts to relate brain size to behaviour and cognition have rarely integrated information from insects with that from vertebrates. Many insects, however, demonstrate that highly differentiated motor repertoires, extensive social structures and cognition are possible with very small brains, emphasising that we need to understand the neural circuits, not just the size of brain regions, which underlie these feats. Neural network analyses show that cognitive features found in insects, such as numerosity, attention and categorisation-like processes, may require only very limited neuron numbers. Thus, brain size may have less of a relationship with behavioural repertoire and cognitive capacity than generally assumed, prompting the question of what large brains are for. Larger brains are, at least partly, a consequence of larger neurons that are necessary in large animals due to basic biophysical constraints. They also contain greater replication of neuronal circuits, adding precision to sensory processes, detail to perception, more parallel processing and enlarged storage capacity. Yet, these advantages are unlikely to produce the qualitative shifts in behaviour that are often assumed to accompany increased brain size. Instead, modularity and interconnectivity may be more important.

Modern theories conceptualize visual selective attention as a competition between objects for the control of cortical receptive fields (RFs). Implicit in this framework is the suggestion that spatially proximal objects, which draw from overlapping pools of RFs, should be more difficult to represent in parallel and with excess capacity than spatially separated objects. The present experiments tested this prediction using analysis of response time distributions in a redundant-targets letter identification task. Data revealed that excess-capacity parallel processing is possible when redundant targets are widely separated within the visual field, but that capacity is near fixed when targets are adjacent. Even at the largest separations tested, however, processing capacity remained strongly limited.

A novel two-step paradigm was used to investigate the parallel programming of consecutive, stimulus-elicited (‘reflexive’) and endogenous (‘voluntary’) saccades. The mean latency of voluntary saccades, made following the first reflexive saccades in two-step conditions, was significantly reduced compared to that of voluntary saccades made in the single-step control trials. The latency of the first reflexive saccades was modulated by the requirement to make a second saccade: first saccade latency increased when a second voluntary saccade was required in the opposite direction to the first saccade, and decreased when a second saccade was required in the same direction as the first reflexive saccade. A second experiment confirmed the basic effect and also showed that a second reflexive saccade may be programmed in parallel with a first voluntary saccade. The results support the view that voluntary and reflexive saccades can be programmed in parallel on a common motor map.

A basic but unresolved issue in the study of memory retrieval is whether multiple independent cues can be used concurrently (i.e., in parallel) to recall a single, common response. A number of empirical results, as well as potentially applicable theories, suggest that retrieval can proceed in parallel, though set forth a model that denies that possibility. In this paper, five quantitative models are developed to test broad candidate principles. In multiple experiments, subjects were trained to retrieve a vocal digit response for each member of a set of letter or color cues. In subsequent test and transfer phases, single cue trials were randomly mixed with dual cue trials on which the two cues always required the same response. For the first few repetitions of each new set of dual cue items, there was no evidence of parallel retrieval over any part of the RT distribution. After more repetitions, dual cue trials were performed faster than single cue trials, but only under conditions that were favorable to development of a "chunked" dual cue representation. These results indicate that associative independence is an important modulating variable that must be heeded in any general model of attention and memory retrieval. Further, the results are most consistent with a model that places the performance bottleneck prior to the retrieval stage of processing.

Modeling of the basal ganglia has played a major role in our understanding of this elusive group of nuclei. Models of the basal ganglia have undergone evolutionary and revolutionary changes over the last 20 years, as new research in the fields of anatomy, physiology and biochemistry of these nuclei has yielded new information. Early models dealt with a single pathway through the nuclei and focused on the nature of the processing performed within it, convergence of information versus parallel processing of information. Later, the Albin-DeLong "box-and-arrow" model characterized the inter-nuclei interaction as multiple pathways while maintaining a simplistic scalar representation of the nuclei themselves. This model made a breakthrough by providing key insights into the behavior of these nuclei in hypo- and hyper-kinetic movement disorders. The next generation of models elaborated the intra-nuclei interactions and focused on the role of the basal ganglia in action selection and sequence generation which form the most current consensus regarding basal ganglia function in both normal and pathological conditions. However, new findings challenge these models and point to a different neural network approach to information processing in the basal ganglia. Here, we take an in-depth look at the reinforcement driven dimensionality reduction (RDDR) model which postulates that the basal ganglia compress cortical information according to a reinforcement signal using optimal extraction methods. The model provides new insights and experimental predictions on the computational capacity of the basal ganglia and their role in health and disease.

Evidence from activation studies suggests that sound recognition and localization are processed in two distinct cortical networks that are each present in both hemispheres. Sound recognition and/or localization may, however, be disrupted by purely unilateral damage, suggesting that processing within one hemisphere may not be sufficient or may be disturbed by the contralateral lesion. Sound recognition and localization were investigated psychophysically and using fMRI in patients with unilateral right hemisphere lesions. Two patients had a combined deficit in sound recognition and sound localization, two a selective deficit in sound localization, one a selective deficit in sound recognition, and two normal performance in both tasks. The overall level of activation in the intact left hemisphere of the patients was smaller than in normal control subjects, irrespective of whether the patient's performance in the psychophysical tasks was impaired. Despite this overall decrease in activation strength, patients with normal performance still exhibited activation patterns similar to those of the control subjects in the recognition and localization tasks, indicating that the specialized brain networks subserving sound recognition and sound localization in normal subjects were also activated in the patients with normal performance, albeit to an altogether lesser degree. In patients with deficient performance, on the other hand, the activation patterns during the sound recognition and localization tasks were severely reduced, comprising fewer and partly atypical activation foci compared to the normal subjects. This indicates that impaired psychophysical performance correlates with a breakdown of parallel processing within specialized networks in the contralesional hemisphere.

In this article a new approach to the distinction between serial/contingent and parallel/independent processing in the human cognitive system is applied to semantic knowledge retrieval and phonological encoding of the word form in picture naming. In two-choice go/nogo tasks pictures of objects were manually classified on the basis of semantic and phonological information. An additional manipulation of the duration of the faster and presumably mediating process (semantic retrieval) allowed to derive differential predictions from the two alternative models. These predictions were tested with two event-related brain potentials (ERPs), the lateralized readiness potential (LRP) and the N200. The findings indicate that phonological encoding can proceed in parallel to the retrieval of semantic features. A suggestion is made how to accommodate these findings with models of speech production.

By taking the MAX from their inputs, neurons in the ventral visual pathway might preserve their selectivity even when stimulated with natural scenes. This computational hypothesis has received recent direct physiological evidence from recordings of V4 neuronal responses, in a recent study by Gawne and Martin (2002). Object vision might rely more heavily on parallel processing than generally thought.

In this ERP study we investigate the processes that occur in syntactically ambiguous German sentences at the point of disambiguation. Whereas most psycholinguistic theories agree on the view that processing difficulties arise when parsing preferences are disconfirmed (so-called garden-path effects), important differences exist with respect to theoretical assumptions about the parser's recovery from a misparse. A key distinction can be made between parsers that compute all alternative syntactic structures in parallel (parallel parsers) and parsers that compute only a single preferred analysis (serial parsers). To distinguish empirically between parallel and serial parsing models, we compare ERP responses to garden-path sentences with ERP responses to truly ungrammatical sentences. Garden-path sentences contain a temporary and ultimately curable ungrammaticality, whereas truly ungrammatical sentences remain so permanently--a difference which gives rise to different predictions in the two classes of parsing architectures. At the disambiguating word, ERPs in both sentence types show negative shifts of similar onset latency, amplitude, and scalp distribution in an initial time window between 300 and 500 ms. In a following time window (500-700 ms), the negative shift to garden-path sentences disappears at right central parietal sites, while it continues in permanently ungrammatical sentences. These data are taken as evidence for a strictly serial parser. The absence of a difference in the early time window indicates that temporary and permanent ungrammaticalities trigger the same kind of parsing responses. Later differences can be related to successful reanalysis in garden-path but not in ungrammatical sentences.

The present study was designed to trace the normal development of local and global processing of hierarchical visual forms. We presented pairs of hierarchical shapes to children and adults and asked them to indicate whether the two shapes were the same or different at either the global or the local level. In Experiments 1 (6-year-olds, 10-year-olds, adults) and 2 (10-year-olds, 14-year-olds, adults), we presented stimuli centrally. All age groups responded faster on global trials than local trials (global precedence effect), but the bias was stronger in children and diminished to the adult level between 10 and 14 years of age. In Experiment 3 (10-year-olds, 14-year-olds, adults), we presented stimuli in the left or right visual field so that they were transmitted first to the contralateral hemisphere. All age groups responded faster on local trials when stimuli were presented in the right visual field (left hemisphere); reaction times on global trials were independent of visual field. The results of Experiment 3 suggest that by 10 years of age the hemispheres have adultlike specialization for the processing of hierarchical shapes, at least when attention is directed to the global versus local level. Nevertheless, their greater bias in Experiments 1 and 2 suggests that 10-year-olds are less able than adults to modulate attention to the output from local versus global channels–perhaps because they are less able to ignore distractors and perhaps because the cerebral hemispheres are less able to engage in parallel processing.

The weaklyelectric fish Gnathonemus petersii detects, localizes, and analyzes objects during active electrolocation even in complete darkness. This enables these fish to lead a nocturnal life and find and identifytheir prey(small insect larvae) on the ground of their freshwater habitat. During active electrolocation, fish produce a series of brief electric signals, electric organ discharges (EOD), with an electric organ in their tail. Each EOD builds up a stable electric field around the fish, which is distorted onlyby nearbyobjects. Field distortions lead to changes of the transepidermal electric current flow at a region of the fish’s electroreceptive skin surface called the ‘electric image’. Within the electric image, locallyperceived EODs can be either altered in amplitude or waveform byan object. Fish measure both parameters to assess object properties, such as the capacitive and resistive components of the object’s complex impedance, the object’s size and shape, and its distance from the fish. None of these object properties can be evaluated in isolation, but have to be inferred during parallel processing of electric image spatial and qualitative parameters. Two anterior skin regions of G. petersii appear to possess particular properties for special electrolocation tasks and we therefore refer to them as ‘foveal’ regions. Because of its high electroreceptor density, the electric field geometry around it, and its behavioral use, the ‘nasal region’ between the nares and the mouth at the head of the fish is suggested to be a fovea for long-range guidance and object detection. We propose that the ‘Schnauzenorgan’, a long and flexible chin appendix covered denselywith electroreceptor organs, is a second electroreceptive fovea associated with a short-range (food) identification system. Together, these two electric foveae constitute an effective preydetection and identification sy stem. # 2003 Elsevier Ltd. All rights reserved.

One of the basic goals of cognitive psychology is the analysis of the covert processes that occur between stimulus and response. In the past 20-30 years, the tools available to cognitive psychologists have been augmented by a number of imaging techniques for studying the 'brain in action' in a non-invasive manner. These techniques have their strength in either temporal or spatial information, but not both. We review here recent advances of a new approach, the event-related optical signal (EROS). This method allows measurements of the time course of neural activity in specific cortical structures, thus combining good spatial and temporal specificity. As an example, we show how EROS can be used to distinguish between serial and parallel models of information processing.

We provide evidence that the saccadic system can simultaneously program two saccades to different goals. We presented subjects with simple visual search displays in which they were required to make a saccade to an odd-colored target embedded in an array of distractors. When there was strong competition between target and distractor stimuli (due to color priming from previous trials), subjects were more likely to make a saccade to a distractor. Such error saccades were often followed, after a very short inter-saccadic interval (10‐100 ms), by a second saccade to the target. The brevity of these inter-saccadic intervals suggests that the programming of the two saccades (one to a distractor and one to the target) overlapped in time. Using a saccade-contingent change in the search display, we show that new visual information presented during the initial saccade does not change the goal of the second saccade. This supports the idea that, by the end of the first saccade, programming of the second saccade is already well underway. We also elicited two-saccade responses (similar to those seen in search) using a double-step task, with the first saccade directed to the initial target step and the second saccade directed to the second target step. If the two saccades are programmed in parallel and programming of each saccade is triggered by one of the two target steps, the second saccade should occur at a relatively fixed time after the onset of the second target step, regardless of the timing of the initial saccade. This prediction was confirmed, supporting the idea that the two saccades are programmed in parallel. Finally, we observed that the shortest inter-saccadic intervals typically followed hypometric initial saccades, suggesting that the initial saccade may have been interrupted by the impending second saccade. Using predictions from physiological studies of interrupted saccades, we tested this hypothesis and found that the hypometric initial saccades did not appear to be interrupted in mid-flight. We discuss the significance of our findings for models of the saccadic system. © 2000 Elsevier Science Ltd. All rights reserved.

In a visual search task, targets containing elementary features are detected in parallel, while a serial search is necessary for the detection of a target without a feature, or for targets containing conjunctions of features. In this study, we re-investigated the role of practice in visual search tasks, using an uncued visual search paradigm. Under some circumstances, initially serial tasks can become parallel with practice. Perceptual learning of feature search tasks is rapid (a few hundreds of trials are sufficient to transform serial into parallel search), long-lasting (a learned task is retained over several months), but far less specific than learning of other visual tasks (see also Sireteanu & Rettenbach, 1995a [Vision Research, 35, 2037–2043]). Learning transfers from one task to another, from one location in the visual field to another, and between the two eyes of a given subject, even if the subject has reduced stereopsis. Search for a conjunction of orientation and colour becomes more efficient, suggesting that a different search strategy emerges after prolonged practice. These results suggest that learning of visual search tasks modifies neural structures located at a high level in the visual pathway, involving different, presumably more central neural circuits, than the learning of visual discriminations and hyperacuity.

Reception of certain environmental energy patterns can allow organisms to successfully respond to present or future environmental conditions. Sensory systems are the means by which this reception occurs. The bioelectric components of this process are typically characterized as "sensory coding." "Coding" logically requires subsequent "decoding," and implies that the decoder has a special, commanding role. In contrast, the term "transformation," which is sometimes applied to the prebioelectric components of sensory systems, can connote a series of changes in the medium, form, or content of sensory processes. Neither coding nor decoding are implied, no notions of "representation" or "reconstruction" of the world are introduced, and distributed, parallel processing is a natural corollary of transformations. It is proposed that the problematic construct of sensory coding, with its concomitant decoding, be replaced with the more neutral and physical concept of transformations. Elimination of the notions of representation or reconstruction of the world in some special nervous system locus is also suggested.

The neural networks of the human brain act as very efficient parallel processing computers co-ordinating memory related responses to a multitude of input signals from sensory organs. Information storage, update and appropriate retrieval are controlled at the molecular level by the neuronal cytoskeleton which serves as the internal communication network within neurons. Information flow in the highly ordered parallel networks of the filamentous protein polymers which make up the cytoskeleton may be compared to atmospheric flows which exhibit long-range spatiotemporal correlations, i.e. long-term memory. Such long-range spatiotemporal correlations are ubiquitous to real world dynamical systems and is recently identified as signature of self-organized criticality or chaos. The signatures of self-organized criticality i.e. long-range temporal correlations have recently been identified in the electrical activity of the brain. A recently developed non-deterministic cell dynamical system model for atmospheric flows predicts the observed long-range spatiotemporal correlations as intrinsic to quantum-like mechanics governing flow dynamics. The model visualises large scale circulations to form as the result of spatial integration of enclosed small scale perturbations with intrinsic two-way ordered energy flow between the scales. Such a concept maybe applied for the collection and integration of a multitude of signals at the cytoskeletal level and manifested in activation of neurons in the macroscale. The cytoskeleton networks inside neurons may be the elementary units of a unified dynamic memory circulation network with intrinsic global response to local stimuli.

Computational models of attentional processing typically view the “attentional spotlight” as a winner-take-all network whose focus can be shifted serially about a display if required. As a result, lateral inhibition is assumed in these models to be an important mechanism involved in visual search. On the basis of this assumption, we predicted that changes in adapting luminance would produce specific changes in search latency functions in virtue of affecting visual inhibition. The results of our first two experiments confirmed these predictions: when search was difficult, and produced reaction time results characteristic of serial processing, there was a main effect of adapting luminance and a significant interaction between adapting luminance and the number of display elements. These effects were both reflected in increases in the slopes and the intercepts of average search latency functions when adapting luminance was decreased. When search was easy, and produced pop out effects characteristic of parallel processing, there were no significant effects of adapting luminance on search latency. The third experiment used adapting luminance to further explore the possibility that arrow junctions are detected preattentively. The results suggested that a visual search for such elements involves a substantial serial component, which weighs against the claim that they are detected by low-level vision. PsychINFO classification: 2323

The question of what is a cortical area needs a thorough definition of borders both in the microstructural and the functional domains. Microstructural parcellation of the human cerebral cortex should be made on multiple criteria based on quantitative measurements of microstructural variables, such as neuron densities, neurotransmitter receptor densities, enzyme densities, etc. Because of the inter-individual variations of extent and topography of microstructurally defined areas, the final microstructurally defined areas appear as population maps. In the functional domain, columns, patches and blobs signifying synaptically active parts of the cortex appear as cortical functional fields. These fields are the largest functional entities of the cerebral cortex according to the cortical field hypothesis. In its strong version, the cortical field hypothesis postulates that all neurons and synapses within the fields perform a co-operative computation. A number of such fields together provide the functional contribution of the cerebral cortex. The functional parcellation of the human cerebral cortex must be based on field population maps, which after intersection analysis appear as functional domains. The major structural-functional hypothesis to be examined is whether these functional domains are equi-territorial to the microstructurally defined meta-maps. The cortical hypothesis predicts that, if two brain tasks make use of one or several identical or largely overlapping fields, they cannot be performed simultaneously without errors or increases in latency. Evidence for such interference is presented. This evidence represents a restriction in the parallel processing of the human brain. In the posterior part of the brain not only visual cortical areas may qualify for parallel processing, but also the somatosensory cortices appear to have separate functional streams for the detection of microgeometry and macrogeometry.

Three different aptitudes involved in sound object recognition were tested in 60 normal subjects and 20 brain-damaged patients: (i) capacity to segregate sound objects on different cues (intensity steps, coherent temporal modulations or signal onset synchrony); (ii) asemantic recognition of sounds of real objects by judging whether two different sound samples belonged to the same object; and (iii) semantic identification of sounds of real objects as judged by means of a multiple choice response test. In 12 patients, different aptitudes involved in auditory recognition were disrupted separately and in a way which speaks in favour of parallel rather than hierarchical processing. There was no strong association between deficits in non-verbal auditory recognition and aphasia or the side of lesion.

In recent years the idea of parallel and independent processing streams for different visual attributes has become a guiding principle for linking the organization, architecture and function of the visual system. Findings concerning the segregation of motion and color information have been at the forefront of the evidence in favor of the parallel processing scheme. A number of studies have shown that motion perception is impaired for isoluminant stimuli, which are thought to isolate the color system. However, there are now many studies, the results of which are incompatible with the simple idea of segregated pathways. We propose two processing streams for motion that differ mostly in their temporal characteristics. Although neither of the two motion streams is color-blind, as was originally suggested, they differ radically in the way they process color information. The view that we propose provides a framework that reconciles a number of seemingly contradictory results. Evidence to support the new framework comes from psychophysical, physiological and lesion studies.

A new theoretical framework, the EPIC (Executive-Process/Interactive-Control) architecture, provides the basis for accurate detailed computational models of human multiple-task performance. Contrary to the traditional response-selection bottleneck hypothesis, EPIC's cognitive processor can select responses and do other procedural operations simultaneously for multiple concurrent tasks. Using this capacity together with flexible executive control of peripheral perceptual-motor components, EPIC computational models account well for various patterns of mean reaction times, systematic individual differences in multiple-task performance, and influences of special training on people's task-coordination strategies. These diverse phenomena, and EPIC's success at modeling them, raise strong doubts about the existence of a pervasive immutable response-selection bottleneck in the human information-processing system. The present research therefore helps further characterize the nature of discrete versus continuous information processing.

The well-known parcellation of the mammalian cerebral cortex into a large number of functionally distinct cytoarchitectonic areas presents a problem for understanding the complex cortical integrative functions that underlie cognition. How do cortical areas having unique individual functional properties cooperate to accomplish these complex operations? Do neurons distributed throughout the cerebral cortex act together in large-scale functional assemblages? This review examines the substantial body of evidence supporting the view that complex integrative functions are carried out by large-scale networks of cortical areas. Pathway tracing studies in non-human primates have revealed widely distributed networks of interconnected cortical areas, providing an anatomical substrate for large-scale parallel processing of information in the cerebral cortex. Functional coactivation of multiple cortical areas has been demonstrated by neurophysiological studies in non-human primates and several different cognitive functions have been shown to depend on multiple distributed areas by human neuropsychological studies. Electriphysiological studies on interareal synchronization have provided evidence that active neurons in different cortical areas may become not only coactive, but also functionally interdependent. The computational advantages of synchronization between cortical areas in large-scale networks have been elucidated by studies using artificial neural network models. Recent observations of time-varying multi-areal cortical synchronization suggest that the functional topology of a large-scale cortical network is dynamically reorganized during visuomotor behavior.

This paper presents an artificial neural network that detects and tracks an object moving within its field of view. This novel network is inspired by processing functions observed in the fly visual system. The network detects changes in input light intensities, determines motion on both the local and the wide-field levels, and outputs displacement information necessary to control pursuit tracking. Software simulations demonstrate the current prototype successfully follows a moving target within specified radiance and motion constraints. The paper reviews these limiting constraints and suggests future network augmentations to remove them. Despite its current limitations, the existing prototype serves as a solid foundation for a future network that promises to provide machines with the improved abilities to do high-speed pursuit tracking, interception, and collision avoidance.

In standard visual search experiments, subjects look for a target item among distractor items. Targets and distractors are generally presented as isolated entities on a blank background. Do theories based on results of such experiments have any application to the real world of spatially continuous stimuli where “items” are not so conveniently delineated? Experiment 1 examines search for conjunctions of color with form and with orientation in novel stimuli designed to resemble aerial views. As with artificially isolated items, conjunction search with these complex stimuli is highly efficient, holding out the promise that models of visual search based on laboratory data can be extended to real-world situations. Experiment 2 shows that some “serial” searches are made significantly less efficient when items are embedded in these specific naturalistic backgrounds. This suggests that even classic serial searches rely on some parallel processing—the processing required to locate the “items” to be serially searched.

This study compared striate and extrastriate contributions to the surface-recorded flash VEP. Laminar visual evoked potential, current source density and multiunit activity profiles were obtained with multicontact electrodes from areas V1 and V4 in three awake macaques. As found earlier, the major striate contribution is to early (N40, P55–80) components. Major contributions to the later (N95, P120, Late Negativity) components arise from V4. Early, afferent-triggered inhibition in V4 also produces a small contribution to N40. Response latencies in V4 vs V1 suggest an input to V4, bypassing VI, emphasizing a parallel processing component of visual system organization.

A Transputer based artificial vision system that allows estimating a mobile robot's absolute position (navigation), it's motion parameters (egomotion) and a depth map of the sight of view is presented. Navigation is achieved by tracking expected features present in basic 3D CAD information of the environment. Egomotion and relative depth are estimated using optic flow calculated on closed contours of points in the scene presenting high spatio-temporal gradients and require no a-priori knowledge.