A selective and critical review of neuropsychological deficits and the frontal lobes

Presumptions about the functions of the frontal lobes, and the sensitivity and specificity of certain tests to measure frontal lobe functions, are having a substantial influence on both clinical and research conclusions. In this paper the authors examine the details of the studies that have contributed to these presumptions, and find that the evidence to support these conclusions is weak. A detailed evaluation of the evidence relating to the Wisconsin Card Sorting Test and the Thurstone Word Fluency Test is also presented. Finally, the development of the belief that frontal lobe functions can be specifically measured is reviewed. The authors of this paper conclude that the bewildering array of deficits attributed to frontal lesions still seems to prevail.     

Refuting the unfolding-argument on the irrelevance of causal structure to consciousness

The unfolding argument (UA) was advanced as a refutation of prominent theories, which posit that phenomenal experience is determined by patterns of neural activation in a recurrent (neural) network (RN) structure. The argument is based on the statement that any input–output function of an RN can be approximated by an “equivalent” feedforward-network (FFN). According to UA, if consciousness depends on causal structure, its presence is unfalsifiable (thus non-scientific), as an equivalent FFN structure is behaviorally indistinguishable with regards to any behavioral test. Here I refute UA by appealing to computational theory and cognitive-neuroscience. I argue that a robust functional equivalence between FFN and RN is not supported by the mathematical work on the Universal Approximator theorem, and is also unlikely to hold, as a conjecture, given data in cognitive neuroscience; I argue that an equivalence of RN and FFN can only apply to static functions between input/output layers and not to the temporal patterns or to the network’s reactions to structural perturbations. Finally, I review data indicating that consciousness has functional characteristics, such as a flexible control of behavior, and that cognitive/brain dynamics reveal interacting top-down and bottom-up processes, which are necessary for the mediation of such control processes.     

Investigating temporal variations in pedestrian crossing behavior at semi-controlled crosswalks: A Bayesian multilevel modeling approach

“Semi-controlled” crosswalks are unsignalized, but have clear pavement markings and “yield to pedestrian” signs. At these locations, pedestrians and motorists frequently interact to determine who should proceed first. When interacting with drivers, pedestrian crossing decisions are complex events that involve a variety of human responses, as well as vehicle dynamics, traffic characteristics, and environmental conditions. In addition, these complexities can be subject to temporal effects. Without considering temporal variations in pedestrian-motorist interaction, statistical methods could lead to biased coefficient estimates and inaccurate conclusions.The study developed a Bayesian multilevel logistic regression (BMLR) model to capture heterogeneities in pedestrian interaction behavior during four different time periods. The proposed method incorporates time-specific effects that vary randomly between time-periods based on a weakly informative prior. The results indicate significant factors, some of which confirm previous research and some that are new ways to explain pedestrian behavior at the individual level. The identification of variables such as FlowOn and FlowWait sheds light on the interactions between pedestrians – providing more information than the single GroupSize measure.Some consequent safety implications are discussed from the perspectives of vehicle dynamics, vehicle flow rate and pedestrian volume. The more detailed metrics developed in this paper will provide a valuable starting point. for the design of crosswalk controls that will foster a higher degree of compliance and less delay.     

A two-part evaluation approach for measuring the usability and user experience of an Augmented Reality-based assistance system to support the temporal coordination of spatially dispersed teams

One key predictor of team performance and productivity is the teams’ ability to coordinate its subtasks as precisely as possible over time. Thereby, the quality of the temporal coordination in teams is highly dependent on several cognitive team skills, like for instance the ability to build a precise and stable mental model of the situation (shared situation awareness) and of the team task process (task state awareness/ TSA). To support these cognitive skills in teams, various methods and trainings already exist. However, considering teams that work de-located, the prerequisites and therefore the requirements for team supportive methods change. This work presents the results of an empirical usability and user experience (UX) study of an interface for an Augmented Reality-based assistance system for spatially dispersed teams, called Ambient Awareness Tool (AAT). The AAT interface consists of graphical information about the teamwork process and aims at enhancing the TSA of the team, thereby supporting its temporal coordination. Within the framework of a participatory design process we conducted a two-part expert-user-study, comprising a laboratory experiment for the evaluation of the interface usability and a follow-up online survey to additionally investigate the UX. By means of the usability scores we first inferred three interface configuration clusters. A subsequent UX evaluation then allowed us to designate the configuration cluster with the highest usability and UX scores. As a result, we defined one interface configuration that will be investigated concerning its actual impact on the temporal coordination of spatially dispersed teams in a further study.     

Timing the “magical number seven”: Presentation rate and regularity affect verbal working memory performance

The informative value of time and temporal structure often remains neglected in cognitive assessments. However, next to information about stimulus identity we can exploit temporal ordering principles, such as regularity, periodicity, or grouping to generate predictions about the timing of future events. Such predictions may improve cognitive performance by optimising adaptation to dynamic stimuli. Here, we investigated the influence of temporal structure on verbal working memory by assessing immediate recall performance for aurally presented digit sequences (forward digit span) as a function of standard (1000 ms stimulus-onset-asynchronies, SOAs), short (700 ms), long (1300 ms) and mixed (700–1300 ms) stimulus timing during the presentation phase. Participant's digit spans were lower for short and mixed SOA presentation relative to standard SOAs. This confirms an impact of temporal structure on the classic “magical number seven,” suggesting that working memory performance can in part be regulated through the systematic application of temporal ordering principles.     

Frontal-Lobe Involvement in Spatial Memory: Evidence from PET,fMRI, and Lesion Studies

Many studies have identified the prefrontal cortex as the brain area that is critical for spatial memory, both in humans and in other primates. Other studies, however, have failed to establish this relation. Therefore, the aim of this paper was to review the literature regarding the role of the human prefrontal lobe in spatial memory. This was done by examining the evidence obtained from neuropsychological patients and from studies using brain-imaging techniques (PET and fMRI). Evidence supporting the notion that the prefrontal cortex is extensively involved in spatial working memory was found. The majority of these studies, however, suggests that frontal-lobe involvement is not related to the type of material that is being processed (e.g., spatial vs. nonspatial), but to process-specific functions, such as encoding and retrieval. Theoretically, these functions could be linked to the central executive within Baddeley's working-memory model, or to recent theories that emphasize the various processes that play a role in working memory. Also, methodological issues were discussed. Further research is needed to enhance our understanding of the precise interaction of domain-specific and general processes.     

Is inhibition of return a reflexive effect?

The inhibition of return (IOR) phenomenon is routinely considered an effect of reflexive attention because the paradigm used to generate IOR employs peripheral cues that are uninformative as to where a target will appear. Because the cues are spatially unreliable it is thought that there is no reason for attention to be committed volitionally to them, and hence, the IOR effect is considered reflexive. What has been generally overlooked, however, is that the cues provide reliable temporal information as to when a target will occur. This predictive information is used by participants to prepare volitionally for when a target is likely to appear. We investigated whether the IOR effect is a product of the volitional application of attention to peripheral cues for the use of their temporal information. To test this idea we rendered the temporal information provided by peripheral cues unreliable. While this eliminated participants using the cues volitionally, it did not abolish the IOR phenomenon. These data demonstrate two new findings. First, the IOR effect is fundamentally a reflexive phenomenon. Second, when peripheral cues are not used volitionally, the IOR effect is attenuated. Together, the present findings indicate that the IOR effect can be modulated by volitional (top-down) processes but it is not the product of them. We argue that an intimate link between fronto-parietal regions and the superior colliculus provide a functional neural mechanism for this volitional effect to impact IOR.     

Seeing to hear better: evidence for early audio-visual interactions in speech identification

Lip reading is the ability to partially understand speech by looking at the speaker's lips. It improves the intelligibility of speech in noise when audio-visual perception is compared with audio-only perception. A recent set of experiments showed that seeing the speaker's lips also enhances sensitivity to acoustic information, decreasing the auditory detection threshold of speech embedded in noise [J. Acoust. Soc. Am. 109 (2001) 2272; J. Acoust. Soc. Am. 108 (2000) 1197]. However, detection is different from comprehension, and it remains to be seen whether improved sensitivity also results in an intelligibility gain in audio-visual speech perception. In this work, we use an original paradigm to show that seeing the speaker's lips enables the listener to hear better and hence to understand better. The audio-visual stimuli used here could not be differentiated by lip reading per se since they contained exactly the same lip gesture matched with different compatible speech sounds. Nevertheless, the noise-masked stimuli were more intelligible in the audio-visual condition than in the audio-only condition due to the contribution of visual information to the extraction of acoustic cues. Replacing the lip gesture by a non-speech visual input with exactly the same time course, providing the same temporal cues for extraction, removed the intelligibility benefit. This early contribution to audio-visual speech identification is discussed in relationships with recent neurophysiological data on audio-visual perception.     

Learning new names for new objects: cortical effects as measured by magnetoencephalography

We tracked the evolvement of naming-related cortical dynamics with magnetoencephalography when five normal adults successfully learned names and/or meanings of unfamiliar objects. In all subjects, the learning of new names was associated with pronounced cortical effects. The learning effect was of long latency and emerged as a change of activation in the same cortical network that was active during naming of familiar items. In four out of five subjects, the cortical learning effect occurred in the inferior parietal lobe. In three of these subjects, the cortical effect was left-sided. These results suggest that the inferior parietal lobe plays an important role in the acquisition of novel words, presumably as a part of working memory systems.