Non-invasive estimation of local field potentials for neuroprosthesis control

Recent experiments have shown the possibility of using the brain electrical activity to directly control the movement of robots or prosthetic devices in real time. Such neuroprostheses can be invasive or non-invasive, depending on how the brain signals are recorded. In principle, invasive approaches will provide a more natural and flexible control of neuroprostheses, but their use in humans is debatable given the inherent medical risks. Non-invasive approaches mainly use scalp electroencephalogram (EEG) signals and their main disadvantage is that these signals represent the noisy spatiotemporal overlapping of activity arising from very diverse brain regions, i.e., a single scalp electrode picks up and mixes the temporal activity of myriads of neurons at very different brain areas. In order to combine the benefits of both approaches, we propose to rely on the non-invasive estimation of local field potentials (LFP) in the whole human brain from the scalp measured EEG data using a recently developed inverse solution (ELECTRA) to the EEG inverse problem. The goal of a linear inverse procedure is to de-convolve or un-mix the scalp signals attributing to each brain area its own temporal activity. To illustrate the advantage of this approach we compare, using an identical set of spectral features, classification of rapid voluntary finger self-tapping with left and right hands based on scalp EEG and non-invasively estimated LFP on two subjects using a different number of electrodes.

From sensory to long-term memory: evidence from auditory memory reactivation studies

Everyday experience tells us that some types of auditory sensory information are retained for long periods of time. For example, we are able to recognize friends by their voice alone or identify the source of familiar noises even years after we last heard the sounds. It is thus somewhat surprising that the results of most studies of auditory sensory memory show that acoustic details, such as the pitch of a tone, fade from memory in ca. 10-15 s. One should, therefore, ask (1) what types of acoustic information can be retained for a longer term, (2) what circumstances allow or help the formation of durable memory records for acoustic details, and (3) how such memory records can be accessed. The present review discusses the results of experiments that used a model of auditory recognition, the auditory memory reactivation paradigm. Results obtained with this paradigm suggest that the brain stores features of individual sounds embedded within representations of acoustic regularities that have been detected for the sound patterns and sequences in which the sounds appeared. Thus, sounds closely linked with their auditory context are more likely to be remembered. The representations of acoustic regularities are automatically activated by matching sounds, enabling object recognition.     

Comprehension of human communicative signs in pet dogs (Canis familiaris).

On the basis of a study by D. J. Povinelli, D. T. Bierschwale, and C. G. Cech (1999), the performance of family dogs (Canis familiaris) was examined in a 2-way food choice task in which 4 types of directional cues were given by the experimenter: pointing and gazing, head-nodding ("at target"), head turning above the correct container ("above target"), and glancing only ("eyes only"). The results showed that the performance of the dogs resembled more closely that of the children in D. J. Povinelli et al.'s study, in contrast to the chimpanzees' performance in the same study. It seems that dogs, like children, interpret the test situation as being a form of communication. The hypothesis is that this similarity is attributable to the social experience and acquired social routines in dogs because they spend more time in close contact with humans than apes do, and as a result dogs are probably more experienced in the recognition of human gestures.     

Does role stress predict burnout over time among health care professionals?

Abstract The main objective of this study is to test the effects over time of three role stress variables (role conflict, role ambiguity and role overload) on the three burnout dimensions (emotional exhaustion, depersonalization and personal accomplishment). Based on theoretical models on burnout and on meta-analytical research, it is hypothesized that the three role stress variables will predict changes over time in emotional exhaustion and depersonalization, but not in personal accomplishment. The results obtained by means of hierarchical regression analysis partially support the hypothesis. The three role stress variables predict emotional exhaustion over time. Role conflict and role overload predict depersonalization over time. Finally, contrary to expectations, role ambiguity predicts personal accomplishment over time.     

Attachment behavior of adult dogs (Canis familiaris) living at rescue centers: forming new bonds

In this study, 60 shelter dogs (Canis familiaris) were observed in the modified version of the Strange Situation Test, which has proved to be a useful method for studying dogs' attachment behavior toward humans (J. Topál, A. Miklósi, V. Csányi, & A. Dóka, 1998). Before testing, 40 dogs were handled 3 times for 10 min. In the test, handled dogs encountered 2 persons: the handler in the role of the "owner" (OW) and an unfamiliar person (UP), whereas the 20 nonhandled dogs encountered unfamiliar persons in both roles. Dogs in the handled group exhibited more contact seeking with the entering OW, less physical contact with the UP, less frequent following of the leaving UP, and less standing by the door in the presence of the OW. The specific response of the handled dogs toward the handler fulfilled the operational criteria of attachment. In shelter conditions, the remarkable demand for social contact with humans may result in rather fast forming of attachment even in adult dogs.     

Quasi-truth,paraconsistency, and the foundations of science

In order to develop an account of scientific rationality, two problems need to be addressed: (i) how to make sense of episodes of theory change in science where the lack of a cumulative development is found, and (ii) how to accommodate cases of scientific change where lack of consistency is involved. In this paper, we sketch a model of scientific rationality that accommodates both problems. We first provide a framework within which it is possible to make sense of scientific revolutions, but which still preserves some (partial) relations between old and new theories. The existence of these relations help to explain why the break between different theories is never too radical as to make it impossible for one to interpret the process in perfectly rational terms. We then defend the view that if scientific theories are taken to be quasi-true, and if the underlying logic is paraconsistent, it’s perfectly rational for scientists and mathematicians to entertain inconsistent theories without triviality. As a result, as opposed to what is demanded by traditional approaches to rationality, it’s not irrational to entertain inconsistent theories. Finally, we conclude the paper by arguing that the view advanced here provides a new way of thinking about the foundations of science. In particular, it extends in important respects both coherentist and foundationalist approaches to knowledge, without the troubles that plague traditional views of scientific rationality.     

Parallel processing of stimulus features during RSVP: evidence from the second response

When observers are asked to report a feature of a single target displayed in rapid serial visual presentation, they frequently make errors. Most frequently, a feature from the to-be-reported dimension pertaining to a stimulus presented near the target is reported. These migrations are so-called illusory conjunctions in the time domain. From parallel models, it is proposed that during the presentation of the series, the response features of the stimuli are extracted. If a high rate of presentation does not enable proper binding processes, the system could base its response on sophisticated guessing on the basis of the relative levels of activation of the available response features. However, the multiple extractions assumption has not received direct empirical support. We report two experiments in which the observers had to report their first and second response candidates. This double response paradigm makes it possible to test the assumption that more than one response feature is available for making a response. Furthermore, the application of the constant ratio rule (following Botella, Barriopedro, & Suero's, 2001, model) to the first responses allows predictions for the ratios between choices of the items for the second responses. The correlations between the observed and the predicted response proportions were .887 and .956 in the two experiments. This high predictive capacity indicates, first, that the observers have more than one response available, among which to choose, and second, that the choice among responses is determined largely in the same way for both, first and second responses. Nevertheless, the small errors in prediction are further reduced if a proportion of pure guesses is assumed in the second responses. These are probably due to memory losses, misidentifications of the features, and other factors impairing performance in second responses in comparison with first responses.