Automatic error recovery using P3 response verification for a brain-computer interface

A brain-computer interface (BCI) is an augmentative communication mechanism that does not rely on peripheral nerves or muscles. Current BCIs are error prone and slow with error rates of 10 to 30% and transmission rates of 10-25 bits/min, however, error recovery and correction in BCI has largely been neglected. The focus of this thesis is the development of a method to automatically recover errors in BCI using the P3 brain signal for response verification. The existence of the P3 signal in responses to controlled goal items is shown in an evoked potential BCI used to control items in a virtual apartment. A reduced response exists when items are accidentally controlled. Offline experiments were run, and with a theoretical mean improvement in accuracy from 78% to 85%, there was a statistically significant improvement (P \u3c 0.008, Wilcoxon signed rank test) in accuracy of 3% using a correlation algorithm for P3 signal detection on responses. The presence of the P3 signal in responses to goal items indicates it can be used for automatic error recovery without requiring additional time, which will improve the speed and accuracy of brain-computer interfaces

Intimate interfaces in action: assessing the usability and subtlety of emg-based motionless gestures

Mobile communication devices, such as mobile phones and networked personal digital assistants (PDAs), allow users to be constantly connected and communicate anywhere and at any time, often resulting in personal and private communication taking place in public spaces. This private -- public contrast can be problematic. As a remedy, we promote intimate interfaces: interfaces that allow subtle and minimal mobile interaction, without disruption of the surrounding environment. In particular, motionless gestures sensed through the electromyographic (EMG) signal have been proposed as a solution to allow subtle input in a mobile context. In this paper we present an expansion of the work on EMG-based motionless gestures including (1) a novel study of their usability in a mobile context for controlling a realistic, multimodal interface and (2) a formal assessment of how noticeable they are to informed observers. Experimental results confirm that subtle gestures can be profitably used within a multimodal interface and that it is difficult for observers to guess when someone is performing a gesture, confirming the hypothesis of subtlety

RAPD Analysis, Plasmid Profiles, Antibiotic Resistance and Occurrence of the Van Genes in Enterococcus Species Isolated from Human And Poultry

The purpose of this study was to evaluate the molecular relatedness of the Enterococcus spp. isolated among poultry and clinical samples. A total of 71 poultry isolates and 29 clinical isolates were examined in this study. The poultry samples obtained from market in Sri Serdang, Selangor and Makmal Kesihatan Awam Veterinar. Petaling Jaya, whereas the clinical samples were from Hospital Universiti. Kuala Lumpur. E. faecalis (41 of 71 , 58%) was the dominant species isolated from poultry samples. Besides that, E. faecium (3 of 71, 4%). E. casseliflavus (4 of 71, 6%), E. durans (18 of 71, 25%) and E. hirae (5 of 71, 7%) were also detected. Twenty-nine isolates from clinical samples were identified as E. faeca/is (19 isolates, 66%), E. faecium (8 isolates, 28%), E. mundtii (1 isolate, 3%) and E. raffinosus (1 isolate, 3%). All isolates were resistant against ceftazidime, erythromycin. kanamycin, nalidixic acid and streptomycin (100%). Clinical isolates also demonstrated high resistance to cephalothin, gentamicin and norf\oxacin (100%). Sixty-four of 71 poultry isolates, and 26 of 29 clinical isolates were resistant to vancomycin and this indicated high prevalence of vancomycin resistant enterococci detected among the isolates. All seventyone isolates from poultry exhibited multiple resistance with Multiple Antibiotic Resistance (MAR) indices ranging between 0.53 to 1.0 while for clinical isolates the range were between 0.6 to 0.86. These high MAR index suggests that a\l the isolates originated from high risk sources. According to plasmid profile analysis. 29 plasmid patterns were observed among poultry isolates with the plasmid DNA bands ranging in sizes from 1.1 to 35.8 megadalton. The plasmid analysis among clinical isolates were grouped into 9 plasmid patterns ranging in sizes from 1.85 to 35.8 megadalton. RAPD-PCR has been used to generate polymorphic genomic fingerprints to discriminate the enterococci isolates. Two primers (GEN15008 and GEN15009) were chosen after screening a set of 10 primers. These two primers yield reproducible and typeable results in most isolates examined with the bands ranging in sizes from 0.25 kb to 5.0 kb. From the dendrogram generated to study the interspecific relatedness among the isolates. 2 main clusters were observed and further subdivided into several subclusters defining the genetic heterogeneity among the isolates. The vanA specific (732 bp) fragment was detected in 96 of 100 (96%) of the isolates. 29 (100%) of dinical isolates and 67 of 71 (94%) of poultry isolates were positive for vanA gene. 4 of 71 (6%) of poultry were positive for vanC2IC3 gene (439 bp). Isolates containing the vanS or vanC1 gene were not found

Evoked currents in human visual cortex

Distinguishing between close spaced sources is a difficult problem in dipole source analysis, especially between areas V1 and V2 (Ales et al., 2007, 2010). Utilizing retinotopic maps from Functional Magnetic Resonance Imaging (fMRI) has recently shown good success as an additional constraint to solve the close source problem (Ales et al., 2007, 2010; Hagler et al., 2008; Goh, 2008). This study sought to eliminate the fMRI step, and remove the time, cost, and reliability issues in fMRI retinotopy, while retaining the benefits of a retinotopic map in distinguishing between close sources and cancellation due to cortical folding. The Interactive Dipolefitting and Simultaneous Retinotopy (IDSR) technique developed here uses a four-minute Pattern Pulse multifocal Visual Evoked Potential (PPmfVEP) and a structural Magnetic Resonance Imaging (MRI) to create dipole source models. Good agreement was found between dipole models created with IDSR against fMRI based models with two participants. Four additional participants had dipole models created with IDSR, without the use of fMRI data, and their resulting current waveforms agree closely with the literature (Ales et al., 2007, 2010; Hagler et al., 2008; Goh, 2008). In addition, IDSR dipole models of all six participants were then evaluated with a repeat recording to verify the optimization step does not overfit the data, and that IDSR is generalizable. Dipole models created with the IDSR technique were used to measure stimulus effects on human V1 and V2 currents to achromatic and chromatic, luminance contrast (LC) and isoluminant (ISO) stimuli. Contrasts at 100% and 50% with all gray stimuli, and red-green ISO, were compared at 50cd/m{u00B2} and 20cd/m{u00B2} for two participants with PPmfVEP dartboard stimuli. The initial major peaks of V1 and V2 show different effects to contrast and luminance. Generally, V1's peak latency decreases with decreasing contrast (100% to 50% to ISO). V2's peak latency is similar for 100% and 50% contrast, but slower at ISO. For both V1 and V2 if the stimulus is bright the amplitudes to 100% and 50% contrast are similar, if the stimulus is dim then amplitude decreases with luminance. Chromatic effects were investigated to determine if ISO effects are wholly or partially effects of using red and green in ISO versus the achromatic 100% and 50% contrast stimuli. Three participants viewed different combinations of red, green, and gray PPmfVEP dartboard stimuli at ISO and 50% contrast, all at 20cd/m{u00B2} mean luminance. V1's initial major peak's latency kept the effect of slower to ISO vs LC regardless of color. V1's amplitude was affected more by the difference in red vs green in the stimuli compared to ISO vs LC. V2's initial major peak did not have a clear effect of ISO vs LC. Finally, a relationship between V1 and V2's components was identified. V1's first major peak (C1) and V2's second peak (C2) have similar responses to the same stimuli, as do V2's first major peak (C1) and V1's second peak (C2), suggesting an influence relationship of C1 on C2 between the visual areas

jdb[at]cs[dot]rit[dot]edu

sinverso[at]gmail[dot]com Recent advances in signal processing have made brain-computer interfaces (BCIs) feasible for use as an alternative control option for those with severe motor impairments. It is possible to increase the accuracy of a BCI system by requiring users to make multiple choices to control a single item, but this comes at a cost of reduced system speed. We present experimental results from an evoked potential BCI used to control items in a virtual apartment and show the existence of the evoked potential P3 component in responses to successfully controlled goal items. A reduced response exists when items are accidentally controlled. The presence of the P3 component in responses to goal items means that it can be used for automatic error correction. Off-line experiments have been run and with a theoretical mean improvement in recognition from 78 % to 85%, we show a statistically significant improvement (p < 0.004, Wilcoxen test, two-tailed) in accuracy of 3 % using the variable averaging algorithm. Since the error correction technique depends on responses to controlled items in a particular experimental paradigm rather than the control of the items themselves, it may be possible to use this response in non-evoked potential BCI systems. Future work is discussed in this context.

Intimate Interfaces in Action: Assessing the Usability and Subtlety of EMG-based Motionless Gestures

Mobile communication devices, such as mobile phones and networked personal digital assistants (PDAs), allow users to be constantly connected and communicate anywhere and at any time, often resulting in personal and private communication taking place in public spaces. This private - public contrast can be problematic. As a remedy, we promote intimate interfaces: interfaces that allow subtle and minimal mobile interaction, without disruption of the Surrounding environment. In particular, motionless gestures sensed through the electromyographic (EMG) signal have been proposed as a solution to allow subtle input in a mobile context. In this paper we present an expansion of the work on EMG-based motionless gestures including (1) a novel study of their usability in a mobile context for controlling a realistic, multimodal interface and (2) a formal assessment of how noticeable they are to informed observers. Experimental results confirm that subtle gestures can be profitably used within a multimodal interface and that it is difficult for observers to guess when someone is performing a gesture, confirming the hypothesis of subtlety

EMG as a Subtle Input Interface for Mobile Computing

Abstract. Rather than merely imitating the desktop metaphor for mobile devices, new interface paradigms that take into account the particular characteristics of mobility, need to be developed. In this paper an input device based on the electromyographic (EMG) signal is proposed as a controller for mobile interaction. The interface can be considered subtle or intimate because individuals are able to interact privately without causing distraction to their immediate environment. The results from a preliminary study are presented to show the feasibility of the proposed system.

Biological

anu.edu.au Mobile communication devices, such as mobile phones and networked personal digital assistants (PDAs), allow users to be constantly connected and communicate anywhere and at any time, often resulting in personal and private communication taking place in public spaces. This private — public contrast can be problematic. As a remedy, we promote intimate interfaces: interfaces that allow subtle and minimal mobile interaction, without disruption of the surrounding environment. In particular, motionless gestures sensed through the electromyographic (EMG) signal have been proposed as a solution to allow subtle input in a mobile context. In this paper we present an expansion of the work on EMG-based motionless gestures including (1) a novel study of their usability in a mobile context for controlling a realistic, multimodal interface and (2) a formal assessment of how noticeable they are to informed observers. Experimental results confirm that subtle gestures can be profitably used within a multimodal interface and that it is difficult for observers to guess when someone is performing a gesture, confirming the hypothesis of subtlety. Author Keywords Mobile computing, wearable computing, electromyogram, subtle interaction, intimate interface, motionless gestures, social acceptance ACM Classification Keyword

Adult neurogenesis produces neurons with unique GABAergic synapses in the olfactory bulb.

International audienceNeuronal regeneration occurs naturally in a few restricted mammalian brain regions, but its functional significance remains debated. Here we search for unique features in the synaptic outputs made by adult-born granule cell interneurons in the mouse olfactory bulb using optogenetic targeting of specific neuronal ages. We find that adult-born interneurons are resistant to presynaptic GABA(B)-mediated depression of GABA release compared with interneurons born just after birth that exhibit strong GABA(B) neuromodulation. Correlated with this functional change, we found altered localization of the GGABA(B)R1 protein within adult-born granule cells. These results suggest that adult neurogenesis produces a population of functionally unique GABAergic synapses in the olfactory bulb