Evolutionary optimization of classifiers and features for single-trial EEG Discrimination

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: State-of-the-art signal processing methods are known to detect information in single-trial event-related EEG data, a crucial aspect in development of real-time applications such as brain computer interfaces. This paper investigates one such novel approach, evaluating how individual classifier and feature subset tailoring affects classification of single-trial EEG finger movements. The discrete wavelet transform was used to extract signal features that were classified using linear regression and non-linear neural network models, which were trained and architecturally optimized with evolutionary algorithms. The input feature subsets were also allowed to evolve, thus performing feature selection in a wrapper fashion. Filter approaches were implemented as well by limiting the degree of optimization. Results: Using only 10 features and 100 patterns, the non-linear wrapper approach achieved the highest validation classification accuracy (subject mean 75%), closely followed by the linear wrapper method (73.5%). The optimal features differed much between subjects, yet some physiologically plausible patterns were observed

Ultra-late EEG potential evoked by preferential activation of unmyelinated tactile afferents in human hairy skin

International audienceHuman tactile sensibility in hairy skin is mediated not only by fast conducting myelinated (A) afferents, but also by a system of slow conducting, unmyelinated afferents that respond preferentially to light touch, C-tactile (CT) afferents. This system has previously been shown to correlate with the pleasantness of tactile stimuli, where a soft brush moving at 1–3 cm/s activates CT afferents strongly. Functional magnetic resonance imaging (fMRI) studies have shown that preferential CT fiber stimulation activates the posterior insula cortex. The present study aims to assess brain activity evoked by the activation of CT afferents using electroencephalography (EEG). We present evidence for a late cortical potential over frontal electrodes, evoked from slow, gentle brush strokes at 3 cm/s. We relate this to the CT afferent input based on the conduction velocity of the CT fibers and the force feedback from the brush; the potential started 0.7 s after the brush contacted the skin and continued throughout the brush stimulation. Furthermore, results from brushing at lower and higher speeds showed that the CT potential was modulated by this stimulation. We conclude that the late potential is consistent with activity in a frontal cortical network following hairy skin peripheral stimulation. This provides an important tool for further studies of the CT fiber system and for clinical examination of peripheral unmyelinated afferents

Effect of milk feeding level on the weight gain of calves and their intake of concentrate and hay

Syftet med denna studie var att undersöka hur två olika stora mjölkgivor påverkar kalvars tillväxt och kraftfoderkonsumtionen under mjölkperioden och vid avvänjningen. Anledningen till att försöket gjordes var att få fram uppdaterade uppgifter om konsumtionen av mjölkersättning och tillväxten för att kunna utnyttja sambandet mellan dessa för att uppskatta hur mycket mjölk kalvar konsumerar som tillåts dia fritt från modern. Kalvarna utfodrades med mjölkersättning med samma energiinnehåll som i helmjölk. Studien var en del av ett större projekt där kalvar gick med mödrarna i ett lösdriftsstall med robotmjölkning. I foderförsöket ingick 47 kalvar av båda könen och av rasen SRB. Kalvarna inhystes i gruppboxar som utrustats med en transponderstyrd mjölkstation och kraftfoderstation. Nyfödda kalvar utfodrades med råmjölk från modern i minst tre dygn. Kalvarna delades in i två försöksled; låg giva (L) som utfodrades med 5 kg mjölkersättning (MER) per dag och hög giva (H) som gavs 9 kg MER per dag. Mjölkersätningen Kalvisan (18,7 MJ/kg, 23,5 % råprotein, 19,0 % råfett) blandades med en koncentration av 150 g pulver per liter vatten. Alla kalvar avvandes tvärt vid åtta veckors ålder. Kalvarna utfodrades ad libitum med kraftfoder och hö för att ge dem möjlighet att kompensera energiintaget vid den låga mjölkgivan jämfört med den höga mjölkgivan. Kraftfodret utgjordes av Talang (Lantmännen, ~11 MJ/kg, 17,0 % råprotein, 3,5 % råfett). Kalvarna vägdes vid födseln och ett dygn efter födseln, därefter vägdes de veckovis fram till tio veckors ålder. Eftersom kalvarna gavs möjlighet att konsumera olika stora mjölkgivor konsumerade självklart H behandlingen signifikant större mängd MER under hela mjölkperioden. Fram till kalvarnas fjärde levnadsvecka fanns det inga signifikanta skillnader i kraftfoderkonsumtionen mellan L och H behandlingen. Efter vecka 4 och fram till avvänjning (v.5-8) konsumerade L gruppen 490 g kraftfoder mer per dag än H gruppen (0,79 kg/dag jmf med 0,30 kg/dag). Även efter avvänjningen är det signifikant skillnad i kraftfoderkonsumtion mellan grupperna. Kalvarnas intag av omsättbar energi från MER och kraftfoder tillsammans var signifikant större i H under hela mjölkperioden. Efter avvänjningen hade dock L behandlingen ett signifikant större energiintag eftersom de äter mer kraftfoder än H behandlingen. Under hela mjölkperioden konsumerar L gruppen mer hö än H gruppen. Skillnaden var som störst runt vecka sex då L gruppen konsumerade ungefär 200 g mer per dag än H gruppen (0,31 kg/dag jmf med 0,10 kg/dag). Efter avvänjningen ökade konsumtionen kraftigt för båda grupperna och under vecka 9-10 konsumerar kalvarna ca 0,85 kg/dag. Den största skillnaden i tillväxt mellan grupperna var under vecka 2-4. De kalvar som utfodrats med hög mjölkgiva växte 230 g mer per dag än de som utfodrats med låg mjölkgiva (0,78 kg/dag jmf med 0,49 kg/dag). Under den andra delen av mjölkperioden (v.5-8) och efter avvänjningen (v.9-10) fanns det ingen signifikant skillnad mellan grupperna. Viktmässigt hade dock H behandlingen en signifikant större vikt vid vecka 8 och 10 med drygt 8 kg.The aim of this study was to evaluate the effects of different levels of milk replacer on calf performance and calf starter intake, during the milk feeding period and at weaning. This study was performed in connection with a study where calves were allowed to suckle freely from the dams when loose housed in a barn with an automatic milking system. The relationships between milk intake and calf gain found in the present study will be used to estimate the amount of milk suckled. 47 SRB calves of both sexes were used in this experiment. The calves were housed in group pens with 10-12 calves equipped with automatic milk-feeders and concentrate-feeders. Transponder identification regulated the amount of milk replacer and registered the milk-and calf starter intake. Newborn calves were offered their mother’s colostrum for at least three days. The calves were divided into two different treatments with either a low or high allowance of milk replacer. In the low group (L) calves were offered 5 kg of milk replacer per day and in the high group (H) 9 kg per day. 150 g of powder from the milk replacer Kalvisan (18,7 MJ/kg, 23,5 % crude protein, 19,0 % crude fat) was mixed with one litre of water to attain a energy content of 2,8 MJ ME per kg milk replacer. The calves were fed hay and calf starter ad libitum allowing them to compensate a low energy intake from a low level of milk replacer versus the high level. Since the two treatments were offered different levels of milk replacer the H group, of course, consumed significant more milk replacer. From birth and until week 4 there were no significant differences in calf starter intake between the L and H treatment. After the fourth week and until weaning (w. 5-8) the L group consumed 490 g more calf starter per day than the H group (0,79 kg/day vs. 0,30 kg/day). Even after weaning the intake of calf starter was significantly greater in the L group. The metabolizable energy intake from both milk replacer and calf starter shows that the energy intake is significantly higher for the H treatment during the milk period. After weaning the L treatment has a significantly higher energy intake due to the higher intake of calf starter. During the milk period the calves in the L group had a higher intake of hay compared to the calves in the H group. The biggest difference in hay intake was around week 6 when the L group ate about 200 g more hay a day than the H group (0,31 kg/day vs. 0,10 kg/day). After weaning the hay intake increased for both groups and at week 10 all calves consumed about 0,85 kg of hay per day. The greatest difference in growth rate was during week 2-4. Calves fed the high amount of milk replacer grew 230g more per day than calves fed a low amount of milk replacer 0,78 kg/day vs. 0,49 kg/day). During the second part of the milk period (w.5-8) and after weaning there were no significant differences between the groups. However, due to the difference in daily gain during the first four weeks, H treatment had a significantly higher weight at week 8 and 10, when the H calves were more than 8 kg heavier than the calves in the L treatment group

LA HISTORIA DE LA RESERVA NACIONAL ABSOLUTA CABO BLANCO: UN INFORME Y SÚPLICA DESDE ESTE SANTUARIO EN COSTA RICA

Nuestra secretaria honoraria, la Sra. Stella Lief, me solicitó contarle a los miembros -tanto antiguos como nuevos- de la Liga Mundial en contra de la Vivisección y para la Protección de los Animales acerca de nosotros y nuestra vida en este lugar, del establecimiento de la Reserva Natural Absoluta Cabo Blanco y de la situación actual. También quería saber acerca del santuario del pájaro bobo y de nuestros esfuerzos actuales por rescatar el último pedacito de bosque que queda alrededor de éste.Tal vez debería comenzar con el cómo y por qué mi esposa y yo llegamos a Costa Rica. Nosotros nos casamos en 1952; desde entonces éramos vegetarianos y nuestra alimentación se basaba en vegetales, granos germinados, manzanas y leche (ni tan siquiera una vez, consumimos alimentos procesados como papas cocinadas, pan, mantequilla, queso o cosas de ese tipo)

An Artificial Neural Network Based Robot Controller that Uses Rat’s Brain Signals

Brain machine interface (BMI) has been proposed as a novel technique to control prosthetic devices aimed at restoring motor functions in paralyzed patients. In this paper, we propose a neural network based controller that maps rat’s brain signals and transforms them into robot movement. First, the rat is trained to move the robot by pressing the right and left lever in order to get food. Next, we collect brain signals with four implanted electrodes, two in the motor cortex and two in the somatosensory cortex area. The collected data are used to train and evaluate different artificial neural controllers. Trained neural controllers are employed online to map brain signals and transform them into robot motion. Offline and online classification results of rat’s brain signals show that the Radial Basis Function Neural Networks (RBFNN) outperforms other neural networks. In addition, online robot control results show that even with a limited number of electrodes, the robot motion generated by RBFNN matched the motion generated by the left and right lever position

CARTA A MIS AMIGOS

Habíamos pensado no escribirles antes de llegar a tener todos los papeles en regla en nuestras manos, los documentos de inmigración y los de la compra de la finca, pero hemos cambiado de opinión y ahora pensamos que es mejor informarles desde ya sobre nuestra situación actual y las condiciones en que nos encontramos viviendo aquí en Costa Rica