Neuromorphic Computing through Time-Multiplexing with a Spin-Torque Nano-Oscillator.

Fabricating powerful neuromorphic chips the size of a thumb requires miniaturizing their basic units: synapses and neurons. The challenge for neurons is to scale them down to submicrometer diameters while maintaining the properties that allow for reliable information processing: high signal to noise ratio, endurance, stability, reproducibility. In this work, we show that compact spin-torque nano-oscillators can naturally implement such neurons, and quantify their ability to realize an actual cognitive task. In particular, we show that they can naturally implement reservoir computing with high performance and detail the recipes for this capability.

Unidirectional thermal effects in current-induced domain wall motion.

We report experimental evidence of thermal effects on the displacement of vortex walls in NiFe nanostrips. With the use of nanosecond current pulses, a unidirectional motion of the magnetic domain walls towards the hotter part of the nanostrips is observed, in addition to current-induced domain wall motion. By tuning the heat dissipation in the samples and modeling the heat diffusion, we conclude that this unidirectional motion can only be explained by the presence of a temperature profile along the nanostrip. A quantitative analysis of the experiments shows that, on top of the classical thermodynamic pressure on the domain wall, another force, probably the magnonic spin Seebeck effect, is displacing the domain walls.

Temporal pattern recognition with delayed feedback spin-torque nano-oscillators.

The recent demonstration of neuromorphic computing with spin-torque nano-oscillators has opened a path to energy efficient data processing. The success of this demonstration hinged on the intrinsic short-term memory of the oscillators. In this study, we extend the memory of the spin-torque nano-oscillators through time-delayed feedback. We leverage this extrinsic memory to increase the efficiency of solving pattern recognition tasks that require memory to discriminate different inputs. The large tunability of these non-linear oscillators allows us to control and optimize the delayed feedback memory using different operating conditions of applied current and magnetic field.

[The clinical semiology of attention deficit hyperactivity disorder according to age, and the effectiveness of treatments at different ages]. / Semiología clínica del trastorno por déficit de atención con hiperactividad en función de la edad y eficacia de los tratamientos en las distintas edades

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) is the most important cause of poor academic performance and is also usually associated with behavioural, emotional and sociability disorders. AIM: To analyse the different clinical features and the response to psychostimulant therapy, according to the age. SUBJECTS AND METHODS: We reviewed the cases of 152 children referred to Neuropaediatrics owing to suspected ADHD over a 6-year period. Diagnosis and comorbidity were investigated by the looking at their case history, by examination and observation, as well as by interviewing the parents (DSM-IV criteria), and by applying Conners' Rating Scale for parents and teachers, in addition to neuropsychological tests. In order to improve data processing, we established four groups according to the patient's age at diagnosis and when treatment was started: G1: 3-5; G2: 6-8; G3: 9-11; and G4: 12-15 years. RESULTS: ADHD was diagnosed in 102 of the 152 children; 53% had the combined type, 26% were of the inattentional type, and 20% were hyperactive/impulsive. Poor school performance increased with age and reached 75% in G4. The same occurred with conduct disorders: at 6 years of age, 23% were found to have oppositional defiant disorder, and from the age of 9 onwards over 60% of them had conduct disorders. Up until 12 years of age they showed some improvement with psychostimulants and later the rate of dropouts from medical clinical controls and from treatment was over 40%. CONCLUSIONS: The older patients are and the later ADHD is attended, the more problems they have. If successful preventive measures are to be implemented, it would be advisable to begin treatment even before children start primary education (5 years old), so as to try and avoid the pedagogical and behavioural repercussions observed in these children at the age of 6.

A demonstration that 5-hydroxytryptamine administered peripherally can affect sexual behavior in male rats.

In the male rat, subcutaneous injections for 7 days of 20 mg/Kg B.W./day of 5-hydroxytryptamine creatinin sulphate (5-HT), caused remarkable inhibitory effects on sexual behavior. The mount and intromission latencies were increased in rats treated with 5-HT, whereas ejaculation latency in the few rats treated with 5-HT that it achieved, was similar to that obtained in control rats. The mount and intromission frequencies were decreased in the rats treated with 5-HT. The mean inter-intromission interval (MIII) and post-ejaculatory interval were prolonged in rats treated with 5-HT. These data provide evidence for the role of peripheral 5-HT in regulating sexual behavior of male rats.

[Neuromagnetic correlates of dyslexia]. / Correlatos neuromagnéticos de la dislexia.

Dyslexia was first described over a century ago and since then many theories have been put forward to explain it, but we still do not have one single unified theory that explains the problem. Furthermore, over the years a great deal of research work has also been carried out that relates dyslexia with disorders in different brain structures, and yet we still do not have a clear idea of exactly which neurophysiological mechanisms are involved. It has been claimed, however, that the disorder may be caused by specific deficits in the left frontotemporal region or atypical asymmetries in the left perisylvian regions. Lastly, neuroimaging techniques, such as functional magnetic resonance or mapping of the electrical activity in the brain, have helped to further studies into dyslexia over the last decade. Recently, the introduction of magnetoencephalography in the study of the brain has opened up a whole new range of possibilities that will allow most of the controversial points raised by research into dyslexia using neuroimaging techniques to be resolved empirically.

[Percutaneous fixation of unstable pelvic ring disruption under CT guidance]. / Osteosíntesis percutánea bajo control de tomografía computarizada de la disrupción posterior del anillo pélvico.

CT-guided percutaneous osteosynthesis of posterior disruption of an unstable pelvic ring is an alternative to the fluoroscopically guided procedure or to open reduction and internal fixation (ORIF), which is the technique of choice for unstable pelvic fracture with disruption of the sacroiliac joint or fracture of the sacral wing. However, ORIF has a high rate of morbidity and mortality, and the CT-guided procedure involves less blood loss and has a lower rate of infectious and postoperative complications. CT guidance of the percutaneous technique also has significant advantages over fluoroscopic guidance. The critical point is the placement of the guidewire inside the sacral body through the external surface of the iliac wing and of the fracture line or sacroiliac diastasis. We describe and illustrate the procedure through three cases, two sacroiliac articular disruptions and a fracture of the sacral wing.