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The final program for the Midwinter Meeting on February 1, 2010 is available (see attachment).
Register befiore January 15, 2010.
Trends in Brain-Machine Interfaces: Jose Carmena (University of California, Berkeley);
The advent of multi-electrode recordings and brain-machine interfaces (BMIs) has provided a powerful tool for the development of systems neuroscience as well as neuroprosthetic systems. Research in BMIs has led to demonstrations of rodents, non-human primates and humans controlling prosthetic devices in real-time through modulation of neural signals. For instance, our previous work demonstrated that monkeys can learn to reach and grasp virtual objects by controlling a robot arm through a BMI using visual feedback, even in the absence of overt arm movements. This and other studies have shown that improvements in performance require learning and are associated with changes in neuronal tuning properties. As these studies incorporated variable ensembles of neurons from day to day, and required daily modifications to the transform of cortical activity into motor output, little is known about long-term consolidation of prosthetic motor skill. Here we demonstrate consolidation, defined as motor skill that is retained, readily recalled and resistant to interference, in two macaque monkeys performing a center-out reaching task using a brain-controlled computer cursor under visual feedback. When a fixed transform was applied to stable recordings from an ensemble of primary motor cortex (M1) neurons across days, there was dramatic long-term consolidation of prosthetic motor skill. This process created a directional tuning map for prosthetic function that was stable across days. Surprisingly the same set of neurons could encode a second motor map without interference with the first map. In contrast, daily modification of the transform, in a manner similar to past studies, resulted in variable performance and an unstable motor map. Taken together, our results demonstrate that the primate brain can achieve skilled control of a neuroprosthetic device through consolidation of a motor memory.
Genetic screens in Drosophila to identify genes that regulate neuronal communication: Patrik Verstreken (Laboratory of Neuronal Communication, K.U.Leuven)
Synaptic transmission is of paramount importance for neuronal circuit integrity; if synapses fail, circuits fail. Transmission of electrical pulses in our brain is critical for normal but also higher brain functions such as learning, memory formation and thought, and understanding the regulatory processes of synaptic transmission may provide insight into neurological and psychiatric disorders, such as Parkinson’s disease, bipolar disorder and drug addiction that arise from defects in specific neuronal circuits in the brain.
Interestingly, the molecular mechanisms of synaptic transmission are very well conserved across species, however, the molecular mechanisms that control vesicle behavior and synaptic transmission remain ill-understood. To identify novel regulatory mechanisms that operate at the synapse and have the capacity to be major regulators of synaptic plasticity we are using the fruit fly Drosophila. This system permits powerful genetic screens, and using genetic tricks and efficient screening assays based on electrophysiology, we have identified numerous novel genes that control chemical synaptic transmission. One of these genes that is conserved from nematodes to man, we named skywalker based on the mutant fly phenotype. Using electron microscopy, live imaging of synaptic vesicles and electrophysiology, our work indicates Skywalker regulates the transport of synaptic vesicles to a novel synaptic endosomal-like compartment and further studies suggest that when vesicles travel through these endosomes they become much more fusion-competent, leading to increased synaptic transmission. Hence, our screens have identified novel critical regulators of synaptic plasticity and provide novel tools to modulate neurotransmission at single synapses but –most likely- also in neuronal circuits.
Technologies for wireless BAN: Kathleen Philips (IMEC-NL)
It is expected that body-worn and implanted sensors will enable a wealth of applications in the domains of remote medical patient monitoring, assisted living, sports, entertainment, etc. In order to realize this vision, a number of technical obstacles need to be solved. First, the sensor nodes need to achieve a high degree of autonomy in terms of power consumption and intelligence. Moreover, while keeping a small form factor and a long battery lifetime, each node must be able to communicate, in a wireless fashion, to a base-station or to other nodes.
The research activities at Holst Centre/IMEC-NL address the challenges for wireless Body-Area-Networks (BAN), along multiple axes. On one hand we have been developing a wireless BAN, with off-the-shelf-components in order to demonstrate functionality and applications. On the other hand, we have been working on the technologies to improve the sensor’s power consumption, normally dominated by the radio. The talk gives an overview of various wireless sensor nodes, along with a demonstration of a few prototypes. Next, we present our in-house radio research and discuss the specific challenges for this application domain.
Wearable and implantable devices: Wouter Serdijn (Delft University of Technology)
In the design process of wearable and implantable medical devices (WIMDs), such as pacemakers, cochlear implants and neurostimulators, the trade off between performance and power consumption is a delicate balancing act and yet today’s devices all fall short on one or more of the following aspects: number of electrodes, ability to detect morphological features of the incoming signal, ability to generate a variety of impulses in a closed-loop (thus adaptive) fashion, ability to transmit and receive reliably over a radio-harsh, signal-blocking radio channel, power consumption, and form factor.
Most of these shortcomings originate from the way the current sensor, pulse generator and transceiver electronics, are specified, designed and tested: in the time or frequency domain; they are therefore successful in the creation and analysis/detection of artificial signals, such as square and sinusoidal waves as, e.g., occur in various communication systems (e.g., for mobile telephony, fiber-optic communication, etc.). However, they are less successful in dealing with more natural signals, such as the non-stationary electrophysiological signals entering WIMDs.
In this presentation we will cover some recent techniques to deal with the acquisition and generation of electrophysiological signals and to provide reliable communication through the body. We will discuss analog wavelet filters and signal-specific analog-to-digital converters that preserve the main features of the signal while removing noise and interference. Finally, we will prove the commonly accepted agreement between antenna designers and circuit designers to adhere to a 50-ohm interface to be on loose grounds, when taking into account the dielectric absorption in the body.
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