Integrated Calendar

Electronic devices for retinal and brain implant are currently being developed by several research teams. The feasibility to create such devices rests in the ability to produce proper interfacing between the chip and the biological system. Extensive research, conducted over the last several years, demonstrated that Nanotechnology can help making better bio-materials for effective interfacing between nerve cells and electronic chips. Using carbon nanotubes, we have been able to produce highly effective neuro micro-electrodes suited for high efficacy recording and stimulation. Using dissociated retinas we were able to show that carbon nanotube electrodes can record neuronal activity with signal to noise as high as 75 and to achieve stimulation at 1 nC charge injection. Through innovative nano and micro-fabrication methods, we have also developed a flexible, Polydimethylsiloxane based system with carbon nanotube micro-electrodes. This system exhibit excellent electrochemistry and is ideally suited for neuro-prosthetic applications. Recent efforts to realize photo-sensitive electrodes based on carbon nanotubes will be also presented.

Avi will review the capabilities and status of LCOGT and the opportunities offered by its various telescopes.

One main alteration in neural function observed in human cocaine addicts is reduced function in the medial prefrontal cortex (mPFC). However, whether altered function of the mPFC precede, or result from, excessive self-administration of cocaine, and the exact neurochemical changes it consists of, is still unknown. To answer these questions, one needs an appropriate animal model of addiction. As, it is well established that differences in the route of, and control over, cocaine-administration, or in the frequency and size of the daily-dose of cocaine, result in significant differences in cocaine-induced neurochemical effects; then if we are to better understand the neuroadaptations that underlie the development of addiction in humans, we should employ animal models that mimic as closely as possible the human situation. Hence, my lab utilize an animal model that employs intravenous self-administration of cocaine, under conditions (based on Ahmed & Koob, 1998) that distinguish the effects of brief versus extended daily access to cocaine upon both behavior and neural substrates. This permits the investigation of neuroadaptations associated with the transition from the drug-naïve state to controlled drug-use, versus the further adaptations associated with the transition from controlled to compulsive drug-use. Using this model, we measured basal, as well as cocaine-induced, release of glutamate and dopamine within the mPFC during and after various levels of exposure to cocaine. The differences we found between controlled and compulsive drug-states, will be discussed in this talk.

Normal development and disease depend strongly on epigenetic regulation of gene expression. Polycomb group (PcG) proteins dynamically define cellular identities through the epigenetic repression of key developmental genes via chromatin-modifying activities. PcG proteins form large multimeric complexes that are recruited to DNA regulatory elements termed polycomb response elements (PREs) via their interaction with sequence specific DNA binding proteins. These proteins recognize specific DNA motifs clustered at PREs, however, paradoxically our genome wide mapping studies revealed that they are also bound to active chromatin sites that are devoid of PcG proteins. Thus, an exhaustive definition of PREs is lacking and it is not understood how PREs specifically recruit PcG complexes. In addition the intriguing possibility that different subclasses of PREs exist that differ in their way to recruit PcG complexes remains unconfirmed. These long standing questions are of highest importance, since deregulation of PcG proteins and their recruiting factors result in aberrant expression of PcG-target genes leading to cell over proliferation and tumorigenesis. To crack the code of PcG recruitment we are currently mapping PREs and PcG-recruiting factors across different Drosophila species. We are analyzing how PRE sequences behave during evolution to identify the complete set of sequence and protein requirements for PcG recruitment.