Our history is imprinted in our genes: population structure and ancient migrations were found to be encoded in human genetic variation. With the revolution of high-throughput DNA genotyping and sequencing, history can now be uncovered in unprecedented detail.

I propose to develop new tools for geography-based historical reconstruction. Contrast to previous approaches, I will use sharing analysis- the study of the lengths of genomic segments shared between individuals. Recent algorithmic breakthrough of the host lab, combined with data from new sequencing technologies, enable now the use of this method, which is expected to be more informative compared to other approaches.

My first goal will be the application of sharing analysis to globally distributed populations. I will then attempt to explain the observed sharing statistics by constructing a geographical model that involves a series of colonization events. I will determine parameters such as migration and admixture rates and bottleneck sizes as those that best fit the data. I will also use our model to resolve long-standing debates over the nature of the distribution of migration rates.

I will also investigate Jewish genetics, for which the host lab has exclusive access to the largest existing collection of genetic variation data. I will study for the first time the relation between Jewish genetics and geography and create geographical models accordingly. Particular properties of Jewish history make its modeling in some cases relatively easy (e.g., one dimensional), and thus, models will be made highly detailed.

In the mammalian olfactory system, odor information is transmitted to the main olfactory bulb (MOB) by the axons of olfactory sensory neurons (OSNs). OSN axons expressing a particular olfactory receptor project to just one or two glomeruli in each hemisphere of the MOB. The glomerular input layer of the MOB is therefore the initial site for processing of odor information. Individual glomeruli are interconnected by the axons of a recently characterised class of dopaminergic (DAergic) periglomerular/short-axon cells. It is clear that the function of DAergic neurons is strongly activity-dependent, as blocking olfactory sensory input results in a dramatic reduction in both tyrosine hydroxylase expression and dopamine production. However, the role of DAergic neuron-mediated interglomerular connections in olfactory processing in the MOB remains poorly understood. This project will utilise recently developed genetic tools that enable specific labelling and activation of DAergic neurons. A combination of electrophysiological and state-of-the-art optogenetic techniques will be employed both in brain slices and in vivo, to investigate the role of DAergic neurons in sensory integration in the MOB, and the activity-dependence of the interglomerular projections that they form. It is envisaged that the results obtained will provide important insights into the mechanisms and activity-dependence of sensory integration in the MOB. Moreover, this study may also provide new diagnostic and therapeutic strategies for a range of neurological and psychiatric conditions in which both olfactory dysfunction and dysregulation of DAergic transmission are features.

Epithelia are fundamental elements of many tissues and organs. During embryo development they undergo a complex pattern of shape changes and display a remarkable dual feature of robustness and plasticity. How epithelia maintain an accurate equilibrium between these two apparently contradictory properties during morphogenesis is unclear. I will address this question using germ band extension (GBE) in the Drosophila embryo as a model system. Here cells intercalate by exchange of their neighbours without losing cohesion. This is achieved by a planar polarized pattern of cell junctions remodelling driven by anisotropic actomyosin mediated contractility. The aim of this proposal is to understand the molecular and cellular basis of junction remodelling with an emphasis on how adhesion and contractility are co-ordinated. To this end I will first characterize fluxes of E-cadherin during junction remodelling in intercalating cells, then I will systematically analyze their interplay with the actomyosin system and finally I will undertake an unbiased approach to identify genes responsible of the specific E-cadherin and actomyosin patterns in intercalating cells. This project is expected to shed more light on how adhesion and contractility are integrated and on the mechanisms of new junction formation. This fellowship will expand my expertise in membrane trafficking in mammalian cells with genetics, cell mechanics and Drosophila as a new model system. In this way I will be able to combine my knowledge of the organization of intracellular systems in cells to the problem of the organization of cells into tissues, the topic I wish to pursue in my future career.

Birds are among the most colorful of vertebrate species, and most birds live in visually rich habitats. Not surprisingly, the avian retina is endowed with one of the most sophisticated cone photoreceptor systems of any vertebrate. Yet, despite this richness, the various optical adaptations of avian cones remain poorly understood. Our lack of knowledge stems, in part, from the fact that most studies of the visual system have focused on mammalian retina. In addition, studies of avian cone function have been hampered by the lack of model systems amenable to molecular/genetic manipulation. For this reason, almost all studies of bird vision have been restricted to wild-type animals. The overarching goal of this proposal is to deconstruct the optical adaptations of avian cone photoreceptors via an interdisciplinary combination of molecular genetics, optical physics, computer modeling and vision-guided behavioral assays in chickens. We plan to co-opt molecular/genetic techniques originally developed in the chicken to study embryogenesis, and use them to engineer post-hatch birds with modified cone photoreceptors. We will then apply cutting-edge optical analysis and modeling to both wild-type and genetically modified photoreceptors to elucidate their adaptations for light handling. Lastly, we will implement innovative vision-guided behavioral assays in newly hatched birds to link the genetic modifications and their optical effects to the resultant functional changes in vision. These studies will shed light on a range of amazing optical adaptations found in avian cones which are either absent or poorly developed in mammals and will thus reveal new insights into the visual world of birds.

The compaction of chromatin governs DNA accessibility and therefore has a crucial function in establishing, maintaining and propagating distinct patterns of gene expression. The opposing activities of Polycomb group (PcG) and trithorax group (trxG) proteins are part of a chromatin regulation system, ensuring the correct expression of specific transcriptional programs at defined developmental stages.

PcG-proteins form chromatin-modifying complexes that implement transcriptional silencing in higher eukaryotes. Three different PcG-protein complexes have been isolated from Drosophila: the Polycomb Repressive Complex 1 (PRC1), PRC2, and the PcG Protein Polycomplike (Pcl-PRC2). The characterization of several PRC2 components in Arabidopsis constituted a first breakthrough, revealing key roles of PcG-proteins in the control of crucial plant developmental processes.

Transcriptional networks play a primary role in regulating development in both plants and animals. The Arabidopsis root is ideally suited to study the effect of PcG-proteins on the transcriptional networks. Using a combination of systems biology, genomics and genetic approaches, we aim at determining the upstream and downstream components of the PRC2 regulatory network in acquisition of root cell type-identity in Arabidopsis.

Asymmetric cell division (ACD) gives rise to two daughter cells, which inherit different determinants, thereby acquiring different fates. Reports in Drosophila showed that during ACD, Notch and its receptor Delta traffic through specific compartments, the Sara endososomes, which are targeted towards only one of the daughter cells, thus contributing to define the Notch signalling-receiving cell. Unpublished observations suggest that Sara endosomes are able to ‘read’ a polarity signal 'written' on the spindle by means of a gradient of tubulin acetylation. This project addresses three key questions: i) what is the full machinery controlling the directional motility of Sara endosomes during ACD? ii) how do motors present at the surface of Sara endosomes ‘read’ the gradient of acetylation? iii) how does interfering with tubulin acetylation in space and time affect the motility of Sara endosomes during ACD? To achieve my goals, I will use an interdisciplinary approach integrating biochemical reconstitutions with experiments in cultured cells and in the whole organism. In particular, I will use microfluidics to engineer microtubules presenting a controlled pattern of acetylation, which will allow me to directly address how tubulin acetylation affects the motility of isolated endosomes and the behavior of motors at the single molecule level. In addition, I will develop a tubulin acetylation biosensor and photoactivable enzymes to monitor and interfere with microtubule acetylation in vivo. This innovative project is poised to shed new light on directional signaling during asymmetric cell division, as well as on the role of tubulin post-translational modifications.

Cyclic expression of genes (i.e. oscillation) is involved in basic processes such as cell-cycle and circadian clock. The molecular mechanisms behind the generation of these oscillations are being elucidated and have led to the identification of “biological clocks” in different biological processes. Ultradian oscillations, i.e. with periods much less than 24 hours, at the molecular level have been observed also in the major signaling pathways, but their relevance is still unclear. We hypothesise that one of the roles of cell signaling is to allow "mutual synchronisation" and "entrainment" of these oscillations across a tissue for robust coordination of biological processes at the tissue-level. Mutual synchronisation of oscillations happens when different “biological clocks” start “beating in time” by spontaneously synchronizing their oscillations via some form of cell-cell coupling, which we hypothesise may be mediated by cell-cell signaling. Entrainment refers to the existence of an external “pace-maker” signal that drives the individual clocks and forces them to beat in time. In this project we will investigate, via an integrated mathematical and experimental approach, the biological mechanisms of entrainment and mutual synchronization of cell-autonomous oscillators involved in signaling. Our objectives are: (1) to characterise, via mathematical modeling, entrainment and mutual synchronization of a population of cell-autonomous oscillators, using recent results from dynamical systems theory and numerical simulations; (2) to use synthetic biology to implement a synthetic cell-autonomous oscillator in mammalian cells to experimentally test entrainment and mutual synchronization, in the context of a well characterized oscillator mechanism; (3) to test the physiological relevance of entrainment and mutual synchronisaton of cyclic gene expression/protein localisation in mammalian cells. We will consider four examples: (i) the hes1-oscillator. We will investigate the 2-hour periodic expression of Notch signaling molecules in different cellular models, where these oscillations are known to occur. (ii) The p53-oscillator. We will focus on the tumor suppressor gene p53, which exhibits oscillations in its expression in individual cells. (iii) The Smad-oscillator. This refers to the cyclic nuclear shuttling of Smad proteins following stimulation by TGFb and serum. (iv) The Stat-oscillator. This is another example of cyclic nuclear shuttling following cytokine stimulation. The experimental protocol will require the determination of the fluorescence intensity in live cells as a function of time, at single cell resolution, and the ability to deliver periodic perturbations to the cells in the form of precisely controlled time-varying concentration of inducer molecules. To this end, we will develop innovative microfluidic ‘lab-on-a- chip’ devices in conjunction with time-lapse microscopy. These devices are able to trap single cells, or small populations of cells, for long-term data acquisition and to precisely control the extracellular environment. The output of this project will be to characterise oscillatory behaviour of genes involved in signaling in a cell population. By investigating different signaling pathways, where oscillations in expression or localization of proteins are known to occur, we will be able to understand whether different kinds of cell-autonomous oscillators make use of similar principle for their entrainment and synchronization, or on the contrary, they exhibit very different properties and rely on different mechanisms.

Melanoma is a particularly invasive and aggressive cancer that exhibits high degree of plasticity and resistance to chemotherapeutic drugs. Melanoma cells possess many features of stem cells including self-renewal capacity, high tumorigenicity and differentiation potential into various lineages. Subpopulations of cells with stem cell properties have been isolated from human melanomas, although at variable frequency depending on the criteria used. Thus, alterations in key regulators of normal melanocytic differentiation may contribute to melanoma initiation/progression. MicroRNAs (miRNAs) are endogenous non-coding small RNAs that play important regulatory roles in different biological processes such as normal cellular development and tissue homeostasis. MiRNAs are altered during melanoma pathogenesis and this alteration correlates with increased proliferation, increased survival, loss-of-differentiation and enhanced migratory capacity. Here, I propose to perform a high-throughput expression screening to identify miRNAs that may affect in vitro differentiation of human embryonic stem cells towards melanocytes. Positive hits (miRNAs that block melanoblast differentiation) will be tested in vivo in an established mouse model of skin re-pigmentation. Furthermore, I will manipulate the expression of the identified miRNAs to test whether imposing an undifferentiated status on melanocytes enhances melanoma-susceptibility and/ or progression. My findings will unravel molecular mechanisms of stem cell and melanocytes biology and provide novel insights on the role of miRNAs in differentiation and cancer.

The research interest in bioluminescence – light emission from chemically produced excited states observed with bacteria, fungi and invertebrates, has been revived recently due to its immense potentials for application to novel ultrasensitive bioanalytical techniques, which include in vivo bioluminescence imaging, gene expression and trace ATP analysis. The firm prospects for further growth of this frontier research field are founded on the requirement for energy-rich factors (ATP) and the highest fluorescence yields observed with the firefly luciferases among all known natural and artificial luminescent reactions based on matrix-unbound emitters. Most of the natural members in the large family of beetle (including the firefly) activated luciferin/luciferase complexes emit yellow-green light, although orange- or red-emitting wild-type and mutant cases have also been isolated and cloned. Yet, the complex chemical equilibrium (six chemical forms) and the pronounced in vitro instability of the emitter, oxyluciferin, have imposed great impediments to the efforts at attaining fundamental understanding of the nature of its excited-state structure and photochemistry. Albeit no less than six mechanisms of color tuning have been proposed, the long-standing conundrum about the molecular-level origin of different color emissions has yet to be resolved.

This project focuses on the excited-state structure and photochemistry of oxyluciferin. We aim at unraveling the exact structural factors that affect the emitted light, and we intend to apply the inferences to assess the performance of purposefully modified emitters for novel biochemical applications. Fundamentally new synthetic strategies will be developed to access a large variety of non-natural oxyluciferins, their precursors and isotopically labeled variants. The oxyluciferin photochemistry will be studied in/ex situ at single-molecule/ensemble/crystal level in solution and under a microscope with a set of unconventional spectroscopic and X-ray photodiffraction techniques.

Although its biological functions remain unknown, sleep is important for memory formation in a variety of animal species including humans, mice, and fruit flies. While sleep influences both the acquisition of new memories and the consolidation of recently formed associations in the fruit fly Drosophila melanogaster, the functional role of sleep in these processes is not understood. To compare the effects of sleep deprivation on memory acquisition and consolidation in the fly more directly, I will test the consequences of sleep loss on memory in an olfactory conditioning assay in which flies are trained and tested individually. Dopamine signaling is necessary for the formation of aversive associations during olfactory conditioning, and is dysregulated following sleep deprivation. Recent studies have identified a single cluster of dopaminergic neurons, the PPL1 cells, which signal unexpected punishment to the MBs and thereby drive associative olfactory conditioning. The PPL1 neuron–MB circuit is thus a likely site of functional impairment following sleep loss. To characterize the effects of sleep deprivation on the functioning of this circuit, I will use 2-photon microscopy and electrophysiology to observe PPL1 activity in sleep deprived flies and rested controls. During the memory consolidation phase, I will also observe the activity of the dorsal paired medial neurons, whose action is required for the formation of long term memory. This proposal will provide an opportunity to further my training in both sleep and memory research and apply recently developed imaging techniques to examine the neurophysiological consequences of sleep loss on memory-related circuitry.

Bacteria can survive on their own, yet in natural environments they are rarely alone. Indeed certain types of bacterial behavior, such as biofilm formation and bioluminescence, require a high concentration of bacteria as well as some form of coordination among the participants. Vibrio species can achieve this coordination by sensing the communication molecules released by organisms of the same species, other Vibrio species, and bacteria of different genera. These sensing capabilities hint at a rich variety of cell-cell interactions, the full implications of which have yet to be determined. We will investigate spatial and temporal aspects of such interactions in Vibrio species, by studying the population spatial structure of Vibrio harveyi, Vibrio cholerae, and mixed suspensions, while the population transitions to social behavior in highly controlled microscopic environments. Tracking single cells in populations, and simultaneously measuring the expression level of genes responsible for social behavior in each cell, will allow us to answer the following questions: Do all cells participate in social behavior? Is the transition to social behavior synchronous? Do chemotaxis and the dynamics of active suspensions lead to clusters or other spatial structures that locally initiate social behaviors? How do suspensions of mixed species organize spatially during social behaviors? We will also develop mathematical models to understand the population-level behavior. The inputs for these models will be measured in another line of experiments, which will include a quantitative characterization of the temporal aspects of the communication signal transduction pathways.

Secreted TGF-b family proteins play key roles in cell differentiation in metazoan organisms. Of great interest, TGF-b proteins drive epithelial-mesenchymal transition (EMT), which plays a key role throughout development and in cancer progression. TGF-b proteins induce changes in gene expression through Smads, which act as transcription regulators. Smads are phosphorylated by TGF-b receptors, and their activities are further regulated through phosphorylation by other kinases. Since protein methylation has been emerging as a post-translational modification that defines protein function, and epigenetic regulation of histone methylation provides a platform for interactions of transcription factors with methylated histones or associated proteins, we hypothesize that interactions of methyltransferases with Smads may play key roles in the TGF-b signaling response. However, up to now, there is no knowledge on the role of methyltransferases in TGF-b family signaling or on functional interactions of Smads with methyltransferases. Through my recent research, I found that Smad3, the major effector Smad for TGF-b signaling, can be methylated and that the methyltransferase ESET interacts specifically with Smad3. I now propose to biochemically and functionally define the interaction of ESET with Smad3 in TGF-b signaling, using the SnoN gene as model target for Smad3-ESET. I hypothesize that functional interactions of Smad3 with ESET define TGF-b signaling and TGF-b-induced transcription regulation through methylation of Smad3, and/or ESET-mediated changes in histone methylation. I will then examine the role of the functional interaction of ESET with Smad3 in TGF-b-induced EMT.

Biofilms form when bacteria attach to a surface and secrete sticky polymeric substances and are of enormous importance in nature, industry and medicine. While nearly all of our knowledge about these communities has been gleaned from biofilms growing on planar surfaces (i.e. agar plates and within flow cells), in many natural systems cells grow in topologically complex environments where there is the potential for strong interactions between fluid motion and growth. These interactions can result in preferential flow channels and large unirrigated regions, the physical and evolutionary implications of which are largely unknown. I propose a combined experimental and theoretical investigation of biofilm development and evolution in heterogeneous environments. Using custom microfluidic channels that simulate a porous media environment, I will characterize how key factors including fluid flow, nutrient loading and bacterial genotype shape patterns of biofilm development. The dominant physical processes will be rationalized using a nondimensional network model. The system will then be used to elucidate interactions between fluid dynamics and evolutionary dynamics and, in particular, social evolution. Efficient biofilm growth requires cell cooperativity. I will study how preferential fluid channel formation affects cooperation, and vice versa, by competing bacterial strains that differ in their level of cooperativity. As a fluid dynamicist who has worked primarily on the motility of marine phytoplankton, this project will represent a significant change in research direction and offer me extensive exposure to evolutionary theory, microbiology and molecular genetics.

Glycogen, the glucose storage molecule, is considered an invaluable asset for cells. Glycogen Storage Diseases (GSDs) are pathologies linked to mutations of the genes in the glycogen metabolism pathway. Symptoms vary from mild metabolic defects to severe degenerative processes. The glycogen found in these disorders is abnormal in quantity, quality, or both. Our hypothesis is that these glycogen molecules harm the cell.

Wild-type glycogen branching enzyme (GBE1) deficiency (Andersen Disease, Adult Polyglucosan Body Disease (APBD)) results in the accumulation of aggregates of linear glycogen. We aim to identify the mechanisms by which such aggregates trigger cell dysfunction and death. To this end, we will model the impact of mutations found in patients on GBE1 structure and function. Using animal and in silico models, we will study the effects of abnormal glycogen accumulation on energy metabolism, mitochondrial function and cell viability. Involving techniques from biology, biophysics and chemistry, this project will reveal the deleterious effects of a molecule, glycogen, generally considered advantageous, and may offer new clues for the treatment of APBD and other GSDs.

Recent studies revealed a novel regulatory mechanism in the cell based on reversible phosphorylation and peptidyl-prolyl isomerisation of Ser/Thr-Pro motifs. Peptidyl-prolyl isomerase Pin1 emerged to be crucial nexus of this regulatory system by recognising with high specificity phosphorylated Ser/Thr-Pro modules in a variety of protein substrates involved in cell cycle control, cell proliferation and apoptosis. Despite a large number of studies carried out to date, the molecular mechanism by which Pin1 interacts with its target proteins remains elusive.
We propose to unravel the molecular mechanism by which Pin1 recognises the tubulin-binding protein tau and catalysis its conversion between biologically-relevant peptidyl-prolyl isomeric states. Differential phosphorylation states of tau regulate microtubule assembly in vivo and their interactions with Pin1 have recently been implicated in Alzheimer’s disease. To unambiguously identify precise tau phosphorylation states that are recognised and catalysed by Pin1, recombinant tau will be specifically phosphorylated using mitotic cell extracts and proline-directed kinases in vitro. Tau phosphorylation-patterns will be identified using limited proteolysis combined with mass spectrometry as well as NMR techniques. Then, the influence of differential tau phosphorylation on microtubule assembly will be measured quantitatively. Also, recognition and turnover of biologically active tau phosphorylation states by Pin1 will be studied at atomic level using unconventional NMR methods. Finally, high resolution structural properties of tau in complex with Pin1 and/or tubulin will be explored using NMR and x-ray crystallography.

Neurons are highly polarized cells in eukaryote organisms consisting of cell body, dendrites and an axon, which can have volumes more than a thousand time the volume of the cell body. Motor proteins drive cargo transport by moving along microtubules to their plus-end (most kinesins) or minus-end (dyneins). Collectively these movements define axonal and dendritic transport.
Anterograde transport is divided into fast transport that involves most membrane-bound organelles and vesicles to the synapse and a slow component that largely consists of microtubules and neurofilaments, microfilaments and other cytoplasmic proteins.
Although it has been shown that plus-end kinesin motors are responsible for fast and slow transport, a central and extremely important question yet to be explored is what active regulatory mechanism underlie the differences between fast and slow axonal transport. The main objective of this proposal is to elucidate how slow and fast axonal transport is accomplished and regulated by developing a novel method to directly image and track individual motor proteins over very long distances using intrinsic fluorescence of single-walled carbon nanotubes. This is only realizable owning to exceptional intrinsic near-IR fluorescence SWNTs that display marked photostability, an absence of fluorescence intermittency, large Stokes shifts and high optical anisotropy. Furthermore, endogenous or background luminescence from biological materials is extremely weak at the relevant detection wavelengths beyond ca. 1100 nm. These factors currently enable detection of SWNT emission with high signal-to-background ratios from cells and tissues that contain nanotubes.

Marine invertebrates harbor intricate ecosystems of diverse microbial life. Less than one percent of these bacterial communities can be cultivated under laboratory conditions. Hence, little is known about the metabolic pathways and chemical signals produced by these often low-abundance organisms. Recent advances in environmental DNA capture have uncovered the genetic potential of these unstudied microbes. However, foreign regulatory and metabolic requirements have prevented functional validation of the pathways in heterologous hosts. I will implement two strategies to surmount the challenges facing the study of metagenomic-derived biogenic pathways. First, I will insert well-defined regulatory elements into gene clusters using restriction-enzyme–independent methods to foster metabolic production. Site-directed DNA cleavage guided by pseudo-complementary polynucleic acids will be used with yeast recombination to insert arabinose-inducible promoters into the model metabolic pathway encoding misakinolide A from the sponge Theonella swinhoei. Second, I will develop a general high-throughput method to activate and monitor protein expression from unknown biogenic pathways. C-Terminal green fluorescent protein (GFP) fusions will be constructed in the griseorhodin A model pathway in Streptomyces albus sp. J1074. Fluorescence-activated cell sorting (FACS) of nanoliter-scale fermentations will monitor soluble GFP expression to determine successful gene cluster activation. I will then apply this system to unknown pathways discovered in sponge-associated Entotheonella spp. This research will create fundamental approaches to study symbiotic microbiota within marine invertebrates.

The genome of eukaryotic cells is organized into a functional and hierarchical architecture: the chromatin. The lowest level of the chromatin organization is represented by individual particles, the nucleosome cores. Positioning of the nucleosome core particles on the sequence is a problem of great interest because of the role nucleosomes play in different cellular processes. Unfortunately, current methods for derivation of the nucleosome occupancy maps suffer from several drawbacks that prevent high mapping accuracy.

We propose to use hydroxyl radicals instead of micrococcal nucleases for DNA cleavage step, causing accuracy improvement that will allow creation of high resolution nucleosome occupancy maps. These maps will allow us to develop new sequence dependent nucleosome positioning models, and to validate and refine existing ones. Using those maps my intention is to detect "canonical" nucleosome occupancy patterns in variable genomic contexts. Detected patterns will allow us to determine the 3D structure of the chromatin that is expected to be dictated by the nucleosome linker lengths.

I would like to measure the influence of the specific nucleosome positioning patterns on a given genomic environment, by transgenic integration. Finally, I am interested in performing a detailed comparison of different patterns detected in different tissues of nematode Caenorhabditis and check the relation to other species patterns.

The radial and tangential expansions that took place in the common mammalian ancestor required substantial changes in the telencephalic developmental program. What developmental changes drove neocortical enlargement? Two major hypotheses have discussed what these changes were. We propose to test them on mice and chick; new techniques shall allow us to study the evolutionary process in depth.

First, we propose to describe the actual cortical homologies between amniotes. Bioinformatic tools analyzing whole expressed transcriptomes from key telencephalic regions and a biological validation of the statistical assay shall describe what avian brain structures are homologous to the mammalian cortical layers.

Second, we shall check if the arrival of new extracortical populations triggered the neocortical enlargement. Are the dorsal pallia of mammals and birds comprised of populations from different origins? We shall quantitatively compare the unique proliferative and migratory features of region-specific single telencephalic germinative cells. We shall employ a new methodology that labels single cells and its progeny with a unique random mixture of five fluorophores. We will be able to describe the actual differences and similarities on the telencephalic developmental program between species.

And finally, we shall employ the same methodology to test if the increased proliferative rate on the dorsal pallium was the mechanisms that drove neocortical evolution.

The project will allow the candidate to grow as an independent researcher. He will use and design new techniques, especially at the Molecular Biology level.

After two decades of effortful neurobiological research, the neural basis of consciousness, and in particular – the role of frontal networks in the process leading to a conscious percept, is still highly controversial. This controversy originates, at least partially, from the inherent limited spatial and temporal resolution of the imaging techniques used so far. Thus, electrophysiological measurements, which allow the sampling of single neurons at millisecond resolution, might be the key for this controversy. While such measurements are feasible in animals, the study of consciousness is awkward – as it relies on the ability of the subject to convey his internal experience. I propose to help resolve this controversy by utilizing a unique clinical opportunity to obtain electrophysiological signals from the brains of conscious humans while they experience subjective spontaneous alternations in the content of consciousness, in the context of binocular rivalry. Recording from frontal as well as temporal regions of the brain will allow us to track the dynamics of this process and explore the flow of information between different brain regions. If indeed frontal networks play causal role in selecting which percepts reach consciousness, then this should be manifested in early frontal signals, which precede and essentially triggers these subjective alternations. Additional forms of bistable perception in the visual and auditory domains will be used to broaden the scope of the results. This proposal, based on a rare opportunity to record the activity of single neurons in conscious humans, promises to yield unique insights into the role of the frontal lobe in conscious perception.