Jennifer Kirkland

I am responsible for the production of our transgenic mice. I also maintain many of our mouse stock lines. In addition, I participate in many other mouse projects such as rederivations, cryogenic preservation of embryos, and production of mouse ES cell lines.

Ira Schieren

I strive to further the research interests of the lab with the use of computers and technology.  I primarily achieve this goal by managing the flow cytometry facility.  But, I also contribute as computer systems administrator, graphic artist, photo editor, web developer, a source for spare parts and a technical tinker.

Joriene de Nooij

I am interested in understanding the molecular mechanisms that underlie the establishment of the ‘simple’ proprioceptive reflex circuits in the spinal cord.  Through an understanding of the generation of the different classes of proprioceptive sensory neurons (group Ia, group Ib and group II), and of the spinal circuits onto which each of these classes provides input, I hope ultimately to test the functional contribution of the distinct proprioceptive circuits in the coordination of locomotor and/or other motor behaviors.

Ivo Lieberam

The role of Cxcr4/Cxcl12 signaling in the establishment of the initial trajectory of motor neurons.

All motor neurons project out of the CNS, emerging from either ventral or dorsal exit points in the neural tube. The transcriptional programs that control this decision are well understood, however the cell surface receptors that mediate these decisions have not been defined. We have found that the chemokine receptor Cxcr4 is expressed on the axons of ventrally projecting MNs (vMNs), whereas its ligand Cxcl12 is expressed by the mesenchyme surrounding the neural tube. In the absence of Cxcl12/Cxcr4 signaling, vMNs adopt the trajectory of dorsally projecting MNs (dMNs) despite maintaining their transcriptional identity.  In ongoing studies I am examining further aspects of chemokine signaling during neuron development.

Julia Kaltschmidt

I am interested in the formation of sensory-motor connections and their control by presynaptic inhibition in the developing spinal cord.  I have developed effective methods for visualizing selective sensory-motor connectivity and the connections inhibitory interneurons make on terminals of sensory afferents.  I am using these methods to evaluate the contribution of neuronal activity to the formation of selective sensory-motor connectivity and to better understand the molecular basis of neuronal circuit formation.

Laskaro Zagoraiou

I am interested in defining the interneuronal circuits that control locomotor function in the mammalian spinal cord. Classical physiological studies have defined many classes of interneurons that regulate motor firing patterns. There is also emerging evidence that ventral interneurons can be classified into four major classes during embryonic development, each class deriving from a different progenitor domain within the ventral neuroepithelium. How these broad interneuron classes diversify to generate functionally coherent subsets of interneurons remains obscure. I am combining molecular genetics and physiology to identify discrete subsets of interneurons and probe their role in the coordination of locomotor behavior.

Sebastian Poliak

A key aspect of the development of neural function is the precision with which neuronal circuits are assembled. In the spinal mono-synaptic stretch reflex circuit, muscle sensory neurons convey information to the spinal cord and form specific synaptic connections with motor neurons that innervate the same muscle. My research in the lab attempts to understand the developmental mechanisms that specify muscle sensory neurons to form these selective synaptic connections as well as the molecular mechanisms that guide motor axons to their specific target muscle during limb development.

Adam Hantman

I am interested in the logic employed by neuronal networks that integrate incoming information and generate useful output commands.

This interest has led me to explore the network function of spinal neurons that which receive sensory information from the periphery and transmit information to higher centers of the brain.  Focusing on individual and identifiable classes of neurons within these spinal laminae makes this problem more tractable.  Using genes selectively expressed as a consequence of their developmental lineages, we can label classes of neurons to allow for efficient study.  These labeled neuronal types can then be characterized in terms of their developmental lineage, molecular features, membrane properties, sources of presynaptic input, action potential generation patterning, and their postsynaptic targets.

Elena Demireva

I am interested in understanding how precise synaptic connections between sensory neurons and their motor neuron targets are formed during development. More specifically I am investigating the role of the cadherin-catenin molecular system in the formation of the sensory-motor circuitry in the mouse spinal cord.

J. Nicholas Betley

The formation of precise synaptic connections is an essential step in the assembly of functional neuronal circuits. In the mammalian central nervous system (CNS), synaptic specificity is thought to depend on the targeting of selected sets of neurons to post-synaptic targets, and on retrograde signals that direct pre-synaptic differentiation. However, the mechanisms that direct selective interactions between defined sets of neurons and their prospective targets in vivo remain largely obscure. In attempting to analyze the emergence of synaptic specificity in the mammalian CNS, I have been examining sets of GABAergic interneurons in the developing spinal cord, known to regulate sensory-motor transformations. Through genetic means, I aim to understand better the requirements for organization and selective connectivity of these neurons.