Sensory transduction and its synaptic control

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Our bodies are constantly bombarded by sensory signals such as light, taste, smell, sound, and pain. The brain must process and coordinate incoming sensory information with ongoing activities to execute relevant behavioral tasks. My laboratory studies mechanical senses, such as touch, vibration, and hearing, and we also work on vision. We are especially interested in transduction, the conversion of sensory signals into electrochemical events. This complex process involves multiple molecules, many of which have not yet been identified in any sensory system in any animal. We also aim to learn how sensory cells encode and transmit signals to the central nervous system and how these processes are modulated by efferent synaptic input. We use large spiders, cockroaches and locusts as our model animals because their sensory cells are easily accessible for powerful experimental approaches such as intracellular recordings during mechanical stimulation, unfeasible in common model species because of the small sizes and/or complex locations of their sense organs. An important feature of spiders is extensive efferent synaptic connections to peripheral regions of their mechanosensory cells with neurotransmitters such as GABA and acetylcholine that modulate sensory neurons via multiple receptor types. Similar phenomena only occur in poorly accessible central nervous systems of most other animals. A decade ago, use of powerful molecular methods such as gene sequencing and genetic manipulation were limited to a small number of model species, but they can now be used in a wide variety of organisms. In recent years, we have developed and applied molecular methods to complement our electrophysiological, optical, and computer-based expertise. Our major research aims are to: 1) uncover the molecular machineries behind mechanotransduction within the spider strain detecting mechanosensory neurons and locust auditory neurons; 2) discover whether differences in receptor subunit composition of spider sensory neurons lead to distinct cellular responses to GABA, the main inhibitory neurotransmitter in all animals; 3) explore the physiological roles of the multiple acetylcholine esterase (AChE) enzymes of the spider central and peripheral nervous systems; and 4) decode the molecular pathways that allow nocturnal insects to see in dim light. Mechanical senses and vision are essential for our survival, and their failure causes disabilities such as deafness and blindness, so unraveling the molecular mechanism of transduction is hugely important. Central efferents modulate sensory neurons of all animals, including humans and their dysfunction leads to chronic pain and movement disorders. GABA receptors and AChE are major targets for drugs to treat human diseases such as anxiety and Alzheimer's and many widely used insecticides act on these molecules, thus better understanding of their selectivity can lead to their more rational use and integrated pest management.