Our Research Focus
Anatomy & Morphology
EM image & tracing courtesy of
Qiyu Zhang & Alan Emanuel
Our sense of touch is crucial for perceiving and reacting to the world around us. The primary sensory neurons that detect and propagate information about our surrounding tactile environment, particularly non-painful and pleasurable touch, are called low-threshold mechanoreceptors (LTMRs). These neurons reside in dorsal root ganglia (DRG), which flank the spinal cord, and have peripheral axonal branches that innervate the skin and respond to diverse types of mechanical stimuli. LTMRs relay touch information from the skin to the spinal cord and higher brain regions. Activation of distinct combinations of cutaneous LTMR subtypes gives rise to the broad and rich spectrum of touch sensations we experience, including our ability to feel a gentle indentation, a brush stroke, or deflection of a single hair.
Left: A schematic of the sensory structures and associated LTMRs that reside in the non-hairy skin (such as the fingertips).
Right: A schematic of the LTMR subtypes that wrap around and innervate hair follicles to aid in sensing hair deflection (Zimmerman, et al. Science, 2014).
Once a physical stimulus is detected by diverse and finely-tuned cutaneous sensory end organs and their associated LTMRs, this information is relayed to the spinal cord and brain through LTMR central projections and spinal cord projection neurons. In the spinal cord dorsal horn, LTMRs terminate within distinct but overlapping laminar domains and synapse upon a large diversity of excitatory and inhibitory interneurons that integrate tactile signals. These interneurons are diverse in their morphological and electrophysiological properties, and in their functions in processing somatosensory signals.
Left: A summary of the diversity of neurons that reside in the dorsal horn of the spinal cord where LTMR central projections synapse (Abraira, Keuhn et al. Cell, 2017).
The Ginty Lab uses a combination of molecular genetics, anatomy, behavior, and electrophysiology to gain a better appreciation of the development, organization, and function of LTMRs and the complex neural circuitry that underlies our sense of touch.
Current efforts in the Ginty lab are aimed at understanding:
1) The unique functions and properties of the various LTMR subtypes innervating different skin areas of the body
2) The organizational logic of synaptic connections between LTMRs, spinal cord dorsal horn interneurons, projection neurons, and dorsal column nuclei neurons
3) The contributions of LTMR subtypes to the central representation of touch
4) The mechanisms by which primary somatosensory neurons acquire their unique morphological and physiological properties and integrate into central tactile circuits during development
5) The pathophysiological mechanisms underlying tactile over-reactivity in autism spectrum disorders and neuropathic pain states