Results Through Rehabilitation & Research
Assistant Professor, Neurology and Neuroscience
Weill Cornell Medical College
The research in my laboratory focuses on sensory signal processing, particularly on how fundamental yet simple synaptic mechanisms underlie our perception of the world around us. The functioning of the sensory systems is mediated by elaborate neuronal circuitry and could be dramatically altered by development, experience or during neurodegenerative diseases. These define major research interests of my laboratory--from fundamental mechanisms to rehabilitation.
We use vertebrate retina to study synaptic interactions and translate these findings to better understand neurological pathologies and evaluate strategies to delay or repair their outcome. This part of the brain is particularly amenable to experimental analysis for several reasons. First, retina is an accessible part of the central nervous system, which can be stimulated physiologically with light. Second, the output of the retina can be monitored with relative ease by intra- and extracellular recordings from its neurons.
Importantly, the retina is a site for several forms of severe neurodegenerative diseases that lead to vision loss and blindness; a number of mouse models that replicate human retinal degenerative diseases are available and provide necessary tools for these studies.
We probe the normal and impaired retina by making whole-cell patch recordings from morphologically identified neurons in the retinal preparation in vitro. These studies are then extended by monitoring the retinal output in living mice using recordings from single optic nerve fibers to characterize both basic properties as well as more complex interactions such as receptive field structure, response gain and adaptation. Recordings of field potentials from corneal surface (ERG) are used to evaluate retinal function noninvasively.
These studies are helping us better understand the functional plasticity of the retina, before, during and after the loss of photoreceptors and will potentially lead us to the development of successful treatment strategies.
Toychiev A.H., Yee C.W., Sagdullaev B.T. (2013) Correlated spontaneous activity persists in adult retina and is suppressed by inhibitory inputs. PLOS One (in press)
Ivanova E., Toychiev A.H., Yee C.W., Sagdullaev B.T. (2013) Optimized protocol for retinal wholemount preparation for imaging and immunohistochemistry. JoVE (in press)
Toychiev A.H., Ivanova E., Yee C.W., Sagdullaev B.T. (2013) Block of gap junctions eliminates aberrant activity and restores light responses during retinal degeneration. J.Neuroscience 33(35), 13972-13977.
Tschetter W., Alam N., Yee C.W., Douglas R., Gorz M., Sagdullaev B.T, and Prusky G.T. (2013) Experience-enabled enhancement of adult visual cortex function. J.Neuroscience 33(12), 5362-5366.
Toychiev A.H., Sagdullaev B., Yee C.W., Ivanova E., Sagdullaev B.T. (2013) A time and cost efficient approach to functional and structural assessment of living neuronal tissue. J.Neuroscience Methods, 214(1), 105-112. PMCID: PMC440334
Yee C.W., Toychiev A.H., Sagdullaev B.T. (2012) Network deficiency
exacerbates impairment in a mouse model of retinal degeneration.
Frontiers in Neuroscience 6(8), 1-14.
Sagdullaev B.T., Eggers E.D., Purgert R., Lukasiewicz P.D. (2011)
Nonlinear interactions between excitatory and inhibitory retinal
synapses control visual output. J.Neuroscience 31(42), 15102-15112.
Valley MT, Mullen TR, Schultz LC, Sagdullaev BT and Firestein S (2009) Ablation of mouse adult neurogenesis alters olfactory bulb structure and olfactory fear conditioning. Frontiers in Neurogenesis 1(3), 1-13.
Le Pichon CE, Valley MT, Polymenidou M, Chesler AT, Sagdullaev BT, Aguzzi A, Firestein S. (2009) Olfactory behavior and physiology are disrupted in prion protein knockout mice. Nature Neuroscience 12(1), 60-69.
Sagdullaev BT, Eggers ED, Ichinose T, Lukasiewicz PD. (2008) Visual signal processing in the inner retina. Ophthalmology Research V. 287-304.
Song Y, Cygnar KD, Sagdullaev BT, Valley M, Hirsh S, Stephan A, Reisert J, Zhao H. (2008) Olfactory CNG channel desensitization by Ca2+/CaM via the B1b subunit affects response termination but not sensitivity to recurring stimulation. Neuron 58(3), 374-386.
DeMarco, PJ, Yarbrough GL, Yee CW, McLean GY, Sagdullaev BT, Ball SL, McCall MA. (2007) Stimulation via a subretinally placed prosthetic elicits central activity and induces a trophic effect on visual responses. Invest Ophthalmol Vis Sci 48(2), 916-926.
Sagdullaev BT, McCall MA, Lukasiewicz PD (2006) Presynaptic inhibition modulates spillover, creating distinct dynamic response ranges of sensory output. Neuron 50(6), 923-935.
Demas J, Sagdullaev BT, Green E, Jaubert-Miazza L, McCall MA, Gregg RG, Wong ROL and Guido W (2006) Failure to maintain eye-specific segregation in nob, a mutant with abnormally patterned retinal activity. Neuron 50(2), 247-259.
Sagdullaev BT and McCall MA. (2005) Stimulus size and intensity alter fundamental receptive field properties of mouse retinal ganglion cells in vivo. Vis Neurosci 22, 249-259.
Seiler MJ, Sagdullaev BT, Woch G, Tomas BB, Aramant RB. (2005) Transsynaptic virus tracing from host brain to subretinal transplants. Eur J Neurosci 21(1), 161-72.
Lukasiewicz PD, Eggers ED, Sagdullaev BT, McCall MA. (2004) GABAC receptor-mediated inhibition in the retina. Vision Res 44(28), 3289-96.
Sagdullaev BT, DeMarco PJ, McCall MA. (2004) Improved contact lens electrode for corneal ERG recordings in mice. Doc Ophthalmol 108(3), 181-4.
Sagdullaev BT, Aramant RB, Seiler MJ, McCall MA. (2003) Retinal transplantation-induced recovery of retinotectal visual function in a rodent model of retinitis pigmentosa. Invest Ophthalmol Vis Sci 44(4), 1686-95.
Woch G, Aramant RB, Seiler MJ, Sagdullaev BT, McCall MA. (2001) Retinal transplants restore visual responses in rats with photoreceptor degeneration. Invest Ophthalmol Vis Sci 42, 1669-1676.
Elena Ivanova, Ph.D. - Instructor in Ophthalmology and Neurology
Abduqodir Toychiev, Ph.D. - Postdoctoral Fellow
Christopher Yee – Lab Manager
Retinal neural processing during retinal degenerative diseases
International Retinal Research Foundation (IRRF)
Functional remodeling of the retinal output after photoreceptor death
The Karl Kirchgessner Foundation