University of Oregon

Niell Lab

 

People

Philip Parker

Postdoctoral Researcher


The mammalian visual system utilizes a powerful set of algorithms to extract crucial information from the environment that informs an individual’s decisions. These algorithms require constant adjustment to match the individual’s current needs – a task achieved partly by neuromodulators such as serotonin. In some cases, these modulatory systems open the door for maladaptive changes to visual processing. For example, visual hallucination is a debilitating yet common neurological symptom arising in many distinct disorders, including schizophrenia and medicated Parkinson’s disease. Serotonin receptors are key mediators of these symptoms, and their blockade by antipsychotics disrupts hallucinations. However, these drugs cause numerous unwanted side effects, and the lack of therapies with greater specificity reflects the gaps in our understanding of exactly how serotonergic signaling modulates visual processing. My fundamental goal is to understand the circuit mechanisms underlying serotonergic modulation of visual processing to better inform models of visual function and therapeutic targeting of visual hallucinations. I combine widefield and two-photon imaging in visual cortex with pharmacological and chemogenetic manipulation of specific neural cell types to gain a better understanding of the mechanisms behind contextual visual processing and its disruption in disease.


Website: cosmouse.net

Contact: pparker (at) uoregon (dot) edu

 
Angie Michaiel

Graduate Student


I am fascinated by the brain’s ability to construct the perception of reality from the sensory world. Our experience is largely based on the integration of sensory information and behavioral state. I am most interested in understanding brain states, such as sensory hallucination, in which sensory information processing is disrupted such that perception does not accurately represent the world. Understanding these disruptions will give us insight about the limits of the brain and aid in the understanding of neuropsychiatric diseases. Schizophrenic patients who suffer from sensory hallucinations are relieved of this phenotype following administration of antipsychotic drugs that block the serotonin-2A receptor. Using multi-channel extracellular electrophysiology, I am exploring how hallucinogens, working through the serotonin-2A receptor, disrupt the processing of visual information at the level of individual neurons and population of neurons.


Contact: amichai3 (at) uoregon (dot) edu

 

Andrew Mosman

Research Technician

 
Cristopher Niell

Assistant Professor, Department of Biology


I have spent most of my research career studying the development and function of neural circuits in the visual system. As a graduate student in Dr. Stephen Smith’s lab at Stanford University, I used two-photon imaging in the zebrafish optic tectum to study both functional receptive field properties and the developmental processes of growth and synapse formation. I then began work on the mouse visual cortex, in the lab of Dr. Michael Stryker at UC San Francisco, utilizing the mouse as genetic model system to investigate aspects of cortical organization and development. In my lab at University of Oregon, which started in 2011, we are focused on understanding visual processing from the level of individual neurons up to brain-wide pathways, particularly in the context of behavior and different brain states.


Curriculum Vitae

Contact: cniell (at) uoregon (dot) edu

 
Hannah Bishop

Postdoctoral Researcher


I am a postdoctoral researcher in the Niell lab and an instructor in the Biology department at UO. I am currently using in situ hybridizations to look at expression of the 5HT2a receptor in mouse neocortex, and working with Jen Hoy using DREADDs to investigate the contribution of different cell types within the superior colliculus to prey capture behavior in mice. 


Contact: hibishop (at) uoregon (dot) edu

 
Jennifer Hoy

Postdoctoral Researcher


My research is focused on understanding the neural circuit and molecular mechanisms underlying natural approach behaviors in mice. I use optogenetics, neurophysiology, molecular genetics, immunohistochemistry and anatomy to understand mammalian visual system development, function and behavior. My work will ultimately lead to an understanding of the biological mechanisms that allow mammalian visual systems to parse visual scenes and extract behaviorally salient information.


Contact: jhoy (at) uoregon (dot) edu

 
Judit Pungor

Postdoctoral Researcher


My research focuses on exploring the functional organization of the visual system of the octopus. Octopuses rely on their keen sense of sight for most everything in their lives, from prey capture and predator evasion, to camouflaging and finding mates. They have a camera-like eye as vertebrates do, which emerged in a stunning case of convergent evolution. While we know a bit about the structural organization of their visual systems, little is known about its functional organization. Using a combination of calcium imaging and tract tracing techniques, I aim to identify what features of the visual world octopuses extract and utilize, and how this visual information is disseminated to higher order processing centers in their central brain.


Contact: jpungor (at) uoregon (dot) edu

 
Johanna Tomorsky

Graduate Student


Through my research, I am working to determine which molecular factors allow neurons in layer 2/3 of visual cortex to form functional synapses during development. Besides being one of the most heavily studied cortical layers due to its proximity to the surface of the brain (making imaging easier), this layer also contains some of the most highly interconnected and visually responsive neuronal types in the cortical circuit. Neurons in layer 2/3 of visual cortex are often more selective than those in other layers, responding only to a highly refined set of visual stimuli. The developmental refinement of these visual preferences occurs in the week following eye opening, corresponding with a period of intense synapse formation and dynamic gene expression in mouse V1. To begin to address the question of which molecular factors enable specific neuronal types to identify their functional targets during synaptogenesis, we identified genes expressed in layer 2/3 excitatory neurons around eye opening. We used a technique developed in the Doe lab at UO for the spatiotemporal isolation of RNA called TU-tagging, to isolate genes found in a specific cell type at a specific developmental time point. I am currently working to knock out one of the many genes identified through this screen to further elucidate its role in the development of layer 2/3 excitatory neurons.


Contact: jtomorsk (at) uoregon (dot) edu

 
Joseph Wekselblatt

Graduate Student


Sensory-driven behaviors engage a cascade of cortical regions to process sensory input and generate motor output. To investigate the temporal dynamics of neural activity at this global scale, we have improved and integrated tools to perform functional imaging across large areas of cortex using a transgenic mouse expressing the genetically encoded calcium sensor GCaMP6s, together with a head-fixed visual discrimination behaviors. This technique allows imaging of activity across the dorsal surface of cortex, with spatial resolution adequate to detect differential activity in local regions at least as small as 100 μm. Imaging during an orientation discrimination task reveals a progression of activity in different cortical regions associated with different phases of the task. After cortex-wide patterns of activity are determined, we demonstrate the ability to select a region that displayed conspicuous responses for two-photon microscopy. We expect that this paradigm will be a useful probe of information flow and network processing in brain-wide circuits involved in many sensory and cognitive processes.


Contact: jwekselb (at) uoregon (dot) edu

 
Penny

Lab Pillow

 

Ryan Di Ricco

Research Technician