Qian-Quan Sun - US grants

DESCRIPTION (provided by applicant): Clinical cortical stimulation and mapping studies led to the idea that the dysplastic neural networks are functionally integrated and atypically organized. However, the mechanisms for the establishment of aberrant neural networks and atypical brain organization await elucidation. In patient with cortical malformation, sensorimotor region are most frequent in finding polymicrogyri, and seizure onset commonly occurs with or near cortical areas for language and motor function. Motivated by these common clinical features of cortical dysplasia, we modified a neonatal freeze lesion animal model to interrogate how efferent activities in the normal motor cortex (M1), interacts with epileptogenic circuits located within ipsilateral malformed sensory cortex (S1). In our new mice model, optogenetic approaches will be combined with traditional focal freeze lesion, to study interactions between long-range motor cortical projections and local circuits within malformed sensory cortex. We hypothesize that 1) long-range connections from M1 onto interneurons are severely altered in malformed S1 cortex, leading to heightened ictogenesis and propagation. 2) Sensorimotor experiences during critical periods may selectively promote glutamatergic innervation of interneurons; thereby mitigate motor cortex induced seizure in S1. This exploratory grant is directed to provide the first proof of the involvement of long-range motor projection induced ictogenesis in S1, as well as its modulation by innate animal behavior. Understanding how glutamatergic synapses and epileptic activities are modulated by innate sensorimotor experiences during critical period will help development of stimulation-based physical therapy strategies might be used to mitigate or eradicate epilepsy pathology in humans.

DESCRIPTION (provided by applicant): In the rodent vibrissal system, sensory processing is highly active and involves active communication between the barrel cortex and the vibrissal motor cortex. During task-dependent whisking behavior in vivo, GABAergic interneurons are more active. The activation of interneurons during active touch is responsible for sparse coding. Recruitment of interneurons, particularly layer 4 fast-spiking cells by TC inputs, has been well documented both in vitro and in vivo. However, no equivalent measurements have yet been reported for long-range M1 inputs within the sensory cortex. We therefore lack understanding of critical components of cortical computation. Our overarching goal is to construct a detailed circuit diagram, with detailed information at the level of specific inhibitory neurons and long-range synapses, to help understand the circuit basis underlying reciprocal sensorimotor associations within the S1 and M1. In Aim 1, we will systematically compare properties M1 S1 projections in 5-HT3R, PV and SST expressing S1 interneurons. In Aim 2, we will systematically compare properties S1 M1 projections in 5-HT3R, PV and SST expressing M1 interneurons. Aim 3 will supplement Aims 1& 2 and examine if there are any correlation between synaptic strength (mapping data, Aim 1& 2) and firing (numbers and probabilities). The proposal will uncover network mechanisms underlying inhibitory contextual motor modulation of sensory processing and sensorimotor integration at motor cortex. This will allow us to gain better understanding about the nature of the excitation-inhibition balance in adult neurons and cellular mechanisms underlying long-range modulation of sensory and motor processing. Successful completion of this study will provide a comprehensive understanding of pathway, layer and cell-type specific nature of motor to sensory projections, and vice versa. This proposal will likely generate novel data and hypotheses for understanding sensory and motor circuit and neurological disorders with sensory-motor integration. Abnormal circuit wiring in cortical neurons is the key features of social and cognitive dysfunction such as epilepsy, autism and schizophrenia. Therefore, unveiling the cortical interneuronal circuit organization will also help o build the groundwork for future dissection of specific interneuronal types, synapses and circuits altered by mental diseases.

DESCRIPTION (provided by applicant): During early postnatal brain development, neurons in the cerebral cortex establish connections that are then fine-tuned by experience-dependent mechanisms. Disturbances in the balance of excitation (E) and inhibition (I) in the neocortex provoke abnormal activities, such as epileptic seizures and abnormal cortical development. Mechanisms that match E-I balance are central to achieving balanced function at the level of individual neuron and circuits. However, the precise nature of E-I balance, and specific mechanisms orchestrating the establishment and maintenance of the E-I balance in adult cortical neurons is largely unknown. Circuit-wide studies documenting coordinated changes in E and I within a functional circuit are rare. Our long-term goal is to use rodent whisker-barrel system to understand the mechanisms by which the developing inhibitory networks in barrel cortex are able to adapt to sensory inputs from whiskers, and to maintain their balance with cortical excitatory networks. Applying innovative mouse genetics and channel rhodopsin assisted circuit targeting, the present proposal will investigate whether a specific, defined interaction between sensory activities with excitatory (E) and inhibitory (I) synapses may be involved in regulating E-I balance during the sensitive period of postnatal development. A major advance in this proposal is to provide new information regarding pathway and input specific E/I balance and their differential modulation by sensory experiences. Because network processing in vivo is driven by specific inputs, understanding input specific regulation of the E-I balance an its maturation is significant. If successful, this proposal will generate novel data and hypotheses for understanding of the roles of sensory experiences in shaping cortical synaptic connectivity at early stages of life. The impact of restricting neuronal activity through sensory neglect is eviden in the human population. Each year in the United States alone, over 500,000 children suffer from neglect and have a much higher probability of emotional, behavioral, cognitive, and physical delays than average children. As such, research aimed at identifying mechanisms underlying activity-induced plasticity of brain circuits and brain function also has significant health relevance. This research will obtain baseline knowledge about normal cortex function, which is critically needed to understand cortical processing deficits in disease states. Thus, this research will potentially advance and expand understanding, diagnosis, and treatment of human developmental disorders with a deregulated E-I balance. The proposed research will have substantial effect on the neuroscience research and education at the University of Wyoming. Engaging students in this innovative research will instigate their interest in pursuing career innovative research.

? DESCRIPTION (provided by applicant): The long-term goal of this research project is to gain an understanding of the broader relationship between sleep, long-range sensorimotor circuits, and epilepsy circuits associated with a mouse model of focal cortical dysplasia (FCD). FCD and related malformations of cortical development (MCDs) are highly correlated with childhood seizure syndromes and cognitive disabilities. MCDs represent an increasingly recognized cause of medically intractable epilepsy. The development of more effective therapies will benefit from a deeper understanding of the pathophysiology and mechanisms of epileptogenesis in animal models. We will study long-range sensorimotor circuit properties in a unilateral single focal neonatal freeze lesion in S1 (SFFLS1R) treated mice. In Aim 1, we will obtain 24-hour EEG data from SFFLS1R mice to validate our preliminary finding that these animals developed continuous spike-waves during slow-wave sleep (CSWS) epileptiform discharges. CSWS is a human epileptic syndrome that is associated with the EEG pattern of electrical status epilepticus during slow wave sleep (ESES). We will then examine the idea that during the pre-ictal state (i.e. latent period), abnormal pre-ictal discharges (APDs) precede CSWS activity and are a biomarker for the severity of CSWS seizures in the same animals. In Aim 2, we will examine the hypothesis that large scale reorganization of long-range sensorimotor and corticothalamic circuits, in addition to local circuits, is required to support generalized APDs and CSWS in SFFLS1R animals. We will combine mouse genetics and the ChR2-assistant circuit mapping (CRACM) approach to characterize the maladaptive reorganization of long- range vs. local inhibitory cortical circuits in the malformed S1. In Aim 3, we will further use complementary approaches to test the idea that paroxysmal epileptiform discharges in SFFLS1R mice are mediated by long- range circuits acting on their targets in the malformed S1 in vivo. We will first use opto- and chemo-genetics tools to manipulate circuit components in vivo to demonstrate whether and to what extent CSWS seizures are modulated by activation/inactivation of certain circuit components. We will then take advantage of the modified enriched environment to determine whether and to what extent CSWS seizures are modulated by sensory experiences during the latent period. Upon successful completion of this project, we can associate chronic spontaneous CSWS/ESES seizures with FCD in a mouse model. Upon successful completion of this project, we can link dynamic changes of long-range circuits with ictogenesis, which will guide our understanding of why dynamic bistability exists in thalamocortical circuits in the pathological state. Understanding the mechanisms by which normal sleeping and sensorimotor circuits are transformed into epileptic circuits will help develop circuit-based treatment strategies for intractable epilepsy associated with CSWS/ESES and FCDs/MCDs. The chronic FCD animal model can potentially be used to develop behavior- based therapies and screen drug targets for novel therapies related to ESES, MCD epilepsy.

Abstract. The Wyoming Sensory Biology Center (SBC), a Center of Biomedical Research Excellence (COBRE), integrates and supports thematic multi-disciplinary sensory biology research at the University of Wyoming. The Administrative core (AC) will assume the organizational and fiscal responsibilities for the SBC. The AC will be responsible for steering the research direction of the SBC, overseeing progress of research projects, coordinating career development and mentorship for junior scientists, reviewing pilot projects, purchasing equipment, improving research infrastructure; and, cost-sharing in start-up packages for research faculty. The AC relies on a team of experienced mentors, internal and external advisory committees under the leadership of the Center Director to guide four Project Leaders toward independent research careers. The SBC will be led by Dr. Qian-Quan Sun, an experienced sensory biologist with a solid federal funding record and extensive mentoring and administrative experiences. The AC of the SBC has the following specific aims: 1) establish a sustainable thematic multi-disciplinary SBC in the University of Wyoming; 2) provide scientific leadership and an administrative structure to oversee the research activities of the four projects and the research core; 3) maintain a rigorous mentoring program to help establish junior scientists as independent investigators and facilitate the selection and recruitment of new junior investigators and new research projects; 4) provide fiscal oversight of the SBC and maximally utilize financial resources to build a sustainable center; 5) coordinate an effective internal and external advisory committee structure to provide expertise, advice, and oversight of the program, and to ensure effective communication between members of the SBC and advisory committees; 6) develop and implement a formative and summative evaluation strategy with specific milestones. Successful operation of the AC will enable the SBC to achieve the following milestones within the initial five years of funding: successful expansion of the state- of-the-art imaging and microscopy core facility, success in all Project Leaders whom competed for R01-level funding; four to six new or early-stage investigators added to the Center; two to four new mentors added (including Project Leaders who recently graduated from COBRE support); and at least 20 manuscripts accepted for publication or published in reputable peer-reviewed journals.

Abstract The primary mission of the Wyoming Sensory Biology COBRE (SBC) is to foster and conduct high-quality scientific research that advances the understanding of our sensory systems and disorders related to them. SBC will accomplish its mission through the augmentation and strengthening of UW's institutional biomedical research capacity. This will be accomplished through building a critical mass of investigators whose research interests center around sensory processes at the molecular, cellular, physiological and system levels. SBC will promote the competitiveness of the core investigators by providing mentoring, training, collaboration and research support. The SBC will be led by the PI with the help of an excellent group of additional mentors. The PI is an established sensory system investigator with expertise that is germane to the research theme of the center, has an active research laboratory, has obtained peer-reviewed funding and has extensive administrative leadership and mentoring experience. The SBC is comprised of the Administration Core, the Integrated Microscopy Core (IMcore), and four interrelated research projects. As a whole, the SBC will support four new junior investigators and four future faculty hires that are committed to the SBC, during the five years of the COBRE funding. The Center will comprise a multi-disciplinary team of investigators with expertise across multiple sensory modalities, including somatosensation, chemosensation, and vision. The SBC investigators' research portfolios demonstrate a balance of basic and translational research across multiple fields. The five-year goals of the SBC are the following: 1. Establish a multi- disciplinary center that brings together investigators with expertise in diverse areas of sensory neuroscience and experimental methodology, and fosters collaborations to address key issues in sensory function and dysfunction. 2. Support the projects of junior investigators by providing strong mentoring and guidance to help them obtain independent funding and professional success. 3. Grow the SBC in both size and scope through the recruitment of new faculty, as described in the Institutional Commitment, and fostering multi-disciplinary research among current UW faculty, respectively. 4. Build the required research infrastructure by expanding the capabilities of the Microscopy Core. 5. Advance our understanding of the development and function of sensory systems and their dysfunctions. Successful operation of the Center is expected to achieve the following milestones within the initial five years of funding: successful expansion of a state-of-the-art imaging and microscopy core facility, all four Project Leaders successfully competing for R01-level funding; four to six new or early-stage investigators added to the Center; two to four new mentors added (including Project Leaders who recently graduated from COBRE support); and at least 20 manuscripts accepted for publication or published in reputable peer-reviewed journals.

ABSTRACT During sleep, the thalamus generates a characteristic brief pattern of 8-15 Hz electroencephalographic (EEG) waves that predominantly occur during light stages of non-rapid eye-movement sleep (NREMS). Reduced spindle may cause impaired learning and Mild Cognitive Impairment (MCI) in AD and is a biomarker for early AD-related changes in brain dynamics. Conversely, promoting sleep oscillations by transcranial stimulation enhances memory consolidation in MCI. By developing a set of novel, noninvasive, bacteriophytochrome-based optogenetic tools to control cAMP synthesis (adenylate cyclase, AC) and breakdown (phosphodiesterase, PDE), we will make spindles accessible for noninvasive manipulations that spare other sleep rhythms. These enzymes are activated by light in the so-called near-infrared optical window (NIRW). The NIRW light-activated modules are suitable for the rapid yet long-lasting and noninvasive manipulation of cAMP in thalamic neurons in intact animals, because NIRW light penetrates through mammalian skulls and brain tissues better than the light of any other spectral region. We will examine a provocative novel hypothesis that cellular pathology and cognitive decline caused by Alzheimer?s disease (AD) related mutations can be restored via enhancing thalamocortical spindles waves during sleep in vivo. We will first develop novel noninvasive optogenetic tools to manipulate AC and spindle oscillations (Aim 1). Then, we will examine whether NIRW-AC and NIRW-PDE bi-directionally modulate the progression of AD?related neuropathology and cognitive decline via their actions re: spindle wave regulations (Aim 2). Upon completion of this project, we will have developed genetically encoded NIRW-light activated tools, allowing noninvasive manipulation in deep brain regions of live animals. Results are expected to provide a sound basis for investigation in disease models that involve spindle wave and cAMP aberrations, such as AD, and suggest novel non- invasive intervention strategies to counteract brain dementias caused by AD.