A5023814498- Neural dynamics and brain function
- Visual perception and processing mechanisms
- EEG and Brain-Computer Interfaces
- Body Composition Measurement Techniques
- Optical Imaging and Spectroscopy Techniques
- Traumatic Brain Injury and Neurovascular Disturbances
- Neuroscience and Neural Engineering
- Neuroscience and Neuropharmacology Research
- Neurobiology and Insect Physiology Research
- Functional Brain Connectivity Studies
- Neural and Behavioral Psychology Studies
- Glaucoma and retinal disorders
- Bone health and osteoporosis research
- Olfactory and Sensory Function Studies
- Hemodynamic Monitoring and Therapy
- Hydrocarbon exploration and reservoir analysis
- Rheumatoid Arthritis Research and Therapies
- Radiation Dose and Imaging
- Memory and Neural Mechanisms
- Seismic Imaging and Inversion Techniques
- Corneal surgery and disorders
- Nuclear Physics and Applications
- Advanced MRI Techniques and Applications
- Reservoir Engineering and Simulation Methods
- Electrical and Bioimpedance Tomography
Carnegie Mellon University
2008-2025
University of York
2025
Neuroscience Institute
2020-2024
Center for the Neural Basis of Cognition
2014-2024
University of Pittsburgh
2015-2024
Ophthalmology Associates (United States)
2013-2019
Eye and Ear Foundation
2014-2018
Shriners Hospitals for Children - Cincinnati
2018
University of Pittsburgh Medical Center
2016-2017
University of Florida
2017
The spiking activity of cortical neurons is correlated. For instance, trial-to-trial fluctuations in response strength are shared between neurons, and spikes often occur synchronously. Understanding the properties mechanisms that generate these forms correlation critical for determining their role processing. We therefore investigated spatial extent functional specificity correlated spontaneous evoked activity. Because feedforward, recurrent, feedback pathways have distinct extents...
Nearby cortical neurons often have correlated trial-to-trial response variability, and a significant fraction of their spikes occur synchronously. These two forms correlation are both believed to arise from common synaptic input, but the origin this input is unclear. We investigated source responsivity by recording pairs single in primary visual cortex anesthetized macaque monkeys comparing variability synchrony for spontaneous activity evoked stimuli different orientations contrasts....
Advances in microelectrode neural recording systems have made it possible to record extracellular activity from a large number of neurons simultaneously. A substantial body work is associated with traditional single-electrode recording, and the robustness method has
The gamma frequencies of the local field potential (LFP) provide a physiological correlate for numerous perceptual and cognitive phenomena have been proposed to play role in cortical function. Understanding spatial extent its relationship spiking activity is critical interpreting this signal elucidating function, but previous studies provided widely disparate views these properties. We addressed issues by simultaneously recording LFPs using microelectrode arrays implanted primary visual...
Rheumatoid arthritis may be associated with generalised as well periarticular osteoporosis. To assess the extent of bone loss and influence corticosteroid treatment total body calcium was measured by in-vivo neutron activation analysis in 63 patients rheumatoid treated non-steroidal anti-inflammatory drugs alone 31 additional low-dose corticosteroids. The results were compared those 40 normal controls matched for age, sex, menopausal state. There significant reductions mean group (5.3% men;...
Neuronal responses are correlated on a range of timescales. Correlations can affect population coding and may play an important role in cortical function. known to depend stimulus drive, behavioral context, experience, but the mechanisms that determine their properties poorly understood. Here we make use laminar organization cortex, with its variations sources input, local circuit architecture, neuronal properties, test whether networks engaged similar functions distinct generate different...
The spiking activity of nearby cortical neurons is correlated on both short and long time scales. Understanding this shared variability in firing patterns critical for appreciating the representation sensory stimuli ensembles neurons, coincident influences common targets, functional implications microcircuitry. Our knowledge about neuronal correlations, however, derives largely from experiments that used different recording methods, analysis techniques, regions. Here we studied structure...
Recent studies have applied dimensionality reduction methods to understand how the multi-dimensional structure of neural population activity gives rise brain function. It is unclear, however, results obtained from generalize recordings with larger numbers neurons and trials or these relate underlying network structure. We address questions by applying factor analysis in visual cortex non-human primates spiking models that self-generate irregular through a balance excitation inhibition....
Delay period activity in the dorso-lateral prefrontal cortex (dlPFC) has been linked to maintenance and control of sensory information working memory. The stability memory related signals found such delay is believed support robust memory-guided behavior during perturbations, as distractors. Here, we directly probed dlPFC's with a diverse set measured their consequences on neural behavior. We applied patterned microstimulation dlPFC monkeys implanted multi-electrode arrays by electrically...
We used fast, pseudorandom temporal sequences of preferred and antipreferred stimuli to drive neuronal firing rates rapidly between minimal maximal across the visual system. Stimuli were tailored preferences cells recorded in lateral geniculate nucleus (magnocellular parvocellular), primary cortex (simple complex), extrastriate motion area MT. found that took longer turn on (to increase their rate) than off reduce rate). The latency difference (onset minus offset) varied from several tens...
Bone mass has previously been shown to be reduced at peripheral bone sites in patients with bronchial asthma receiving corticosteroids. To assess whether total is body calcium was measured by vivo neutron activation analysis various treatments for and compared results from normal controls rheumatoid arthritis polymyalgia rheumatica. Compared 13.6% (p less than 0.001) daily oral corticosteroids but only 9.0% 0.005) a similar group of who had received supplements the start their corticosteroid...
Glass patterns are texture stimuli made by pairing randomly placed dots with partners at specific offsets. The strong percept of global form that arises from the sparse local orientation cues has these subject psychophysical investigations, yet neuronal responses to have not been studied. We measured neurons in macaque striate cortex (V1) dynamic, translational as a function dot separation and dot-pair orientation. Responses were selective, but on average more than an order magnitude weaker...
The response of a neuron in primary visual cortex (V1) to an optimal stimulus its classical receptive field (CRF) can be reduced by the presence orthogonal mask, phenomenon known as cross-orientation suppression. parallel outside CRF have similar effect, this case surround We used novel probe time course suppression and found that it is very fast, starting even before excitatory stimuli. However, occurs with some delay after offset response, considered measure earliest signals reach CRF....
Many approaches for multiple testing begin with the assumption that all tests in a given study should be combined into global false-discovery-rate analysis. But this may inappropriate many of today's large-scale screening problems, where auxiliary information about each test is often available, and analysis can lead to poorly calibrated error rates within different subsets experiment. To address issue, we introduce an approach called regression directly uses inform outcome test. The method...