A5016715548- Retinal Development and Disorders
- Visual perception and processing mechanisms
- Retinal Diseases and Treatments
- Photoreceptor and optogenetics research
- Functional Brain Connectivity Studies
- Virus-based gene therapy research
- Face Recognition and Perception
- Neural dynamics and brain function
- Glaucoma and retinal disorders
- Advanced MRI Techniques and Applications
- Circadian rhythm and melatonin
- Advanced Neuroimaging Techniques and Applications
- Olfactory and Sensory Function Studies
- Retinal Imaging and Analysis
- Animal Genetics and Reproduction
- RNA regulation and disease
- Neural and Behavioral Psychology Studies
- Adenosine and Purinergic Signaling
- bioluminescence and chemiluminescence research
- Migraine and Headache Studies
- Neurological diseases and metabolism
- melanin and skin pigmentation
- Lysosomal Storage Disorders Research
- Human-Animal Interaction Studies
- Ocular Disorders and Treatments
University of Pennsylvania
2016-2025
California University of Pennsylvania
2002-2025
Children's Hospital of Philadelphia
2024
Fomento de San Sebastián (Spain)
2024
Hospital of the University of Pennsylvania
1997-2023
University of Georgia
2023
University of Veterinary Medicine Hannover, Foundation
2023
Auburn University
2023
Penn Presbyterian Medical Center
1987-2020
Penn Center for AIDS Research
2017-2019
A number of neuroimaging findings have been interpreted as evidence that the left inferior frontal gyrus (IFG) subserves retrieval semantic knowledge. We provide a fundamentally different interpretation, it is not knowledge per se associated with IFG activity but rather selection information among competing alternatives from memory. Selection demands were varied across three tasks in single group subjects. Functional magnetic resonance imaging signal overlapping regions was dependent on all...
Cerebral hemodynamic responses to brief periods of neural activity are delayed and dispersed in time. The specific shape these is some importance the design analysis blood oxygenation level-dependent (BOLD), functional magnetic resonance imaging (fMRI) experiments. Using fMRI scanning, we examine here characteristics variability from central sulcus human subjects during an event-related, simple reaction time task. Specifically, determine contribution subject, day, scanning session (within a...
Single-unit recordings in monkeys have revealed neurons the lateral prefrontal cortex that increase their firing during a delay between presentation of information and its later use behavior. Based on monkey lesion neurophysiology studies, it has been proposed dorsal region is necessary for temporary storage spatial whereas more ventral maintenance nonspatial information. Functional neuroimaging however, not clearly demonstrated such division humans. We present here an analysis all reported...
Temporal autocorrelation, spatial coherency, and their effects on voxel-wise parametric statistics were examined in BOLD fMRI null-hypothesis, or "noise," datasets. Seventeen normal, young subjects scanned using while not performing any time-locked experimental behavior. autocorrelation these datasets was described well by a 1/frequency relationship. Voxel-wise statistical analysis of noise which assumed independence (i.e., ignored temporal autocorrelation) rejected the null hypothesis at...
The hippocampus has been proposed as the site of neural representation large-scale environmental space, based upon identification place cells (neurons with receptive fields for current position in environment) within rat and demonstration that hippocampal lesions impair learning rat. inability to identify monkey observation unilateral do not selectively topographic behavior humans suggest alternate regions may subserve this function man. To examine contribution adjacent medial-temporal lobe...
In the companion to this paper (E. Zarahn, G. K. Aguirre, and M. D'Esposito, 1997,NeuroImage,179–197), we describe an implementation of a general linear model for autocorrelated observations in which voxel-wise false-positive rates fMRI "noise" datasets were stabilized brought close theoretical values. Here, implementations are tested use with statistical parametric mapping analysis spatially smoothed data. Analyses using varying models intrinsic temporal autocorrelation either including or...
The use of functional neuroimaging to test hypotheses regarding age-related changes in the neural substrates cognitive processes relies on assumptions coupling activity signal. Differences signal response between young and elderly subjects can be mapped directly differences only if such does not change with age. Here we examined spatial temporal characteristics BOLD fMRI hemodynamic primary sensorimotor cortex during performance a simple reaction time task. We found that 75% (n = 20)...
Isolated, ventral brain lesions in humans occasionally produce specific impairments the ability to use landmarks, particularly buildings, for way-finding. Using functional MRI, we tested hypothesis that there exists a cortical region specialized perception of buildings. Across subjects, straddling right lingual sulcus was identified possessed correlates predicted building area. A series experiments discounted several alternative explanations behavior this site. These results are discussed...
The neural substrates of mental image generation were investigated with functional MRI. Subjects listened to words under two different instructional conditions: generate visual images the words' referents, or simply listen each word and wait for next word. Analyses performed which directly compared regional brain activity during condition, goal discovering whether engages modality-specific areas, it primary cortex, recruits left hemisphere a greater extent than right. Results revealed that...
The short- and long-term effects of gene therapy using AAV-mediated RPE65 transfer to canine retinal pigment epithelium were investigated in dogs affected with disease caused by deficiency. Results AAV 2/2, 2/1, 2/5 vector pseudotypes, human or cDNA, constitutive tissue-specific promoters similar. Subretinally administered vectors restored function 23 26 eyes, but intravitreal injections consistently did not. Photoreceptoral postreceptoral both rod cone systems improved therapy. In followed...
An experimental design for functional MRI (fMRI) is presented whose conceptual units of analysis are behavioral trials, in contrast to blocks trials. This type referred as a trial-based (TB) fMRI design. It explained how TB designs can afford the ability to: (1) randomize presentation trials and (2) utilize intertrial variance uncontrolled measures examine their correlates. A particular that involves modeling trial-evoked responses with one or more shifted impulse response functions...
Several domains of neuroscience offer map-like models that link location on the cortical surface to properties sensory representation. Within visual areas V1, V2, and V3, algebraic transformations can relate position in field retinotopic representation flattened sheet. A limit practical application this structure-function model is cortex, while topologically a two-dimensional surface, curved. Flattening curved plane unavoidably introduces local geometric distortions are not accounted for...
Abstract The illumination of the environment undergoes both intensity and spectral changes during 24 h cycle a day. Daylight power distributions are well described by low-dimensional models such as CIE (Commission Internationale de l’Éclairage) daylight model, but performance this model in non-daylight regimes is not characterised. We measured downwelling irradiance across multiple days two locations North America: One rural location (Cherry Springs State Park, PA) with minimal anthropogenic...
Abstract Functional magnetic resonance imaging (fMRI) has become the most widely used modality for visualizing regional brain activation in response to sensorimotor or cognitive tasks. While majority of fMRI studies have blood oxygenation level‐dependent (BOLD) contrast as a marker neural activation, baseline drift effects result poor sensitivity detecting slow variations activity. By contrast, are minimized arterial spin labeling (ASL) perfusion primarily successive pairwise subtraction...
Abstract Lesion and neuroimaging studies suggest the amygdala is important in perception production of negative emotion; however, effects emotion regulation on amygdalar response to stimuli remain unknown. Using event-related fMRI, we tested hypothesis that voluntary modulation associated with changes neural activity within amygdala. Negative neutral pictures were presented instructions either “maintain” emotional or “passively view” picture without regulating emotion. Each presentation was...
Abstract We have found two immunologically distinguishable cone types in the retina of mouse, each localized to opposite halves eye. One type was labelled by monoclonal antibody COS‐1 specific middle‐to‐long wave sensitive visual pigment mammals, while other stained shortwave‐specific (OS‐2). These results were confirmed with antibodies directed against sequences pigments. As a result uneven distribution mouse is divided into fields separated an oblique meridional line. The middlewave cones...