People in the lab

Assistant Professor of Neurology - University of Pennsylvania

E-mail: aguirreg@mail.med.upenn.edu

I am a Neurologist and cognitive neuroscientist. My clinical and research work concerns the organization of the brain for mental operations, in particular the loss and recovery of visual ability. Using functional MRI, a non-invasive tool for measuring brain activity, I study how neurons are normally arranged to represent and store the appearance of people, places, and things. I use these techniques to understand as well how blindness changes the brain, and with my collaborators at the University of Pennsylvania, how the brain adapts to the recovery of vision. As a clinician, I treat patients with a variety of disturbances of thinking and memory, with my practice informed by recent insights into the organization of the brain for these functions. I also study the methodological development and application of imaging techniques.

Post-Doctoral Fellow

I have a blossoming interest in higher-order visual processing. Currently, I am using MRI imaging to investigate structural and functional plasticity of the visual cortex in blind subjects. Specifically, I am measuring cross-modal occipital activation, volumetry, white matter integrity, and perfusion, to determine the extent to which these changes are linked or independent. I have completed neurology residency and neuro-ophthalmology fellowship at Penn, and I am currently in a two-year cognitive research fellowship in Dr. Aguirre's lab.

Post-Doctoral Fellow

E-mail: ridatta@mail.med.upenn.edu

I am a joint post-doc under the mentorship of Dr. Geoffrey Aguirre and Dr. John Detre. I am part of an interdisciplinary team studying mechanisms of cortical plasticity and recovery of function. My doctoral dissertation involved mapping the cortical topographic representation of visuospatial attention in human subjects for all locations (near fovea and to more peripheral locations) in the subject's visual field. My results concluded that the attentional topography is more complex than a simple "spotlight" or "gradient" but incorporates features of both.

Post-Doctoral Fellow - Radiology

My main research interest is the use of diffusion imaging to study white matter in the brain. My previous work has focused on modeling uncertainty in the fiber tracking process and providing open-source tools to the diffusion imaging community. I am currently part of the team investigating white matter connectivity and visual function in the congenitally blind, under the mentorship of Professors Geoffrey Aguirre and James Gee.

Graduate Student - Neuroscience

I am broadly interested in social cognition and face perception. My current work explores the neural representation of face identity and similarity in event related potentials (ERP), and I am interested in expanding our investigation to probe representations of other facial dimensions such as emotion.

Post-Doctoral Fellow

Now a post-doctoral fellow in Antonio Rangel's lab.

Email: amharris@caltech.edu or aharris@alum.mit.edu

My research examines the neural correlates of face and object perception using a variety of techniques, including magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). Using MEG, I have quantified the properties of the M170 response, an early "face-selective" component, both in normal adults and in developmental prosopagnosics, individuals with behavioral impairments in face recognition (in collaboration with Dr. Brad Duchaine). In my work with Dr. Geoffrey Aguirre, I used fMRI to explore the nature of representations within "face-selective" regions of interest (ROIs). Together, the results from these two lines of inquiry suggest that the neural encoding of faces includes not only global or holistic information about the entire face, as has been previously proposed, but also representation of individual face features or parts.

Psychology Graduate Student

Now a post-doctoral fellow with Nicole Rust, also at Penn

I am broadly interested in the neural bases of similarity spaces. I study the focal and distributed representations of visual similarity of parameterized shape spaces in human object recognition cortex, as well as inferences about neural populations that can be made from the metric properties of fMRI data.

Research Assistant / Undergrad Honors Student

Currently enrolled in the UCLA MD/PhD program

My research involves the application of computational methods to mimic and understand visual perception and processing. I am particularly interested in describing a perceptual space of images using multidimensional scaling (MDS) and other models on reaction time data. My current projects are focused on the perception of textures and the interdependency between the many quantifiable properties of textures. Within these projects, I have also become interested in algorithms for texture generation, replication, and morphing; specifically reaction diffusion and steerable pyramids. My previous work has included the implementation of support vector machines (SVM) to fMRI to discriminate which face a subject is viewing.

Neuroscience Graduate Student

Currently enrolled in the SUNY Upstate MD/PhD program

Her work pertained to the organization of the visual system of patients with occipital cortex damage, and in establishing if remapping of retinotopic organization can occur visual cortex lesions. She studied the residual visual functioning, both behaviorally and on a neural level (using fMRI), of a patient with Blindsight, as well as the representation of the ipsilateral visual field in healthy control subjects. Petya worked with Joseph Cohen of Mount Holyoke as an undergraduate.

Research Assistant/Med Student

I am a third-year medical student pursuing a career in helping patients with neurological disorders. I love to work with computational tools that help us visualize the mysterious human brain in different ways. In Dr. Aguirre's lab, I am privileged to do just that. My current work involves building an atlas of brain images to allow standardized analysis among a large collection of subjects. My previous projects involve designing databases and image-processing programs to manipulating different modalities of brain images, including MRI, MRSI, DTI, and fMRI.

Post-Doctoral Fellow

E-mail: ggingras09@gmail.com

Most of my training had been focused on assessing the effects of visual deprivation early in life by performing animal psychophysical experiments in attempts to re-create the ophthalmologic disease often visited upon human patients in childhood. During my masters studies, I showed that hamsters with experimentally-induced retinal outputs to the auditory cortex could see [PNAS (2001), 98, 11068-11073]. Additionally, during my doctoral studies, I investigated the spatial localization abilities of cats rendered amblyopic by surgically created strabismus or by imposition of various regimens of monocular deprivation. Similarly to human amblyopes, the spatial localization deficits in the amblyopic animals increased with the spatial scale of the stimuli. Moreover, these deficits could not be explained by a loss of contrast sensitivity in the deprived eye [Vision Research (2005), 45, 975-989].

In Dr. Aguirre's laboratory, I studied a canine animal model of Leber's Congenital Amaurosis (LCA) using behavioral measures.

Research Specialist

I am involved in a variety of facial perception studies including the development of a neuropsychological battery of face perception and many other fMRI and behavioral studies.

Dyno-ball leader

My chief activities include suggesting that Kahn work on the cross-word puzzle, and asking Daniel to stop by for a dyno-ball competition.

• David Yaron - Johns Hopkins Undergrad
• Jeff Ratliff - Syracuse School of Medicine
• Tanya Weerakkody - University of Pennsylvania Neuroscience Graduate Group
• Lauren Brandes - University of Pennsylvania Undergraduate