Aaron Wilber, PhD

 

 

wilber@psy.fsu.edu

 

Dr. Aaron Wilber is now Assistant Professor of Psychology & Neuroscience at Florida State University and may be found here. Congratulations Aaron!

RESEARCH INTERESTS

I have two main areas of focus:

1) Understanding the neurobiological mechanisms that allow us to derive a sense of location from a body-centered view of the world and how these same systems participate in learning and memory. A critical role of this brain network is to update our internal map of the environment when there is a conflict with the external environment (something we experience when getting reoriented after being lost).

2) This work exploring normal mechanisms is informing parallel research on how these neural networks are altered by mental disorders and memory disorders such as Alzheimer’s disease.

 

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Figure 1:  Whole brain semi-automated quantification of disease pathology. A. NeuN (Red) and Ab conformation specific M22 (Green) staining for a single section (Left). Right. Z-project of the approximate region marked with a white box in the parietal cortex (top) and in the CA1 field of the hippocampus (bottom) of a 3xTgAD female mouse from Fig. 2. B. Automatically quantified intraneuronal 6e10 data from a more rostral section in the same mouse. A blue dot is plotted for each DAPI positive cell, changed to a red dot if the cell is NeuN positive and changed to a green dot if the automatically segmented neuron contour contained enough 6e10 staining to cross a threshold. We are fine tuning parameters; still quantified counts are visually correlated. Edge effects are removed later in the processing. Whole section images were cropped to one hemisphere for space.

These areas of focus are designed to advance our progress towards a long term goal to use maternal separation as a model to assess the contribution of neonatal stress to the development of mental and age-related cognitive disorders. To accomplish this goal we use custom 3D printed recording arrays to monitor many single cells in multiple brain regions and simultaneously record population related neural activity (local field potentials). We also use optogenetics to manipulation specific circuits, semi-automated density based measures of brain connectivity, and mouse models of disease (e.g., Alzheimer’s). These approaches are applied in the context of behavioral tasks performed in rodents that are navigating freely moving or in virtual environments.

 

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Figure 2:  AAV expression in posterior parietal cortex. A. Terminal labeling in layer IV and VIa of posterior parietal cortex following AAV-ChR2 injection into lateraldorsal thalamus. B. Single Z plane from a confocal stack from layer VI of posterior parietal cortex.  The approximate location of the image shown in B is marked with a white box on A. Robust terminal labeling was observed in both layer IV and layer VI.

Previously, we used a model of adverse early experience, maternal separation, and a simple type of motor learning, eyeblink conditioning, to assess neonatal stress programming of adult learning and memory. More recent research has been directed at understanding a brain network for performing coordinate transformation between person-centered and world-centered representations of the external environment. This network was predicted by two computational models, and includes the posterior parietal cortex, the hippocampus and structures in-between. We are also exploring the role of this parietal-hippocampal network in learning and remembering spatial sequences using behavioral tasks and by assessing memory replay during rest.
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Figure 3:  Using IEG expression to quantify AAV mediated manipulations. Left. Z-project from a confocal stack collected in the stimulated hemisphere of parietal cortex showing IEG activation from 10 Hz stimulation (Arc – red) and 100 Hz stimulation (homer1a – green). Middle. Z-project from a confocal stack showing a lack of Arc and homer1a IEGs in the identical location in the contralateral hemisphere (unstimulated control). Right. Total counts of homer1a and Arc positive cells were made from an evenly spaced series under the fiber optic. To obtain these counts confocal mosaics were collected for the entire parietal cortex (stimulated hemisphere and contralateral unstimulated hemisphere).