Positions

Overview

  • My career has been devoted to understanding neural computation, both for its own sake and for the sake of making neural prosthesis that restore and augment human function. My specific research has been to investigate complex neural computations in retinal ganglion cells, the first locus in the visual system of highly specific and nonlinear analyses such as motion and directional selectivity.

    The first task I took on as a retinal researcher was to identify, by intracellular recording and staining, all the major ganglion cell classes in a mammalian retina (rabbit), including directionally selective, orientation-selective and edge-detecting ganglion cells. My colleagues and I have shown that the morphologies of at least 20 different physiological classes of rabbit retinal ganglion cells are distinct, and typically associated with important physiological properties of each class. Most of these classes are likely to be highly conserved across mammals, including primates. Following this necessary, pioneering, and now classic work, I investigated the retinal circuitry and mechanisms underlying complex receptive field properties such as directional selectivity, including the receptor types exhibited by various ganglion cell classes, and their projection targets in the brain in order to understand the role of different ganglion cell classes in various aspects of visual acuity and perception.

    These investigations have used virtually the entire suite of single cell neurophysiological techniques, including single cell extracellular recording, sharp electrode intracellular recording and staining, patch clamp recording, optical imaging with both calcium and potentiometric dyes, dual electrode recording, and, most recently, microelectrode array recording. This research has been supported by the NEI over a continuous, 20-year period of support. Some computational aspects were also supported by the Sloan Foundation and the Office of Naval Research, while the EyeSight Foundation of Alabama has supported some efforts that have clinical implications.
  • Selected Publications

    Academic Article

    Year Title Altmetric
    2019 The effect of expectation on transcranial direct current stimulation (tDCS) to suppress food craving and eating in individuals with overweight and obesity 2019
    2018 Effects of tDCS-like electrical stimulation on retinal ganglion cells 2018
    2017 A Feasibility Study Evaluating the Emotionally Expressive Robot SAM 2017
    2016 Effects of transcranial direct current stimulation (tDCS) on binge eating disorder 2016
    2015 Nicotinic and muscarinic acetylcholine receptors shape ganglion cell response properties 2015
    2014 The effect of speed of processing training on microsaccade amplitude 2014
    2013 Processing speed training increases the efficiency of attentional resource allocation in young adults 2013
    2013 Processing speed training increases the efficiency of attentional resource allocation in young adults 2013
    2012 Functional imaging of glucose-evoked rat islet activities using transient intrinsic optical signals 2012
    2011 Avatar assistant: Improving social skills in students with an asd through a computer-based intervention 2011
    2011 Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells 2011
    2011 Intrinsic optical signal imaging of glucose-stimulated insulin secreting β-cells 2011
    2010 Parallel optical monitoring of visual signal propagation from the photoreceptors to the inner retina layers 2010
    2010 Muscarinic acetylcholine receptor localization and activation effects on ganglion response properties 2010
    2010 High spatiotemporal resolution imaging of fast intrinsic optical signals activated by retinal flicker stimulation 2010
    2010 The response dynamics of rabbit retinal ganglion cells to simulated blur 2010
    2010 High-speed line-scan confocal imaging of stimulusevoked intrinsic optical signals in the Retina 2010
    2007 Properties of stimulus-dependent synchrony in retinal ganglion cells 2007
    2007 Nicotinic acetylcholine receptor expression by directionally selective ganglion cells 2007
    2007 Robust directional computation in on-off directionally selective ganglion cells of rabbit retina 2007
    2007 Strychnine, but not PMBA, inhibits neuronal nicotinic acetylcholine receptors expressed by rabbit retinal ganglion cells 2007
    2005 Retinal ganglion cell coding in simulated active vision 2005
    2005 Stimulus-dependent correlated firing in directionally selective retinal ganglion cells 2005
    2005 Rabbit retinal ganglion cells express functional α7 nicotinic acetylcholine receptors 2005
    2005 Directionally selective ganglion cells in rabbit retina express functional A7 nAChRs 2005
    2005 Low-dose strychnine and its effects on alpha 7 nicotinic receptor function 2005
    2004 MLA-sensitive cholinergic receptors involved in the detection of complex moving stimuli in retina 2004
    2003 Rabbit retinal ganglion cell responses to nicotine can be mediated by β2-containing nicotinic acetylcholine receptors 2003
    2003 A new transparent multi-unit recording array system fabricated by in-house laboratory technology 2003
    2003 Requirement for alpha 7-LIKE nAChRS in the cholinergic pathway that mediates motion detection in the retina 2003
    2003 Synaptic input to the on-off directionally selective ganglion cell in the rabbit retina 2003
    2002 Effects of the destruction of starburst-cholinergic amacrine cells by the toxin AF64A on rabbit retinal directional selectivity 2002
    2002 Rabbit retinal ganglion cell responses mediated by α-bungarotoxin-sensitive nicotinic acetylcholine receptors 2002
    2002 New multiunit array recording from rabbit retinal ganglion cells 2002
    2001 Pharmacological analysis shows multiple nAChR subtypes in rabbit retina and a possible role for the alpha 7 subunit in directional selectivity. 2001
    2001 Synchronous firing is stimulus dependent in directionally selective (DS) and non-DS rabbit retinal ganglion cells. 2001
    2000 The role of NMDA channels in rabbit retinal directional selectivity 2000
    1998 Complementary roles of two excitatory pathways in retinal directional selectivity 1998
    1998 Non-monotonic contrast behavior in directionally selective ganglion cells and evidence for its dependence on their GABAergic input 1998
    1998 Necessity of acetylcholine for retinal directionally selective responses to drifting gratings in rabbit 1998
    1997 Is the input to a GABAergic or cholinergic synapse the sole asymmetry in rabbit's retinal directional selectivity? 1997
    1996 Pharmacological evidence for two asymmetric pathways in rabbit retinal directional selectivity 1996
    1996 Extra-receptive-field motion facilitation in on-off directionally selective ganglion cells of the rabbit retina 1996
    1995 Spatial organization of retinal information about the direction of image motion 1995
    1995 ARE CHOLINERGIC SYNAPSES TO DIRECTIONALLY SELECTIVE GANGLION-CELLS SPATIALLY ASYMMETRIC 1995
    1995 Automating the quantitative analysis of 2-D neural dendritic trees 1995
    1995 Interaction between center and surround in rabbit retinal ganglion cells 1995
    1994 RETINAL COVERAGE AND PHYSIOLOGICAL INPUTS TO DIRECTIONALLY SELECTIVE RABBIT RETINAL GANGLION-CELLS 1994
    1994 Directional hyperacuity in ganglion cells of the rabbit retina 1994
    1993 Dendritic architecture of ON-OFF direction-selective ganglion cells in the rabbit retina 1993
    1993 Directional selectivity in vertebrate retinal ganglion cells. 1993
    1993 Facilitation in ON-OFF directionally selective ganglion cells of the rabbit retina 1993
    1993 Inhibition in ON-OFF directionally selective ganglion cells of the rabbit retina 1993
    1991 Nonlinearity of the inhibition underlying retinal directional selectivity 1991
    1990 Applicability of quadratic and threshold models to motion discrimination in the rabbit retina 1990
    1990 Dendritic morphologies of retinal ganglion cells projecting to the lateral geniculate nucleus in the rabbit 1990
    1990 Dendritic morphologies of retinal ganglion cells projecting to the nucleus of the optic tract in the rabbit 1990
    1989 Morphologies of rabbit retinal ganglion cells with complex receptive fields 1989
    1989 Morphologies of rabbit retinal ganglion cells with concentric receptive fields 1989
    1986 Staining of retinal neurons in the isolated eyecup by extracellular horseradish peroxidase injection 1986
    1984 Morphology of on-off direction-selective ganglion cells in the rabbit retina 1984
    1984 A modified slurry beveler for HRP-filled intracellular micropipettes 1984
    1983 Functional implications of On-Off response variation in frog retinal ganglion cells 1983
    1983 Quantitative morphology of rabbit retinal ganglion cells 1983
    1977 Trichromatic vision in the cat 1977

    Research Overview

  • Retinal physiology and anatomy in normal and disease processes, retinal prostheses
  • Teaching Activities

  • PY380 - Perception (Summer Term 2019) 2019
  • PY253 - Brain Mind and Behavior (Spring Term 2019) 2019
  • PY380 - Perception (Spring Term 2019) 2019
  • PY463 - Cognitive Neuroscience (Spring Term 2019) 2019
  • PY353 - Behavioral Neuroscience (Summer Term 2018) 2018
  • PY380 - Perception (Summer Term 2018) 2018
  • PY380 - Perception (Spring Term 2018) 2018
  • PY463 - Cognitive Neuroscience (Spring Term 2018) 2018
  • PY793 - Cognitive Neuroscience (Spring Term 2018) 2018
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2017) 2017
  • PY799 - Doctoral Dissertation Research (Summer Term 2017) 2017
  • PY463 - Cognitive Neuroscience (Spring Term 2017) 2017
  • PY756 - Research Sem Behav Neurosci (Spring Term 2017) 2017
  • PY793 - Cognitive Neuroscience (Spring Term 2017) 2017
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2017) 2017
  • PY799 - Doctoral Dissertation Research (Spring Term 2017) 2017
  • PY453 - Adv Behavioral Neuroscience (Fall Term 2016) 2016
  • PY753 - Foundations Behav Neuroscience (Fall Term 2016) 2016
  • PY756 - Research Sem Behav Neurosci (Fall Term 2016) 2016
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2016) 2016
  • PY799 - Doctoral Dissertation Research (Fall Term 2016) 2016
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2016) 2016
  • PY799 - Doctoral Dissertation Research (Summer Term 2016) 2016
  • PY463 - Cognitive Neuroscience (Spring Term 2016) 2016
  • PY756 - Research Sem Behav Neurosci (Spring Term 2016) 2016
  • PY756 - Research Sem Behav Neurosci (Spring Term 2016) 2016
  • PY793 - Cognitive Neuroscience (Spring Term 2016) 2016
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2016) 2016
  • PY799 - Doctoral Dissertation Research (Spring Term 2016) 2016
  • PY453 - Adv Behavioral Neuroscience (Fall Term 2015) 2015
  • PY753 - Foundations Behav Neuroscience (Fall Term 2015) 2015
  • PY756 - Research Sem Behav Neurosci (Fall Term 2015) 2015
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2015) 2015
  • PY799 - Doctoral Dissertation Research (Fall Term 2015) 2015
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2015) 2015
  • PY799 - Doctoral Dissertation Research (Summer Term 2015) 2015
  • PY463 - Cognitive Neuroscience (Spring Term 2015) 2015
  • PY756 - Research Sem Behav Neurosci (Spring Term 2015) 2015
  • PY793 - Cognitive Neuroscience (Spring Term 2015) 2015
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2015) 2015
  • PY799 - Doctoral Dissertation Research (Spring Term 2015) 2015
  • PY453 - Adv Behavioral Neuroscience (Fall Term 2014) 2014
  • PY753 - Overview Behav Neuroscience (Fall Term 2014) 2014
  • PY756 - Research Sem Behav Neurosci (Fall Term 2014) 2014
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2014) 2014
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2014) 2014
  • PY799 - Doctoral Dissertation Research (Fall Term 2014) 2014
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2014) 2014
  • PY799 - Doctoral Dissertation Research (Summer Term 2014) 2014
  • PY420 - Special Topics (Spring Term 2014) 2014
  • PY463 - Cognitive Neuroscience (Spring Term 2014) 2014
  • PY756 - Research Sem Behav Neurosci (Spring Term 2014) 2014
  • PY791 - Special Topics (Spring Term 2014) 2014
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2014) 2014
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2014) 2014
  • PY799 - Doctoral Dissertation Research (Spring Term 2014) 2014
  • PY453 - Adv Behavioral Neuroscience (Fall Term 2013) 2013
  • PY753 - Overview Behav Neuroscience (Fall Term 2013) 2013
  • PY756 - Research Sem Behav Neurosci (Fall Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Fall Term 2013) 2013
  • PY799 - Doctoral Dissertation Research (Fall Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Summer Term 2013) 2013
  • PY799 - Doctoral Dissertation Research (Summer Term 2013) 2013
  • PY463 - Cognitive Neuroscience (Spring Term 2013) 2013
  • PY756 - Research Sem Behav Neurosci (Spring Term 2013) 2013
  • PY793 - Cognitive Neuroscience (Spring Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2013) 2013
  • PY798 - Predoctoral Degree Grad Res (Spring Term 2013) 2013
  • PY799 - Doctoral Dissertation Research (Spring Term 2013) 2013
  • PY380 - Perception (Fall Term 2012) 2012
  • PY453 - Adv Behavioral Neuroscience (Fall Term 2012) 2012
  • PY463 - Cognitive Neuroscience (Fall Term 2012) 2012
  • PY753 - Overview Behav Neuroscience (Fall Term 2012) 2012
  • PY353 - Behavioral Neuroscience (Summer Term 2012) 2012
  • PY380 - Perception (Summer Term 2012) 2012
  • PY363 - Cognitive Psychology (Spring Term 2012) 2012
  • PY380 - Perception (Spring Term 2012) 2012
  • PY380 - Perception (Fall Term 2011) 2011
  • PY463 - Cognitive Neuroscience (Fall Term 2011) 2011
  • PY380 - Perception (Summer Term 2011) 2011
  • PY363 - Cognitive Psychology (Spring Term 2011) 2011
  • PY463 - Cognitive Neuroscience (Fall Term 2010) 2010
  • PY363 - Cognitive Psychology (Spring Term 2009) 2009
  • PY380 - Perception (Spring Term 2009) 2009
  • PY363 - Cognitive Psychology (Fall Term 2008) 2008
  • PY420 - Contemporary Issues in Psych (Fall Term 2008) 2008
  • PY363 - Cognitive Psychology (Spring Term 2008) 2008
  • PY463 - Cognitive Neuroscience (Spring Term 2008) 2008
  • PY363 - Cognitive Psychology (Fall Term 2007) 2007
  • PY380 - Perception (Fall Term 2007) 2007
  • Full Name

  • Franklin Amthor