James R. Dearworth

turtleJRDAssistant Professor of Biology – Vertebrate Anatomy
dearworj@lafayette.edu e-mail
(610) 330-5466 voice
(610) 330-5705 FAX
Personal WWW page

My research investigates the anatomical substrates of vision in vertebrates.

Recent abstracts and publications:

1. Functional anatomical mapping of the turtle retina. The turtle possesses one of the most complex retinas found among vertebrates. Using this neural network, my research investigates the anatomical substrates underlying sensory processes which lead to visual functions. My laboratory uses electrophysiological, pharmacological, and molecular methods to examine the anatomy and function of the retina.

  • Oil droplets in the turtle retina. Scale bar is equal to 10 micrometers.

    Oil droplets in the turtle retina. Scale bar is equal to 10 micrometers.

    Lanzone, A.J. (’07) and Dearworth, J.R. (2007). Does melanopsin exist in the retina of the turtle? 35th Annual Hunter College Psychology Conventions and the 11th Annual NEURON (NorthEast Undergraduate Research Organization for Neuroscience) Conference, Program Addendum, (Abstract).

  • Marcincin, C.L. (’06) and Dearworth, J.R., Jr. (2006). Computer image analysis of retinal oil droplets in different vertebrate species. Journal of the Pennsylvania Academy of Science 79: 116 (abstract).
  • Marinucci, M.N. (’05), Prestiano, N.A. (’05) and Dearworth, J.R., Jr. (2005). Density of retinal oil droplets in the red-eared slider turtle. Journal of the Pennsylvania Academy of Science 78: 122 (Abstract).
  • Dearworth, J.R., Jr. and Granda, A.M. (2002). Multiplied functions unify shapes of ganglion-cell receptive fields in retina of turtle. Journal of Vision 2(3): 204-217.
  • Granda, A.M., Dearworth, J.R., Jr., and Subramaniam, B. (1999). Balanced interactions in ganglion-cell receptive fields. Visual Neuroscience 16(2): 319-332.

2.  Sensory processing done by the retina evokes reflexive motor behaviors which help protect the eye and aid in image formation.  These include the pupillary light response and eye blinks.

  • Dearworth, J.R., Brenner, J.E. (’07), and Jones, M.S.  (2007).  Pupil constriction in the turtle evoked by microstimulation of the oculomotor nerve.  2007 Abstract Viewer/Itinerary Planner.  Program No. 718.20.  San Diego, CA: Society for Neuroscience.
  • Dearworth, J.R., Brune, E.E. (’05), and Boyd, A. (’06). (2007).  The partial consensual pupillary light response in the turtle.  2007 Abstract Viewer/Itinerary Planner.  Program No.  5538.  Fort Lauderdale, FL: Association for Research in Vision and Ophthalmology (ARVO).
  • Brenner, J.E. (’07), Dearworth, J.R., and Jones, M.S.  (2007).  Pupil constriction in the turtle by microstimulation of the oculomotor nerve.  35th Annual Hunter College Psychology Conventions and the 11th Annual NEURON (NorthEast Undergraduate Research Organization for Neuroscience) Conference, p. 8-9, (Abstract).
  • Riegel, R.A.L (’07), and Dearworth, J.R.  (2007).  The intensity–dependent consensual pupillary light response in the turtle. Journal of the Pennsylvania Academy of Science, Vol. 80, 124 (Abstract).
  • Kelly, J.N. (’07), George, K.R. (’07), Karwiel, A.N. (’07), and Dearworth, J.R.  (2007).  Blink response of the red eared slider turtle. Journal of the Pennsylvania Academy of Science, Vol. 80, 114, (Abstract).
  • Blaum, J.F. (’08) and Dearworth, J.R.  (2007).  Intrinsic light response by the iris of the turtle under different laboratory conditions.”  Journal of the Pennsylvania Academy of Science, Vol. 80, p. 101-102, (Abstract).
  • Cooper, L.J. (’07) and Dearworth, J.R.  (2007).  Parasympathetic and sympathetic control of the pupillary light response in the turtle.  11th Annual NEURON (NorthEast Undergraduate Research Organization for Neuroscience) Conference at Simmons College, Program Number 5, (Abstract).
  • Dearworth, J.R., Jr., Cooper, L.J. (’07), and Littlefield, T.E. (’06) (2006). Effects of mydriatic drugs and enucleation on the pupillary light response of the turtle. 2006 Abstract Viewer/Itinerary Planner. Program No. 726. Fort Lauderdale, FL: Association for Research in Vision and Ophthalmology (ARVO).
  • As part of her independent study project, Erin Brune ('05, BS, Biology), inserts a turtle into a light-integrating sphere to measure the consensual pupillary light response.

    As part of her independent study project, Erin Brune ('05, BS, Biology), inserts a turtle into a light-integrating sphere to measure the consensual pupillary light response.

    Littlefield, T.E. (’06) and Dearworth, J.R., Jr. (2006). The pupillary response to light in the enucleated eye of the turtle. Journal of the Pennsylvania Academy of Science 79: 115 (Abstract).

  • Dearworth, J.R., Jr., McGee, C. (’05) and Cooper, L.J. (’07) (2005). Neural control of the pupillary light response in the turtle. 2005 Abstract Viewer/Itinerary Planner. Program No. 507.12. Washington, DC: Society for Neuroscience.
  • Brune, E.E. (’05), Fenton, S.B. (’05), and Dearworth, J.R., Jr. (2005). The consensual pupillary light response in the turtle. Journal of the Pennsylvania Academy of Science 78; 105 (Abstract).
  • Dearworth, J.R., Jr. and Gamlin, P.D.R. (2002). Periarcuate cortex neurons sensitive to rapidly approaching targets. 2002 Abstract Viewer/Itinerary Planner. Program number 56.12. Orlando, FL: Society for Neuroscience. http://sfn.scholarone.com/itin2002/
  • Dearworth, J.R. and Cooper (’07), L.J. Sympathetic influence of the pupillary light response in the red-eared slider turtle, (Trachemys scripta elegans). Veterinary Ophthalmology. (Currently, under peer review).
  • Dearworth, J.R., Cooper (’07), L.J., and McGee (’06), C.  (2007). Parasympathetic control of the pupillary light response in the red-eared slider turtle, (Pseudemys scripta elegans). Veterinary Ophthalmology 10(2), 106-110.
  • Granda, A.M., Dearworth, J.R., Jr., Kittila, C.A., and Boyd, W.D. (1995). The pupillary response to light in the turtle. Visual Neuroscience 12(6): 1127-1133.

3.  Sensory processes in the retina also  initiate more complicated behaviors.  In humans and other frontal eyed animals, these include vergence eye movements, the eye movements used for tracking targets moving in depth.  Eyes converge to track targets moving inward and diverge to track targets moving away.

  • Dearworth, J.R., Jr., R.C. Davison, and P.D.R. Gamlin. (2004). Vergence target selection in rhesus monkeys: behavior and modeling, Society for Neuroscience, Vol. 30 (Program number 378.7), (Abstract).
  • Dearworth, J.R., Jr.,  Li, X., and Gamlin, P.D.R. (2001).  Primate frontal cortex contains neurons that respond to motion-in-depth stimuli.  Society for Neuroscience, 27 (Program number 165.28), (Abstract).  http://sfn.scholarone.com/itin2001/
  • Dearworth, J.R., Jr., Li., X., Davison, R.C., and Gamlin, P.D.R.  (2001).  Target selection of transient vergence eye movements in the Rhesus monkey.  [ARVO Abstract].  Investigative Ophthalmology & Visual Science 42 (4), S622.Dearworth, J.R., Jr., Davison, R.C., Li., X., and Gamlin, P.D.R.  (2005).  Vergence target selection in rhesus monkeys: behavior and modeling.  Vision Research 45(6): 731-747.

4.  I design my courses so that students are given a practical hands-on approach.  These include performing laboratory exercises, critiquing primary literature sources, and designing research projects.

  • Mead, K., Dearworth, J., Grisham, W., Herin, G.A., Jarrard, H., Paul, C.A., Waldeck, R., Yates, J., and Young, J. (2007).  IFEL TOUR: A Description of the Introduction to FUN Electrophysiology Labs Workshop at Bowdoin College, July 27-30, and the Resultant Faculty Learning Community.”  The Journal of Undergraduate Neuroscience Education (JUNE), Spring 2007, 5(2): A42-A48.  http://www.funjournal.org/downloads/meadetaljunes07.pdf