Light Response of Crayfish Neurons: Results

Click here to see a demonstration of the optic nerve fiber and caudal photoreceptor dissection

Click here to see a demonstration of the optic nerve fiber and caudal photoreceptor dissection

  • Latencies of responses from the optic nerve fibers were much shorter than those of the caudal photoreceptors (75ms versus 2-3s)
  • Mean firing rates were determined from five repeated trials
    • The firing rates were measured for 5s in both the light and dark conditions
  • This was performed for one preparation of the optic nerve fibers and the caudal photoreceptor
  • Figure 1:

    Figure 11A: Examples of traces of action potentials shown for the optic nerve fibers                                                                                        Figure 11B: Examples of traces of action potentials shown for the caudal photoreceptor (Journal of Undergraduate Neuroscience Education)

Figure 12:

Figure 12A: Optic Nerve Fibers; Figure 12B: Caudal Photorecepto (Journal of Undergraduate Neuroscience Education)

 

  • Firing rates were found to be greater for the optic nerve fibers than for the caudal photoreceptor
  • Mean firing rate for optic nerve fiber
    • Dark conditions: 13 +/- 1.3Hz
    • Light conditions: 178 +/- 6.7Hz
  • Mean firing rate for caudal photoreceptor
    • Dark conditions: 2 +/- 0.6Hz
    • Light conditions: 13 +/- 2.1Hz
  • As expected, there was a significant difference observed between the firing rates during dark and light conditions of the optic nerve fibers and the caudal photoreceptor
    • Optic nerve fibers (t=22; P<0.01)
    • Caudal photoreceptor (t=6.7; P< 0.01)

 

References