Thermal Sensitivity of Lateral Inhibition in Limulus Eye

The effectiveness of lateral inhibition, measured as spike response decrement in a test ommatidium, produced by activity in a group of neighboring ommatidia, decreases as temperature decreases (Q₁₀ of 2.6). The corresponding sensory transducer-spike encoding processes have a weaker temperature dependence (Q₁₀ of 1.6). Relative synaptic delay, the time difference between the latency of inhibition onset and the latency of test receptor excitation, has a strong temperature dependence (Q₁₀ of 5), while receptor potential onset latency (Q₁₀ of 1.4) and optic nerve spike conduction velocity (Q₁₀ of 1.7), two factors inherent in relative synaptic delay, are less temperature sensitive. Oscillations of optic nerve spike response ("bursting") may be produced by thermal adjustment of temperature-sensitive parameters of the lateral inhibitory network in the retina. Burst interval has a strong temperature dependence (Q₁₀ of 2.4) and broad interspike interval distribution compared to the thermal sensitivity (Q₁₀ of 1.4) and narrow spike interval spectrum of the response of a single unit within the bursting group.