研究目的
Investigating the temporal resolution of single photon responses in primate rod photoreceptors and the limits imposed by cellular noise.
研究成果
The temporal resolution of the single photon response in primate rods is much finer than previously appreciated, with a resolution of ~50 ms. The study identifies continuous noise and single photon response variability as key limiting sources of transduction noise. The thermal activation rate of rhodopsin is found to be lower than previous estimates, suggesting that other noise sources are more important than previously thought. The limiting noise relevant for behavior depends critically on how rod signals are pooled by downstream neurons.
研究不足
The study focuses on noise generated in the rod outer segment currents, neglecting potential noise introduced by downstream cellular and synaptic processes. Additionally, the study does not account for the impact of gap junctions between rod inner segments on the ability to separate single photon responses from continuous noise.
1：Experimental Design and Method Selection:
The study involved recording rod outer segment currents with suction electrodes to measure responses to dim flashes of light. The methodology included isolating single photon responses from trials producing zero or multiple photoisomerizations (Rh*).
2：Sample Selection and Data Sources:
Primate (Macaca fascicularis and Papio anubis) retinas were used, provided by the laboratory of D. Dacey at the University of Washington. The retinas were dark-adapted for >1 hour at 37°C in bicarbonate-buffered Ames solution.
3：List of Experimental Equipment and Materials:
Suction electrodes for recording rod outer segment currents, light-emitting diode (LED) for light stimulation, calibrated photodiode for measuring light intensities, and BAPTA-AM for slowing Ca2+ kinetics in some rods.
4：Experimental Procedures and Operational Workflow:
Rod responses were recorded in darkness, with flashes of light delivered at various intensities and durations. Single photon responses were identified and segregated from responses to zero and multiple Rh* by constructing a histogram of response amplitudes.
5：Data Analysis Methods:
Fisher's linear discriminant was used to classify responses as resulting from an early or late flash. Principal components analysis (PCA) was performed on the ensemble of rod responses prior to classification.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
