CHALLENGE D
Predict the spike timing of a single post-synaptic neuron in the lateral geniculate nucleus (LGN) knowing the spike train on the pre-synaptic side (i.e. in a retinal ganglion cell (RGC)).
Experimental Methods
Experiments are described thoroughly in Carandini et al. (2007) and Sincich et al. (2007). Briefly, extracellular recordings were performed in-vivo in rhesus monkeys. Epoxylite-coated tungsten electrode was positioned 5 mm above the LGN. Extracellular potentials recorded by single tungsten electrodes (Frederick Haer & Co., Bowdoin ME) were amplified 1000x, band-pass filtered between 300 and 3 kHz, and digitized at 25 kHz (Power 1401, Cambridge Electronic Design, Cambridge). Retinal EPSPs and geniculate action potentials were identified by off-line waveform templating (Spike2; Cambridge Electronics Design). Only LGN neurons with EPSP that exhibited an absolute refractory period were included in the data set. Visual stimuli were restricted to the receptive field center, as established by manually mapping the field boundaries. The light intensity of a LED illuminating only the field center varied continuously, with a naturalistic temporal frequency power spectrum between 0.2 and 80 Hz. Experiments used procedures approved by the University of California, San Francisco Institutional Animal Care and Use Committee in accordance with National Institutes of Health guidelines. The visual stimulus is 10 s long and is repeated 76 times. The first 5 s was common across trials and the last 5 s segment was unique to the trial.
Evaluation Methods
The training set consists of all the odd repeats and the test set consist of the last 5s in all the even repeats. For training the participants have access to both the retinal (pre-synaptic) and geniculate (post-synaptic) spike times. For testing, the participants must predict the geniculate spike times (post-synaptic) knowing only the retinal spike times (pre-synaptic). Details on the quantitative aspects regarding the evaluation are given in the instructions.
Submission
Submissions are made through this web site. The participant must provide his prediction of the geniculate spike trains for each repetition. The submission consists of a folder containing 38 files, one for each repetition. Each file contains the predicted spike time in milliseconds (ms) since the beginning of the repetition. Spike times are stored column wise in ASCII file format. The files are labeled from 2 to 76 and are called ’repXX.txt’ (rep2.txt, rep4.txt, ... , rep76.txt). Submissions must comply with these specifications to ensure that the automatic evaluation of the results is successful.
