Interneurons exhibiting centre--surround antagonism within their receptive fields are commonly found in peripheral visual pathways. We propose that this organization enables the system to encode spatial detail a manner minimizes deleterious effects of intrinsic noise, by exploiting correlation exists natural scenes. The antagonistic surround takes weighted mean signals neighbouring receptors generate statistical prediction signal at centre. predicted value is subtracted from actual centre...

The contrast-response function of a class first order interneurons in the fly's compound eye approximates to cumulative probability distribution contrast levels natural scenes. Elementary information theory shows that this matching enables neurons encode fluctuations most efficiently.

The initiation and propagation of action potentials (APs) places high demands on the energetic resources neural tissue. Each AP forces ATP-driven ion pumps to work harder restore ionic concentration gradients, thus consuming more energy. Here, we ask whether currents underlying can be predicted theoretically from principle minimum energy consumption. A long-held supposition that APs are energetically wasteful, based theoretical analysis squid giant axon AP, has recently been overturned by...

Trade-offs between energy consumption and neuronal performance must shape the design evolution of nervous systems, but we lack empirical data showing how costs vary according to performance. Using intracellular recordings from intact retinas four flies, Drosophila melanogaster, D. virilis, Calliphora vicina, Sarcophaga carnaria, measured rates at which homologous R1-6 photoreceptors these species transmit information same stimuli estimated they consumed. In all species, both rate increase...

Recordings from the motion-sensitive giant neuron H1 of lobula plate fly Lucilia cuprina , indicate that small field, possibly retinotopic, units presynaptic to H1, adapt in response motion much same way as photoreceptors do their signal, light intensity. As a result is related what we have called velocity contrast. This adaptation shown take place during or after computation motion, and strongly dependent on contrast frequency (temporal moving grating). Photometric contributes less rate...

We investigate the effects of synaptic transmission on early visual processing by examining passage signals from photoreceptors to second order neurons (LMCS). concentrate roles played three properties transmission: (1) shape characteristic curve, relating pre- and postsynaptic signal amplitudes, (2) dynamics (3) noise introduced during transmission. The curve is sigmoidal follows a simple model (Appendix) in which transmitter release rises exponentially with presynaptic potential. According...

It is generally assumed that axons use action potentials (APs) to transmit information fast and reliably synapses. Yet, the reliability of transmission along fibers below 0.5 microm diameter, such as cortical cerebellar axons, unknown. Using detailed models rodent squid stochastic simulations, we show how conduction thin affected by probabilistic nature voltage-gated ion channels (channel noise). We identify four distinct effects corrupt propagating spike trains in axons: spikes were added,...