Error correction and fast detectors implemented by ultrafast neuronal plasticity

Abstract

We experimentally show that the neuron functions as a precise time-integrator, where the accumulated changes in neuronal response latencies, under complex and random stimulation patterns, are solely a function of a global quantity, the average time-lag between stimulations. In contrast, momentary leaps in the neuronal response latency follow trends of consecutive stimulations, indicating ultra-fast neuronal plasticity. On a circuit level, this ultra-fast neuronal plasticity phenomenon implements error-correction mechanisms and fast detectors for misplaced stimulations. Additionally, at moderate/high stimulation rates this phenomenon destabilizes/stabilizes a periodic neuronal activity disrupted by misplaced stimulations. I. INTRODUCTIONOn the network and circuit level, both synaptic and neuronal plasticity are present. These two distinct types of plasticity have different effects on the dynamics of a network [1,2]. On one hand, synaptic plasticity has been vastly researched, from the single neuron to the network level, specifically long and short-term plasticity. Shortterm synaptic plasticity reflects an increase (facilitation) and decrease (depression) in the probability of neurotransmitter release [3,4]. It affects the speed of synaptic signal transmission and can last from hundreds of milliseconds to seconds [3,5]. This phenomenon varies enormously depending on the neuronal and synaptic features as well as on the neuron's recent history of activity [6][7][8]. Neuronal plasticity, on the other hand, was examined mainly on the single neuron level [9,10], hence investigation of this phenomenon is still demanded.Short-term synaptic plasticity, in the form of facilitation and depression (FAD), is suggested to carry critical computational functions in neural circuits [1,11,12], thus one can hypothesize that neuronal plasticity carries similar computational functions. This hypothesis was not experimentally verified on the network level, and in addition its enormous variation seems to prevent reliable information processing [13,14]. Here we experimentally demonstrate neuronal ultra-fast plasticity on a time scale of several milliseconds and its applications to advanced computational tasks.

Neuronal response impedance mechanism implementing cooperative networks with low firing rates and μs precision

“…In contrast, when the same neuron is stimulated solely with τ = 25 ms its neuronal response latency profile above L ST is clearly different (Figures 3A,B ). Before the latency stabilizes, it is solely a function of a global quantity, the averaged time-lag between all previous stimulations constitute the current neuronal response latency stretching (Vardi et al, 2014 ). This behavior indicates neuronal long-term memory (Vardi et al, 2014 ), in contrast to the behavior after stabilization.…”

“…Alternatively, temporary higher frequency stimulations to a subset of neurons result in abrupt changes of their NRLs (Figure 3 ). The accumulation of these changes along neuronal pathways (Vardi et al, 2013a , b , 2014 ; Goldental et al, 2014 ) dynamically changes the topography of the network (Vardi et al, 2013b ; Goldental et al, 2014 ). Both abovementioned scenarios only temporarily influence the baseline cortical state, as the NRL stretching is a fully reversible phenomenon (De Col et al, 2008 ; Vardi et al, 2013c ).…”

Mimicking Collective Firing Patterns of Hundreds of Connected Neurons using a Single-Neuron Experiment

“…When a neuron is stimulated repeatedly, the time-lag between a stimulation and its corresponding evoked spike, the neuronal response latency (NRL), stretches gradually (Wagenaar et al, 2004 ; De Col et al, 2008 ; Vardi et al, 2014 , 2015 ; Figure 2A and Materials and Methods). Above a critical stimulation frequency, f c , which varies much among neurons (Vardi et al, 2015 ), this stretching terminates at the intermittent phase.…”

Chaotic and non-chaotic phases in experimental responses of a single neuron

“…In order to enhance the temporal resolution, a neuronal chain [22] can be suggested (as in fig. 4(b), top).…”

“…Methods.-Culture preparation, synaptic blockers, stimulation and recording, cell selection, stimulation control, data analysis and spike detection were performed as described in previous publications [15,22].…”