SpikeTiming

Spike timing refers to the exact moments at which neurons emit action potentials and to the temporal structure of spike trains. It emphasizes millisecond-scale timing as a carrier of information, in contrast to rate-based descriptions that summarize activity by average firing rate over a time window.

In neural coding, precise spike timing can convey information about stimuli, motion, or the timing of events. In sensory systems such as audition and somatosensation, neurons can phase-lock to periodic inputs, use onset timing, and encode features through the timing of spikes. The reliability and precision of timing are important factors that influence the information content of neural signals, and timing can be degraded by noise and variability in neural responses.

Spike timing interacts with plasticity through spike-timing-dependent plasticity (STDP): if a presynaptic spike precedes a postsynaptic spike within a short window, synaptic strength tends to increase; if it follows, strength tends to decrease. The typical timing window for STDP is on the order of tens of milliseconds, and these rules influence learning, memory formation, and the development of neural circuits.

In networks, spike timing influences synchronization, oscillations, and pattern generation. Computational models using integrate-and-fire or conductance-based neurons implement timing-dependent mechanisms to study how temporal structure supports computation and learning. Experimental and theoretical work on spike timing integrates methods from spike train analysis and neural coding to understand how timing contributes to neural function.

Methods for analyzing spike timing include peristimulus time histograms, cross-correlation, and distance measures such as Victor-Purpura or van Rossum. Applications span neuromorphic engineering and brain-machine interfaces, where timing information can be critical, though the role of timing-based coding varies across brain areas.

See also: Spike-timing-dependent plasticity, neural coding, spike train analysis.