Burst firing is a neural code in an insect auditory system
Hugo G. Eyherabide, Ariel Rokem, Andreas V. M. Herz & Inés Samengo
Abstract
Various classes of neurons alternate between high-frequency
discharges and silent intervals. This phenomenon is called burst
firing. To analyze burst activity in an insect system,
grasshopper auditory receptor neurons were recorded in vivo for
several distinct stimulus types. The experimental data show that
both burst probability and burst characteristics are strongly
influenced by temporal modulations of the acoustic stimulus. The
tendency to burst, hence, is not only determined by
cell-intrinsic processes, but also by their interaction with the
stimulus time course. We study this interaction quantitatively
and observe that bursts containing a certain number of spikes
occur shortly after stimulus deflections of specific intensity
and duration. Our findings suggest a sparse neural code where
information about the stimulus is represented by the number of
spikes per burst, irrespective of the detailed
interspike-interval structure within a burst. This compact
representation cannot be interpreted as a firing-rate code. An
information-theoretical analysis reveals that the number of
spikes per burst reliably conveys information about the
amplitude and duration of sound transients, whereas their time
of occurrence is reflected by the burst onset time. The
investigated neurons encode almost half of the total transmitted
information in burst activity.
Last modified: Tue Mar 10 10:06:27 CET 2009