Front Neural Circuits
2016[]; 10
(?): 38
PMID27242446
show ga
Spontaneous activity patterns propagate through many parts of the developing
nervous system and shape the wiring of emerging circuits. Prior to vision, waves
of activity originating in the retina propagate through the lateral geniculate
nucleus (LGN) of the thalamus to primary visual cortex (V1). Retinal waves have
been shown to instruct the wiring of ganglion cell axons in LGN and of
thalamocortical axons in V1 via correlation-based plasticity rules. Across
species, retinal waves mature in three stereotypic stages (I-III), in which
distinct circuit mechanisms give rise to unique activity patterns that serve
specific functions in visual system refinement. Here, I review insights into the
patterns, mechanisms, and functions of stage III retinal waves, which rely on
glutamatergic signaling. As glutamatergic waves spread across the retina,
neighboring ganglion cells with opposite light responses (ON vs. OFF) are
activated sequentially. Recent studies identified lateral excitatory networks in
the inner retina that generate and propagate glutamatergic waves, and vertical
inhibitory networks that desynchronize the activity of ON and OFF cells in the
wavefront. Stage III wave activity patterns may help segregate axons of ON and
OFF ganglion cells in the LGN, and could contribute to the emergence of
orientation selectivity in V1.
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