Redwood Neuroscience
Title: “Spike timing and visual coding in the LGN:
How the cortex gets news of the world.”
Pam
Reinagel
San
Diego
Abstract:
We
are interested the neural code used to transmit sensory information to cortex.
Cortex may be responsible for the sophisticated computations that give rise to
conscious vision, object recognition, and memory. But (as the data processing
inequality guarantees us) all the visual information the cortex will ever have
is embedded in the spike trains it receives from the thalamus. How is this
primary information encoded?
We
have found that the LGN encodes visual information in precise spike timing.
There are several fundamental questions about any such code even at the level
of single cells: how reproducible is the occurrence of each spike? how precise is the time of each spike? is
each spike independent, or are patterns of spikes important? how
universal or unique is the temporal code of different neurons? I will present
the case that LGN spikes are reproducible from trial to trial, precise to order
1ms, patterned to at least order 10ms, and largely universal within a cell
class. On the basis of this framework, I will outline some of the open
questions we are now exploring. For example we are interested in how these
coding properties depend on visual stimulus statistics; the significance of an
intrinsic conductance that causes bursting; how coding properties change in the
course of sensory adaptation; the cellular mechanisms for achieving temporal
precision; the diversity and discreteness of neural types; and how to
understand coding at the population level in the face of the curse of
dimensionality.