[Comp-neuro] Poulet 2008 [ Brain state regulates membrane potential synchrony; resting state; signal-to-noise ]

Malcolm Dean malcolmdean at gmail.com
Thu Jul 31 21:41:37 CEST 2008

"...a change in brain state dynamically and profoundly regulates cortical
membrane potential synchrony during behaviour. The change in brain state is
regulated by an internally generated signal... Active cortical brain states
may therefore serve to augment the total cortical information processing
capacity through decorrelation of membrane potential synchrony while
increasing signal-to-noise ratios for AP initiation."

Nature advance online publication 16 July 2008
Internal brain state regulates membrane potential synchrony in barrel cortex
of behaving mice
James F. A. Poulet & Carl C. H. Petersen

Internal brain states form key determinants for sensory perception,
sensorimotor coordination and learning1, 2. A prominent reflection of
different brain states in the mammalian central nervous system is the
presence of distinct patterns of cortical synchrony, as revealed by
extracellular recordings of the electroencephalogram, local field potential
and action potentials. Such temporal correlations of cortical activity are
thought to be fundamental mechanisms of neuronal computation3, 4, 5, 6, 7,
8, 9, 10, 11. However, it is unknown how cortical synchrony is reflected in
the intracellular membrane potential (V m) dynamics of behaving animals.
Here we show, using dual whole-cell recordings from layer 2/3 primary
somatosensory barrel cortex in behaving mice, that the V m of nearby neurons
is highly correlated during quiet wakefulness. However, when the mouse is
whisking, an internally generated state change reduces the V m correlation,
resulting in a desynchronized local field potential and
electroencephalogram. Action potential activity was sparse during both quiet
wakefulness and active whisking. Single action potentials were driven by a
large, brief and specific excitatory input that was not present in the V m
of neighbouring cells. Action potential initiation occurs with a higher
signal-to-noise ratio during active whisking than during quiet periods.
Therefore, we show that an internal brain state dynamically regulates
cortical membrane potential synchrony during behaviour and defines different
modes of cortical processing.
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