Optical recording of suprathreshold neural activity with single-cell and single-spike resolution.

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution.

Impact of cortical plasticity on patterns of suprathreshold activity in the cerebral cortex.

There are many cellular and synaptic mechanisms of plasticity in the vertebrate cortex. How the patterns of suprathreshold spiking activity in a population of neurons change because of this plasticity, however, has hardly been subjected to experimental studies. Here, we measured how evoked patterns of suprathreshold spiking activity in a cortical network were modified by cortical plasticity with single-cell and single-spike resolution.

Impact of cortical plasticity on information signaled by populations of neurons in the cerebral cortex.

The performance of neural codes to represent attributes of sensory signals has been evaluated in the vertebrate peripheral and central nervous system. Here, we determine how information signaled by populations of neurons is modified by plasticity. Suprathreshold neuronal responses from a large number of neurons were recorded in the juvenile mouse barrel cortex using dithered random-access scanning.

Correlations decrease with propagation of spiking activity in the mouse barrel cortex.

Propagation of suprathreshold spiking activity through neuronal populations is important for the function of the central nervous system. Neural correlations have an impact on cortical function particularly on the signaling of information and propagation of spiking activity. Therefore we measured the change in correlations as suprathreshold spiking activity propagated between recurrent neuronal networks of the mammalian cerebral cortex.

Optical recording of neuronal spiking activity from unbiased populations of neurons with high spike detection efficiency and high temporal precision.

Activity in populations of neurons is essential for cortical function including signaling of information and signal transport. Previous methods have made advances in recording activity from many neurons but have both technical and analytical limitations. Here we present an optical method, dithered random-access functional calcium imaging, to record somatic calcium signals from up to 100 neurons, in vitro and in vivo.

Target cell-dependent normalization of transmitter release at neocortical synapses.

The efficacy and short-term modification of neocortical synaptic connections vary with the type of target neuron. We investigated presynaptic Ca2+ and release probability at single synaptic contacts between pairs of neurons in layer 2/3 of the rat neocortex. The amplitude of Ca2+ signals in boutons of pyramids contacting bitufted or multipolar interneurons or other pyramids was dependent on the target cell type.

Intracellular domains of NMDA receptor subtypes are determinants for long-term potentiation induction.

NMDA receptors (NMDARs) are essential for modulating synaptic strength at central synapses. At hippocampal CA3-to-CA1 synapses of adult mice, different NMDAR subtypes with distinct functionality assemble from NR1 with NR2A and/or NR2B subunits. Here we investigated the role of these NMDA receptor subtypes in long-term potentiation (LTP) induction.

Normalization of Ca2+ signals by small oblique dendrites of CA1 pyramidal neurons.

Oblique dendrites of CA1 pyramidal neurons predominate in stratum radiatum and receive approximately 80% of the synaptic input from Schaffer collaterals. Despite this fact, most of our understanding of dendritic signal processing in these neurons comes from studies of the main apical dendrite. Using a combination of Ca2+ imaging and whole-cell recording techniques in rat hippocampal slices, we found that the properties of the oblique dendrites differ markedly from those of the main dendrites.