Ethanol's effect on selective gating of somatic sensory inputs to single cortical neurons

Limiting redundancy in the real-world sensory inputs is of obvious benefit for efficient neural coding, but little is known about how this may be accomplished by biophysical neural mechanisms. One possible cellular mechanism is through adaptation to relatively constant inputs. Recent investigations in primary visual (V1) cortical neurons have demonstrated that adaptation to prolonged changes in stimulus contrast is mediated in part through intrinsic ionic currents, a Ca2+-activated K+ current ( IKCa) and especially a Na+-activated K+ current ( IKNa). The present study was designed to test the hypothesis that the activation of adaptation ionic currents may provide a cellular mechanism for temporal decorrelation in V1. A conductance-based neuron model was simulated, which included an IKCa and an IKNa. We show that the model neuron reproduces the adaptive behavior of V1 neurons in response to high contrast inputs. When the stimulus is stochastic with 1/ f 2 or 1/ f-type temporal correlations, these autocorrelations are greatly reduced in the output spike train of the model neuron. The IKCa is effective at reducing positive temporal correlations at approximately 100-ms time scale, while a slower adaptation mediated by IKNa is effective in reducing temporal correlations over the range of 1–20 s. Intracellular injection of stochastic currents into layer 2/3 and 4 (pyramidal and stellate) neurons in ferret primary visual cortical slices revealed neuronal responses that exhibited temporal decorrelation in similarity with the model. Enhancing the slow afterhyperpolarization resulted in a strengthening of the decorrelation effect. These results demonstrate the intrinsic membrane properties of neocortical neurons provide a mechanism for decorrelation of sensory inputs.

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Independent representations of reward-predicting cues and reward history in frontal cortical neurons

10.1101/2020.01.23.916460 ◽

2020 ◽

Author(s):

Masashi Kondo ◽

Masanori Matsuzaki

Keyword(s):

Calcium Imaging ◽

Cortical Neurons ◽

Deep Layer ◽

Wide Field ◽

Water Reward ◽

Sensory Inputs ◽

Two Photon ◽

Dorsomedial Frontal Cortex ◽

Actual Outcome ◽

Sensory Cue

SummaryThe transformation of sensory inputs to appropriate goal-directed actions requires estimation of sensory-cue values based on outcome history. To clarify how cortical neurons represent an outcome-predicting cue and actual outcome, we conducted wide-field and two-photon calcium imaging of the mouse neocortex during performance of a classical conditioning task with two cues with different water-reward probabilities. Although licking behavior dominated the area-averaged activity over the whole dorsal neocortex, dorsomedial frontal cortex (dmFrC) affected other dorsal frontal cortical activities, and its inhibition extinguished differences in anticipatory licking between the cues. In individual frontal cortical neurons, the reward-predicting cue was not simultaneously represented with the current or past reward, but licking behavior was frequently multiplexed with the reward-predicting cue and current or past reward. Deep-layer neurons in dmFrC most strongly represented the reward-predicting cue and recent reward history. Our results suggest that these neurons ignite the cortical processes required to select appropriate actions.

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Spatiotemporal Coding in the Cortex: Information Flow-Based Learning in Spiking Neural Networks

Neural Computation ◽

10.1162/089976699300016502 ◽

1999 ◽

Vol 11 (4) ◽

pp. 919-934 ◽

Cited By ~ 6

Author(s):

Gustavo Deco ◽

Bernd Schürmann

Keyword(s):

Information Flow ◽

Cortical Neurons ◽

Spiking Neurons ◽

Reconstruction Method ◽

First Principle ◽

Information Theoretic ◽

Discrimination Ability ◽

Sensory Inputs ◽

Integrate And Fire ◽

Synchronous Firing

We introduce a learning paradigm for networks of integrate-and-fire spiking neurons that is based on an information-theoretic criterion. This criterion can be viewed as a first principle that demonstrates the experimentally observed fact that cortical neurons display synchronous firing for some stimuli and not for others. The principle can be regarded as the postulation of a nonparametric reconstruction method as optimization criteria for learning the required functional connectivity that justifies and explains synchronous firing for binding of features as a mechanism for spatiotemporal coding. This can be expressed in an information-theoretic way by maximizing the discrimination ability between different sensory inputs in minimal time.

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Role of Sustained Excitability of the Leg Motor Cortex After Transcranial Magnetic Stimulation in Associative Plasticity

Journal of Neurophysiology ◽

10.1152/jn.00197.2007 ◽

2007 ◽

Vol 98 (2) ◽

pp. 657-667 ◽

Cited By ~ 32

Author(s):

François D. Roy ◽

Jonathan A. Norton ◽

Monica A. Gorassini

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Cortical Neurons ◽

Magnetic Stimulation ◽

Motor Evoked Potentials ◽

Low Frequency ◽

Single Pulse ◽

Common Peroneal Nerve ◽

Lower Limbs ◽

Sensory Inputs

Changes in the strength of corticospinal projections to muscles in the upper and lower limbs are induced in conscious humans after paired associative stimulation (PAS) to the motor cortex. We tested whether an intervention of PAS consisting of 90 low-frequency (0.1-Hz) stimuli to the common peroneal nerve combined with suprathreshold transcranial magnetic stimulation (TMS) produces specific changes to the motor-evoked potentials (MEPs) in lower leg muscles if the afferent volley from peripheral stimulation is timed to arrive at the motor cortex after TMS-induced firing of corticospinal neurons. Unlike PAS in the hand, MEP facilitation in the leg was produced when sensory inputs were estimated to arrive at the motor cortex over a range of 15 to 90 ms after cortical stimulation. We examined whether this broad range of facilitation occurred as a result of prolonged subthreshold excitability of the motor cortex after a single pulse of suprathreshold TMS so that coincident excitation from sensory inputs arriving many milliseconds after TMS can occur. We found that significant facilitation of MEP responses (>200%) occurred when the motor cortex was conditioned with suprathreshold TMS tens of milliseconds earlier. Likewise, it was possible to induce strong MEP facilitation (85% at 60 min) when afferent inputs were directly paired with subthreshold TMS. We argue that in the leg motor cortex, facilitation of MEP responses from PAS occurred over a large range of interstimulus intervals as a result of the paired activation of sensory inputs with sustained, subthreshold activity of cortical neurons that follow a pulse of suprathreshold TMS.

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