scholarly journals Author response: Spike-timing-dependent ensemble encoding by non-classically responsive cortical neurons

2019 ◽  
Author(s):  
Michele N Insanally ◽  
Ioana Carcea ◽  
Rachel E Field ◽  
Chris C Rodgers ◽  
Brian DePasquale ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Spike Timing ◽  
Author Response ◽  
Ensemble Encoding

scholarly journals Spike-timing-dependent ensemble encoding by non-classically responsive cortical neurons

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Michele N Insanally ◽  
Ioana Carcea ◽  
Rachel E Field ◽  
Chris C Rodgers ◽  
Brian DePasquale ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Cortical Neurons ◽  
Sensory Input ◽  
Spike Timing ◽  
Stimulus Category ◽  
Significant Information ◽  
Sensory Stimuli ◽  
Rate Modulation ◽  
Ensemble Encoding ◽  
And Behavior

Neurons recorded in behaving animals often do not discernibly respond to sensory input and are not overtly task-modulated. These non-classically responsive neurons are difficult to interpret and are typically neglected from analysis, confounding attempts to connect neural activity to perception and behavior. Here, we describe a trial-by-trial, spike-timing-based algorithm to reveal the coding capacities of these neurons in auditory and frontal cortex of behaving rats. Classically responsive and non-classically responsive cells contained significant information about sensory stimuli and behavioral decisions. Stimulus category was more accurately represented in frontal cortex than auditory cortex, via ensembles of non-classically responsive cells coordinating the behavioral meaning of spike timings on correct but not error trials. This unbiased approach allows the contribution of all recorded neurons – particularly those without obvious task-related, trial-averaged firing rate modulation – to be assessed for behavioral relevance on single trials.

scholarly journals Dopaminergic Neuromodulation of Spike Timing Dependent Plasticity in Mature Adult Rodent and Human Cortical Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Emma Louise Louth ◽  
Rasmus Langelund Jørgensen ◽  
Anders Rosendal Korshoej ◽  
Jens Christian Hedemann Sørensen ◽  
Marco Capogna
Keyword(s):  
Learning And Memory ◽  
Cortical Neurons ◽  
Synaptic Depression ◽  
Spike Timing ◽  
Therapeutic Interventions ◽  
Spike Timing Dependent Plasticity ◽  
Mature Adult ◽  
Dependent Plasticity ◽  
Cortical Synapses

Synapses in the cerebral cortex constantly change and this dynamic property regulated by the action of neuromodulators such as dopamine (DA), is essential for reward learning and memory. DA modulates spike-timing-dependent plasticity (STDP), a cellular model of learning and memory, in juvenile rodent cortical neurons. However, it is unknown whether this neuromodulation also occurs at excitatory synapses of cortical neurons in mature adult mice or in humans. Cortical layer V pyramidal neurons were recorded with whole cell patch clamp electrophysiology and an extracellular stimulating electrode was used to induce STDP. DA was either bath-applied or optogenetically released in slices from mice. Classical STDP induction protocols triggered non-hebbian excitatory synaptic depression in the mouse or no plasticity at human cortical synapses. DA reverted long term synaptic depression to baseline in mouse via dopamine 2 type receptors or elicited long term synaptic potentiation in human cortical synapses. Furthermore, when DA was applied during an STDP protocol it depressed presynaptic inhibition in the mouse but not in the human cortex. Thus, DA modulates excitatory synaptic plasticity differently in human vs. mouse cortex. The data strengthens the importance of DA in gating cognition in humans, and may inform on therapeutic interventions to recover brain function from diseases.

scholarly journals Sparse bursts optimize information transmission in a multiplexed neural code

2018 ◽  
Vol 115 (27) ◽  
pp. E6329-E6338 ◽  
Author(s):  
Richard Naud ◽  
Henning Sprekeler
Keyword(s):  
Firing Rate ◽  
Cortical Neurons ◽  
Neural Code ◽  
Spike Timing ◽  
Neural Ensemble ◽  
Multiple Input ◽  
Cortical Hierarchy ◽  
Connectivity Patterns ◽  
Rate Coding

Many cortical neurons combine the information ascending and descending the cortical hierarchy. In the classical view, this information is combined nonlinearly to give rise to a single firing-rate output, which collapses all input streams into one. We analyze the extent to which neurons can simultaneously represent multiple input streams by using a code that distinguishes spike timing patterns at the level of a neural ensemble. Using computational simulations constrained by experimental data, we show that cortical neurons are well suited to generate such multiplexing. Interestingly, this neural code maximizes information for short and sparse bursts, a regime consistent with in vivo recordings. Neurons can also demultiplex this information, using specific connectivity patterns. The anatomy of the adult mammalian cortex suggests that these connectivity patterns are used by the nervous system to maintain sparse bursting and optimal multiplexing. Contrary to firing-rate coding, our findings indicate that the physiology and anatomy of the cortex may be interpreted as optimizing the transmission of multiple independent signals to different targets.

scholarly journals Mimicking and mitigating the cutaneous response to transcranial electrical stimulation using interferential and combinatorial techniques

2021 ◽  
Author(s):  
Bryan Howell ◽  
Cameron C McIntyre
Keyword(s):  
Electrical Stimulation ◽  
Cortical Neurons ◽  
Repeated Administration ◽  
Neurological Impairment ◽  
Spike Timing ◽  
Transcranial Electrical Stimulation ◽  
Adjunct Treatment ◽  
New Strategy ◽  
Standard Limit ◽  
New Strategies

Transcranial electrical stimulation (tES) is a promising adjunct treatment for neurological impairment and mental health disorders. The modulatory effects of tES are small to moderate, and accrue over days to weeks with repeated administration, but these effects are also inconsistent across individuals, which poses a challenge for its clinical administration. Some of the variability in tES may stem from uncontrolled behavioral factors, and inadequate dosing of current across individuals, so new strategies are needed to address these issues. We evaluated the biophysics of emerging techniques for tES and provided new testable hypotheses for the tolerability of interferentail and combinatorial waveforms. Millisecond pulsatile currents may serve as suitable alternatives to alternating currents in modulating neural spike timing from tES. Pulsatile currents limit spike generation in nerves and may be tolerated above the standard limit of 2 mA when combined with a direct current to block nerve activation. Additionally, we posit that combinations of kilohertz interferential currents can mimic the nerve response of different tES waveforms but with minimal modulation of cortical neurons, providing a new strategy for active placebo stimulation. These results will help guide design of interferential tES strategies for better blinding and provide a testable model for evaluating the tolerability of new combinatorial strategies.

scholarly journals Dopaminergic neuromodulation of spike timing dependent plasticity in mature adult rodent and human cortical neurons

2020 ◽  
Author(s):  
Emma Louise Louth ◽  
Rasmus Langelund Jørgensen ◽  
Anders Rosendal Korshøj ◽  
Jens Christian Hedemann Sørensen ◽  
Marco Capogna
Keyword(s):  
Learning And Memory ◽  
Cortical Neurons ◽  
Synaptic Depression ◽  
Spike Timing ◽  
Therapeutic Interventions ◽  
Spike Timing Dependent Plasticity ◽  
Mature Adult ◽  
Dependent Plasticity ◽  
Cortical Synapses

AbstractSynapses in the cerebral cortex constantly change and this dynamic property regulated by the action of neuromodulators such as dopamine (DA), is essential for reward learning and memory. DA modulates spike-timing-dependent plasticity (STDP), a cellular model of learning and memory, in juvenile rodent cortical neurons. However, it is unknown whether this neuromodulation also occurs at excitatory synapses of cortical neurons in mature adult mice or in humans. Cortical layer V pyramidal neurons were recorded with whole cell patch clamp electrophysiology and an extracellular stimulating electrode was used to induce STDP. DA was either bath-applied or optogenetically released in slices from mice. Classical STDP induction protocols triggered non-Hebbian excitatory synaptic depression in the mouse or no plasticity at human cortical synapses. DA reverted long term synaptic depression to baseline in mouse or elicited long term synaptic potentiation in human cortical synapses. Furthermore, when DA was applied during a STDP protocol it depressed presynaptic inhibition in the mouse but not in the human cortex. Thus, DA modulates excitatory synaptic plasticity differently in human versus mouse cortex. The data strengthens the importance of DA in gating cognition in humans, and may inform on therapeutic interventions to recover brain function from diseases.

scholarly journals An integrate-and-fire spiking neural network model simulating artificially induced cortical plasticity

2020 ◽  
Author(s):  
Larry Shupe ◽  
Eberhard E. Fetz
Keyword(s):  
Neural Network ◽  
Cortical Neurons ◽  
Closed Loop ◽  
Cortical Plasticity ◽  
Spike Timing ◽  
Emg Activity ◽  
Beta Activity ◽  
Spiking Neural Network ◽  
Integrate And Fire ◽  
Closed Loop Stimulation

AbstractWe describe an integrate-and-fire (IF) spiking neural network that incorporates spike-timing dependent plasticity (STDP) and simulates the experimental outcomes of four different conditioning protocols that produce cortical plasticity. The original conditioning experiments were performed in freely moving non-human primates with an autonomous head-fixed bidirectional brain-computer interface. Three protocols involved closed-loop stimulation triggered from (a) spike activity of single cortical neurons, (b) EMG activity from forearm muscles, and (c) cycles of spontaneous cortical beta activity. A fourth protocol involved open-loop delivery of pairs of stimuli at neighboring cortical sites. The IF network that replicates the experimental results consists of 360 units with simulated membrane potentials produced by synaptic inputs and triggering a spike when reaching threshold. The 240 cortical units produce either excitatory or inhibitory post-synaptic potentials in their target units. In addition to the experimentally observed conditioning effects, the model also allows computation of underlying network behavior not originally documented. Furthermore, the model makes predictions about outcomes from protocols not yet investigated, including spike-triggered inhibition, gamma-triggered stimulation and disynaptic conditioning. The success of the simulations suggests that a simple voltage-based IF model incorporating STDP can capture the essential mechanisms mediating targeted plasticity with closed-loop stimulation.

scholarly journals Effects of spatiotemporal stimulus properties on spike timing correlations in owl monkey primary somatosensory cortex

2012 ◽  
Vol 108 (12) ◽  
pp. 3353-3369 ◽  
Author(s):  
Jamie L. Reed ◽  
Pierre Pouget ◽  
Hui-Xin Qi ◽  
Zhiyi Zhou ◽  
Melanie R. Bernard ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Stimulus Onset ◽  
Spike Timing ◽  
Primary Somatosensory Cortex ◽  
Spatial Proximity ◽  
Electrode Arrays ◽  
Paired Stimuli ◽  
Tactile Stimuli ◽  
Source Of Information

The correlated discharges of cortical neurons in primary somatosensory cortex are a potential source of information about somatosensory stimuli. One aspect of neuronal correlations that has not been well studied is how the spatiotemporal properties of tactile stimuli affect the presence and magnitude of correlations. We presented single- and dual-point stimuli with varying spatiotemporal relationships to the hands of three anesthetized owl monkeys and recorded neuronal activity from 100-electrode arrays implanted in primary somatosensory cortex. Correlation magnitudes derived from joint peristimulus time histogram (JPSTH) analysis of single neuron pairs were used to determine the level of spike timing correlations under selected spatiotemporal stimulus conditions. Correlated activities between neuron pairs were commonly observed, and the proportions of correlated pairs tended to decrease with distance between the recorded neurons. Distance between stimulus sites also affected correlations. When stimuli were presented simultaneously at two sites, ∼37% of the recorded neuron pairs showed significant correlations when adjacent phalanges were stimulated, and ∼21% of the pairs were significantly correlated when nonadjacent digits were stimulated. Spatial proximity of paired stimuli also increased the average correlation magnitude. Stimulus onset asynchronies in the paired stimuli had small effects on the correlation magnitude. These results show that correlated discharges between neurons at the first level of cortical processing provide information about the relative locations of two stimuli on the hand.

Sign in / Sign up

Export Citation Format

Share Document