Limits...
The role of inhibition in a computational model of an auditory cortical neuron during the encoding of temporal information.

Bendor D - PLoS Comput. Biol. (2015)

Bottom Line: Using a computational neuronal model, we find that stimulus-locked responses are generated when sound-evoked excitation is combined with strong, delayed inhibition.In contrast to this, a non-synchronized rate representation is generated when the net excitation evoked by the sound is weak, which occurs when excitation is coincident and balanced with inhibition.Together these data suggest that feedforward inhibition provides a parsimonious explanation of the neural coding dichotomy observed in auditory cortex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, United Kingdom.

ABSTRACT
In auditory cortex, temporal information within a sound is represented by two complementary neural codes: a temporal representation based on stimulus-locked firing and a rate representation, where discharge rate co-varies with the timing between acoustic events but lacks a stimulus-synchronized response. Using a computational neuronal model, we find that stimulus-locked responses are generated when sound-evoked excitation is combined with strong, delayed inhibition. In contrast to this, a non-synchronized rate representation is generated when the net excitation evoked by the sound is weak, which occurs when excitation is coincident and balanced with inhibition. Using single-unit recordings from awake marmosets (Callithrix jacchus), we validate several model predictions, including differences in the temporal fidelity, discharge rates and temporal dynamics of stimulus-evoked responses between neurons with rate and temporal representations. Together these data suggest that feedforward inhibition provides a parsimonious explanation of the neural coding dichotomy observed in auditory cortex.

No MeSH data available.


Related in: MedlinePlus

Dependence on input parameters of computational model.Classification of neuron-type [non-sync (o), sync (x), mixed (+), atypical (square)] across all three parameters (I-E delay, Excitatory input, and I/E ratio). If pure tone responses were less than 1 spk/s or greater than 50 spk/s, neurons were considered to have responses outside the allowable range (cyan) and were not included in our analysis.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4400160&req=5

pcbi.1004197.g003: Dependence on input parameters of computational model.Classification of neuron-type [non-sync (o), sync (x), mixed (+), atypical (square)] across all three parameters (I-E delay, Excitatory input, and I/E ratio). If pure tone responses were less than 1 spk/s or greater than 50 spk/s, neurons were considered to have responses outside the allowable range (cyan) and were not included in our analysis.

Mentions: What determines whether a neuron encodes an acoustic pulse train using a temporal and/or a rate representation? We observed that synchronized, non-synchronized, and mixed responses were generated within three distinct regions of the model’s parameter space (Fig. 3).


The role of inhibition in a computational model of an auditory cortical neuron during the encoding of temporal information.

Bendor D - PLoS Comput. Biol. (2015)

Dependence on input parameters of computational model.Classification of neuron-type [non-sync (o), sync (x), mixed (+), atypical (square)] across all three parameters (I-E delay, Excitatory input, and I/E ratio). If pure tone responses were less than 1 spk/s or greater than 50 spk/s, neurons were considered to have responses outside the allowable range (cyan) and were not included in our analysis.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400160&req=5

pcbi.1004197.g003: Dependence on input parameters of computational model.Classification of neuron-type [non-sync (o), sync (x), mixed (+), atypical (square)] across all three parameters (I-E delay, Excitatory input, and I/E ratio). If pure tone responses were less than 1 spk/s or greater than 50 spk/s, neurons were considered to have responses outside the allowable range (cyan) and were not included in our analysis.
Mentions: What determines whether a neuron encodes an acoustic pulse train using a temporal and/or a rate representation? We observed that synchronized, non-synchronized, and mixed responses were generated within three distinct regions of the model’s parameter space (Fig. 3).

Bottom Line: Using a computational neuronal model, we find that stimulus-locked responses are generated when sound-evoked excitation is combined with strong, delayed inhibition.In contrast to this, a non-synchronized rate representation is generated when the net excitation evoked by the sound is weak, which occurs when excitation is coincident and balanced with inhibition.Together these data suggest that feedforward inhibition provides a parsimonious explanation of the neural coding dichotomy observed in auditory cortex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, United Kingdom.

ABSTRACT
In auditory cortex, temporal information within a sound is represented by two complementary neural codes: a temporal representation based on stimulus-locked firing and a rate representation, where discharge rate co-varies with the timing between acoustic events but lacks a stimulus-synchronized response. Using a computational neuronal model, we find that stimulus-locked responses are generated when sound-evoked excitation is combined with strong, delayed inhibition. In contrast to this, a non-synchronized rate representation is generated when the net excitation evoked by the sound is weak, which occurs when excitation is coincident and balanced with inhibition. Using single-unit recordings from awake marmosets (Callithrix jacchus), we validate several model predictions, including differences in the temporal fidelity, discharge rates and temporal dynamics of stimulus-evoked responses between neurons with rate and temporal representations. Together these data suggest that feedforward inhibition provides a parsimonious explanation of the neural coding dichotomy observed in auditory cortex.

No MeSH data available.


Related in: MedlinePlus