In Search of the Neural Underpinnings of Temporal Binding: Linking Synaptic Depression with Neural Adaptation in Auditory Cortex
Final Report Abstract
Most sounds only make sense in their immediate temporal context. Therefore, the brain’s ability to represent the temporal evolution of sounds is of central importance in auditory processing. This requires short-term memory where incoming sounds are associated with a repeatedly updated representation of the immediate past. The neural basis of auditory short-term memory is still open, although recent research points to auditory cortex (AC) as the key site in the auditory system and to short-term synaptic depression (STSD) of neuronal transmission as one of its key mechanisms. To explore how the architecture of AC and STSD contribute to auditory short-term memory, we integrated computational modelling of AC with experimental data from the AC of monkeys and humans. In all three approaches, we explored the effect of stimulus history on AC activity in terms of the adaptation time constant that describes the recovery of AC responses to repeated stimulation with the same stimulus. Systematic variations of parameter values revealed that the model output matches the experimentally determined response of AC recorded with MEG very well. We showed that optimal model parameter values could be estimated by combining the AC model with an advanced evolutionary algorithm. Further, our simulations suggest that the recovery time constant from adaptation varies substantially between the different AC fields in the model. In experiments with humans and monkeys, we could verify some model predictions. In Magnetoencephalographie (MEG) recordings, we found that adaptation lifetimes differ between left and right AC of humans, implicitly supporting the modelling result of different recovery time constants of AC fields. Recordings from monkey AC revealed that individual neurons show a variety of dependencies on stimulus history. About one third of the neurons investigated showed a stimulus-history dependency similar to the one in large-scale neuronal populations observed with MEG. Neuronal recovery time constants varied over a wide range and compared well to those observed with MEG. In contrast to model predictions, no significant differences of the recovery time constant between neurons from different AC fields were observed. Furthermore, the recovery time constant did not vary systematically with sound characteristics.
Publications
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Layer-Specific Intracortical Amplification Shortens the Lifetime of Thalamocortical Repetition Suppression in Auditory Cortex. Springer Science and Business Media LLC.
Ma, Jing; Brunk, Michael; Matysiak, Artur; Härtwich, Nina; Ohl, Frank; May, Patrick; Happel, Max; König, Reinhard & Deliano, Matthias
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Adaptation in primate auditory cortex: results from multiunit recordings based on predictions from computational modelling. Poster at the 7th Int. Conf. on Auditory Cortex, Magdeburg
Zare A.; May P. J. C.; Marosi E. L.; Dar A. H.; König R. & Brosch M.
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Optimisation of an auditory cortex model via an evolutionary algorithm. Poster at the 7th Int. Conf. on Auditory Cortex, Magdeburg
Turczak 1 E.; Härtwich N.; Rozmarynowski A.; König R.; May P. J. C. & Sielużycki C.
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Hemispheric differences in time constants of auditory adaptation in humans using Magnetoencephalography. Poster at the 7th Int. Conf. on Auditory Cortex, Magdeburg
Dar A. H.; Härtwich N.; Hajizadeh A.; Zare A.; Brosch M.; May P. J. C. & König R.
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Optimising a computational model of human auditory cortex with an evolutionary algorithm. Hearing Research, 439, 108879.
Tomana, Ewelina; Härtwich, Nina; Rozmarynowski, Adam; König, Reinhard; May, Patrick J.C. & Sielużycki, Cezary
