scholarly journals Perceptual learning and adult cortical plasticity

2009 ◽  
Vol 587 (12) ◽  
pp. 2743-2751 ◽  
Author(s):  
Charles D. Gilbert ◽  
Wu Li ◽  
Valentin Piech
Keyword(s):  
Perceptual Learning ◽  
Cortical Plasticity

scholarly journals Perceptual learning and sensomotor flexibility: cortical plasticity under attentional control?

2008 ◽  
Vol 364 (1515) ◽  
pp. 313-319 ◽  
Author(s):  
Manfred Fahle
Keyword(s):  
Perceptual Learning ◽  
Cortical Plasticity ◽  
Signal To Noise Ratio ◽  
Receptive Fields ◽  
Intraocular Lenses ◽  
Top Down ◽  
Multifocal Intraocular Lenses ◽  
Sensory Cortices ◽  
Perceptual Abilities ◽  
Selection Of

Recent research reveals long-lasting cortical plasticity of early sensory cortices even in adults. Sensory signals could be modified under top-down control if necessary quite early in order to optimize their signal-to-noise ratio, leading to ‘low level’ or ‘early’ perceptual learning (PL). For easy tasks, such elaborate top-down influences are usually not required, and learning is restricted to late selection of the appropriate signals on higher cortical levels, which seems easier and faster to achieve. But to reach the absolute limits of sensory performance, PL seems to optimize the entire chain of sensory processing. Hence, improvement for these extreme perceptual abilities is quite specific for a number of stimulus parameters, such as the position in the visual field and sometimes even the trained eye, reflecting the specificity of receptive fields in early sensory cortices. Early PL may be just one example—even if a very extensive one—of the mechanisms of neuronal plasticity and sensomotor flexibility that are constantly updating our sensomotor representations as a result of experience. As an illustration, this review contains some new experimental results on PL and sensory flexibility in the context of adaptation to multifocal intraocular lenses.

scholarly journals Synaptic Mechanisms of Top-Down Control by The Auditory Cortico-Collicular Pathway

2021 ◽  
Author(s):  
Hannah M Oberle ◽  
Alex Ford ◽  
Jordyn Czarny ◽  
Pierre F. Apostolides
Keyword(s):  
Perceptual Learning ◽  
Cortical Plasticity ◽  
Auditory Pathway ◽  
Descending Pathways ◽  
Cellular Mechanisms ◽  
Feature Selectivity ◽  
Patch Clamp Electrophysiology ◽  
Acoustic Responses

Corticofugal projections to evolutionarily ancient, sub-cortical structures are ubiquitous across mammalian sensory systems. These descending pathways enable the neocortex to control ascending sensory representations in a predictive or feedback manner, but the underlying cellular mechanisms are poorly understood. Here we combine optogenetic approaches with in vivo and in vitro patch-clamp electrophysiology to study the projection from auditory cortex to the inferior colliculus (IC), a major descending auditory pathway that controls IC neuron feature selectivity, plasticity and auditory perceptual learning. Although individual auditory cortico-collicular synapses were generally weak, IC neurons often integrated inputs from multiple corticofugal axons that generated reliable, tonic depolarizations even during prolonged presynaptic activity. Latency measurements in vivo showed that descending signals reach the IC within 30 ms of sound onset, which in IC neurons corresponded to the peak of synaptic depolarizations evoked by short sounds. Activating ascending and descending pathways at latencies expected in vivo caused a NMDA receptor dependent, supra-linear EPSP summation, indicating that descending signals can non-linearly amplify moment-to-moment acoustic responses. Our results shed light upon the synaptic bases of descending sensory control, and imply that heterosynaptic cooperativity contributes to sub-cortical plasticity and perceptual learning.

Perceptual Learning of Vocoded Speech With and Without Contralateral Hearing: Implications for Cochlear Implant Rehabilitation

2020 ◽  
pp. 1-10
Author(s):  
Martin Chavant ◽  
Alexis Hervais-Adelman ◽  
Olivier Macherey
Keyword(s):  
Cochlear Implant ◽  
Perceptual Learning ◽  
Speech Signal ◽  
Training Phase ◽  
Monosyllabic Words ◽  
Low Pass ◽  
Contralateral Ear ◽  
Number Of Individuals ◽  
Insight Into ◽  
Vocoded Speech

Purpose An increasing number of individuals with residual or even normal contralateral hearing are being considered for cochlear implantation. It remains unknown whether the presence of contralateral hearing is beneficial or detrimental to their perceptual learning of cochlear implant (CI)–processed speech. The aim of this experiment was to provide a first insight into this question using acoustic simulations of CI processing. Method Sixty normal-hearing listeners took part in an auditory perceptual learning experiment. Each subject was randomly assigned to one of three groups of 20 referred to as NORMAL, LOWPASS, and NOTHING. The experiment consisted of two test phases separated by a training phase. In the test phases, all subjects were tested on recognition of monosyllabic words passed through a six-channel “PSHC” vocoder presented to a single ear. In the training phase, which consisted of listening to a 25-min audio book, all subjects were also presented with the same vocoded speech in one ear but the signal they received in their other ear differed across groups. The NORMAL group was presented with the unprocessed speech signal, the LOWPASS group with a low-pass filtered version of the speech signal, and the NOTHING group with no sound at all. Results The improvement in speech scores following training was significantly smaller for the NORMAL than for the LOWPASS and NOTHING groups. Conclusions This study suggests that the presentation of normal speech in the contralateral ear reduces or slows down perceptual learning of vocoded speech but that an unintelligible low-pass filtered contralateral signal does not have this effect. Potential implications for the rehabilitation of CI patients with partial or full contralateral hearing are discussed.

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