Synaptic plasticity as a cortical coding scheme

Abstract

Processing of auditory information requires constant adjustment due to alterations of the environment and changing conditions in the nervous system with age, health, and experience. Consequently, patterns of activity in cortical networks have complex dynamics over a wide range of timescales, from milliseconds to days and longer. In the primary auditory cortex (AI), multiple forms of adaptation and plasticity shape synaptic input and action potential output. However, the variance of neuronal responses has made it difficult to characterize AI receptive fields and to determine the function of AI in processing auditory information such as vocalizations. Here we describe recent studies on the temporal modulation of cortical responses and consider the relation of synaptic plasticity to neural coding.

Impaired auditory processing and altered structure of the endbulb of Held synapse in mice lacking the GluA3 subunit of AMPA receptors

“…The auditory system is able to adapt to changing conditions during development, aging and auditory experience (Brugge, 1992; Kandler et al, 2009; Froemke and Schreiner, 2015). Auditory experience can drive changes in sensory processing mechanisms in developing and adult auditory systems (Fallon et al, 2008; Syka, 2002).…”

Contrast Enhancement without Transient Map Expansion for Species-Specific Vocalizations in Core Auditory Cortex during Learning

“…Plasticity in AC, whether at the level of maps or not, is generally thought to be a key mechanism for perceptual learning (Polley et al, 2006; Froemke and Schreiner, 2015). Map plasticity seems to be more robust when the perceptual cue being learned depends on the onset of the sound (Bieszczad and Weinberger, 2010c), which in most laboratory conditioning paradigms is a pure tone of a single specific frequency.…”

How neuroscience can inform the study of individual differences in cognitive abilities

“…For example, auditory stimulus sequences such as those found in speech vary over time and thus require integration of information beyond the immediate input. The receptive fields of units in auditory cortex have spectral-temporal tuning characteristics (Froemke and Schreiner, 2015) making them appropriate for encoding time-varying signals. Thorson et al (2015) have described how neurons modeled as recursive filters with short term plasticity are better able to account for sensory tuning properties of auditory neurons than simple linear filters.…”

“…These extensive feedback pathways provide a basis for the construction of recursive spatial-temporal filters that can extract different types of information from the visual input depending upon their connectivity (Fregnac and Bathellier, 2015). Grossberg (2013) has modeled a number of recursive neural circuits that can account for numerous details of vision as well as other aspects of brain function such as speech and cognition.…”