Context-dependent modulation of auditory processing by serotonin

Abstract

Context-dependent plasticity in auditory processing is achieved in part by physiological mechanisms that link behavioral state to neural responses to sound. The neuromodulator serotonin has many characteristics suitable for such a role. Serotonergic neurons are extrinsic to the auditory system but send projections to most auditory regions. These projections release serotonin during particular behavioral contexts. Heightened levels of behavioral arousal and specific extrinsic events, including stressful or social events, increase serotonin availability in the auditory system. Although the release of serotonin is likely to be relatively diffuse, highly specific effects of serotonin on auditory neural circuitry are achieved through the localization of serotonergic projections, and through a large array of receptor types that are expressed by specific subsets of auditory neurons. Through this array, serotonin enacts plasticity in auditory processing in multiple ways. Serotonin changes the responses of auditory neurons to input through the alteration of intrinsic and synaptic properties, and alters both short- and long-term forms of plasticity. The infrastructure of the serotonergic system itself is also plastic, responding to age and cochlear trauma. These diverse findings support a view of serotonin as a widespread mechanism for behaviorally relevant plasticity in the regulation of auditory processing. This view also accommodates models of how the same regulatory mechanism can have pathological consequences for auditory processing.

Depressive State and Auditory Brainstem Response a Tentative Future Method for Diagnosis and Pharmacological Control of Depression

“…The impetus to investigate ABR and depression also comes from the fact that Serotonins have an influence on the auditory sorting processing by direct connections of neurons from the raphae nuclei to diverse nuclei of the auditory pathway [15]. In preliminary ABR studies regarding depression, we could not find any significant group differences for depressive/healthy subjects by comparisons of amplitudes and latencies of the ABR waves I to VII.…”

“…It may be further enhanced by changing the stimuli to incite reactions in specific serotonin/adrenalin regulating functions in the auditory pathway; and to go deeper in analysisboth phenomenologically and technically [15].…”

Sex Differences in Forebrain Monoaminergic Response to Song Performance

“…Serotonin may be an important modulator of auditory sensitivity [Hurley et al, 2004;Shepard et al, 2013]. Researchers have made great strides in understanding the modulatory effects of serotonin in the mammalian auditory system [Hurley and Hall, 2011]. In bats, adding serotonin to the auditory midbrain decreases responses to conspecific vocalizations in most neurons but enhances the response in a select number of neurons.…”

“…Within perceptual centers of the brain, monoamines are implicated in modulating aspects of perception and sensory processing. Monoamines, which include serotonin, dopamine, and norepinephrine, function by integrating information about the internal state of the individual with information about external stimuli [Bao et al, 2001;Berridge and Waterhouse, 2003;Hurley et al, 2004;Castelino and Schmidt, 2010;Hurley and Hall, 2011]. Serotonin facilitates sensory encoding in mammalian auditory systems [Hurley and Hall, 2011].…”

“…Monoamines, which include serotonin, dopamine, and norepinephrine, function by integrating information about the internal state of the individual with information about external stimuli [Bao et al, 2001;Berridge and Waterhouse, 2003;Hurley et al, 2004;Castelino and Schmidt, 2010;Hurley and Hall, 2011]. Serotonin facilitates sensory encoding in mammalian auditory systems [Hurley and Hall, 2011]. Dopamine is involved in regulating learning and neuroplasticity [Bao et al, 2001] and in encoding aspects of stimulus reward [Berridge and Robinson, 1998;Maney, 2013].…”