Central auditory system plasticity: Generalization to novel stimuli following listening training

Tremblay, Kelly L.; Kraus, Nina; Carrell, Thomas D.; McGee, Therese

doi:10.1121/1.420139

Cited by 262 publications

(242 citation statements)

References 56 publications

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“…For example, after conditioning, 42% of sites showed significant response facilitation to the noise preceded by only one of the two tones (i.e., to one or the other of the Degraded Sequences), compared with 19% in controls (P Ͻ 0.05). The tolerance of these sites to some variation from the original sequence is likely to be indicative of the spectrotemporal receptive field plasticity responsible for context-dependent facilitation and may contribute to behavioral generalization of complex stimuli (28)(29)(30).…”

Section: Resultsmentioning

confidence: 99%

Order-sensitive plasticity in adult primary auditory cortex

Kilgard¹,

Merzenich²

2002

Proc. Natl. Acad. Sci. U.S.A.

107

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The neural response to a stimulus presented as part of a rapid sequence is often quite different from the response to the same stimulus presented in isolation. In primary auditory cortex (A1), although the most common effect of preceding stimuli is inhibitory, most neurons can also exhibit response facilitation if the appropriate spectral and temporal separation of sequence elements is presented. In this study, we investigated whether A1 neurons in adult animals can develop context-dependent facilitation to a novel acoustic sequence. After repeatedly pairing electrical stimulation of the basal forebrain with a three-element sequence (high frequency tone-low frequency tone-noise burst), 25% of A1 neurons exhibited facilitation to the low tone when preceded by the high tone, compared with only 5% in controls. In contrast, there was no increase in the percent of sites that showed facilitation for the reversed tone order (low preceding high). Nearly 60% of sites exhibited a facilitated response to the noise burst when preceded by the two tones. Although facilitation was greatest in response to the paired sequence, facilitation also generalized to related sequences that were either temporally distorted or missing one of the tones. Pairing basal forebrain stimulation with the acoustic sequence also caused a decrease in the time to peak response and an increase in population discharge synchrony, which was not seen after pairing simple tones, tone trains, or broadband stimuli. These results indicate that contextdependent facilitation and response synchronization can be substantially altered in an experience-dependent fashion and provide a potential mechanism for learning spectrotemporal patterns.M ore than 90% of primary auditory cortex (A1) neurons exhibit context-dependent facilitation to some combination of tones (1-5). Facilitated responses are most frequent when the two tones are separated by 1 octave and 100 ms. Although recent work has shown that context-dependent facilitation is common in both real and simulated neural networks (3, 5-7), it is not yet clear how this facilitation contributes to the coding of sensory streams rich in spectrotemporal transitions, such as music and speech. Auditory neurons in many species, including humans, exhibit facilitated responses to species-specific vocalizations (8-15). Experience-dependent plasticity mechanisms are known to sharpen the neural representation of behaviorally relevant stimuli (16)(17)(18)(19).Previous studies have shown that cortical receptive fields and temporal response properties can be substantially reorganized in an experience-dependent manner as a result of behavioral training or basal forebrain (BF) stimulation (20-26). The demonstration that cortical selectivity for simple stimuli remains plastic throughout adulthood has provided important insight into both the mechanisms and functional consequences of cortical plasticity. In this study, we used BF stimulation to explore how cortical plasticity contributes to the coding of spectrotemporally complex acou...

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Section: Resultsmentioning

confidence: 99%

Order-sensitive plasticity in adult primary auditory cortex

Kilgard¹,

Merzenich²

2002

Proc. Natl. Acad. Sci. U.S.A.

107

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“…Although AV training has not been investigated to date, auditory training has been shown to impact early cortical components of auditory-evoked potentials in young adults and language-impaired children. NH adults who were trained to discriminate small differences in syllable contrasts, such as voice onset times, showed training-related increases in P1 and N1 peak amplitudes and mismatch negativity components (Tremblay et al 1997(Tremblay et al , 2001. A subsequent study suggested that the capacity for short-term training-related plasticity may be greatest in the right hemisphere (Tremblay & Kraus 2002).…”

Section: Implications For Rehabilitation and Researchmentioning

confidence: 99%

Audiovisual Deficits in Older Adults with Hearing Loss: Biological Evidence

Musacchia

Arum²,

Nicol³

et al. 2009

Ear &Amp; Hearing

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Objective:To examine the impact of hearing loss (HL) on audiovisual (AV) processing in the aging population. We hypothesized that agerelated HL would have a pervasive effect on sensory processing, extending beyond the auditory domain. Specifically, we predicted that decreased auditory input to the neural system, in the form of HL over time, would have deleterious effects on multisensory mechanisms. Design:This study compared AV processing between older adults with normal hearing (N ϭ 12) and older adults with mild to moderate sensorineural HL (N ϭ 12). To do this, we recorded cortical evoked potentials that were elicited by watching and listening to recordings of a speaker saying the syllable "bi." Stimuli were presented in three conditions: when hearing the syllable "bi" (auditory), when viewing a person say "bi" (visual), and when seeing and hearing the syllables simultaneously (AV). Presentation level of the auditory stimulus was set to ϩ30 dB SL for each listener to equalize auditory input across groups. Results:In the AV condition, the normal-hearing group showed a clear and consistent decrease in P1 and N1 latencies as well as a reduction in P1 amplitude compared with the sum of the unimodal components (auditory ϩ visual). These integration effects were absent or less consistent in HL participants.Conclusions: Despite controlling for auditory sensation level, visual influence on auditory processing was significantly less pronounced in HL individuals compared with controls, indicating diminished AV integration in this population. These results demonstrate that HL has a deleterious effect on how older adults combine what they see and hear. Although auditory amplification vastly improves the communication abilities in most HLs, the associated atrophy of multisensory mechanisms may contribute to a patient's difficulty in everyday settings. Our findings and related studies emphasize the potential value of multimodal tasks and stimuli in the assessment and rehabilitation of hearing impairments.

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“…For example, unilateral sound deprivation in adolescent ferrets has been shown to lead to subcortical changes (Moore, 1993), whereas frequency discrimination training in monkeys has been shown to produce alterations in the auditory cortex associated with changes in discrimination ability (Recanzone et al, 1993). When humans have been trained to discriminate speech sounds, changes in preattentive auditory neurophysiologic responses have been linked to perceptual changes (Kraus et al, 1995;Tremblay et al, 1997Tremblay et al, , 1998.…”

Section: Introductionmentioning

confidence: 99%