Spectral Features Control Temporal Plasticity in Auditory Cortex

Kilgard, Michael P.; Pandya, Pritesh K.; Vazquez, Jessica; Rathbun, Daniel L.; Engineer, Navzer D.; Moucha, Raluca

doi:10.1159/000046832

Cited by 20 publications

(15 citation statements)

References 49 publications

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“…In contrast, pairing the high-low-noise sequence with the same BF activation did not significantly alter either cortical topography or frequency bandwidth (data not shown). In addition, BF-sequence pairing led to shorter response latencies and increased population discharge synchrony that was not observed in any of the four earlier studies with simple tones or broadband stimuli (23)(24)(25)(26). The average time to peak (see Methods) was decreased by 3 ms after BF-sequence pairing (15.2 vs. 18.2 ms, P Ͻ 0.00001, Fig.…”

Section: Increased Response Synchronizationmentioning

confidence: 52%

“…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)(21)(22)(23)(24)(25)(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.…”

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confidence: 99%

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Order-sensitive plasticity in adult primary auditory cortex

Kilgard¹,

Merzenich²

2002

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

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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: Increased Response Synchronizationmentioning

confidence: 52%

mentioning

confidence: 99%

Order-sensitive plasticity in adult primary auditory cortex

Kilgard¹,

Merzenich²

2002

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

Self Cite

107

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“…However, changes in spontaneous activity are not always observed in animals exposed to nucleus basalis stimulation. Pairing a single tone did not significantly alter spontaneous activity in any region of A1 (Kilgard et al, 2001b). In contrast, spontaneous activity was reduced when seven different tones distributed across the rat frequency range were randomly interleaved and paired with nucleus basalis stimulation (Kilgard et al, 2001b).…”

Section: Experiential Specificitymentioning

confidence: 69%

“…Pairing a single tone did not significantly alter spontaneous activity in any region of A1 (Kilgard et al, 2001b). In contrast, spontaneous activity was reduced when seven different tones distributed across the rat frequency range were randomly interleaved and paired with nucleus basalis stimulation (Kilgard et al, 2001b). Collectively these nucleus basalis induced plasticity studies suggest that the pattern of acoustic experience may also be important in determining the level of spontaneous activity.…”

Section: Experiential Specificitymentioning

confidence: 86%

“…Pairing either an FM sweep or a train of simple tones increased response strength and decreased the mean onset latency (Kilgard et al, 2001a;Mercado et al, 2001;Moucha et al, in press). Pairing complex stimuli, such as a spectral ripple or a tone-tone-noise sequence, decreased latency without affecting response strength (Kilgard and Merzenich, 2002;Kilgard et al, 2001b). No changes in response strength or latency were noted after two nearby tones were paired with NB stimulation.…”

Section: Changes In Cortical Excitability and Latencymentioning

confidence: 98%

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Asynchronous inputs alter excitability, spike timing, and topography in primary auditory cortex

Pandya¹,

Moucha²,

Engineer³

et al. 2005

Hearing Research

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Correlation-based synaptic plasticity provides a potential cellular mechanism for learning and memory. Studies in the visual and somatosensory systems have shown that behavioral and surgical manipulation of sensory inputs leads to changes in cortical organization that are consistent with the operation of these learning rules. In this study, we examine how the organization of primary auditory cortex (A1) is altered by tones designed to decrease the average input correlation across the frequency map. After one month of separately pairing nucleus basalis stimulation with 2 and 14 kHz tones, a greater proportion of A1 neurons responded to frequencies below 2 kHz and above 14 kHz. Despite the expanded representation of these tones, cortical excitability was specifically reduced in the high and low frequency regions of A1, as evidenced by increased neural thresholds and decreased response strength. In contrast, in the frequency region between the two paired tones, driven rates were unaffected and spontaneous firing rate was increased. Neural response latencies were increased across the frequency map when nucleus basalis stimulation was associated with asynchronous activation of the high and low frequency regions of A1. This set of changes did not occur when pulsed noise bursts were paired with nucleus basalis stimulation. These results are consistent with earlier observations that sensory input statistics can shape cortical map organization and spike timing.

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