Aspects of Temporal Processing of FM Stimuli in Primary Auditory Cortex

The anatomy and connectivity of the primate auditory cortex has been modeled as a core region receiving direct thalamic input surrounded by a belt of secondary fields. The core contains multiple tonotopic fields (including the primary auditory cortex, AI, and the rostral field, R), but available data only partially address the degree to which those fields are functionally distinct. This report, based on single-unit recordings across four hemispheres in awake macaques, argues that the functional organization of auditory cortex is best understood in terms of temporal processing. Frequency tuning, response threshold, and strength of activation are similar between AI and R, validating their inclusion as a unified core, but the temporal properties of the fields clearly differ. Onset latencies to pure tones are longer in R (median, 33 ms) than in AI (20 ms); moreover, synchronization of spike discharges to dynamic modulations of stimulus amplitude and frequency, similar to those present in macaque and human vocalizations, suggest distinctly different windows of temporal integration in AI (20–30 ms) and R (100 ms). Incorporating data from the adjacent auditory belt reveals that the divergence of temporal properties within the core is in some cases greater than the temporal differences between core and belt.

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Fast Inhibitory Decay Facilitates Adult-like Temporal Processing in Layer 5 of Developing Primary Auditory Cortex

Cerebral Cortex ◽

10.1093/cercor/bhx284 ◽

2017 ◽

Vol 28 (12) ◽

pp. 4319-4335 ◽

Cited By ~ 1

Author(s):

Fenghua Xie ◽

Ling You ◽

Dongqin Cai ◽

Miaomiao Liu ◽

Yin Yue ◽

...

Keyword(s):

Auditory Cortex ◽

Temporal Processing ◽

Primary Auditory Cortex

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Feeling the beat: an investigation into the neural correlates of vibrotactile beat perception

10.32920/ryerson.14643864 ◽

2021 ◽

Author(s):

Sean A. Gilmore

Keyword(s):

Auditory Cortex ◽

Temporal Processing ◽

Statistical Difference ◽

Primary Auditory Cortex ◽

Neural Correlates ◽

Neural Signal ◽

Neural Data ◽

Neural Entrainment ◽

Eeg Recordings

The current study investigates our ability to perceive and synchronize movements to the beat of rhythms presented through vibrations to the skin. I compared EEG recordings and tapping accuracy to rhythms that varied in modality: auditory-only, vibrotactile, multimodal (vibrotactile and auditory) and complexity: metronome and simple rhythms. The neural data showed that signals localized to the primary auditory cortex showed a larger spike in power at beat frequencies presentation of auditory compared to vibrotactile rhythms. Tapping ability was found to be lowest in vibrotactile compared to auditory and multimodal rhythms. Auditory only and multimodal rhythms did not show a statistical difference in the neural or tapping data. Tapping variability predicted neural entrainment, such that more variable tapping elicited a more entrained neural signal in primary auditory cortex, and less in pre-motor regions. In conclusion, these results show how the temporal processing of rhythm is superior in auditory modalities.

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Perceptual Training Restores Impaired Cortical Temporal Processing Due to Lead Exposure

Cerebral Cortex ◽

10.1093/cercor/bhu258 ◽

2014 ◽

Vol 26 (1) ◽

pp. 334-345 ◽

Cited By ~ 11

Author(s):

Xiaoqing Zhu ◽

Xia Liu ◽

Fanfan Wei ◽

Fang Wang ◽

Michael M. Merzenich ◽

...

Keyword(s):

Auditory Cortex ◽

Lead Exposure ◽

Temporal Processing ◽

Repetition Rate ◽

Discrimination Task ◽

Primary Auditory Cortex ◽

Perceptual Training ◽

Auditory Temporal Processing ◽

Low Level ◽

Rate Discrimination

Abstract Low-level lead exposure is a risk factor for cognitive and learning disabilities in children and has been specifically associated with deficits in auditory temporal processing that impair aural language and reading abilities. Here, we show that rats exposed to low levels of lead in early life display a significant behavioral impairment in an auditory temporal rate discrimination task. Lead exposure also results in a degradation of the neuronal repetition-rate following capacity and response synchronization in primary auditory cortex. A modified go/no-go repetition-rate discrimination task applied in adult animals for ∼50 days nearly restores to normal these lead-induced deficits in cortical temporal fidelity. Cortical expressions of parvalbumin, brain-derived neurotrophic factor, and NMDA receptor subunits NR2a and NR2b, which are down-regulated in lead-exposed animals, are also partially reversed with training. These studies in an animal model identify the primary auditory cortex as a novel target for low-level lead exposure and demonstrate that perceptual training can ameliorate lead-induced deficits in cortical discrimination between sound sequences.

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Passive stimulation and behavioral training differentially transform temporal processing in the inferior colliculus and primary auditory cortex

Journal of Neurophysiology ◽

10.1152/jn.00392.2016 ◽

2017 ◽

Vol 117 (1) ◽

pp. 47-64 ◽

Cited By ~ 12

Author(s):

Maike Vollmer ◽

Ralph E. Beitel ◽

Christoph E. Schreiner ◽

Patricia A. Leake

Keyword(s):

Auditory Cortex ◽

Inferior Colliculus ◽

Temporal Processing ◽

Electric Stimulation ◽

Primary Auditory Cortex ◽

Central Nucleus ◽

Electrophysiological Recording ◽

Response Patterns ◽

Behavioral Training ◽

Auditory Midbrain

In profoundly deaf cats, behavioral training with intracochlear electric stimulation (ICES) can improve temporal processing in the primary auditory cortex (AI). To investigate whether similar effects are manifest in the auditory midbrain, ICES was initiated in neonatally deafened cats either during development after short durations of deafness (8 wk of age) or in adulthood after long durations of deafness (≥3.5 yr). All of these animals received behaviorally meaningless, “passive” ICES. Some animals also received behavioral training with ICES. Two long-deaf cats received no ICES prior to acute electrophysiological recording. After several months of passive ICES and behavioral training, animals were anesthetized, and neuronal responses to pulse trains of increasing rates were recorded in the central (ICC) and external (ICX) nuclei of the inferior colliculus. Neuronal temporal response patterns (repetition rate coding, minimum latencies, response precision) were compared with results from recordings made in the AI of the same animals (Beitel RE, Vollmer M, Raggio MW, Schreiner CE. J Neurophysiol 106: 944–959, 2011; Vollmer M, Beitel RE. J Neurophysiol 106: 2423–2436, 2011). Passive ICES in long-deaf cats remediated severely degraded temporal processing in the ICC and had no effects in the ICX. In contrast to observations in the AI, behaviorally relevant ICES had no effects on temporal processing in the ICC or ICX, with the single exception of shorter latencies in the ICC in short-deaf cats. The results suggest that independent of deafness duration passive stimulation and behavioral training differentially transform temporal processing in auditory midbrain and cortex, and primary auditory cortex emerges as a pivotal site for behaviorally driven neuronal temporal plasticity in the deaf cat. NEW & NOTEWORTHY Behaviorally relevant vs. passive electric stimulation of the auditory nerve differentially affects neuronal temporal processing in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (AI) in profoundly short-deaf and long-deaf cats. Temporal plasticity in the ICC depends on a critical amount of electric stimulation, independent of its behavioral relevance. In contrast, the AI emerges as a pivotal site for behaviorally driven neuronal temporal plasticity in the deaf auditory system.

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Behavioral training restores temporal processing in auditory cortex of long-deaf cats

Journal of Neurophysiology ◽

10.1152/jn.00565.2011 ◽

2011 ◽

Vol 106 (5) ◽

pp. 2423-2436 ◽

Cited By ~ 21

Author(s):

Maike Vollmer ◽

Ralph E. Beitel

Keyword(s):

Auditory Cortex ◽

Temporal Processing ◽

Cortical Neurons ◽

Primary Auditory Cortex ◽

Spike Timing ◽

Cochlear Prosthesis ◽

Behavioral Training ◽

Stimulus Rate ◽

Spiral Ganglion Cell

Temporal auditory processing is poor in prelingually hearing-impaired patients fitted with cochlear prostheses as adults. In an animal model of prelingual long-term deafness, we investigated the effects of behavioral training on temporal processing in the adult primary auditory cortex (AI). Neuronal responses to pulse trains of increasing frequencies were recorded in three groups of neonatally deafened cats that received a cochlear prosthesis after >3 yr of deafness: 1) acutely implanted animals that received no electric stimulation before study, 2) animals that received chronic-passive stimulation for several weeks to months before study, and 3) animals that received chronic-passive stimulation and additional behavioral training (signal detection). A fourth group of normal adult cats that was deafened acutely and implanted served as controls. The neuronal temporal response parameters of interest included the stimulus rate that evoked the maximum number of phase-locked spikes [best repetition rate (BRR)], the stimulus rate that produced 50% of the spike count at BRR (cutoff rate), the peak-response latency, and the first spike latency and timing-jitter. All long-deaf animals demonstrated a severe reduction in spiral ganglion cell density (mean, <6% of normal). Long-term deafness resulted in a significantly reduced temporal following capacity and spike-timing precision of cortical neurons in all parameters tested. Neurons in deaf animals that received only chronic-passive stimulation showed a gain in BRR but otherwise were similar to deaf cats that received no stimulation. In contrast, training with behaviorally relevant stimulation significantly enhanced all temporal processing parameters to normal levels with the exception of minimum latencies. These results demonstrate the high efficacy of learning-based remodeling of fundamental timing properties in cortical processing even in the adult, long-deaf auditory system, suggesting rehabilitative strategies for patients with long-term hearing loss.

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