Plasticity in the frequency representation of primary auditory cortex following discrimination training in adult owl monkeys

Abstract

Previous studies have shown that the tonotopic organization of primary auditory cortex is altered subsequent to restricted cochlear lesions (Robertson and Irvine, 1989) and that the topographic reorganization of the primary somatosensory cortex is correlated with changes in the perceptual acuity of the animal (Recanzone et al., 1992a-d). Here we report an increase in the cortical area of representation of a restricted frequency range in primary auditory cortex of adult owl monkeys that is correlated with the animal's performance at a frequency discrimination task. Monkeys trained for several weeks to discriminate small differences in the frequency of sequentially presented tonal stimuli revealed a progressive improvement in performance with training. At the end of the training period, the tonotopic organization of Al was defined by recording multiple-unit responses at 70-258 cortical locations. These responses were compared to those derived from three normal monkeys and from two monkeys that received the same auditory stimuli but that were engaged in a tactile discrimination task. The cortical representation, the sharpness of tuning, and the latency of the response were greater for the behaviorally relevant frequencies of trained monkeys when compared to the same frequencies of control monkeys. The cortical area of representation was the only studied parameter that was correlated with behavioral performance. These results demonstrate that attended natural stimulation can modify the tonotopic organization of Al in the adult primate, and that this alteration is correlated with changes in perceptual acuity.

Spectral integration plasticity in cat auditory cortex induced by perceptual training

“…Discrimination thresholds for shifts in the spectral envelope improved steadily over the course of the behavioral training, similar to other auditory discrimination tasks (e.g., Prosen et al;Recanzone et al, 1993;Polley et al, 2006). Analysis of the hit rate and false-alarm rate early and late in training support the conclusion that the observed improvements in discrimination reflect changes in perceptual capacity and not changes in response criterion.…”

“…In this way, the spatial resolution of both the signal and the receiver might be improved. The results of this study and others that have observed training-induced refinement of spectral receptive field bandwidth (Recanzone et al, 1993;Witte et al, 2005) might represent initial progress towards this goal.…”

“…It was found that animals discriminate many speech-like features in a similar fashion as humans. The ability to discriminate signals can improve with training and is accompanied by plastic changes in response characteristics of central auditory neurons (e.g., Allard et al, 1992;Bakin et al, 1996;Beitel et al, 2001;Edeline, 1999;Recanzone et al, 1993;Polley et al 2004Polley et al , 2006Prosen et al, 1990;Weinberger et al, 1988). Since the process of behavioral assessment can influence the perceptual capacity of an animal, it may not be valid to equate physiological data from untrained animals with the psychophysical performance of trained animal.…”

Consequences of unilateral hearing loss: Cortical adjustment to unilateral deprivation

“…Furthermore, neurons in auditory cortex alter their response properties subsequent to changes in stimulus pairings involved in learning and attention paradigms (e.g., Recanzone et al, 1993;Kilgard et al, 2007;Weinberger, 2007;Zatorre, 2007).…”

Neural plasticity following auditory training in children with learning problems

“…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.…”