Frequency and intensity discrimination in humans and monkeys

Sinnott, Joan M.; Petersen, Michael R.; Hopp, Steven L.

doi:10.1121/1.392654

Cited by 66 publications

(60 citation statements)

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“…The discrimination thresholds of our animals were within the normal range found for training primates (6,(28)(29)(30). Our animals had discrimination thresholds, (⌬F͞F), of 0.06 and 0.03.…”

Section: Discussionsupporting

confidence: 80%

Neural correlates of instrumental learning in primary auditory cortex

Blake

Strata

Churchland

et al. 2002

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

122

106

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In instrumental learning, Thorndike's law of effect states that stimulus-response relations are strengthened if they occur prior to positive reinforcement and weakened if they occur prior to negative reinforcement. In this study, we demonstrate that neural correlates of Thorndike's law may be observed in the primary auditory cortex, A1. Adult owl monkeys learned to discriminate tones higher than a standard frequency. Responses recorded from implanted microelectrodes initially exhibited broad spectral selectivity over a four-to-five octave range. With training, frequency discrimination thresholds changed from close to one octave to about 1 12 octave. Physiological recordings during the week in which the monkey came under behavioral control signaled by a drop in measured threshold had stronger responses to all frequencies. During the same week, A1 neural responses to target stimuli increased relative to standard and nontarget stimuli. This emergent difference in responsiveness persisted throughout the subsequent weeks of behavioral training. These data suggest that behavioral responses to stimuli modulate responsiveness in primary cortical areas. In instrumental learning, an animal progressively associates its actions with future outcomes (1). One principle in instrumental learning is Thorndike's law of effect, which states that stimulus-response relationships are strengthened if their pairing leads to future positive reinforcement and weakened if their pairing leads to future negative reinforcement. This learning should be reflected by changes in associated neural response. In the current experiment, a chronic multisite recording implant technology (2) was used to document possible neural substrates of instrumental learning in the primary auditory cortex of the awake primate.Learning-induced representational change in mature primary sensory cortex occurs in a task-dependent manner (3-8) and can include changes in receptive field size (3,6,7,9), observed cortical column size (4, 8), and cortical representational area associated with behaviorally important sensory inputs (4, 7). One study (6), especially relevant to the experiments reported here, used operant training to drive cortical representational changes in the primary auditory cortex, A1, of adult owl monkeys. Animals oriented in a behavioral apparatus and attended to a series of tone pairs. If the elements of a pair differed in frequency, and the animal removed itself from the apparatus within time limits, it was rewarded with a food pellet. Misses resulted in a brief time-out. In trained animals, the cortical area that responded to the frequency range of the target and standard tones expanded. This change in representational area was inversely correlated with the progressively improved frequency discrimination thresholds.In the present study, owl monkeys were again engaged in auditory frequency discrimination, but in a different behavioral task. Animals oriented in a listening posture and received a series of single tones, which were initially at a constan...

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Section: Discussionsupporting

confidence: 80%

Neural correlates of instrumental learning in primary auditory cortex

Blake

Strata

Churchland

et al. 2002

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

122

106

View full text Add to dashboard Cite

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“…Therefore, if an organism's sensitivity shows signs of deteriorating with increased SL, then this may indicate that a rate code is involved. We have previously reported that monkeys exhibit qualitatively different SL functions from humans in pure tone frequency discrimination: Monkey DLs increase with increased SL, whereas human DLs decrease (Sinnott et al, 1985(Sinnott et al, , 1987a. These results are also consistent with a hypothesis that monkeys use a rate code that breaks down due to rate saturation as SL increases.…”

supporting

confidence: 92%

“…For birds and monkeys, however, this ratio appeared much smaller. Animals appeared sensitive to formant changes of less than 125 Hz in vowels, yet their pure tone DLs are as high as 15-20 Hz at 1.0 kHz (Sinnott et al, 1980(Sinnott et al, , 1985. Thus animal formant DLs appear to be only about five or six times larger than their pure tone frequency DLs.…”

mentioning

confidence: 87%

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Differential sensitivity to vowel continua in Old World monkeys (Macaca) and humans

Sinnott

Kreiter

1991

The Journal of the Acoustical Society of America

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Previous studies indicate that monkey pure tone frequency discrimination is quantitatively and qualitatively very different from that of humans: Monkey DLs at 1.0 and 2.0 kHz are up to 20 times larger than human DLs, and monkeys DLs increase as sensation level increases, in contrast to human DLs [Sinnott et al., J. Acoust. Soc. Am. 78, 1977-1985 (1985); Sinnott et al., J. Comp. Psychol. 101, 126-131 (1987)]. These results led to an hypothesis that monkey frequency discrimination is more dependent upon "rate" coding than is that of humans. The present study compared monkey and human DLs for formant frequency changes along three synthetic vowel continua /I-i/, /ae-epsilon/, and /a-v/. Here, monkey DLs for formants near 1.0 and 2.0 kHz (32-48 Hz) were only about two to three times larger than human DLs (11-21 Hz), and both monkeys and humans exhibited relatively similar, flat sensation level functions. Taken together, these data indicate that monkey and human frequency discrimination is more similar in the case of a complex vowel stimulus than in the case of a simple pure tone stimulus. Results are discussed in relation to "rate" versus "temporal" coding of tones and vowels in the auditory system.

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“…The auditory thresholds were slightly lower than those determined with a similar method in Old World monkeys, using a 2-kHz standard (Sinnott, Owren, & Petersen, 1987) or a I-kHz standard (Sinnott, Petersen, & Hopp, 1985). They were also in agreement with those derived in human infants, but they were higher than those derived in human adults (Sinnott & Aslin, 1985;Wier, Jesteadt, & Green, 1977).…”

Section: Comparison To Other Paradigmssupporting

confidence: 74%