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Causal contribution of primate auditory cortex to auditory perceptual decision-making.

Tsunada J, Liu AS, Gold JI, Cohen YE - Nat. Neurosci. (2015)

Bottom Line: However, the specific and causal contributions of different brain regions in this pathway, including the middle-lateral (ML) and anterolateral (AL) belt regions of the auditory cortex, to auditory decisions have not been fully identified.Both ML and AL neural activity was modulated by the frequency content of the stimulus.Together, these findings suggest that AL directly and causally contributes sensory evidence to form this auditory decision.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

ABSTRACT
Auditory perceptual decisions are thought to be mediated by the ventral auditory pathway. However, the specific and causal contributions of different brain regions in this pathway, including the middle-lateral (ML) and anterolateral (AL) belt regions of the auditory cortex, to auditory decisions have not been fully identified. To identify these contributions, we recorded from and microstimulated ML and AL sites while monkeys decided whether an auditory stimulus contained more low-frequency or high-frequency tone bursts. Both ML and AL neural activity was modulated by the frequency content of the stimulus. But, only the responses of the most stimulus-sensitive AL neurons were systematically modulated by the monkeys' choices. Consistent with this observation, microstimulation of AL, but not ML, systematically biased the monkeys' behavior toward the choice associated with the preferred frequency of the stimulated site. Together, these findings suggest that AL directly and causally contributes sensory evidence to form this auditory decision.

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Stimuli and taska, The auditory stimulus was a temporal sequences of tone bursts. Coherence refers to the percentage of high-frequency bursts (up to +100%) or low-frequency bursts (down to −100%). b, The monkey indicated its choice by moving a joystick to the right to report “low frequency” or to the left to report “high frequency.” The monkey could report its choice any time after stimulus onset.
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Figure 1: Stimuli and taska, The auditory stimulus was a temporal sequences of tone bursts. Coherence refers to the percentage of high-frequency bursts (up to +100%) or low-frequency bursts (down to −100%). b, The monkey indicated its choice by moving a joystick to the right to report “low frequency” or to the left to report “high frequency.” The monkey could report its choice any time after stimulus onset.

Mentions: To achieve this goal, we recorded and manipulated ML and AL spiking activity in monkeys while they made a difficult decision about whether a noisy stimulus contained more low- or high-frequency tone bursts (Fig. 1). This approach provided three primary benefits9. First, we could assess the sensitivity of individual neurons in each brain region to the frequency content of the stimulus and compare such neurometric sensitivity to concurrently measured behavioral sensitivity around psychophysical threshold. These measures can help to identify neural signals that, in principle, could be used to form the decision10. Second, we could identify neural signals that were (weakly) modulated by the monkeys’ choices for nominally identical stimuli. Under certain conditions, such modulation is expected of neural signals that represent the evidence used to form a perceptual decision9, 11. Third, combined with electrical microstimulation in ML and AL, we could assess the causal contributions of these brain regions to the decision process.


Causal contribution of primate auditory cortex to auditory perceptual decision-making.

Tsunada J, Liu AS, Gold JI, Cohen YE - Nat. Neurosci. (2015)

Stimuli and taska, The auditory stimulus was a temporal sequences of tone bursts. Coherence refers to the percentage of high-frequency bursts (up to +100%) or low-frequency bursts (down to −100%). b, The monkey indicated its choice by moving a joystick to the right to report “low frequency” or to the left to report “high frequency.” The monkey could report its choice any time after stimulus onset.
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Related In: Results  -  Collection

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Figure 1: Stimuli and taska, The auditory stimulus was a temporal sequences of tone bursts. Coherence refers to the percentage of high-frequency bursts (up to +100%) or low-frequency bursts (down to −100%). b, The monkey indicated its choice by moving a joystick to the right to report “low frequency” or to the left to report “high frequency.” The monkey could report its choice any time after stimulus onset.
Mentions: To achieve this goal, we recorded and manipulated ML and AL spiking activity in monkeys while they made a difficult decision about whether a noisy stimulus contained more low- or high-frequency tone bursts (Fig. 1). This approach provided three primary benefits9. First, we could assess the sensitivity of individual neurons in each brain region to the frequency content of the stimulus and compare such neurometric sensitivity to concurrently measured behavioral sensitivity around psychophysical threshold. These measures can help to identify neural signals that, in principle, could be used to form the decision10. Second, we could identify neural signals that were (weakly) modulated by the monkeys’ choices for nominally identical stimuli. Under certain conditions, such modulation is expected of neural signals that represent the evidence used to form a perceptual decision9, 11. Third, combined with electrical microstimulation in ML and AL, we could assess the causal contributions of these brain regions to the decision process.

Bottom Line: However, the specific and causal contributions of different brain regions in this pathway, including the middle-lateral (ML) and anterolateral (AL) belt regions of the auditory cortex, to auditory decisions have not been fully identified.Both ML and AL neural activity was modulated by the frequency content of the stimulus.Together, these findings suggest that AL directly and causally contributes sensory evidence to form this auditory decision.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

ABSTRACT
Auditory perceptual decisions are thought to be mediated by the ventral auditory pathway. However, the specific and causal contributions of different brain regions in this pathway, including the middle-lateral (ML) and anterolateral (AL) belt regions of the auditory cortex, to auditory decisions have not been fully identified. To identify these contributions, we recorded from and microstimulated ML and AL sites while monkeys decided whether an auditory stimulus contained more low-frequency or high-frequency tone bursts. Both ML and AL neural activity was modulated by the frequency content of the stimulus. But, only the responses of the most stimulus-sensitive AL neurons were systematically modulated by the monkeys' choices. Consistent with this observation, microstimulation of AL, but not ML, systematically biased the monkeys' behavior toward the choice associated with the preferred frequency of the stimulated site. Together, these findings suggest that AL directly and causally contributes sensory evidence to form this auditory decision.

Show MeSH