Prefrontal Neurons Predict Choices during an Auditory Same-Different Task

Department of Psychological and Brain Sciences, Center for Cognitive Neuroscience, Dartmouth College, Hanover, NH 03755, USA.
Current Biology (Impact Factor: 9.57). 10/2008; 18(19):1483-8. DOI: 10.1016/j.cub.2008.08.054
Source: PubMed


The detection of stimuli is critical for an animal's survival [1]. However, it is not adaptive for an animal to respond automatically to every stimulus that is present in the environment [2-5]. Given that the prefrontal cortex (PFC) plays a key role in executive function [6-8], we hypothesized that PFC activity should be involved in context-dependent responses to uncommon stimuli. As a test of this hypothesis, monkeys participated in a same-different task, a variant of an oddball task [2]. During this task, a monkey heard multiple presentations of a "reference" stimulus that were followed by a "test" stimulus and reported whether these stimuli were the same or different. While they participated in this task, we recorded from neurons in the ventrolateral prefrontal cortex (vPFC; a cortical area involved in aspects of nonspatial auditory processing [9, 10]). We found that vPFC activity was correlated with the monkeys' choices. This finding demonstrates a direct link between single neurons and behavioral choices in the PFC on a nonspatial auditory task.

Download full-text


Available from: Yale Cohen, Sep 17, 2014
1 Follower
23 Reads
  • Source
    • "The neural responses to the target and standard sounds were nearly unaffected by the cat's behavioral choice. Our present results suggest that the role of PU, as the major input site of the basal ganglia, might primarily be to provide sensory evidence and reward association to other brain areas, such as prefrontal cortex [5] [50] and premotor cortex [51], to encode the output of the decision process. However, it is worth noting that we only collected a small quantity of units (n = 16 in reward unit group) in the analysis of effects of behavioral choice, because the cats have been well trained with the use of the two discrimination tasks and seldom showed a miss or false alarm response. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The striatum integrates diverse convergent input and plays a critical role in the goal-directed behaviors. To date, the auditory functions of striatum are less studied. Recently, it was demonstrated that auditory cortico-striatal projections influence behavioral performance during a frequency discrimination task. To reveal the functions of striatal neurons in auditory discrimination, we recorded the single-unit spike activities in the putamen (dorsal striatum) of free-moving cats while performing a Go/No-go task to discriminate the sounds with different modulation rates (12.5Hz vs. 50Hz) or envelopes (damped vs. ramped). We found that the putamen neurons can be broadly divided into four groups according to their contributions to sound discrimination. First, 40% of neurons showed vigorous responses synchronized to the sound envelope, and could precisely discriminate different sounds. Second, 18% of neurons showed a high preference of ramped to damped sounds, but no preference for modulation rate. They could only discriminate the change of sound envelope. Third, 27% of neurons rapidly adapted to the sound stimuli, had no ability of sound discrimination. Fourth, 15% of neurons discriminated the sounds dependent on the reward-prediction. Comparing to passively listening condition, the activities of putamen neurons were significantly enhanced by the engagement of the auditory tasks, but not modulated by the cat's behavioral choice. The coexistence of multiple types of neurons suggests that the putamen is involved in the transformation from auditory representation to stimulus-reward association. Copyright © 2015. Published by Elsevier B.V.
    Behavioural brain research 07/2015; 292. DOI:10.1016/j.bbr.2015.07.002 · 3.03 Impact Factor
  • Source
    • "For example, VLPFC neurons were modulated during non-spatial auditory discrimination but showed no modulation during spatial auditory discrimination (Cohen et al., 2009). Further recordings over a large region of PFC which Cohen termed “vPFC” during categorization and decision making paradigms, demonstrate that prefrontal neuronal activity is correlated with behavioral choices (Russ et al., 2008b; Lee et al., 2009), although the location of these prefrontal neurons does not appear to overlap entirely with the ventrolateral PFC regions previously shown to be auditory responsive (Romanski et al., 2005). Nonetheless, inactivation studies are needed to determine whether VLPFC is essential in the performance of working memory or decision making tasks. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC). In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG) most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition.
    Frontiers in Neuroscience 07/2014; 8(8):199. DOI:10.3389/fnins.2014.00199 · 3.66 Impact Factor
  • Source
    • "Beyond the auditory cortex, do latter processing stages (e.g., the monkey ventral prefrontal cortex and human inferior frontal cortex) process categories for even more complex sounds? A reexamination of previous findings from our lab (Russ et al., 2008b; Tsunada et al., 2011) indicated important differences in neural categorization between the lateral belt and the ventral prefrontal cortex (Figure 3). We found that, at the population level, the category sensitivity for speech sounds in the prefrontal cortex was weaker than that in the lateral belt although neural activity in the prefrontal cortex transmitted a significant amount of categorical information. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Categorization enables listeners to efficiently encode and respond to auditory stimuli. Behavioral evidence for auditory categorization has been well documented across a broad range of human and non-human animal species. Moreover, neural correlates of auditory categorization have been documented in a variety of different brain regions in the ventral auditory pathway, which is thought to underlie auditory-object processing and auditory perception. Here, we review and discuss how neural representations of auditory categories are transformed across different scales of neural organization in the ventral auditory pathway: from across different brain areas to within local microcircuits. We propose different neural transformations across different scales of neural organization in auditory categorization. Along the ascending auditory system in the ventral pathway, there is a progression in the encoding of categories from simple acoustic categories to categories for abstract information. On the other hand, in local microcircuits, different classes of neurons differentially compute categorical information.
    Frontiers in Neuroscience 06/2014; 8(8):161. DOI:10.3389/fnins.2014.00161 · 3.66 Impact Factor
Show more