Unfortunately most neurophysiology studies utilize visual working memory paradigms. In the last two decades there have been a wealth of neuroimaging studies in human subject and single-unit recording studies in non-human primates, which confirm a role in working memory for the prefrontal cortex ( Funahashi et al., 1993 Awh et al., 1996 McCarthy et al., 1996 Miller et al., 1996 Owen et al., 1996 Courtney et al., 1997 D'Esposito et al., 2000 Fuster et al., 2000 Bunge et al., 2003 Postle et al., 2003 Bor et al., 2004 Rowe et al., 2008). ![]() In contrast, lesions of VLPFC resulted in impaired performance in non-spatial tasks and implicated VLPFC in object recognition ( Mishkin and Manning, 1978). Later, more precise lesion studies implicated DLPFC in spatial and delay processes ( Malmo, 1942 Mishkin, 1957 Passingham, 1975 Mishkin and Manning, 1978). Early lesion studies indicated that lesions of prefrontal cortex caused impairments in delay response, delay spatial alternation, and delay object alternation tasks ( Pribram et al., 1952 Mishkin and Pribram, 1955, 1956 Pribram and Mishkin, 1956 Mishkin et al., 1969). The frontal lobe is well-known for its role in speech and language processes and executive functions that include working memory, planning, and decision making ( Fuster, 2008). Possible auditory functions and connections of frontal pole, medial and orbital areas of the frontal lobe are described elsewhere including Medalla and Barbas (2014). This review will focus on the lateral prefrontal cortex including the dorsolateral regions (DLPFC) (areas 8, 46, and 9) and the ventrolateral regions (VLPFC) (areas 12/47, 45, and 12 orbital) (Figure 1). The frontal cortex is a heterogeneous region with multiple functional subdivisions, including the prefrontal cortex, which lies in the anterior frontal lobe and consists of medial, lateral, and orbital subdivisions. Discerning what types of auditory information reaches the frontal cortex, where that auditory input originates, and how information is utilized by the frontal lobes for complex behaviors, such as communication, is a fundamental question of neuroscience. 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.Ĭonnections from the auditory cortex to the frontal lobes mediate a number of functions including language, object recognition and spatial localization. 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. ![]() In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. 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. ![]() Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. 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. 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). Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. 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. Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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