The Neurophysiology of Functionally Meaningful Categories: Macaque Ventrolateral Prefrontal Cortex Plays a Critical Role in Spontaneous Categorization of Species-Specific Vocalizations

Dartmouth College, Hanover, NH 03755, USA.
Journal of Cognitive Neuroscience (Impact Factor: 4.09). 10/2005; 17(9):1471-82. DOI: 10.1162/0898929054985464
Source: PubMed


Neurophysiological studies in nonhuman primates have demonstrated that the prefrontal cortex (PFC) plays a critical role in the acquisition of learned categories following training. What is presently unclear is whether this cortical area also plays a role in spontaneous recognition and discrimination of natural categories. Here, we explore this possibility by recording from neurons in the PFC while rhesus listen to species-specific vocalizations that vary in terms of their social function and acoustic morphology. We found that ventral prefrontal cortex (vPFC) activity, on average, did not differentiate between food calls that were associated with the same functional category, despite having different acoustic properties. In contrast, vPFC activity differentiated between food calls associated with different functional classes and specifically, information about the quality and motivational value of the food. These results suggest that the vPFC is involved in the categorization of socially meaningful signals, thereby both extending its previously conceived role in the acquisition of learned categories and showing the significance of using natural categorical distinctions in the study of neural mechanisms.

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Available from: Katherine A Maclean, Aug 14, 2014
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    • "For instance, compared to A1, secondary auditory areas in primates respond with longer latencies, higher stimulus selectivity, and can be robustly driven by band-pass noise, frequency-modulated sweeps, and species-specific vocalizations (Rauschecker et al. 1995; Rauschecker 1998; Tian et al. 2001; Wang et al. 2005; Kajikawa et al. 2008). Many of these secondary processing areas ultimately project to specific areas of prefrontal cortex (Hackett et al. 1999; Romanski et al. 1999; Romanski and Goldman-Rakic 2002; Romanski 2003) that are likely involved in even higher level processing such as stimulus categorization (Gifford et al. 2005; Cohen et al. 2006). The auditory cortex thus appears, and is often assumed to be, designed to perform increasingly complex and integrative computations as information flows from primary to secondary regions and, ultimately, to frontal areas. "
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    • "Similarly, the monkey ventral prefrontal cortex encodes abstract categories. We have found that neurons in the ventral prefrontal cortex represent categories for food-related calls based on the transmitted information (e.g., high quality food vs. low quality food) (Gifford et al., 2005; Cohen et al., 2006). A more recent study found that neural activity in the monkey prefrontal cortex categorically represents the number of auditory stimuli (Nieder, 2012). "
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    • "Neurons in prefrontal cortex exhibit strong category selectivity and likely contribute to the behavioral response (i.e. motor output) [8,76,86,87]. "
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