Chapter 4

1. Chapter 4 Author: Brudzynski

2. Fig. 1. Pathways supporting vocal communication in humans and monkeys. The pathways for parallel brain processing are labeled with black arrows. These are termed “ what, ” “ where ” and “ how, ” reflecting their respective contribution in evaluating what a sensory object is, where it is located in sensory space and how it was generated. Although the figure suggests a close correspondence between the human and monkey brain, it remains unclear how many pathways there are, their precise roles and the extent of the homologies between the species. The inserts illustrate the functional organization of the auditory cortex. Cortical processing begins with the primary auditory cortex (see the lighter region in the enlarged inserts, which includes field AI in monkeys and its presumed homolog hAI in humans). The colors of the insert reflect the direction of the tonotopic gradients of the auditory fields (dark blue: fields with high to low frequency preference toward the anterior direction; light green: fields with low to high frequency preference in the anterior direction). Data such as these can be used to functionally parcellate the auditory cortex and delineate borders between fields with mirror reversed tonotopic gradients. More detailed processing of sound follows in the hierarchically higher auditory “ belt ” and “ parabelt ” regions of auditory cortex. See the text for further details and references. This figure contains a rendered human brain image kindly contributed by J. Obleser and an example of the mapping of human auditory cortical fields contributed by E. Formisano. Abbreviations: AL: antero-lateral; CL: caudo-lateral; CM: caudo-medial; CPB: caudal parabelt; LS: lateral sulcus; ML: medio-lateral MM: medio-medial; STS: superior temporal sulcus; RM: rostro-medial; RPB: rostral parabelt; RL: rostro-lateral; RT: rostro-temporal; RTL: rostrotemporal lateral; RTM: rostro-temporal medial

3. Fig. 2. Comparative summary of human, chimpanzee and macaque processing of species-specific communication sounds. Colored circles summarize several functional imaging results (see key) focusing on the stimulus-bound processing of vocal signals in the temporal lobe. For humans, we summarize the peaks of activity reported in studies of voice sensitivity ( Belin et al., 2000 ; Belin and Zatorre, 2003 ; von Kriegstein et al., 2003 ), voice identity ( Belin and Zatorre, 2003 ; von Kriegstein et al., 2003 ) and the sublexical or stimulus-bound aspects of speech ( Dehaene-Lambertz et al., 2005 ; Liebenthal et al., 2005 ; Rimol et al., 2005 ; Obleser et al., 2006 ; Obleser et al., 2007 ); for the exact coordinates of the summaries in humans and monkeys see Petkov et al., 2009 (in press). For chimpanzees we summarize a recent study evaluating chimp vocal sound processing in these great apes ( Taglialatela et al., 2009 ). For the macaque brain we show the sensitivity to macaque vocalizations from both PET ( Poremba et al., 2004 ; Gil-da-Costa et al., 2006 ) and fMRI ( Petkov et al., 2008 ) studies. The monkey voice sensitive regions (orange circles) and voice-identity selective regions (yellow circle) identified in the monkey fMRI study ( Petkov et al., 2008 ) can be directly compared with the human studies on human voice sensitivity and selectivity (compare the orange and yellow circles in the human and macaque). For macaques, we also identify electrophysiological recording sites (see the lower key), from the temporal ( Rauschecker et al., 1995 ; Tian et al., 2001 ; Ghazanfar et al., 2005 ; Ghazanfar et al., 2008 ; Russ et al., 2008 ), parietal ( Gifford and Cohen, 2005 ) and prefrontal cortices ( Romanski and Goldman- Rakic, 2002 ; Cohen et al., 2004 ; Gifford et al., 2005 ; Sugihara et al., 2006 ). This figure contains a rendered chimpanzee brain image kindly contributed by J. Taglialatela. For abbreviations, see Fig. 1