The brain of the African wild dog. III. The auditory system

Abstract

The large external pinnae and extensive vocal repertoire of the African wild dog (Lycaon pictus) has led to the assumption that the auditory system of this unique canid may be specialized. Here, using cytoarchitecture, myeloarchitecture, and a range of immunohistochemical stains, we describe the systems‐level anatomy of the auditory system of the African wild dog. We observed the cochlear nuclear complex, superior olivary nuclear complex, lateral lemniscus, inferior colliculus, medial geniculate body, and auditory cortex all being in their expected locations, and exhibiting the standard subdivisions of this system. While located in the ectosylvian gyri, the auditory cortex includes several areas, resembling the parcellation observed in cats and ferrets, although not all of the auditory areas known from these species could be identified in the African wild dog. These observations suggest that, broadly speaking, the systems‐level anatomy of the auditory system, and by extension the processing of auditory information, within the brain of the African wild dog closely resembles that observed in other carnivores. Our findings indicate that it is likely that the extraction of the semantic content of the vocalizations of African wild dogs, and the behaviors generated, occurs beyond the classically defined auditory system, in limbic or association neocortical regions involved in cognitive functions. Thus, to obtain a deeper understanding of how auditory stimuli are processed, and how communication is achieved, in the African wild dog compared to other canids, cortical regions beyond the primary sensory areas will need to be examined in detail.

Comparative neuroimaging of the carnivoran brain: Neocortical sulcal anatomy

“…Previous histological and electrophysiological investigations in the domestic cat (Reale and Imig, 1980), domestic dog (Kosmal, 2000; Tunturi, 1950), and African wild dog (Chengetanai et al, 2020a) indicate that large parts of the cortical territory between the middle and caudal parts of the suprasylvian and ectosylvian sulcus (i.e., on the ectosylvian gyrus) house primary and higher-order auditory regions (see also Figure 6 ). In the domestic cat, which has a split ectosylvian sulcus, the primary auditory cortex extends ventrally to occupy the cortical area between the sections of the split ectosylvian sulcus (Reale and Imig, 1980).…”

“…While knowledge of the sensory regions in carnivoran brains is still limited, the best-understood brain of the species in our sample was the domestic cat (second row, right), followed by the domestic dog (top row, left), African wild dog (top row, second from right), and the raccoon, coati, and red panda (fourth row). Based on prior electrophysiological, histological and neuroimaging research (e.g., Boch et al, 2021; Chengetanai et al, 2020a, 2020b; Douglas Jameson et al, 1968; Guran et al, 2024; Hardin et al, 1968; Kosmal, 2000; Stolzberg et al, 2017; Tunturi, 1944; Welker and Campos, 1963), we indicate approximate locations of unimodal sensory cortices on a lateral view of the brains of these species. Darker shades indicate primary sensory cortices, including the primary visual (V1, yellow), auditory (A1, pink), motor (M1) and somatosensory (S1) cortex.…”

“…Intuitively, one would assume that they lacked the ecto sylvian gyrus; however, in the ferret, which lacks an ectosylvian sulcus, the first gyrus curving around the pseudo-sylvian fissure is consistently referred to as ectosylvian gyrus (see e.g., Radtke-Schuller, 2018). This terminology might be attributed to the cortex forming this gyrus housing the primary auditory cortex, a feature shared with the ectosylvian gyrus of the domestic cat and dog or African wild dog (Bizley et al, 2005; Chengetanai et al, 2020a; Kosmal, 2000; Stolzberg et al, 2017, and see next section). In the meerkat, the caudal ectosylvian sulcus and suprasylvian sulcus form an incomplete arc, which defines the outer boundary of a gyrus curving around the pseudo-sylvian fissure.…”

“…For the majority of the species, functional properties of brain areas have not been studied yet, or the focus was only on the somatosensory cortex, such as for the South American coati and red panda (Welker and Campos, 1963). The sensory cortices of the domestic cat are best understood and studied most extensively (see e.g., Stolzberg et al, 2017 for a detailed atlas), followed by the domestic dog (Adrian, 1941; Kosmal, 2000; Kosmal et al, 2004; Pinto Hamuy et al, 1956; Tunturi, 1944), raccoon (Douglas Jameson et al, 1968; Hardin et al, 1968; Welker and Seidenstein, 1959), and African wild dog (Chengetanai et al, 2020a, 2020b).…”

The brain of the African wild dog.IV. The visual system

“…Indeed, studies of the neural basis of face recognition in the domestic dog (Cuaya et al, 2016; Dilks et al, 2015), indicate that a cortical territory occupying the lateral‐most portions of the ectosylvian and sylvian gyri is activated during stimulus presentation. This region of the cortex located rostral to the temporal visual cortex and lateral to the auditory cortex (Chengetanai et al, 2020b), is known to be connected to the unimodal temporal visual cortex in the domestic ferret (Dell et al, 2019c). Thus, this cortex could potentially be a higher‐order cortical region involved in processing information of importance to social behaviors associated with the identification of individuals.…”