Processing Of Communication Calls In Guinea Pig Auditory Cortex
Acoustic noise; Action potentials; Anesthesia; Auditory cortex; Brain research; Broadband; Communication; conspecific; Auditory cortex; Cortex (temporal); cortical discrimination; Councils; functional specialization; Guinea pigs; Localization; Macaque; Medical research; Monkeys; neural representation; Neurobiology; neurons; Neurosciences; Ohio; purr call; rhesus-monkey; Saimiri; Science & Technology - Other Topics; Sciences: Comprehensive Works; single neurons; social vocalizations; Sound; species-specific vocalizations; squirrel-monkeys; Stimuli; United Kingdom--UK; Urethane; Vocalization; vocalizations
Vocal communication is an important aspect of guinea pig behaviour and a large contributor to their acoustic environment. We postulated that some cortical areas have distinctive roles in processing conspecific calls. In order to test this hypothesis we presented exemplars from all ten of their main adult vocalizations to urethane anesthetised animals while recording from each of the eight areas of the auditory cortex. We demonstrate that the primary area (AI) and three adjacent auditory belt areas contain many units that give isomorphic responses to vocalizations. These are the ventrorostral belt (VRB), the transitional belt area (T) that is ventral to AI and the small area (area S) that is rostral to AI. Area VRB has a denser representation of cells that are better at discriminating among calls by using either a rate code or a temporal code than any other area. Furthermore, 10% of VRB cells responded to communication calls but did not respond to stimuli such as clicks, broadband noise or pure tones. Area S has a sparse distribution of call responsive cells that showed excellent temporal locking, 31% of which selectively responded to a single call. AI responded well to all vocalizations and was much more responsive to vocalizations than the adjacent dorsocaudal core area. Areas VRB, AI and S contained units with the highest levels of mutual information about call stimuli. Area T also responded well to some calls but seems to be specialized for low sound levels. The two dorsal belt areas are comparatively unresponsive to vocalizations and contain little information about the calls. AI projects to areas S, VRB and T, so there may be both rostral and ventral pathways for processing vocalizations in the guinea pig.
Grimsley J M S; Shanbhag S J; Palmer A R; Wallace M N
Plos One
2012
2012-12
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1371/journal.pone.0051646" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0051646</a>
The influence of masseter and temporalis sarcomere length operating ranges as determined by laser diffraction on architectural estimates of muscle force and excursion in macaques (Macaca fascicularis and Macaca mulatta)
Fiber length; Macaque; Masseter; Sarcomere length; Temporalis
OBJECTIVE: Determine sarcomere length (Ls) operating ranges of the superficial masseter and temporalis in vitro in a macaque model and examine the impact of position-dependent variation on Ls and architectural estimates of muscle function (i.e., fiber length, PCSA) before and after Ls-normalization. DESIGN: Heads of adult Macaca fascicularis (n = 4) and M. mulatta (n = 3) were bisected postmortem. One side of the jaw was fixed in occlusion, the other in maximum gape. Ls was measured bilaterally using laser diffraction and these measurements were used to estimate sarcomere-length operating ranges. Differences in fiber length and PCSA between sides were tested for significance prior to and following Ls-normalization. RESULTS: Sarcomere-length operating ranges were widest for the anterior superficial masseter and narrowest for the posterior temporalis. Compared with other mammals, macaque operating ranges were wider and shifted to the right of the descending limb of a representative length-tension curve. Fibers were significantly stretched by as much as 100%, and PCSAs reduced by as much as 43%, on the maximally gaped compared with occluded sides. Ls-normalization substantially reduced position-dependent variance. CONCLUSIONS: The superficial masseter ranges between 87-143% and the temporalis between 88-130% of optimal Ls from maximum gape to occlusion, indicating maximum relative Ls for these macaque muscles exceeds the upper end range previously reported for the jaw muscles of smaller mammals. The wider macaque operating ranges may be functionally linked to the propensity for facially prognathic primates to engage in agonistic canine display behaviors that require jaw-muscle stretch to facilitate production of wide jaw gapes.
Taylor Andrea B; Terhune Claire E; Vinyard Christopher J
Archives of Oral Biology
2019
2019-09
<a href="http://doi.org/10.1016/j.archoralbio.2019.05.015" target="_blank" rel="noreferrer noopener">10.1016/j.archoralbio.2019.05.015</a>