Two distinct representations of social vocalizations in the basolateral amygdala.
*Discrimination (Psychology); *Social Behavior; *Vocalization; acoustic communication; Action Potentials; Amygdala/cytology/*physiology; Animal; Animals; bat; Chiroptera; electrocardiogram; Eptesicus fuscus; Female; Heart Rate; Male; Neurons/classification/*physiology; vocalizations
Acoustic communication signals carry information related to the types of social interactions by means of their "acoustic context," the sequencing and temporal emission pattern of vocalizations. Here we describe responses to natural vocal sequences in adult big brown bats (Eptesicus fuscus). We first assessed how vocal sequences modify the internal affective state of a listener (via heart rate). The heart rate of listening bats was differentially modulated by vocal sequences, showing significantly greater elevation in response to moderately aggressive sequences than appeasement or neutral sequences. Next, we characterized single-neuron responses in the basolateral amygdala (BLA) of awake, restrained bats to isolated syllables and vocal sequences. Two populations of neurons distinguished by background firing rates also differed in acoustic stimulus selectivity. Low-background neurons (\textless1 spike/s) were highly selective, responding on average to one tested stimulus. These may participate in a sparse code of vocal stimuli, in which each neuron responds to one or a few stimuli and the population responds to the range of vocalizations across behavioral contexts. Neurons with higher background rates (\textgreater/=1 spike/s) responded broadly to tested stimuli and better represented the timing of syllables within sequences. We found that spike timing information improved the ability of these neurons to discriminate among vocal sequences and among the behavioral contexts associated with sequences compared with a rate code alone. These findings demonstrate that the BLA contains multiple robust representations of vocal stimuli that can provide the basis for emotional/physiological responses to these stimuli.
Gadziola Marie A; Shanbhag Sharad J; Wenstrup Jeffrey J
Journal of neurophysiology
2016
2016-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.00953.2015" target="_blank" rel="noreferrer noopener">10.1152/jn.00953.2015</a>
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>