scholarly journals Differential encoding of signals and preferences by noradrenaline in the anuran brain

2020 ◽  
Vol 223 (18) ◽  
pp. jeb214148
Author(s):  
Sabrina S. Burmeister ◽  
Verónica G. Rodriguez Moncalvo ◽  
Karin S. Pfennig
Keyword(s):  
Social Preferences ◽  
Preoptic Area ◽  
Close Relative ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Differential Encoding ◽  
Spadefoot Toad ◽  
Spea Bombifrons ◽  
Independent Preferences ◽  
Noradrenaline Levels

ABSTRACTSocial preferences enable animals to selectively interact with some individuals over others. One influential idea for the evolution of social preferences is that preferred signals evolve because they elicit greater neural responses from sensory systems. However, in juvenile plains spadefoot toad (Spea bombifrons), a species with condition-dependent mating preferences, responses of the preoptic area, but not of the auditory midbrain, mirror adult social preferences. To examine whether this separation of signal representation from signal valuation generalizes to other anurans, we compared the relative contributions of noradrenergic signalling in the preoptic area and auditory midbrain of S. bombifrons and its close relative Spea multiplicata. We manipulated body condition in juvenile toads by controlling diet and used high pressure liquid chromatography to compare call-induced levels of noradrenaline and its metabolite MHPG in the auditory midbrain and preoptic area of the two species. We found that calls from the two species induced different levels of noradrenaline and MHPG in the auditory system, with higher levels measured in both species for the more energetic S. bombifrons call. In contrast, noradrenaline levels in the preoptic area mirrored patterns of social preferences in both S. bombifrons and S. multiplicata. That is, noradrenaline levels were higher in response to the preferred calls within each species and were modified by diet in S. bombifrons (with condition-dependent preferences) but not S. multiplicata (with condition-independent preferences). Our results are consistent with a potentially important role for preoptic noradrenaline in the development of social preferences and indicate that it could be a target of selection in the evolution of condition-dependent social preferences.

Effects of noise and cue enhancement on neural responses to speech in auditory midbrain, thalamus and cortex

2002 ◽  
Vol 169 (1-2) ◽  
pp. 97-111 ◽  
Author(s):  
Jenna Cunningham ◽  
Trent Nicol ◽  
Cynthia King ◽  
Steven G Zecker ◽  
Nina Kraus
Keyword(s):  
Neural Responses ◽  
Auditory Midbrain

scholarly journals Specific loss of neural sensitivity to interaural time difference of unmodulated noise stimuli following noise-induced hearing loss

2020 ◽  
Vol 124 (4) ◽  
pp. 1165-1182
Author(s):  
Hariprakash Haragopal ◽  
Ryan Dorkoski ◽  
Austin R. Pollard ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Interaural Time Difference ◽  
Acoustic Trauma ◽  
Sound Level ◽  
Broadband Noise ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Midbrain Neurons ◽  
Perceptual Abilities ◽  
Encode Time

Sensorineural hearing loss compromises perceptual abilities that arise from hearing with two ears, yet its effects on binaural aspects of neural responses are largely unknown. We found that, following severe hearing loss because of acoustic trauma, auditory midbrain neurons specifically lost the ability to encode time differences between the arrival of a broadband noise stimulus to the two ears, whereas the encoding of sound level differences between the two ears remained uncompromised.

scholarly journals Leptin Manipulation Reduces Appetite and Causes a Switch in Mating Preference in the Plains Spadefoot Toad (Spea bombifrons)

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0125981 ◽  
Author(s):  
Nicholas W. Garcia ◽  
Karin S. Pfennig ◽  
Sabrina S. Burmeister
Keyword(s):  
Mating Preference ◽  
Spadefoot Toad ◽  
Spea Bombifrons

The role of Spadefoot Toad tadpoles in wetland trophic structure as influenced by environmental and morphological factors

2011 ◽  
Vol 89 (1) ◽  
pp. 47-59 ◽  
Author(s):  
D. M. Ghioca-Robrecht ◽  
L. M. Smith
Keyword(s):  
Body Size ◽  
Great Plains ◽  
Trophic Structure ◽  
Trophic Levels ◽  
Wetland Ecosystems ◽  
Southern Great Plains ◽  
Larval Amphibians ◽  
Spadefoot Toad ◽  
Spea Bombifrons ◽  
And Function

Larval amphibians reach high densities in playa wetlands in the Southern Great Plains (SGP), USA, and thus may influence the entire structure and function of these ecosystems. We investigated whether both carnivorous and omnivorous morphotypes of Spadefoot Toad tadpoles (New Mexico Spadefoot, Spea multiplicata (Cope, 1863), and Plains Spadefoot, Spea bombifrons (Cope, 1863)) would exhibit a macrophagous feeding behavior that would allow them to occupy several trophic levels in playas. We also compared tadpole diets and foregut widths as influenced by the land use surrounding playas (cultivated versus grassland watersheds), year (dry versus wet year), and body size (snout-to-vent length). Tadpole diets were dominated by detritus and diatoms and tadpole foreguts increased with body size. Generally, more arthropods and less cyanobacteria were found in Spea tadpole diets as tadpoles grew larger, suggesting they influence different trophic levels with age. Foreguts were wider in carnivores than omnivores, suggesting carnivores had increased ability to ingest larger prey. Also, omnivores had wider foreguts in cropland than grassland playas, suggesting they ingest larger food items in cropland playas. From estimates of the amounts of invertebrates, detritus, and algae consumed by Spea tadpoles, we demonstrate that these larvae influence the entire trophic structure of wetland ecosystems.

The Representation of Amplitude Modulations in the Mammalian Auditory Midbrain

2008 ◽  
Vol 100 (3) ◽  
pp. 1602-1609 ◽  
Author(s):  
Bjarne Krebs ◽  
Nicholas A. Lesica ◽  
Benedikt Grothe
Keyword(s):  
Auditory System ◽  
Duty Cycle ◽  
Modulation Frequency ◽  
Acoustic Signals ◽  
Interpulse Interval ◽  
Neural Responses ◽  
Stimulus Amplitude ◽  
Auditory Midbrain ◽  
Pulse Trains ◽  
The Relationship

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown that the responses of many neurons are strongly tuned to modulation frequency, leading to the hypothesis that AMs are represented by their periodicity in the auditory midbrain. However, AMs in general are defined not only by their modulation frequency, but also by a number of other parameters (duration, duty cycle, etc.), which covary with modulation frequency in SAM stimuli. Thus the relationship between modulation frequency and neural responses as characterized with SAM stimuli alone is ambiguous. In this study, we characterize the representation of AMs in the gerbil inferior colliculus by analyzing neural responses to a series of pulse trains in which duration and interpulse interval are systematically varied to quantify the importance of duration, interpulse interval, duty cycle, and modulation frequency independently. We find that, although modulation frequency is indeed an important parameter for some neurons, the responses of many neurons are also strongly influenced by other AM parameters, typically duration and duty cycle. These results suggest that AMs are represented in the auditory midbrain not only by their periodicity, but by a complex combination of several important parameters.

scholarly journals Discrimination of Communication Vocalizations by Single Neurons and Groups of Neurons in the Auditory Midbrain

2010 ◽  
Vol 103 (6) ◽  
pp. 3248-3265 ◽  
Author(s):  
David M. Schneider ◽  
Sarah M. N. Woolley
Keyword(s):  
Individual Recognition ◽  
Spike Trains ◽  
Single Neurons ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Bird Songs ◽  
Complex Sounds ◽  
Temporal Precision ◽  
Midbrain Neurons ◽  
Wide Range

Many social animals including songbirds use communication vocalizations for individual recognition. The perception of vocalizations depends on the encoding of complex sounds by neurons in the ascending auditory system, each of which is tuned to a particular subset of acoustic features. Here, we examined how well the responses of single auditory neurons could be used to discriminate among bird songs and we compared discriminability to spectrotemporal tuning. We then used biologically realistic models of pooled neural responses to test whether the responses of groups of neurons discriminated among songs better than the responses of single neurons and whether discrimination by groups of neurons was related to spectrotemporal tuning and trial-to-trial response variability. The responses of single auditory midbrain neurons could be used to discriminate among vocalizations with a wide range of abilities, ranging from chance to 100%. The ability to discriminate among songs using single neuron responses was not correlated with spectrotemporal tuning. Pooling the responses of pairs of neurons generally led to better discrimination than the average of the two inputs and the most discriminating input. Pooling the responses of three to five single neurons continued to improve neural discrimination. The increase in discriminability was largest for groups of neurons with similar spectrotemporal tuning. Further, we found that groups of neurons with correlated spike trains achieved the largest gains in discriminability. We simulated neurons with varying levels of temporal precision and measured the discriminability of responses from single simulated neurons and groups of simulated neurons. Simulated neurons with biologically observed levels of temporal precision benefited more from pooling correlated inputs than did neurons with highly precise or imprecise spike trains. These findings suggest that pooling correlated neural responses with the levels of precision observed in the auditory midbrain increases neural discrimination of complex vocalizations.

scholarly journals Novel brain gene-expression patterns are associated with a novel predaceous behaviour in tadpoles

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Cris C. Ledón-Rettig
Keyword(s):  
Gene Expression ◽  
Gene Networks ◽  
Expression Patterns ◽  
Gene Expression Patterns ◽  
The Novel ◽  
Brain Gene Expression ◽  
Larval Behaviour ◽  
Spadefoot Toad ◽  
Spea Bombifrons ◽  
Morphological Innovation

Novel behaviours can spur evolutionary change and sometimes even precede morphological innovation, but the evolutionary and developmental contexts for their origins can be elusive. One proposed mechanism to generate behavioural innovation is a shift in the developmental timing of gene-expression patterns underlying an ancestral behaviour, or molecular heterochrony. Alternatively, novel suites of gene expression, which could provide new contexts for signalling pathways with conserved behavioural functions, could promote novel behavioural variation. To determine the relative contributions of these alternatives to behavioural innovation, I used a species of spadefoot toad, Spea bombifrons . Based on environmental cues, Spea larvae develop as either of two morphs: ‘omnivores' that, like their ancestors, feed on detritus, or ‘carnivores' that are predaceous and cannibalistic. Because all anuran larvae undergo a natural transition to obligate carnivory during metamorphosis, it has been proposed that the novel, predaceous behaviour in Spea larvae represents the accelerated activation of gene networks influencing post-metamorphic behaviours. Based on comparisons of brain transcriptional profiles, my results reject widespread heterochrony as a mechanism promoting the expression of predaceous larval behaviour. They instead suggest that the evolution of this trait relied on novel patterns of gene expression that include components of pathways with conserved behavioural functions.

scholarly journals Asymmetric reproductive character displacement in male aggregation behaviour

2010 ◽  
Vol 278 (1716) ◽  
pp. 2348-2354 ◽  
Author(s):  
Karin S. Pfennig ◽  
Alyssa B. Stewart
Keyword(s):  
Mating Behaviour ◽  
Character Displacement ◽  
Mate Preferences ◽  
Reproductive Character Displacement ◽  
Spadefoot Toad ◽  
Reproductive Character ◽  
Aggregation Behaviour ◽  
Spea Bombifrons ◽  
Reproductive Activities ◽  
Aggregative Behaviour

Reproductive character displacement—the evolution of traits that minimize reproductive interactions between species—can promote striking divergence in male signals or female mate preferences between populations that do and do not occur with heterospecifics. However, reproductive character displacement can affect other aspects of mating behaviour. Indeed, avoidance of heterospecific interactions might contribute to spatial (or temporal) aggregation of conspecifics. We examined this possibility in two species of hybridizing spadefoot toad (genus Spea ). We found that in Spea bombifrons sympatric males were more likely than allopatric males to associate with calling males. Moreover, contrary to allopatric males, sympatric S. bombifrons males preferentially associated with conspecific male calls. By contrast, Spea multiplicata showed no differences between sympatry and allopatry in likelihood to associate with calling males. Further, sympatric and allopatric males did not differ in preference for conspecifics. However, allopatric S. multiplicata were more variable than sympatric males in their responses. Thus, in S. multiplicata , character displacement may have refined pre-existing aggregation behaviour. Our results suggest that heterospecific interactions can foster aggregative behaviour that might ultimately contribute to clustering of conspecifics. Such clustering can generate spatial or temporal segregation of reproductive activities among species and ultimately promote reproductive isolation.

scholarly journals Stimulus-frequency-dependent dominance of sound localization cues across the cochleotopic map of the inferior colliculus

2020 ◽  
Vol 123 (5) ◽  
pp. 1791-1807 ◽  
Author(s):  
Ryan Dorkoski ◽  
Kenneth E. Hancock ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
Noelle C. Stroud ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Division Of Labor ◽  
Sound Localization ◽  
High Frequency ◽  
Stimulus Frequency ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Sound Sources ◽  
High Frequencies ◽  
Midbrain Neurons

A “division of labor” has previously been assumed in which the directions of low- and high-frequency sound sources are thought to be encoded by neurons preferentially sensitive to low and high frequencies, respectively. Contrary to this, we found that auditory midbrain neurons encode the directions of both low- and high-frequency sounds regardless of their preferred frequencies. Neural responses were shaped by different sound localization cues depending on the stimulus spectrum—even within the same neuron.

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