Directional hearing in grasshoppers: neurophysiological testing of a bioacoustic model

1999 ◽  
Vol 202 (2) ◽  
pp. 121-133 ◽  
Author(s):  
J. Schul ◽  
M. Holderied ◽  
D.V. Helversen ◽  
O.V. Helversen
Keyword(s):  
Schistocerca Gregaria ◽  
Neuronal Response ◽  
Individual Variability ◽  
Biophysical Model ◽  
Directional Hearing ◽  
Complex Stimulus ◽  
Directional Information ◽  
Model Calculations ◽  
Chorthippus Biguttulus ◽  
Nerve Recordings

A recently proposed biophysical model for directional hearing in grasshoppers was tested using complex stimulus situations, with two loudspeakers, one on either side of the animal, synchronously emitting sinusoids with defined phase and amplitude relationships. Hearing responses were determined from whole nerve recordings and compared with the predictions of the model. In Schistocerca gregaria, there were only minor differences between the predictions of the model and measurements and, by reducing the value of the gain of the internal sound path measured previously, a close agreement was achieved between model and measured hearing responses. In Chorthippus biguttulus, larger discrepancies between model calculations using the values measured previously and neuronal response functions were found in both shape and amplitude. A better fit between measurements and model predictions was achieved by increasing the values of the internal delay over those measured previously. The measurements presented here indicate high inter-individual variability of the parameters of the internal pathway, with a range of 60 degrees for the internal phase delay. Calculating the directional characteristics using this range of values for the internal delay indicated that sufficient directional information was available down to 5 kHz. Increasing the value of the internal delay over that measured in an earlier study therefore provides an explanation for the discrepancy between the poor directional information attributed to C. biguttulus in that study and the excellent lateralization ability of males of this species at 5 kHz.

Directional sound processing and interaural sound transmission in a small and a large grasshopper

1995 ◽  
Vol 198 (9) ◽  
pp. 1817-1827 ◽  
Author(s):  
A Michelsen ◽  
K Rohrseitz
Keyword(s):  
Outer Surface ◽  
Sound Pressure ◽  
Schistocerca Gregaria ◽  
Sound Transmission ◽  
Directional Hearing ◽  
Sound Processing ◽  
Low Frequencies ◽  
High Frequencies ◽  
Physical Mechanisms ◽  
Chorthippus Biguttulus

Physical mechanisms involved in directional hearing are investigated in two species of short-horned grasshoppers that differ in body length by a factor of 3­4. The directional cues (the effects of the direction of sound incidence on the amplitude and phase angle of the sounds at the ears) are more pronounced in the larger animal, but the scaling is not simple. At high frequencies (10­20 kHz), the sound pressures at the ears of the larger species (Schistocerca gregaria) differ sufficiently to provide a useful directionality. In contrast, at low frequencies (3­5 kHz), the ears must be acoustically coupled and work as pressure difference receivers. At 3­5 kHz, the interaural sound transmission is approximately 0.5 (that is, when a tympanum is driven by a sound pressure of unit amplitude at its outer surface, the tympanum of the opposite ear receives a sound pressure with an amplitude of 0.5 through the interaural pathway). The interaural transmission decreases with frequency, and above 10 kHz it is only 0.1­0.2. It still has a significant effect on the directionality, however, because the directional cues are large. In the smaller species (Chorthippus biguttulus), the interaural sound transmission is also around 0.5 at 5 kHz, but the directionality is poor. The reason for this is not the modest directional cues, but rather the fact that the transmitted sound is not sufficiently delayed for the ear to exploit the directional cues. Above 7 kHz, the transmission increases to approximately 0.8 and the transmission delay increases; this allows the ear to become more directional, despite the still modest directional cues.

scholarly journals Fear signaling in the prelimbic-amygdala circuit: a computational modeling and recording study

2013 ◽  
Vol 110 (4) ◽  
pp. 844-861 ◽  
Author(s):  
Sandeep Pendyam ◽  
Christian Bravo-Rivera ◽  
Anthony Burgos-Robles ◽  
Francisco Sotres-Bayon ◽  
Gregory J. Quirk ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Fear Conditioning ◽  
Large Scale ◽  
Conditioned Fear ◽  
Individual Variability ◽  
Biophysical Model ◽  
Human Homolog ◽  
Lateral Amygdala ◽  
Internal Inhibition ◽  
Β Blocker

The acquisition and expression of conditioned fear depends on prefrontal-amygdala circuits. Auditory fear conditioning increases the tone responses of lateral amygdala neurons, but the increase is transient, lasting only a few hundred milliseconds after tone onset. It was recently reported that that the prelimbic (PL) prefrontal cortex transforms transient lateral amygdala input into a sustained PL output, which could drive fear responses via projections to the lateral division of basal amygdala (BL). To explore the possible mechanisms involved in this transformation, we developed a large-scale biophysical model of the BL-PL network, consisting of 850 conductance-based Hodgkin-Huxley-type cells, calcium-based learning, and neuromodulator effects. The model predicts that sustained firing in PL can be derived from BL-induced release of dopamine and norepinephrine that is maintained by PL-BL interconnections. These predictions were confirmed with physiological recordings from PL neurons during fear conditioning with the selective β-blocker propranolol and by inactivation of BL with muscimol. Our model suggests that PL has a higher bandwidth than BL, due to PL's decreased internal inhibition and lower spiking thresholds. It also suggests that variations in specific microcircuits in the PL-BL interconnection can have a significant impact on the expression of fear, possibly explaining individual variability in fear responses. The human homolog of PL could thus be an effective target for anxiety disorders.

scholarly journals Plasticity of behavioural variability reflects conflicting selection in group-living and solitary desert locusts

2020 ◽  
Author(s):  
Ben Cooper ◽  
Jonathan M. Smith ◽  
Tom Matheson ◽  
Swidbert R. Ott
Keyword(s):  
Empirical Evidence ◽  
Schistocerca Gregaria ◽  
Group Living ◽  
Social Contexts ◽  
Individual Variability ◽  
Intrinsic Variability ◽  
Selection Pressures ◽  
Phase Polyphenism ◽  
Log Normal ◽  
The Individual

Animals living in groups tend to express less variable behaviour than animals living alone. It is widely assumed that this difference reflects, at least in part, an adaptive response to contrasting selection pressures: group-living should favour the evolution of more uniform behaviour whereas lone-living should favour behaviour that is less predictable. Empirical evidence linking these contrasting selection pressures to intrinsic differences in behavioural variability is, however, largely lacking. The desert locust, Schistocerca gregaria, manifests in two very distinct eco-phenotypes, a lone-living cryptic “solitarious phase” and a swarming “gregarious phase” that aggregates into very large and dense groups. This “phase polyphenism” has evolved in response to contrasting selection pressures that change rapidly and unpredictably. Phase differences in mean behaviour are well-characterised, but no previous study has considered differences in variability. Here we used locust phase polyphenism to test the hypothesis that group living leads to the evolution of reduced intrinsic variability in behaviour. We measured two behaviours in both phenotypes: locomotor activity in the presence of conspecifics, and locomotor hesitation in approaching food when alone. We assayed each individual repeatedly and estimated variability relative to the mean in log-normal mixed-effects models that explicitly account for the means-variance dependency in the behavioural measures. Our results demonstrate that relative behavioural variability differs between the two phases in line with predictions from ecological theory: both within-individual and between-individual variability were lower in the group-living gregarious phenotype. This contrasts with previous studies on social niche construction in spiders and crickets, and highlights the importance of social ecology: in animals that form non-social collectives, such as locusts, reduced individual behavioural variability is key for coherent collective behaviour. The differences in variability persisted when gregarious locusts were tested in isolation and solitarious locusts were tested in groups, indicating that they arise not simply as flexible reactions to different social contexts, but are intrinsic to the individual animals of each phase. This “variance polyphenism” in locusts provides empirical evidence that evolutionary adaptation for group living has driven a reduction in within- and between-individual behavioural variability.

scholarly journals Phonotactic steering and representation of directional information in the ascending auditory pathway of a cricket

2020 ◽  
Vol 123 (3) ◽  
pp. 865-875 ◽  
Author(s):  
M. Lv ◽  
X. Zhang ◽  
B. Hedwig
Keyword(s):  
Longitudinal Axis ◽  
Auditory Pathway ◽  
Response Strength ◽  
Acoustic Stimulation ◽  
Directional Hearing ◽  
Directional Information ◽  
Significant Difference ◽  
Auditory Interneuron ◽  
Bilateral Differences ◽  
The Brain

Directional hearing is crucial for animals depending on acoustic signals to locate a mate. We focused on crickets to explore the reliability of directional information forwarded to the brain by the ascending auditory interneuron AN1, which is crucial for phonotactic behavior. We presented calling song from −45° to +45° in steps of 3° and compared the phonotactic steering of females walking on a trackball with the directional responses of AN1. Forty percent of females showed good steering behavior and changed their walking direction when the speaker passed the body’s longitudinal axis. The bilateral latency difference between right and left AN1 responses was small and may not be reliable for auditory steering. In respect to spike count, all AN1 recordings presented significant bilateral differences for angles larger than ±18°, yet 35% showed a mean significant difference of 1–3 action potentials per chirp when the frontal stimulus deviated by 3° from their length axis. For small angles, some females had a very similar AN1 activity forwarded to the brain, but the accuracy of their steering behavior was substantially different. Our results indicate a correlation between directional steering and the response strength of AN1, especially for large angles. The reliable steering of animals at small angles would have to be based on small bilateral differences of AN1 activity, if AN1 is the only source providing directional information. We discuss whether such bilateral response difference at small angles can provide a reliable measure to generate auditory steering commands descending from the brain, as pattern recognition is intensity independent. NEW & NOTEWORTHY The ascending auditory interneuron AN1 has been implicated in cricket auditory steering, but at small acoustic stimulation angles, it does not provide reliable directional information. We conclude that either the small bilateral auditory activity differences of the AN1 neurons are enhanced to generate reliable descending steering commands or, more likely, directional auditory steering is mediated via a thoracic pathway, as indicated by the reactive steering hypothesis.

Directional hearing of a grasshopper in the field

2000 ◽  
Vol 203 (6) ◽  
pp. 983-993 ◽  
Author(s):  
F. Gilbert ◽  
N. Elsner
Keyword(s):  
Sound Field ◽  
Contralateral Side ◽  
Directional Hearing ◽  
Natural Habitats ◽  
Nerve Activity ◽  
Sparse Vegetation ◽  
Dense Vegetation ◽  
Field Situation ◽  
Chorthippus Biguttulus ◽  
Similar Accuracy

An electrophysiological method for making long-term recordings from the tympanal nerve was developed in Chorthippus biguttulus (Gomphocerinae) to gain insight into the ecophysiological constraints of sound localization in acridid grasshoppers. Using this ‘biological microphone’, the directional dependence of auditory nerve activity was monitored both in the laboratory and in various natural habitats of this species. On gravel and in sparse vegetation, the overall patterns of directionality were found to be very similar to those in the free sound field in the laboratory, regardless of whether the animal was positioned horizontally or vertically. However, the differences between the ipsi- and contralateral sides were smaller in these habitats than in the laboratory. In dense vegetation, the directional patterns were greatly affected by the environment. Moreover, a minimum in nerve activity was not always reached on the contralateral side, as is typical for the free sound field situation. On the basis of these data, predictions can be made about the ability of the animals to determine the correct side of a sound source. In the free sound field of the laboratory, correct lateralizations are expected at all angles of sound incidence between 20 and 160 degrees, a prediction corresponding to the results of behavioural studies. In sparse vegetation, a similar accuracy can be anticipated, whereas on gravel and in dense vegetation directional hearing is expected to be severely degraded, especially if the animal is oriented horizontally. The predictions from our present electrophysiological investigations must now be confirmed by behavioural studies in the field.

Directional Hearing in the Japanese Quail (Coturnix Coturnix Japonica): II. Cochlear Physiology

1980 ◽  
Vol 86 (1) ◽  
pp. 153-170
Author(s):  
R. B. COLES ◽  
D. B. LEWIS ◽  
K. G. HILL ◽  
M. E. HUTCHINGS ◽  
D. M. GOWER
Keyword(s):  
Pressure Gradient ◽  
Free Field ◽  
Directional Hearing ◽  
Directional Sensitivity ◽  
Ear Canal ◽  
Directional Information ◽  
Cochlear Physiology ◽  
Directivity Patterns ◽  
The Difference ◽  
Sound Diffraction

The directional sensitivity of cochlear microphonics (CM) was studied inthe quail by rotating a free-field sound source (pure tones, 160-10 kHz)through 360° in the horizontal plane, under anechoic conditions. Sound diffraction by the head was monitored simultaneously by a microphone at the entrance to the ipsilateral (recorded) ear canal. Pressure-field fluctuations measured by the microphone were non-directional (≤ 4 dB) up to 4 kHz; the maximum head shadow was 8 dB at 6.3 kHz. In comparison, the CM sensitivity under went directional fluctuations ranging up to 25 dB for certain low, mid and high frequency band widths. There was noticeable variation between quail for frequencies producing maximum directional effects, although consistently poor directionality was seen near 820 Hz andto a lesser extent near 3.5 kHz. Well-defined CM directivity patterns reflected the presence of nulls (insensitive regions) at critical positions around the head and the number of nulls increased with frequency. Five major types of directivity patterns were defined using polar co-ordinates: cardioid, supercardioid, figure-of-eight, tripartite and multilobed. Such patterns were largely unrelated to head shadow effects. Blocking the ear canal contralateral to there corded ear was shown to effectively abolish CM directionality, largely by eliminating regions of insensitivity to sound. It is inferred that the quail ear functions as an asym metrical pressure gradient receiver, the pressure gradient function being mediated by the interauralcavity. It is proposed that the central auditory system codes directional information by a null detecting method and computes an unambiguous (i.e.intensity independent) directional cue. This spatial cue is achieved by the difference between the directional sensitivities of the two ears, defined as the Directional Index (DI). The spatial distribution of DI values (difference pattern) demonstrated ranges and peaks which closely reflected the extent and position of nulls determined from monaural directivity functions. Large directional cues (up to 25 dB) extended throughout most of the audible spectrum of the quail and the sharpness of difference patterns increased with frequency. Primary ‘best’ directions, estimated from peaks in difference patterns, tended to move towards the front of the head at higher frequencies; rearward secondary peaks also occurred. From the properties of directional cues it is suggested that the ability of birds to localize sound need not necessarily depend on frequency; however, spatial acuity may be both frequency and direction dependent, and include the possibility of front-torearerrors. The directional properties of bird vocalizations may need to bere assessed on the basis of the proposed mechanism for directional hearing.

scholarly journals Impact of functional synapse clusters on neuronal response selectivity

2019 ◽  
Author(s):  
Balázs B Ujfalussy ◽  
Judit K Makara
Keyword(s):  
Large Scale ◽  
Pyramidal Neurons ◽  
Neuronal Response ◽  
Cluster Formation ◽  
Biophysical Model ◽  
Functional Clustering ◽  
Synaptic Interactions ◽  
Nonlinear Amplification ◽  
Output Transformation

SummaryClustering of functionally similar synapses in dendrites is thought to affect input-output transformation by inducing dendritic nonlinearities. However, neither the in vivo impact of synaptic clusters on somatic membrane potential (sVm), nor the rules of cluster formation are elucidated. We developed a computational approach to measure the effect of functional synaptic clusters on sVm response of biophysical model CA1 and L2/3 pyramidal neurons to behaviorally relevant in vivo-like inputs. Large-scale dendritic spatial inhomogeneities in synaptic tuning properties did influence sVm, but small synaptic clusters appearing randomly with unstructured connectivity did not. With structured connectivity, ~10-20 synapses per cluster was optimal for clustering-based tuning, but larger responses were achieved by 2-fold potentiation of the same synapses. We further show that without nonlinear amplification of the effect of random clusters, action potential-based, global plasticity rules can not generate functional clustering. Our results suggest that clusters likely form via local synaptic interactions, and have to be moderately large to impact sVm responses.

Principal and Independent Components of Macaque Vocalizations: Constructing Stimuli to Probe High-Level Sensory Processing

2004 ◽  
Vol 91 (6) ◽  
pp. 2897-2909 ◽  
Author(s):  
Bruno B. Averbeck ◽  
Lizabeth M. Romanski
Keyword(s):  
Neuronal Response ◽  
Principal Component ◽  
Component Analysis ◽  
Complex Stimulus ◽  
Sensory Stimuli ◽  
Independent Components ◽  
Novel Approach ◽  
Original Stimulus ◽  
Complex Features ◽  
High Level

Neurons in high-level sensory cortical areas respond to complex features in sensory stimuli. Feature elimination is a useful technique for studying these responses. In this approach, a complex stimulus, which evokes a neuronal response, is simplified, and if the cell responds to the reduced stimulus, it is considered selective for the remaining features. We have developed a feature-elimination technique that uses either the principal or the independent components of a stimulus to define a subset of features, to which a neuron might be sensitive. The original stimulus can be filtered using these components, resulting in a stimulus that retains only a fraction of the features present in the original. We demonstrate the use of this technique on macaque vocalizations, an important class of stimuli being used to study auditory function in awake, behaving primate experiments. We show that principal-component analysis extracts features that are closely related to the dominant Fourier components of the stimuli, often called formants in the study of speech perception. Conversely, independent-component analysis extracts features that preserve the relative phase across a set of harmonically related frequencies. We have used several statistical techniques to explore the original and filtered stimuli, as well as the components extracted by each technique. This novel approach provides a powerful method for determining the essential features within complex stimuli that activate higher-order sensory neurons.

scholarly journals Sex-specific speed–accuracy trade-offs shape neural processing of acoustic signals in a grasshopper

2021 ◽  
Vol 288 (1945) ◽  
pp. 20210005
Author(s):  
Jan Clemens ◽  
Bernhard Ronacher ◽  
Michael S. Reichert
Keyword(s):  
Temporal Integration ◽  
Neural Model ◽  
Integration Time ◽  
Directional Information ◽  
Trade Offs ◽  
Neural Integration ◽  
Chorthippus Biguttulus ◽  
Low Threshold ◽  
Courtship Signals ◽  
Speed Accuracy

Speed–accuracy trade-offs—being fast at the risk of being wrong—are fundamental to many decisions and natural selection is expected to resolve these trade-offs according to the costs and benefits of behaviour. We here test the prediction that females and males should integrate information from courtship signals differently because they experience different pay-offs along the speed–accuracy continuum. We fitted a neural model of decision making (a drift–diffusion model of integration to threshold) to behavioural data from the grasshopper Chorthippus biguttulus to determine the parameters of temporal integration of acoustic directional information used by male grasshoppers to locate receptive females. The model revealed that males had a low threshold for initiating a turning response, yet a large integration time constant enabled them to continue to gather information when cues were weak. This contrasts with parameters estimated for females of the same species when evaluating potential mates, in which response thresholds were much higher and behaviour was strongly influenced by unattractive stimuli. Our results reveal differences in neural integration consistent with the sex-specific costs of mate search: males often face competition and need to be fast, while females often pay high error costs and need to be deliberate.

Sign in / Sign up

Export Citation Format

Share Document