scholarly journals Echolocating whales use ultra-fast echo-kinetic responses to track evasive prey.

2021 ◽  
Author(s):  
Heather M Vance ◽  
Peter T Madsen ◽  
Natacha Aguilar de Soto ◽  
Danuta M Wisniewska ◽  
Michael Ladegaard ◽  
...  
Keyword(s):  
High Resolution ◽  
Information Flow ◽  
Response Times ◽  
Moving Target ◽  
Neural Processing ◽  
Neural Responses ◽  
Predator Prey ◽  
Prey Escape ◽  
Escape Responses ◽  
Fast Acting

Visual predators rely on fast-acting optokinetic reflexes to track and capture agile prey. Most toothed whales, however, rely on echolocation for hunting and have converged on biosonar clicking rates reaching 500/s during prey pursuits. If echoes are processed on a click-by-click basis, as assumed, neural responses 100x faster than those in vision are required to keep pace with this information flow. Using high-resolution bio-logging of wild predator-prey interactions we show that toothed whales adjust clicking rates to track prey movement within 50-200ms of prey escape responses. Hypothesising that these stereotyped biosonar adjustments are elicited by sudden prey accelerations, we measured echo-kinetic responses from trained harbour porpoises to a moving target and found similar latencies. High biosonar sampling rates are, therefore, not supported by extreme speeds of neural processing and muscular responses. Instead, the neuro-kinetic response times in echolocation are similar to those of tracking reflexes in vision, suggesting a common neural underpinning.

scholarly journals Echolocating toothed whales use ultra-fast echo-kinetic responses to track evasive prey

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Heather Vance ◽  
Peter T Madsen ◽  
Natacha Aguilar de Soto ◽  
Danuta Maria Wisniewska ◽  
Michael Ladegaard ◽  
...  
Keyword(s):  
Information Flow ◽  
Response Times ◽  
Moving Target ◽  
Neural Processing ◽  
Neural Responses ◽  
Predator Prey ◽  
Optokinetic Responses ◽  
Prey Escape ◽  
Escape Responses ◽  
Fast Acting

Visual predators rely on fast-acting optokinetic responses to track and capture agile prey. Most toothed whales, however, rely on echolocation for hunting and have converged on biosonar clicking rates reaching 500/s during prey pursuits. If echoes are processed on a click-by-click basis, as assumed, neural responses 100× faster than those in vision are required to keep pace with this information flow. Using high-resolution biologging of wild predator-prey interactions, we show that toothed whales adjust clicking rates to track prey movement within 50–200 ms of prey escape responses. Hypothesising that these stereotyped biosonar adjustments are elicited by sudden prey accelerations, we measured echo-kinetic responses from trained harbour porpoises to a moving target and found similar latencies. High biosonar sampling rates are, therefore, not supported by extreme speeds of neural processing and muscular responses. Instead, the neurokinetic response times in echolocation are similar to those of tracking responses in vision, suggesting a common neural underpinning.

Adaptive Sparse Recovery of Moving Targets for Distributed MIMO Radar

2014 ◽  
Vol 933 ◽  
pp. 450-455
Author(s):  
Hui Yu ◽  
Guang Hua Lu ◽  
Hai Long Zhang
Keyword(s):  
High Resolution ◽  
Sparse Recovery ◽  
Mimo Radar ◽  
Moving Target ◽  
Recovery Algorithm ◽  
Low Snr ◽  
Computation Efficiency ◽  
Target Imaging ◽  
Moving Target Imaging ◽  
Recovery Error

The high resolution and better recovery performance with distributed MIMO radar would be significantly degraded when the target moves at an unknown velocity. In this paper, we propose an adaptive sparse recovery algorithm for moving target imaging to estimate the velocity and image jointly with high computation efficiency. With an iteration mechanism, the proposed method updates the image and estimates the velocity alternately by sequentially minimizing the norm and the recovery error. Numerical simulations are carried out to demonstrate that the proposed algorithm can retrieve high-resolution image and accurate velocity simultaneously even in low SNR.

scholarly journals Subjective social status and neural processing of race in Mexican American adolescents

2018 ◽  
Vol 30 (5) ◽  
pp. 1837-1848 ◽  
Author(s):  
Keely A. Muscatell ◽  
Ethan McCormick ◽  
Eva H. Telzer
Keyword(s):  
Social Status ◽  
Mexican American ◽  
Educational Background ◽  
Subjective Social Status ◽  
Sensitive Period ◽  
Neural Processing ◽  
Neural Responses ◽  
Black And White ◽  
Face Area ◽  
Mexican American Adolescents

AbstractAdolescence is a sensitive period for sociocultural development in which facets of social identity, including social status and race, become especially salient. Despite the heightened importance of both social status and race during this developmental period, no known work has examined how individual differences in social status influence perceptions of race in adolescents. Thus, in the present study, we investigated how both subjective social status and objective socioeconomic status (SES) influence neural responses to race. Twenty-three Mexican American adolescents (15 females; mean age = 17.22 years) were scanned using functional magnetic resonance imaging while they viewed Black and White faces in a standard labeling task. Adolescents rated their subjective social status in US society, while their parents responded to questions about their educational background, occupation, and economic strain (objective SES). Results demonstrated a negative association between subjective social status and neural responses in the amygdala, fusiform face area, and medial prefrontal cortex when adolescents viewed Black (relative to White) faces. In other words, adolescents with lower subjective social status showed greater activity in neural regions involved in processing salience, perceptual expertise, and thinking about the minds of others when they viewed images of Black faces, suggesting enhanced salience of race for these youth. There was no relationship between objective SES and neural responses to the faces. Moreover, instructing participants to focus on the gender or emotion expression on the face attenuated the relationship between subjective social status and neural processing of race. Together, these results demonstrate that subjective social status shapes the way the brain responds to race, which may have implications for psychopathology.

The effect of size on the fast-start performance of rainbow trout Salmo gairdneri, and a consideration of piscivorous predator-prey interactions

1976 ◽  
Vol 65 (1) ◽  
pp. 157-177 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Rainbow Trout ◽  
Reaction Time ◽  
Reaction Times ◽  
The Body ◽  
Salmo Gairdneri ◽  
Escape Behaviour ◽  
Predator Prey ◽  
Average Value ◽  
Fast Start ◽  
Prey Escape

The fast-start (acceleration) performance of seven groups of rainbow trout from 9-6 to 38-7 cm total length was measured in response to d.c. electric shock stimuli. Two fast-start kinematic patterns, L- and S-start were observed. In L-starts the body was bent into an L or U shape and a recoil turn normally accompanied acceleration. Free manoeuvre was not possible in L-starts without loss of speed. In S-starts the body was bent into an S-shape and fish accelerated without a recoil turn. The frequency of S-starts increased with size from 0 for the smallest fish to 60–65% for the largest fish. Acceleration turns were common. The radius of smallest turn for both fast-start patterns was proportional to length (L) with an overall radius of 0–17 L. The duration of the primary acceleration stages increased with size from 0–07 s for the group of smallest fish to 0–10 s for the group of largest fish. Acceleration rates were independent of size. The overall mean maximum rate was 3438 cm/s2 and the average value to the end of the primary acceleration movements was 1562 cm/s2. The distance covered and velocity attained after a given time for fish accelerating from rest were independent of size. The results are discussed in the context of interactions between a predator and prey fish following initial approach by the predator. It is concluded that the outcome of an interaction is likely to depend on reaction times of interacting fish responding to manoeuvres initiated by the predator or prey. The prey reaction time results in the performance of the predator exceeding that of the prey at any instant. The predator reaction time and predator error in responses to unpredictable prey manoeuvre are required for prey escape. It is predicted that a predator should strike the prey within 0-1 s if the fish are initially 5–15 cm apart as reported in the literature for predator-prey interactions. These distances would be increased for non-optimal prey escape behaviour and when the prey body was more compressed or depressed than the predator.

Subfornical organ efferents to paraventricular nucleus utilize angiotensin as a neurotransmitter

1993 ◽  
Vol 265 (2) ◽  
pp. R302-R309 ◽  
Author(s):  
Z. Li ◽  
A. V. Ferguson
Keyword(s):  
Electrical Stimulation ◽  
Paraventricular Nucleus ◽  
Response Times ◽  
Subfornical Organ ◽  
Ang Ii ◽  
Neural Responses ◽  
Local Pressure ◽  
Electrophysiological Studies ◽  
Excitatory Responses ◽  
Control Stimulation

In this study, we have utilized electrophysiological single unit recordings to evaluate the effects of nonpeptidergic angiotensin II (ANG II) antagonists on neural responses of hypothalamic paraventricular nucleus (PVN) neurons to either electrical stimulation in subfornical organ (SFO) or direct application of ANG II. Electrical stimulation (200-400 microA; 0.1 ms) in the SFO resulted in excitatory responses in 36 of 50 PVN neurons tested. Peristimulus histogram analysis of such excitatory effects demonstrated latencies of < 30 ms and variability of response times of approximately 50 ms in 14 of these 36 neurons. In view of previous anatomic and electrophysiological studies such inputs were therefore considered to be monosynaptically mediated by direct neural inputs from the SFO. The remaining 22 cells excited by such SFO stimulation showed responses of longer latency and duration suggestive of a different underlying synaptic mechanism. Local pressure ejection of ANG II into the PVN resulted in increased neural activity in 50% (9 of 18) of the neurons tested. After systemic (3 mg/kg iv) or local (2 x 10(-2) M; 1-25 s; 2-40 psi) microinjection of the nonpeptidergic angiotensin II1 (AT1) receptor antagonist losartan, SFO excitations were attenuated in 63.9% (23 of 36) of the PVN neurons tested, such pharmacologically blocked excitatory responses being reduced by 68.3 +/- 5.2% from control stimulation effects (P < 0.001). Similar losartan-induced attenuations of both short latency (presumed monosynaptic) (50.0%) and longer latency (72.7%) responses were observed. In addition, losartan also abolished the excitatory effects of local administration of ANG II on 77.8% (7 of 9) of ANG II-sensitive neurons in PVN tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Neural Processing of Amplitude-Modulated Sounds

2004 ◽  
Vol 84 (2) ◽  
pp. 541-577 ◽  
Author(s):  
P. X. JORIS ◽  
C. E. SCHREINER ◽  
A. REES
Keyword(s):  
Modulation Depth ◽  
Average Rate ◽  
Modulation Frequency ◽  
Limited Range ◽  
Neural Processing ◽  
Neural Responses ◽  
Critical Stimulus ◽  
Stimulus Attribute ◽  
Neural Architecture ◽  
Physiological Properties

Joris, P. X., C. E. Schreiner, and A. Rees. Neural Processing of Amplitude-Modulated Sounds. Physiol Rev 84: 541–577, 2004; 10.1152/physrev.00029.2003.—Amplitude modulation (AM) is a temporal feature of most natural acoustic signals. A long psychophysical tradition has shown that AM is important in a variety of perceptual tasks, over a range of time scales. Technical possibilities in stimulus synthesis have reinvigorated this field and brought the modulation dimension back into focus. We address the question whether specialized neural mechanisms exist to extract AM information, and thus whether consideration of the modulation domain is essential in understanding the neural architecture of the auditory system. The available evidence suggests that this is the case. Peripheral neural structures not only transmit envelope information in the form of neural activity synchronized to the modulation waveform but are often tuned so that they only respond over a limited range of modulation frequencies. Ascendingthe auditory neuraxis, AM tuning persists but increasingly takes the form of tuning in average firing rate, rather than synchronization, to modulation frequency. There is a decrease in the highest modulation frequencies that influence the neural response, either in average rate or synchronization, as one records at higher and higher levels along the neuraxis. In parallel, there is an increasing tolerance of modulation tuning for other stimulus parameters such as sound pressure level, modulation depth, and type of carrier. At several anatomical levels, consideration of modulation response properties assists the prediction of neural responses to complex natural stimuli. Finally, some evidence exists for a topographic ordering of neurons according to modulation tuning. The picture that emerges is that temporal modulations are a critical stimulus attribute that assists us in the detection, discrimination, identification, parsing, and localization of acoustic sources and that this wide-ranging role is reflected in dedicated physiological properties at different anatomical levels.

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