scholarly journals Deimatism: a neglected component of antipredator defence

2017 ◽  
Vol 13 (4) ◽  
pp. 20160936 ◽  
Author(s):  
Kate D. L. Umbers ◽  
Sebastiano De Bona ◽  
Thomas E. White ◽  
Jussi Lehtonen ◽  
Johanna Mappes ◽  
...  
Keyword(s):  
Sensory Input ◽  
Sudden Change ◽  
Fundamental Difference ◽  
Neural Mechanisms ◽  
Survival Advantage ◽  
Antipredator Defence

Deimatic or ‘startle’ displays cause a receiver to recoil reflexively in response to a sudden change in sensory input. Deimatism is sometimes implicitly treated as a form of aposematism (unprofitability associated with a signal). However, the fundamental difference is, in order to provide protection, deimatism does not require a predator to have any learned or innate aversion. Instead, deimatism can confer a survival advantage by exploiting existing neural mechanisms in a way that releases a reflexive response in the predator. We discuss the differences among deimatism, aposematism, and forms of mimicry, and their ecological and evolutionary implications. We highlight outstanding questions critical to progress in understanding deimatism.

The Neurophysiological Basis of the Auditory Continuity Illusion: A Mismatch Negativity Study

2003 ◽  
Vol 15 (5) ◽  
pp. 747-758 ◽  
Author(s):  
Christophe Micheyl ◽  
Robert P. Carlyon ◽  
Yury Shtyrov ◽  
Olaf Hauk ◽  
Tara Dodson ◽  
...  
Keyword(s):  
Mismatch Negativity ◽  
Sudden Change ◽  
Frequency Region ◽  
Neural Mechanisms ◽  
Oddball Paradigm ◽  
Standard Type ◽  
Upper Limit ◽  
Noise Frequency ◽  
Filtered Noise ◽  
Neurophysiological Basis

A sound turned off for a short moment can be perceived as continuous if the silent gap is filled with noise. The neural mechanisms underlying this “continuity illusion” were investigated using the mismatch negativity (MMN), an eventrelated potential reflecting the perception of a sudden change in an otherwise regular stimulus sequence. The MMN was recorded in four conditions using an oddball paradigm. The standards consisted of 500-Hz, 120-msec tone pips that were either physically continuous (Condition 1) or were interrupted by a 40-msec silent gap (Condition 2). The deviants consisted of the interrupted tone, but with the silent gap filled by a burst of bandpass-filtered noise. The noise either occupied the same frequency region as the tone and elicited the continuity illusion (Conditions 1a and 2a), or occupied a remote frequency region and did not elicit the illusion (Conditions 1b and 2b). We predicted that, if the continuity illusion is determined before MMN generation, then, other things being equal, the MMN should be larger in conditions where the deviants are perceived as continuous and the standards as interrupted or vice versa, than when both were perceived as continuous or both interrupted. Consistent with this prediction, we observed an interaction between standard type and noise frequency region, with the MMN being larger in Condition 1a than in Condition 1b, but smaller in Condition 2a than in Condition 2b. Because the subjects were instructed to ignore the tones and watch a silent movie during the recordings, the results indicate that the continuity illusion can occur outside the focus of attention. Furthermore, the latency of the MMN (less than approximately 200 msec postdeviance onset) places an upper limit on the stage of neural processing responsible for the illusion.

scholarly journals Numerosities and Other Magnitudes in the Brains: A Comparative View

2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Lorenzi ◽  
Matilde Perrino ◽  
Giorgio Vallortigara
Keyword(s):  
Neural Networks ◽  
Nervous System ◽  
Artificial Neural Networks ◽  
Sensory Input ◽  
Animal Species ◽  
Neural Mechanisms ◽  
Number Cognition ◽  
Underlying Mechanisms ◽  
Taxonomic Groups ◽  
Basic Similarity

The ability to represent, discriminate, and perform arithmetic operations on discrete quantities (numerosities) has been documented in a variety of species of different taxonomic groups, both vertebrates and invertebrates. We do not know, however, to what extent similarity in behavioral data corresponds to basic similarity in underlying neural mechanisms. Here, we review evidence for magnitude representation, both discrete (countable) and continuous, following the sensory input path from primary sensory systems to associative pallial territories in the vertebrate brains. We also speculate on possible underlying mechanisms in invertebrate brains and on the role played by modeling with artificial neural networks. This may provide a general overview on the nervous system involvement in approximating quantity in different animal species, and a general theoretical framework to future comparative studies on the neurobiology of number cognition.

scholarly journals Individual differences in the influence of mental imagery on conscious perception

2019 ◽  
Author(s):  
N. Dijkstra ◽  
M. Hinne ◽  
S.E. Bosch ◽  
M.A.J. van Gerven
Keyword(s):  
Mental Imagery ◽  
Cognitive Processes ◽  
Sensory Input ◽  
Neural Mechanisms ◽  
Conscious Perception ◽  
Group Level ◽  
Response Curves ◽  
Bayesian Hierarchical ◽  
Sensory Evidence ◽  
As Effects

AbstractMental imagery and visual perception rely on similar neural mechanisms, but the function of this overlap remains unclear. One idea is that imagery can influence perception. Previous research has shown that imagining a stimulus prior to binocular presentation of rivalling stimuli increases the chance of perceiving the imagined stimulus. In this study we investigated how this effect interacts with bottom-up sensory input by comparing psychometric response curves for congruent and incongruent imagery in humans. A Bayesian hierarchical model was used, allowing us to simultaneously study group-level effects as well as effects for individual participants. We found strong effects of both imagery as well as its interaction with sensory evidence within individual participants. However, the direction of these effects were highly variable between individuals, leading to weak effects at the group level. This highlights the heterogeneity of conscious perception and emphasizes the need for individualized investigation of such complex cognitive processes.

Development of Attention Networks

2013 ◽  
pp. 682-705 ◽  
Author(s):  
M. Rosario Rueda ◽  
Michael I. Posner
Keyword(s):  
Sensory Input ◽  
Neural Mechanisms ◽  
Attention Training ◽  
First Year ◽  
External Stimulation ◽  
Attention Networks ◽  
Learned Behavior ◽  
Infancy And Childhood ◽  
First Year Of Life ◽  
Selection Of

Functions of attention include achievement and maintenance of a state of alertness, selection of information from sensory input, and regulation of responses when dominant or well-learned behavior is not appropriate. These functions have been associated with activation of separate networks of brain areas. We review the developmental course of the attention networks during infancy and childhood and the neural mechanisms underlying their maturation. Alerting is active early in infancy, although the ability to endogenously maintain the level of alertness develops through late childhood. The capacity to orient attention to external stimulation is also present from quite early in life, and most aspects of orienting related to the control of disengagement and voluntary orientation improve during childhood. Executive attention starts developing by the second half of the first year of life, showing significant maturation during the preschool years. The efficiency of all three functions is subject to important individual differences, which may be partially due to variations in genes related to neurotransmitters that modulate the activation of the attention networks. Additionally, attention can be fostered by training, and attention training has the potential to benefit aspects of behavior central to education and socialization processes. Finally, we discuss changes in attention that occur late in life.

Crayfish Escape Behaviour: Commands for Fast Movement Inhibit Postural Tone and Reflexes, and Prevent Habituation of Slow Reflexes

1979 ◽  
Vol 79 (1) ◽  
pp. 205-224
Author(s):  
JOHN Y. KUWADA ◽  
JEFFREY J. WINE
Keyword(s):  
Nervous System ◽  
Sensory Input ◽  
Neural Mechanisms ◽  
Simultaneous Occurrence ◽  
Neural Pathways ◽  
Escape Behaviour ◽  
Motor Neurones ◽  
Fast Movement ◽  
Postural Tone ◽  
Stimulation Of

Organized behaviour requires central neural mechanisms to prevent the simultaneous occurrence of incompatible movements. We investigated neural pathways in crayfish that suppress slow flexion of the abdomen during rapid flexions (‘tailflips’) produced by a separate set of muscles. The slow flexors are innervated in each half segment of the abdomen by five motor neurones and one peripheral inhibitor. In isolated preparations of the abdominal nervous system, stimulation of identified command neurones, which trigger tailflips in intact animals, inhibited spontaneous activity in the motor neurones to the slow flexors and excited the peripheral inhibitor. These effects are mediated by a population of interganglionic intemeurones interposed between the command cells and the slow flexor efferents. Slow flexor reflexes also were inhibited by escape commands. This inhibition includes pathways that act upon early stages of sensory input. As a result, habituation of reflexes, which normally is produced by repeated stimulation, is abolished if each sensory stimulus is preceded by a burst of impulses in the command neurone.

scholarly journals Multiple sensory neurons mediate starvation-dependent aversive navigation inCaenorhabditis elegans

2019 ◽  
Vol 116 (37) ◽  
pp. 18673-18683 ◽  
Author(s):  
Moon Sun Jang ◽  
Yu Toyoshima ◽  
Masahiro Tomioka ◽  
Hirofumi Kunitomo ◽  
Yuichi Iino
Keyword(s):  
Sensory Neurons ◽  
Salt Concentration ◽  
Sensory Input ◽  
Sensory Information ◽  
Neural Mechanisms ◽  
Soil Nematode ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Migration Direction ◽  
Freely Moving

Animals demonstrate flexible behaviors through associative learning based on their experiences. Deciphering the neural mechanisms for sensing and integrating multiple types of sensory information is critical for understanding such behavioral controls. The soil nematodeCaenorhabditis elegansavoids salt concentrations it has previously experienced under starvation conditions. Here, we identify a pair of sensory neurons, the ASG neuron pair, which in cooperation with the ASER salt-sensing neuron generate starvation-dependent salt avoidance. Animals whose sensory input is restricted to only ASER failed to show learned avoidance due to inappropriately directed navigation behaviors. However, their navigation through a salt concentration gradient was improved by allowing sensory inputs to ASG in addition to ASER. Detailed behavioral analyses of these animals revealed that input from ASG neurons is required not only for controlling the frequency of initiating a set of sharp turns (called pirouettes) based on detected ambient salt concentrations but also adjusting the migration direction during pirouettes. Optogenetic activation of ASER by ChR2 induced turning behaviors in a salt concentration-dependent manner where presence of intact ASG was important for the starvation-dependent responses. Calcium imaging of the activity of ASG neurons in freely moving worms revealed that ASG is activated upon turning behavior. Our results indicate that ASG neurons cooperate with the ASER neuron to generate destination-directed reorientation in starvation-associated salt concentration avoidance.

scholarly journals Increased insula activity precedes the formation of subjective Gestalt

2022 ◽  
Author(s):  
Marilena Wilding ◽  
Christof Koerner ◽  
Anja Ischebeck ◽  
Natalia Zaretskaya
Keyword(s):  
Sensory Input ◽  
Brain Activity ◽  
Human Perception ◽  
Resting State Fmri ◽  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Superior Parietal Cortex ◽  
Increased Activity ◽  
Rare Opportunity

The constructive nature of human perception sometimes leads us to perceiving rather complex impressions from simple sensory input. Bistable stimuli give us a rare opportunity to study the neural mechanisms behind this process. Such stimuli can be visually interpreted as simple or as more complex on the basis of the same sensory input. Previous studies demonstrated increased activity in the superior parietal cortex when participants perceived an illusory Gestalt impression compared to a simpler interpretation of individual elements. Here we tested whether activity related to the illusory Gestalt can be detected not only during, but also prior to it, by examining the slow fluctuations of resting-state-fMRI activity before the stimulus onset. We presented 31 participants with a bistable motion stimulus, which can be perceived either as four moving dot pairs (local) or two moving illusory squares (global). This allowed us to isolate the specific neural mechanisms that accompany the experience of an illusion under matched sensory input. fMRI was used to measure brain activity in a sparse event-related design. We observed stronger IPS and putamen responses to the stimulus when participants perceived the global interpretation compared to local, confirming the previously reported role of these areas in perceptual grouping. Most importantly, we also observed that the global stimulus interpretation was preceded by an increased activity of the bilateral dorsal insula, which is known to process saliency and gate information for conscious access. Our data suggest an important role of the dorsal insula in shaping an internally generated illusory Gestalt percept.

scholarly journals Persistent thermal input controls steering behavior in Caenorhabditis elegans

2021 ◽  
Vol 17 (1) ◽  
pp. e1007916
Author(s):  
Muneki Ikeda ◽  
Hirotaka Matsumoto ◽  
Eduardo J. Izquierdo
Keyword(s):  
Motor Neurons ◽  
Time Scale ◽  
Sensory Input ◽  
Neural Mechanisms ◽  
Small Animals ◽  
Thermal Gradients ◽  
Environmental Signals ◽  
Neural Activities ◽  
Higher Temperature ◽  
Spectrum Decomposition

Motile organisms actively detect environmental signals and migrate to a preferable environment. Especially, small animals convert subtle spatial difference in sensory input into orientation behavioral output for directly steering toward a destination, but the neural mechanisms underlying steering behavior remain elusive. Here, we analyze a C. elegans thermotactic behavior in which a small number of neurons are shown to mediate steering toward a destination temperature. We construct a neuroanatomical model and use an evolutionary algorithm to find configurations of the model that reproduce empirical thermotactic behavior. We find that, in all the evolved models, steering curvature are modulated by temporally persistent thermal signals sensed beyond the time scale of sinusoidal locomotion of C. elegans. Persistent rise in temperature decreases steering curvature resulting in straight movement of model worms, whereas fall in temperature increases curvature resulting in crooked movement. This relationship between temperature change and steering curvature reproduces the empirical thermotactic migration up thermal gradients and steering bias toward higher temperature. Further, spectrum decomposition of neural activities in model worms show that thermal signals are transmitted from a sensory neuron to motor neurons on the longer time scale than sinusoidal locomotion of C. elegans. Our results suggest that employments of temporally persistent sensory signals enable small animals to steer toward a destination in natural environment with variable, noisy, and subtle cues.

How Do Infants Adapt to Loading of the Limb During the Swing Phase of Stepping?

2003 ◽  
Vol 89 (4) ◽  
pp. 1920-1928 ◽  
Author(s):  
Tania Lam ◽  
Claire Wolstenholme ◽  
Jaynie F. Yang
Keyword(s):  
Sensory Input ◽  
Sagittal Plane ◽  
Sudden Change ◽  
Flexor Muscle ◽  
Human Infants ◽  
After Effects ◽  
After Effect ◽  
Leg Motion ◽  
Hip Flexion ◽  
Hip Flexor

Previous results from this laboratory have shown that human infants (<12 mo old) respond appropriately to transient changes in sensory input during stepping. We examined how infants adapted to a more enduring change in sensory input by applying load to one limb during stepping. A small weight (500–900 g) was strapped around the lower leg of infants aged 3–11 mo. Stepping with the weight on was recorded on the treadmill for a period of 0.5–3 min. The weight was then quickly detached during stepping, and the immediate response to unexpected loss of the weight recorded. Three-segment dynamic analysis of leg motion was used to estimate hip, knee, and ankle torques during swing in the sagittal plane. All infants adapted to the additional load on the leg by immediately increasing the generation of hip and knee flexor muscle torques. When the weight was removed, 7 of the 22 infants tested exhibited an after-effect (high stepping) in the first step after removal of the weight. The after-effect was manifested as an increase in toe trajectory height and hip flexion and coincided with higher hip flexor muscle torque in early swing. In an additional series of control experiments using seven infants, after-effects were shown to be unrelated to a sudden change in cutaneous input with removal of the weight. The presence of an after-effect indicates that some infants made an enduring adaptation to their stepping pattern that is revealed with the unexpected removal of the weight.

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