Producing directed behaviour: muscle activity patterns of the cockroach escape response

1996 ◽  
Vol 199 (3) ◽  
pp. 563-568 ◽  
Author(s):  
R Levi ◽  
J Camhi
Keyword(s):  
Alternative Hypothesis ◽  
Activity Patterns ◽  
Activation Mechanism ◽  
Movement Direction ◽  
Co Activation ◽  
Antagonistic Muscle ◽  
Turning Response ◽  
Motor Neurones ◽  
The Right ◽  
Turn Direction

The cockroach responds to wind from the front left by making an escape turn to the right, and vice versa. So far, no interneurones in the escape system are known that respond only to wind from the left or only to wind from the right. In this study, we used electromyographic recordings to determine whether motor neurones respond in this direction-selective manner during escape behaviour. In the mesothoracic coxal-femoral joint, whose movement direction is diagnostic for escape direction, the fast motor neurones of one muscle respond selectively to one wind direction, and those of the antagonistic muscle respond selectively to wind from the other direction, resulting in an appropriate turning response. This rules out an alternative hypothesis, a co-activation mechanism of specifying turn direction. These results suggest that it would be fruitful to search among the interneurones of the escape system for additional cells and circuit properties that could give rise to this sharp directional discrimination.

scholarly journals Neural alignment predicts learning outcomes in students taking an introduction to computer science course

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meir Meshulam ◽  
Liat Hasenfratz ◽  
Hanna Hillman ◽  
Yun-Fei Liu ◽  
Mai Nguyen ◽  
...  
Keyword(s):  
Computer Science ◽  
Learning Outcomes ◽  
Brain Activity ◽  
Activity Patterns ◽  
Real Life ◽  
Final Exam ◽  
Neural Representations ◽  
Real Life Setting ◽  
The Right ◽  
Mri Study

AbstractDespite major advances in measuring human brain activity during and after educational experiences, it is unclear how learners internalize new content, especially in real-life and online settings. In this work, we introduce a neural approach to predicting and assessing learning outcomes in a real-life setting. Our approach hinges on the idea that successful learning involves forming the right set of neural representations, which are captured in canonical activity patterns shared across individuals. Specifically, we hypothesized that learning is mirrored in neural alignment: the degree to which an individual learner’s neural representations match those of experts, as well as those of other learners. We tested this hypothesis in a longitudinal functional MRI study that regularly scanned college students enrolled in an introduction to computer science course. We additionally scanned graduate student experts in computer science. We show that alignment among students successfully predicts overall performance in a final exam. Furthermore, within individual students, we find better learning outcomes for concepts that evoke better alignment with experts and with other students, revealing neural patterns associated with specific learned concepts in individuals.

Hypothesis testing with error correction models

2021 ◽  
pp. 1-9
Author(s):  
Patrick W. Kraft ◽  
Ellen M. Key ◽  
Matthew J. Lebo
Keyword(s):  
Hypothesis Testing ◽  
Error Correction ◽  
Null Hypothesis ◽  
Alternative Hypothesis ◽  
Correction Coefficient ◽  
Correction Model ◽  
Long Run ◽  
Independent Variable ◽  
The Right ◽  
General Error

Abstract Grant and Lebo (2016) and Keele et al. (2016) clarify the conditions under which the popular general error correction model (GECM) can be used and interpreted easily: In a bivariate GECM the data must be integrated in order to rely on the error correction coefficient, $\alpha _1^\ast$ , to test cointegration and measure the rate of error correction between a single exogenous x and a dependent variable, y. Here we demonstrate that even if the data are all integrated, the test on $\alpha _1^\ast$ is misunderstood when there is more than a single independent variable. The null hypothesis is that there is no cointegration between y and any x but the correct alternative hypothesis is that y is cointegrated with at least one—but not necessarily more than one—of the x's. A significant $\alpha _1^\ast$ can occur when some I(1) regressors are not cointegrated and the equation is not balanced. Thus, the correct limiting distributions of the right-hand-side long-run coefficients may be unknown. We use simulations to demonstrate the problem and then discuss implications for applied examples.

The Physiology and Morphology of Median Nerve Motor Neurones in the Thoracic Ganglia of the Locust

1982 ◽  
Vol 96 (1) ◽  
pp. 325-341
Author(s):  
MALCOLM BURROWS
Keyword(s):  
Synaptic Input ◽  
Motor Neurone ◽  
Abdominal Muscles ◽  
Thoracic Ganglia ◽  
Synaptic Potentials ◽  
Metathoracic Ganglion ◽  
Inspiratory Motor ◽  
Motor Neurones ◽  
Chemical Synapses ◽  
The Right

Simultaneous intracellular recordings have been made from the two expiratory, and from the two inspiratory motor neurones which have their axons in the unpaired median nerves of the thoracic ganglia. Each motor neurone has an axon that branches to innervate muscles on the left and on the right side of one segment. The expiratory neurones studied were those in the meso- and meta-thoracic ganglia which innervate spiracular closer muscles. The depolarizing synaptic potentials underlying the spikes during expiration are common to the two closer motor neurones in a particular segment. Similarly, during inspiration when there are usually no spikes, the hyperpolarizing, inhibitory potentials are also common to both motor neurones. The synaptic input to the neurones can be derived from four interneurones; two responsible for the depolarizing potentials during expiration and two for the inhibitory potentials during inspiration. The inspiratory neurones studied were those in the abdominal ganglia fused to the metathoracic ganglion which innervate dorso-ventral abdominal muscles. During inspiration the two motor neurones of one segment spike at a similar and steady frequency. The underlying synaptic input to the two is common. During expiration, when there are usually no spikes, the hyperpolarizing synaptic potentials are also common to both neurones. In addition they match exactly the depolarizing potentials occurring at the same time in the closer motor neurones. The same set of interneurones could be responsible. No evidence has been revealed to indicate that the two closer, or the two inspiratory motor neurones of one segment are directly coupled by electrical or chemical synapses. The morphology of both types of motor neurone is distinct from that of other motor neurones in these ganglia. Both types branch extensively in both the left and in the right areas of the neuropile.

The vibrational startle response of the desert locust Schistocerca gregaria

1999 ◽  
Vol 202 (16) ◽  
pp. 2151-2159 ◽  
Author(s):  
T. Friedel
Keyword(s):  
Stimulus Intensity ◽  
Startle Response ◽  
Schistocerca Gregaria ◽  
Whole Body ◽  
Desert Locust ◽  
Intracellular Recordings ◽  
Stimulus Amplitude ◽  
Co Activation ◽  
Motor Neurones ◽  
Fast Twitch

Substratum vibrations elicit a fast startle response in unrestrained quiescent desert locusts (Schistocerca gregaria). The response is graded with stimulus intensity and consists of a small, rapid but conspicuous movement of the legs and body, but it does not result in any positional change of the animal. With stimuli just above threshold, it begins with a fast twitch of the hindlegs generated by movements of the coxa-trochanter and femur-tibia joints. With increasing stimulus intensity, a rapid movement of all legs may follow, resulting in an up-down movement of the whole body. The magnitude of both the hindleg movement and electromyographic recordings from hindleg extensor and flexor tibiae muscles increases with stimulus amplitude and reaches a plateau at vibration accelerations above 20 m s(−)(2) (peak-to-peak). Hindleg extensor and flexor tibiae muscles in unrestrained animals are co-activated with a mean latency of 30 ms. Behavioural thresholds are as low as 0. 47 m s(−)(2) (peak-to-peak) at frequencies below 100 Hz but rise steeply above 200 Hz. The response habituates rapidly, and inter-stimulus intervals of 2 min or more are necessary to evoke maximal reactions. Intracellular recordings in fixed (upside-down) locusts also revealed co-activation of both flexor and extensor motor neurones with latencies of approximately 25 ms. This shows that the neuronal network underlying the startle movement is functional in a restrained preparation and can therefore be studied in great detail at the level of identified neurones.

scholarly journals Enhancing the smoothness of joint motion induced by functional electrical stimulation using co-activation strategies

2017 ◽  
Vol 3 (2) ◽  
pp. 155-159
Author(s):  
Mirjana Ruppel ◽  
Christian Klauer ◽  
Thomas Schauer
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Joint Stiffness ◽  
Joint Motion ◽  
Activation Level ◽  
Pendulum Test ◽  
Co Activation ◽  
Antagonistic Muscle ◽  
Induced Motion ◽  
Neuroprosthetic Devices

AbstractThe motor precision of today’s neuroprosthetic devices that use artificial generation of limb motion using Functional Electrical Stimulation (FES) is generally low. We investigate the adoption of natural co-activation strategies as present in antagonistic muscle pairs aiming to improve motor precision produced by FES. In a test in which artificial knee-joint movements were generated, we could improve the smoothness of FES-induced motion by 513% when applying co-activation during the phases in which torque production is switched between muscles – compared to no co-activation. We further demonstrated how the co-activation level influences the joint stiffness in a pendulum test.

scholarly journals Prefrontal High Gamma in ECoG tags periodicity of musical rhythms in perception and imagination

2019 ◽  
Author(s):  
S. A. Herff ◽  
C. Herff ◽  
A. J. Milne ◽  
G. D. Johnson ◽  
J. J. Shih ◽  
...  
Keyword(s):  
Auditory Processing ◽  
Right Hemisphere ◽  
Brain Activity ◽  
Activity Patterns ◽  
Superior Temporal Gyrus ◽  
Gamma Activity ◽  
Rhythm Perception ◽  
High Gamma ◽  
The Right ◽  
Musical Rhythms

AbstractRhythmic auditory stimuli are known to elicit matching activity patterns in neural populations. Furthermore, recent research has established the particular importance of high-gamma brain activity in auditory processing by showing its involvement in auditory phrase segmentation and envelope-tracking. Here, we use electrocorticographic (ECoG) recordings from eight human listeners, to see whether periodicities in high-gamma activity track the periodicities in the envelope of musical rhythms during rhythm perception and imagination. Rhythm imagination was elicited by instructing participants to imagine the rhythm to continue during pauses of several repetitions. To identify electrodes whose periodicities in high-gamma activity track the periodicities in the musical rhythms, we compute the correlation between the autocorrelations (ACC) of both the musical rhythms and the neural signals. A condition in which participants listened to white noise was used to establish a baseline. High-gamma autocorrelations in auditory areas in the superior temporal gyrus and in frontal areas on both hemispheres significantly matched the autocorrelation of the musical rhythms. Overall, numerous significant electrodes are observed on the right hemisphere. Of particular interest is a large cluster of electrodes in the right prefrontal cortex that is active during both rhythm perception and imagination. This indicates conscious processing of the rhythms’ structure as opposed to mere auditory phenomena. The ACC approach clearly highlights that high-gamma activity measured from cortical electrodes tracks both attended and imagined rhythms.

Re-description of Azygokeras columbiae Koeller & Littlepage, 1976 (Calanoida: Aetideidae) and musculature of the male grasping antennule

Zootaxa ◽  
2019 ◽  
Vol 4565 (3) ◽  
pp. 361
Author(s):  
JANET M. BRADFORD-GRIEVE ◽  
GEOFFREY A. BOXSHALL
Keyword(s):  
British Columbia ◽  
Knee Joint ◽  
Original Description ◽  
Antagonistic Muscle ◽  
The Right

Azygokeras columbiae from Bute Inlet, British Columbia, Canada, is re-described, correcting some details and adding information not available in the original description. Azygokeras columbiae is unique amongst male Aetideidae in having the right antennule modified for grasping but without a true knee joint (geniculation) between segments XX and XXI nor a hiatus in the musculature at this joint, typical of taxa with a geniculate male antennule. Male Azygokeras have wide pivot points and arthrodial membranes between segments XXI and XXII, XXIII and XXIV and XXV and XXVI that allow greater movement in several planes than in homologous segments of Euaugaptilus and Heterorhabdus. Modifications of the terminal antennular joints allow for extensive movement in several planes associated with a series of short muscles in segments XIX to XXVI. These muscles become progressively more massive from proximal to distal on the antennule and are paired with an antagonistic muscle also increasing in mass distally. 

Properties of reach-related neuronal activity in cortical area 7A

1992 ◽  
Vol 67 (5) ◽  
pp. 1335-1345 ◽  
Author(s):  
W. A. MacKay
Keyword(s):  
The Body ◽  
Movement Direction ◽  
Video Monitor ◽  
Visual Responses ◽  
Motor Sequence ◽  
Related Activity ◽  
Significant Drop ◽  
Discharge Rates ◽  
Area 7A ◽  
The Right

1. In protocol 1, two macaque monkeys were trained to reach to illuminated buttons with the right arm as reach-related unit activity was monitored in area 7a of the left hemisphere. 2. Of 402 neurons recorded in area 7a, 109 changed their discharge rates during the reach task. The change could occur early or late in the trajectory, or during the return movement of the arm to the rest plate. Spatial preferences were seen in 59/109 reach-related cells, usually for the right or center buttons. 3. In protocol 2, another monkey was trained to reach with either arm to targets displayed on a touch-sensitive video monitor. Of 273 neurons sampled in area 7a (both hemispheres) during the bilateral task performance, 84 were reach-related: 33 responded similarly to reaches of either arm. Most of the rest had a contralateral arm preference. When bilateral reach-related cells had a spatial preference, that preference was the same for both arms. 4. With the use of two target sequences in either protocol, it was found that spatial preferences were observable only for primary reaches from the side of the body up to the target. Relatively few cells responded to other trajectories, and those that did usually failed to discriminate movement direction. Movement extent did not influence discharge rates. 5. Although a total of 125/270 reach cells had observable visual responses, only 4 out of 18 cells tested in both dark and light conditions showed a significant drop in reach-related activity in the dark. Thus visual input from the moving hand probably is responsible for only part of the reach activity in area 7a. 6. Reach-related activity in area 7a appears to signal specific phases of the motor performance and is often restricted to distinct spatial regions. As such, it could be used by the frontal lobe to facilitate upcoming elements of a motor sequence, including terminal corrections.

Multi-Item Discriminability Pattern to Faces in Developmental Prosopagnosia Reveals Distinct Mechanisms of Face Processing

2019 ◽  
Vol 30 (5) ◽  
pp. 2986-2996
Author(s):  
Xue Tian ◽  
Ruosi Wang ◽  
Yuanfang Zhao ◽  
Zonglei Zhen ◽  
Yiying Song ◽  
...  
Keyword(s):  
Face Processing ◽  
Alternative Hypothesis ◽  
Normal Population ◽  
Imaging Study ◽  
Multiple Sources ◽  
Neural Basis ◽  
Face Area ◽  
Normal Individuals ◽  
The Face ◽  
The Right

Abstract Previous studies have shown that individuals with developmental prosopagnosia (DP) show specific deficits in face processing. However, the mechanism underlying the deficits remains largely unknown. One hypothesis suggests that DP shares the same mechanism as normal population, though their faces processing is disproportionally impaired. An alternative hypothesis emphasizes a qualitatively different mechanism of DP processing faces. To test these hypotheses, we instructed DP and normal individuals to perceive faces and objects. Instead of calculating accuracy averaging across stimulus items, we used the discrimination accuracy for each item to construct a multi-item discriminability pattern. We found DP’s discriminability pattern was less similar to that of normal individuals when perceiving faces than perceiving objects, suggesting that DP has qualitatively different mechanism in representing faces. A functional magnetic resonance imaging study was conducted to reveal the neural basis and found that multi-voxel activation patterns for faces in the right fusiform face area and occipital face area of DP were deviated away from the mean activation pattern of normal individuals. Further, the face representation was more heterogeneous in DP, suggesting that deficits of DP may come from multiple sources. In short, our study provides the first direct evidence that DP processes faces qualitatively different from normal population.

Reflexive Limb Selection and Control of Reach Direction to Moving Targets in Cats, Monkeys, and Humans

2010 ◽  
Vol 104 (5) ◽  
pp. 2423-2432 ◽  
Author(s):  
Sergei Perfiliev ◽  
Tadashi Isa ◽  
Bo Johnels ◽  
Göran Steg ◽  
Johan Wessberg
Keyword(s):  
Target Position ◽  
Arm Movement ◽  
Parametric Programming ◽  
Visual Signal ◽  
Movement Direction ◽  
Electromyographic Activity ◽  
Motor Strategy ◽  
Limb Selection ◽  
The Right ◽  
And Control

When we reach for an object, we have to decide which arm to use and the direction in which to move. According to the established view, this is voluntarily controlled and programmed in advance in time-consuming and elaborate computations. Here, we systematically tested the motor strategy used by cats, monkeys, and humans when catching an object moving at high velocity to the left or right. In all species, targets moving to the right selectively initiated movement of the right forelimb and vice versa for targets moving to the left. Movements were from the start directed toward a prospective target position. In humans, the earliest onset of electromyographic activity from start of motion of the target ranged from 90 to 110 ms in different subjects. This indicates that the selection of the arm and specification of movement direction did not result from the subject's voluntary decision, but were determined in a reflex-like manner by the parameters of the target motion. As a whole the data suggest that control of goal-directed arm movement relies largely on an innate neuronal network that, when activated by the visual signal from the target, automatically guides the arm throughout the entire movement toward the target. In the view of the present data, parametric programming of reaching in advance seems to be superfluous.

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