The antennal motor system of crickets: modulation of muscle contractions by a common inhibitor, DUM neurons, and proctolin

1993 ◽  
Vol 173 (4) ◽  
Author(s):  
C. Allg�uer ◽  
H.W. Honegger
1993 ◽  
Vol 174 (1) ◽  
pp. 343-362 ◽  
Author(s):  
J. H. Belanger ◽  
I. Orchard

The pentapeptide proctolin has multiple effects on the locust oviposition digging system. At the neuromuscular junction of the ventral opener muscle, it has a concentration-dependent range of modulatory effects. At low concentrations (10–10 mol l-1), proctolin causes an increase in the frequency of miniature excitatory junctional potentials, but has no apparent effects on the muscle membrane or contractile properties. In the middle range of concentrations (approximately 10–9 mol l- 1) proctolin increases neurally evoked twitch tension three- to fourfold with little change in the basal tension. At high concentrations (>10–8 mol l-1), proctolin causes a large increase in basal tension, upon which is occasionally superimposed a slow (approximately 0.3–0.5 Hz) myogenic rhythm. Stimulation of the ventral opener nerve at 30 Hz for 5 min releases approximately 8 % of the proctolin store of the muscle. In vitro ganglion-muscle preparations which are expressing the oviposition digging rhythm produced in the terminal abdominal ganglion release about 25 % of the store of endogenous proctolin during 5 min of superfusion. This declines to below the level of detectability over about 20 min of superfusion. Muscle contractions decline and then cease over the same period, although the patterned neural input and muscle electromyogram responses are still present. Superfusion of 10–9 mol l-1 proctolin restores the muscle contractions to their original magnitude. Superfusion of 10–8 mol l-1 proctolin over preparations in which the oviposition digging pattern has slowed results in the frequency of the rhythm being restored to its original levels. We suggest that, rather than having a facultative modulatory role in this neuromuscular system, proctolin is required for it to function normally. Furthermore, proctolin may maintain the functional integrity of the central systems driving oviposition digging.


Author(s):  
Markus Krüger ◽  
Horst Krist

Abstract. Recent studies have ascertained a link between the motor system and imagery in children. A motor effect on imagery is demonstrated by the influence of stimuli-related movement constraints (i. e., constraints defined by the musculoskeletal system) on mental rotation, or by interference effects due to participants’ own body movements or body postures. This link is usually seen as qualitatively different or stronger in children as opposed to adults. In the present research, we put this interpretation to further scrutiny using a new paradigm: In a motor condition we asked our participants (kindergartners and third-graders) to manually rotate a circular board with a covered picture on it. This condition was compared with a perceptual condition where the board was rotated by an experimenter. Additionally, in a pure imagery condition, children were instructed to merely imagine the rotation of the board. The children’s task was to mark the presumed end position of a salient detail of the respective picture. The children’s performance was clearly the worst in the pure imagery condition. However, contrary to what embodiment theories would suggest, there was no difference in participants’ performance between the active rotation (i. e., motor) and the passive rotation (i. e., perception) condition. Control experiments revealed that this was also the case when, in the perception condition, gaze shifting was controlled for and when the board was rotated mechanically rather than by the experimenter. Our findings indicate that young children depend heavily on external support when imagining physical events. Furthermore, they indicate that motor-assisted imagery is not generally superior to perceptually driven dynamic imagery.


2011 ◽  
Author(s):  
F. Waszak ◽  
S. Schuetz-Bosbach ◽  
C. Weiss ◽  
L. Ticini

2013 ◽  
Author(s):  
Julie Carranza ◽  
Matthew Bachman ◽  
Michael P. Kaschak ◽  
Edward M. Bernat ◽  
John L. Jones ◽  
...  

2012 ◽  
Vol 132 (8) ◽  
pp. 802-807
Author(s):  
Takuto Ichikawa ◽  
Toshiya Yoshida ◽  
Osamu Miyashita
Keyword(s):  

2017 ◽  
Author(s):  
Carl Michael Orquiola Galang

Excitability in the motor cortex is modulated when we observe other people receiving a painful stimulus (Avenanti et al., 2005). However, the task dependency of this modulation is not well understood, as different paradigms have yielded seemingly different results. Previous neurophysiological work employing transcranial magnetic stimulation (TMS) suggests that watching another person’s hand being pierced by a needle leads to a muscle specific inhibition, assessed via motor evoked potentials. Results from previous behavioural studies suggest that overt behavioural responses are facilitated due to pain observation (Morrison et al., 2007a; 2007b). There are several paradigmatic differences both between typical TMS studies and behavioural studies, and within behavioural studies themselves, that limit our overall understanding of how pain observation affects the motor system. In the current study, we combine elements of typical TMS experimental designs in a behavioural assessment of how pain observation affects overt behavioural responding. Specifically, we examined the muscle specificity, timing, and direction of modulation of motor responses due to pain observation. To assess muscle specificity, we employed pain and non-pain videos from previous TMS studies in a Go/No-Go task in which participants responded by either pressing a key with their index finger or with their foot. To assess timing, we examined response times for Go signals presented at 0ms or 500ms after the video. Results indicate that observation of another individual receiving a painful stimulus leads to a non-effector specific, temporally extended response facilitation (e.g., finger and foot facilitation present at 0ms and 500ms delays), compared to observation of non-pain videos. This behavioural facilitation effect differs from the typical motor inhibition seen in TMS studies, and we argue that the effects of pain observation on the motor system are state-dependent, with different states induced via task instructions. We discuss our results in light of previous work on motor responses to pain observation.


2018 ◽  
Author(s):  
Claudia Gianelli ◽  
Katharina Kühne ◽  
Silvia Mencaraglia ◽  
Riccardo Dalla Volta

In two experiments, we compared the dynamics of corticospinal excitability when processing visually or linguistically presented tool-oriented hand actions in native speakers and sequential bilinguals. In a third experiment we used the same procedure to test non-motor, low-level stimuli, i.e. scrambled images and pseudo-words. Stimuli were presented in sequence: pictures (tool + tool-oriented hand action or their scrambled counterpart) and words (tool noun + tool-action verb or pseudo-words). Experiment 1 presented German linguistic stimuli to native speakers, while Experiment 2 presented English stimuli to non-natives. Experiment 3 tested Italian native speakers. Single-pulse trascranial brain stimulation (spTMS) was applied to the left motor cortex at five different timings: baseline, 200ms after tool/noun onset, 150, 350 and 500ms after hand/verb onset with motor-evoked potentials (MEPs) recorded from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles.We report strong similarities in the dynamics of corticospinal excitability across the visual and linguistic modalities. MEPs’ suppression started as early as 150ms and lasted for the duration of stimulus presentation (500ms). Moreover, we show that this modulation is absent for stimuli with no motor content. Overall, our study supports the notion of a core, overarching system of action semantics shared by different modalities.


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