A method for selective stimulation of leg chemoreceptors in whole crustaceans

Author(s):  
Paolo Solari ◽  
Giorgia Sollai ◽  
Francesco Palmas ◽  
Andrea Sabatini ◽  
Roberto Crnjar

The integration of sensory information with adequate motor outputs is critical for animal survival. Here, we present an innovative technique based on a non-invasive closed-circuit device consisting of a perfusion/stimulation chamber chronically applied on a single leg of the crayfish Procambarus clarkii. Using this technique, we focally stimulated the leg inside the chamber and studied the leg-dependent sensory-motor integration involving other sensory appendages, such as antennules and maxillipeds, which remain unstimulated outside the chamber. Results show that the stimulation of a single leg with chemicals, such as disaccharides, is sufficient to trigger a complex search behaviour involving locomotion coupled with the reflex activation of antennules and maxillipeds. This technique can be easily adapted to other decapods and/or other sensory appendages. Thus, it has opened possibilities for studying sensory-motor integration evoked by leg stimulation in whole aquatic animals under natural conditions to supplement, with a direct approach, current ablation/silencing techniques.

2010 ◽  
Vol 104 (2) ◽  
pp. 675-684 ◽  
Author(s):  
Yen-Chyi Liu ◽  
Jens Herberholz

Crayfish ( Procambarus clarkii ) have bilateral pairs of giant interneurons that control rapid escape movements in response to predatory threats. The medial giant neurons (MGs) can be made to fire an action potential by visual or tactile stimuli directed to the front of the animal and this leads to an escape tail-flip that thrusts the animal directly backward. The lateral giant neurons (LGs) can be made to fire an action potential by strong tactile stimuli directed to the rear of the animal, and this produces flexions of the abdomen that propel the crayfish upward and forward. These observations have led to the notion that the receptive fields of the giant neurons are locally restricted and do not overlap with each other. Using extra- and intracellular electrophysiology in whole animal preparations of juvenile crayfish, we found that the receptive fields of the LGs are far more extensive than previously assumed. The LGs receive excitatory inputs from descending interneurons originating in the brain; these interneurons can be activated by stimulation of the antenna II nerve or the protocerebral tract. In our experiments, descending inputs alone could not cause action potentials in the LGs, but when paired with excitatory postsynaptic potentials elicited by stimulation of tail afferents, the inputs summed to yield firing. Thus the LG escape neurons integrate sensory information received through both rostral and caudal receptive fields, and excitatory inputs that are activated rostrally can bring the LGs' membrane potential closer to threshold. This enhances the animal's sensitivity to an approaching predator, a finding that may generalize to other species with similarly organized escape systems.


1990 ◽  
Vol 151 (1) ◽  
pp. 133-160 ◽  
Author(s):  
ANSGAR BÜSCHGES

In the stick insect Carausius morosus (Phasmida) intracellular recordings were made from local nonspiking interneurones involved in the reflex activation of the extensor motoneurones of the femur-tibia joint during ramp-like stimulation of the transducer of this joint, the femoral chordotonal organ (ChO). The nonspiking interneurones in the femur-tibia control loop were characterized by their inputs from the ChO, their output properties onto the extensor motoneurones and their morphology. Eight different morphological and physiological types of nonspiking interneurones are described that are involved in the femur-tibia control loop. The results show that velocity signals from the ChO are the most important movement parameter processed by the nonspiking interneurones. Altering the membrane potential of these interneurones had marked effects on the reflex activation in the extensor motoneurones as the interneurones were able to increase or decrease the response of the participating motoneurones. The processing of information by the nonspiking pathways showed another remarkable aspect: nonspiking interneurones were found to process sensory information from the ChO onto extensor motoneurones in a way that seems not always to support the generation of the visible resistance reflexes in the extensor tibiae motoneurones in response to imposed flexion and extension movements of the joint. The present investigation demonstrated interneuronal pathways in the joint-control loop that show ‘assisting’ characteristics.


1991 ◽  
Vol 157 (1) ◽  
pp. 205-226
Author(s):  
JEAN-YVES BARTHE ◽  
MICHELLE BÉVENGUT ◽  
FRANÇOIS CLARAC

An in vitro preparation was developed consisting of the five thoracic and abdominal ganglia of the crayfish nerve cord, isolated from anterior nervous structures and from peripheral sensory inputs. The central activities of the thoracic leg, swimmeret and abdominal positioning motor systems and their relationships were studied. When motor outputs were tonic in the thoracic leg nerves (90% of the preparations), continuous rhythmic activity occurred and persisted for several hours in the swimmeret nerves. Interruptions of the swimmeret rhythm were associated with rhythmic motor outputs in the leg nerves (10% of the preparations). Motor activity in the abdominal positioning system was mainly tonic. Swimmeret rhythm reversibly disappeared during application of a sucrose block between the thoracic and abdominal parts of the nerve cord. Electrical stimulation of the connectives posterior to the block induced bouts of rhythmic swimmeret activity. Comparisons of the swimmeret rhythm (period) and the metachronal wave (duration, phase) showed that sectioning of the connectives between the thoracic and abdominal ganglia modified the period but did not affect the properties of the metachronal wave. We conclude that the presence of descending inputs from thoracic ganglia is necessary for persistent swimmeret activity.


Author(s):  
Juan Luis RodrÍguez Hermosa ◽  
Myriam Calle ◽  
Ina Guerassimova ◽  
Baldomero FernÁndez ◽  
Víctor Javier Montero ◽  
...  

2021 ◽  
Author(s):  
Robert M. Hardwick ◽  
Amanda S. Therrien ◽  
Elise Lesage
Keyword(s):  

2011 ◽  
Vol 122 (10) ◽  
pp. 2071-2080 ◽  
Author(s):  
Walter Troni ◽  
Alessia Di Sapio ◽  
Eliana Berra ◽  
Sergio Duca ◽  
Aristide Merola ◽  
...  

1981 ◽  
Vol 90 (1) ◽  
pp. 85-100
Author(s):  
CHARLES H. PAGE

Postural extensions of the abdomen of the crayfish, Procambarus clarkii, could be evoked by mechanical stimulation of a single thoracic leg. Movement of a single leg joint was sufficient to initiate an extension response. Vigorous abdominal extensions were initiated either by depression of the whole leg (WLD) or by flexion of the mero-carpal joint (MCF). Weaker extension responses were obtained by depression of the thoracic-coxal and coxo-basal joints. Similar stimulation of the chelipeds did not elicit an abdominal extension response. Single-frame analysis of motion pictures of crayfish responding to WLD or MCF stimulation of a 2nd thoracic leg showed that the responses evoked by the two different stimulus situations were nearly identical. They differed principally in the responses of the leg located contralateral to the stimulated leg. Movements of most of the cephalic, thoracic and abdominal appendages accompanied the abdominal extension response. Only the eyes remained stationary throughout the response. The mean values of the latencies for the initiation of appendage movement ranged from 125 to 204 ma; abdominal movement had a mean latency of about 220 ms. The abdominal extension reflex resulted from the activity of the tonic superficial extensor muscles. The deep phasic extensor muscles were silent during the response. The mean latencies for the initiation of superficial extensor muscle activity by WLD and MCF stimulation were 53·7 and 50·0 ms respectively.


2008 ◽  
Vol 99 (3) ◽  
pp. 1267-1273 ◽  
Author(s):  
Takeshi Suwabe ◽  
Hideyuki Fukami ◽  
Robert M. Bradley

Salivary secretion results from reflex stimulation of autonomic neurons via afferent sensory information relayed to neurons in the rostral nucleus of the solitary tract (rNST), which synapse with autonomic neurons of the salivatory nuclei. We investigated the synaptic properties of the afferent sensory connection to neurons in the inferior salivatory nucleus (ISN) controlling the parotid and von Ebner salivary glands. Mean synaptic latency recorded from parotid gland neurons was significantly shorter than von Ebner gland neurons. Superfusion of GABA and glycine resulted in a concentration-dependent membrane hyperpolarization. Use of glutamate receptor antagonists indicated that both AMPA and N-methyl-d-aspartate (NMDA) receptors are involved in the evoked excitatory postsynaptic potentials (EPSPs). Inhibitory postsynaptic potential (IPSP) amplitude increased with higher intensity ST stimulation. Addition of the glycine antagonist strychnine did not affect the amplitude of the IPSPs significantly. The GABAA receptor antagonist, bicuculline (BMI) or mixture of strychnine and BMI abolished the IPSPs in all neurons. IPSP latency was longer than EPSP latency, suggesting that more than one synapse is involved in the inhibitory pathway. Results show that ISN neurons receive both excitatory and inhibitory afferent input mediated by glutamate and GABA respectively. The ISN neuron response to glycine probably derives from descending connections. Difference in the synaptic characteristics of ISN neurons controlling the parotid and von Ebner glands may relate to the different function of these two glands.


2019 ◽  
Author(s):  
Mark D. Fletcher ◽  
Amatullah Hadeedi ◽  
Tobias Goehring ◽  
Sean R Mills

Cochlear implant (CI) users receive only limited sound information through their implant, which means that they struggle to understand speech in noisy environments. Recent work has suggested that combining the electrical signal from the CI with a haptic signal that provides crucial missing sound information (“electro-haptic stimulation”; EHS) could improve speech-in-noise performance. The aim of the current study was to test whether EHS could enhance speech-in-noise performance in CI users using: (1) a tactile signal derived using an algorithm that could be applied in real time, (2) a stimulation site appropriate for a real-world application, and (3) a tactile signal that could readily be produced by a compact, portable device. We measured speech intelligibility in multi-talker noise with and without vibro-tactile stimulation of the wrist in CI users, before and after a short training regime. No effect of EHS was found before training, but after training EHS was found to improve the number of words correctly identified by an average of 8.3 %-points, with some users improving by more than 20 %-points. Our approach could offer an inexpensive and non-invasive means of improving speech-in-noise performance in CI users.


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