scholarly journals Control of Locomotion in the Freshwater Snail Planorbis Corneus: II. Differential Control of Various Zones of the Ciliated Epithelium

1990 ◽  
Vol 152 (1) ◽  
pp. 405-423
Author(s):  
T. G. DELIAGINA ◽  
G. N. ORLOVSKY
Keyword(s):  
Locomotor Activity ◽  
Freshwater Snail ◽  
Ciliated Epithelium ◽  
Small Disk ◽  
Ciliary Beating ◽  
Tactile Stimuli ◽  
Neuronal Mechanisms ◽  
Planorbis Corneus ◽  
Differential Control ◽  
Spontaneous Fluctuations

In the freshwater snail Planorbis corneus, the neuronal mechanisms of the pedal ganglia that control ciliary locomotion were studied. The foot was attached to the bottom of a recording chamber with the ciliated epithelium facing upwards. To record the total motor effect produced by ciliary beating, a small disk with its edge lying on the sole of the foot was used. The ciliary beating forced the disk to rotate. In the pedal ganglia, efferent locomotor neurones (ELNs) were found, which control the locomotor activity of the ciliated epithelium. This locomotor activity increased with excitation of an ELN, and decreased with its inhibition. Axons of the ELNs, controlling the anterior, middle and posterior zones, traverse the corresponding pedal nerves. For the anterior zone, two ELNs were found. For the middle and posterior zones, only one ELN per zone was found. The activity of ELNs correlated with the intensity of ciliary beating during the following central and reflex influences upon the locomotor mechanisms: (1) spontaneous fluctuations of the locomotor activity, (2) changes of temperature, (3) transections of central connections (interganglionic connectives), (4) defensive reactions evoked by tactile stimuli or switching off the light, and (5) activation of feeding behaviour by natural stimuli. The data strongly suggest that ELNs are responsible for the differential control of locomotor activity in various zones of the ciliated epithelium during different behavioural acts.

Control of feeding movements in the freshwater snail Planorbis corneus

1988 ◽  
Vol 70 (2) ◽  
pp. 332-341 ◽  
Author(s):  
Yu. I. Arshavsky ◽  
T. G. Deliagina ◽  
G. N. Orlovsky ◽  
Yu. V. Panchin
Keyword(s):  
Freshwater Snail ◽  
Planorbis Corneus

Neuronal correlates of siphon withdrawal in freely behaving Aplysia

1979 ◽  
Vol 42 (6) ◽  
pp. 1538-1556 ◽  
Author(s):  
J. E. Kanz ◽  
L. B. Eberly ◽  
J. S. Cobbs ◽  
H. M. Pinsker
Keyword(s):  
Low Frequency ◽  
Short Latency ◽  
Moderate Intensity ◽  
Efferent Activity ◽  
Nerve Cuff ◽  
Tactile Stimuli ◽  
Cuff Electrodes ◽  
Neuronal Mechanisms ◽  
Wide Range ◽  
Freely Behaving

1. Central neuronal mechanisms of siphon withdrawal in Aplysia were studied for the first time in intact, freely behaving animals by means of population recordings from implanted whole-nerve cuff electrodes. Intracellular follow-up studies were then conducted when the same animal was reduced to a semi-intact preparation. 2. Background spontaneous activity in the siphon nerve consisted of low-frequency firing of a population of efferent units containing identified siphon motoneurons. 3. Spontaneous patterned bursts of efferent activity occurred irregularly and were associated with all-or-nothing contractions of the parapodia, gill, and siphon. Spontaneous bursts were due to centrally generated activity in the interneuron II (INT II) network, an oscillatory network with endogenous pacemaker properties. 4. In intact animals, even weak tactile stimuli to the siphon typically triggered an INTII burst shortly after the stimulus-locked efferent activity. Thus, the stimulus can phase-advance the INT II oscillator. In semi-intact preparations, short-latency INT II bursts were triggered less less frequently and required more intense stimuli. 5. With weak to moderate-intensity stimuli in intact animals, the presence of short-latency triggered INT II bursts largely determined the duration of the siphon component and amplitude of the gill component of the withdrawal reflex. 6. When stimuli were repeated over a range of interstimulus intervals (from 60 to 1 min), the likelihood of triggering a short-latency INT II burst die not change systematically. Thus, the ability of the siphon stimulus to stably entrain the all-or-none INT II component over a wide range of intervals will interact behaviorally with the decrement of the monosynaptic component of the reflex with repetition.

Stumbling corrective reaction: a phase-dependent compensatory reaction during locomotion

1979 ◽  
Vol 42 (4) ◽  
pp. 936-953 ◽  
Author(s):  
H. Forssberg
Keyword(s):  
Locomotor Activity ◽  
Proximal Part ◽  
Electrical Stimulus ◽  
Swing Phase ◽  
Short Latency ◽  
Step Cycle ◽  
Tactile Stimuli ◽  
Flexor Muscles ◽  
Compensatory Reactions ◽  
Support Phase

1. Tactile stimuli to the paw consisting of a stick making contact or an air puff aimed at the dorsum were used to study the phasic influence of locomotor activity on the reflex pattern elicited in extensor and flexor muscles and on the induced compensatory movements in intact cats. The resulting movements and reflex pattern are called "stumbling corrective reactions." 2. The basic reflex pattern and movements of the stumbling corrective reaction are: a) if the stimulus occurs during the swing phase, a short-latency activation of the flexor muscles, which induces an additional flexion of the limb lifting the paw over the obstacle; b) if the stimulus occurs during the support phase, an inhibition followed by an excitation of the extensor muscles, which neither increase nor decrease the extension. However, the stimulus evokes an increased flexor activity in the succeeding swing phase, which induces a brisker flexion. 3. Tactile stimuli to the proximal part of the limb or to the belly in front of the knee evoked the same type of phase-dependent compensatory reactions. Such reactions would presumably be beneficial for the animal to avoid high obstacles that impede movement. 4. A nonnoxious electrical stimulus (typically 2 mA; 1 ms) applied to the dorsum of the paw was used to study systematically the reflex pattern of the stumbling corrective reaction. Two pathways were defined to the knee flexor (semitendinosus). One early burst was evoked at about 10 ms and one later at about 25 ms after the stimulus. Short inhibitory pathways and longer excitatory pathways (20-50 ms) projected to the extensor nuclei. A short-latency (10 ms) excitatory pathway to the ankle extensor (lateral gastrocnemius) was also activated. 5. A painful electrical stimulus applied to the dorsum of the paw evoked large flexor responses during the whole step cycle. During the support phase the locomotion was disrupted as the supporting limb was withdrawn. 6. The results demonstrate that intact cats are able to compensate rapidly for unpredicted perturbations and that the reflex pattern and the induced corrective movements are adapted to the locomotor activity so that functionally meaningful movements are evoked in each phase of the step cycle. 7. The evoked reflexes and their modulation are consistent with those previously found in chronic spinal cats during walking and in paralyzed spinal cats performing "fictive locomotion." It is suggested that the same spinal pathways are used, and that they are controlled by the spinal "locomotor generator."

Control of Locomotion in the Freshwater Snail Planorbis Corneus: I. Locomotory Repertoire of the Snail

1990 ◽  
Vol 152 (1) ◽  
pp. 389-404
Author(s):  
T. G. DELIAGINA ◽  
G. N. ORLOVSKY
Keyword(s):  
Nervous System ◽  
Water Surface ◽  
Anterior Part ◽  
Vertical Wall ◽  
Freshwater Snail ◽  
Diurnal Changes ◽  
Vertical Orientation ◽  
Planorbis Corneus ◽  
Food Particles ◽  
Sole Of The Foot

The freshwater snail Planorbis corneas moves as a result of the beating of cilia covering the sole of the foot. The tracks of snails crawling on the walls and on the bottom of an aquarium were recorded visually under various conditions of snail feeding. The following results were obtained. 1. In the absence of food, the snails exhibited diurnal changes in locomotor activity, with a maximum during the day. Horizontal tracks on the aquarium walls were commonest during the day and vertical ones at night. When crawling on the aquarium wall, the snail actively stabilized its horizontal or vertical orientation: when encountering an obstacle or after a forced turn, the snail re-established the initial direction of locomotion. 2. When fed on the water surface, the snail decreased its locomotor speed if food particles entered its mouth. The decrease in speed resulted from the slowing down of ciliary beating in the anterior part of the sole of the foot. This finding demonstrates that motor activity in different parts of the ciliated epithelium can be controlled independently by the nervous system. 3. When searching for food particles, the snail exhibited very sinuous tracks, the turns occurring spontaneously at irregular intervals. This finding shows that there is a programme of ‘looping’ in the nervous system. 4. When the snail was fed on the bottom near a vertical wall, it used the wall to climb to the water surface for lung ventilation. After ventilation, the snail performed a standard 180° turn and then returned to the food along the original outward track. Motion along a track was performed with high accuracy. 5. The locomotor apparatus of a snail allowed it to crawl not only on a flat surface but also along the very thin mucus thread that it makes.

scholarly journals Serotonergic control in initiating defensive responses to unexpected tactile stimuli in the trap-jaw ant Odontomachus kuroiwae

2020 ◽  
Vol 223 (19) ◽  
pp. jeb228874 ◽  
Author(s):  
Hitoshi Aonuma
Keyword(s):  
Oral Administration ◽  
Defensive Behavior ◽  
Tactile Stimulation ◽  
Defensive Response ◽  
Potential Threat ◽  
Defensive Responses ◽  
Tactile Stimuli ◽  
Neuronal Mechanisms ◽  
The Brain ◽  
Unexpected Stimulus

ABSTRACTThe decision to express either a defensive response or an escape response to a potential threat is crucial for insects to survive. This study investigated an aminergic mechanism underlying defensive responses to unexpected touch in an ant that has powerful mandibles, the so-called trap-jaw. The mandibles close extremely quickly and are used as a weapon during hunting. Tactile stimulation to the abdomen elicited quick forward movements in a dart escape in 90% of the ants in a colony. Less than 10% of the ants responded with a quick defensive turn towards the source of stimulation. To reveal the neuronal mechanisms underlying this defensive behavior, the effect of brain biogenic amines on the responses to tactile stimuli were investigated. The levels of octopamine (OA), dopamine (DA) and serotonin (5HT) in the brain were significantly elevated in ants that responded with a defensive turn to the unexpected stimulus compared with ants that responded with a dart escape. Oral administration of DA and 5HT demonstrated that both amines contributed to the initiation of a defensive response. Oral administration of l-DOPA weakly affected the initiation of the defensive turn, while 5-hydroxy-l-tryptophan (5HTP) strongly affected the initiation of defensive behavior. Oral administration of ketanserin, a 5HT antagonist, inhibited the initiation of the defensive turn in aggressive workers, abolishing the effects of both 5HT and 5HTP on the initiation of turn responses. These results indicate that 5HTergic control in the nervous system is a key for the initiation of defensive behavior in the trap-jaw ant.

Neuronal mechanisms of defense reaction to statocyst receptor stimulation in the freshwater snail Planorbarius corneus

1991 ◽  
Vol 22 (6) ◽  
pp. 587-593
Author(s):  
Yu. I. Arshavskii ◽  
T. G. Delyagina ◽  
I. L. Okshtein ◽  
G. N. Orlovskii ◽  
Yu. V. Panchin
Keyword(s):  
Freshwater Snail ◽  
Defense Reaction ◽  
Receptor Stimulation ◽  
Planorbarius Corneus ◽  
Neuronal Mechanisms

scholarly journals The sensory code within sense of time

2021 ◽  
Author(s):  
Sebastian Reinartz ◽  
Arash Fassihi ◽  
Luciano Paz ◽  
Francesca Pulecchi ◽  
Marco Gigante ◽  
...  
Keyword(s):  
Time Perception ◽  
Sensory Cortex ◽  
Process Time ◽  
Sensory Coding ◽  
Causal Function ◽  
Tactile Stimuli ◽  
Primary Sensory Cortex ◽  
Neuronal Mechanisms ◽  
Sense Of Time ◽  
Sensory Code

Sensory experiences are accompanied by the perception of the passage of time; a cell phone vibration, for instance, is sensed as brief or long. The neuronal mechanisms underlying the perception of elapsed time remain unknown1. Recent work agrees on a role for cortical processing networks2,3, however the causal function of sensory cortex in time perception has not yet been specified. We hypothesize that the mechanisms for time perception are embedded within primary sensory cortex and are thus governed by the basic rules of sensory coding. By recording and optogenetically modulating neuronal activity in rat vibrissal somatosensory cortex, we find that the percept of stimulus duration is dilated and compressed by optogenetic excitation and inhibition, respectively, during stimulus delivery. A second set of rats judged the intensity of tactile stimuli; here, optogenetic excitation amplified the intensity percept, demonstrating sensory cortex to be the common gateway to both time and stimulus feature processing. The coding algorithms for sensory features are well established4–10. Guided by these algorithms, we formulated a 3–stage model beginning with the membrane currents evoked by vibrissal and optogenetic drive and culminating in the representation of perceived time; this model successfully replicated rats′ choices. Our finding that stimulus coding is intrinsic to sense of time disagrees with dedicated pacemaker-accumulator operation models11–13, where sensory input acts only to trigger the onset and offset of the timekeeping process. Time perception is thus as deeply intermeshed within the sensory processing pathway as is the sense of touch itself14,15 and can now be treated through the computational language of sensory coding. The model presented here readily generalizes to humans14,16 and opens up new approaches to understanding the time misperception at the core of numerous neurological conditions17,18.

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