Picrotoxin prevents habituation of the gill withdrawal reflex in Aplysia

1978 ◽  
Vol 56 (6) ◽  
pp. 1079-1082 ◽  
Author(s):  
Ken Lukowiak
Keyword(s):  
Tactile Stimulation ◽  
Aminobutyric Acid ◽  
Adaptive Behaviour ◽  
Repeated Presentation ◽  
Reflex Amplitude ◽  
Repeated Stimulation ◽  
Withdrawal Reflex ◽  
Reflex Latency ◽  
Cns Control ◽  
Stimulation Of

The gill withdrawal reflex evoked by tactile stimulation of the siphon in Aplysia habituates with repeated presentation of the stimulus. This adaptive behaviour is mediated by the integrated activity of the central (CNS) and peripheral (PNS) nervous systems. The PNS mediates the basic reflex and its habituation while the CNS exerts both suppressive and facilitatory control over the PNS. This results in greater adaptability of the reflex behaviours. In young Aplysia the CNS control is absent and this is due to the incomplete development of pathways in the CNS. In an attempt to identify the pathway an attempt was made to manipulate the CNS's suppressive influence by agents which antagonize putative neurotransmitters. The application of picrotoxin-containing seawater over the CNS removed the CNS's suppressive influence but not its facilitatory influence. Thus the reflex amplitude was increased, the reflex latency decreased, and repeated stimulation did not result in habituation. This effect of picrotoxin was completely reversible. It is thus proposed that γ-aminobutyric acid, a putative neurotransmitter, plays an important rote in the mediation of the CNS's suppressive influence.

The development of central nervous system control of the gill withdrawal reflex evoked by siphon stimulation in Aplysia

1979 ◽  
Vol 57 (9) ◽  
pp. 987-997 ◽  
Author(s):  
Ken Lukowiak
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Abdominal Ganglion ◽  
System Control ◽  
Reflex Amplitude ◽  
Withdrawal Reflex ◽  
Reflex Latency ◽  
Neural Processes ◽  
The Central Nervous System ◽  
Cns Control

In older Aplysia, the central nervous system (CNS) (abdominal ganglion) exerts suppressive and facilitatory control over the peripheral nervous system (PNS) which initially mediates the gill withdrawal reflex and its subsequent habituation evoked by tactile stimulation of the siphon. In young animals, both the suppressive and facilitatory CNS control were found to be absent. In older animals, removal of branchial nerve (Br) input to the gill resulted in a significantly reduced reflex latency and, with ctenidial (Ct) and siphon (Sn) nerves intact, a significantly increased reflex amplitude and an inability of the reflex to habituate with repeated siphon stimulation. In young animals, removal of Br had no effect on reflex latency and with Ct and Sn intact, the reflex amplitude latency was not increased and the reflex habituated. Older animals can easily discriminate between different intensity stimuli applied to the siphon as evidenced by differences in reflex amplitude, rates of habituation, and evoked neural activity. On the other hand, young animals cannot discriminate well between different stimulus intensities. The lack of CNS control in young animals was found to be due to incompletely developed neural processes within the abdominal ganglion and not the PNS. The lack of CNS control in young Aplysia results in gill reflex behaviours being less adaptive in light of changing stimulus conditions, but may be of positive survival value in that the young will not habituate as easily. The fact that CNS control is present in older animals strengthens the idea that in any analysis of the underlying neural mechanisms of habituation the entire integrated CNS–PNS must be taken into account.

Transfer of Habituation Shows an Interaction Between Neuronal Circuits of the Gill Withdrawal Reflex in Aplysia Californica

1982 ◽  
Vol 96 (1) ◽  
pp. 107-124
Author(s):  
JEFF GOLDBERG ◽  
KEN LUKOWIAK
Keyword(s):  
Tactile Stimulation ◽  
Neural Circuits ◽  
Repetitive Stimulation ◽  
Integrated System ◽  
Neuronal Circuits ◽  
Withdrawal Reflex ◽  
Motor Neurones ◽  
Excitatory Responses ◽  
Lines Of Evidence ◽  
Stimulation Of

The gill withdrawal reflex (GWR) and its subsequent habituation can be evoked by tactile stimulation of the siphon or gill when the CNS is either intact or removed. It has been suggested that the neural circuits that mediate the GWR evoked at these two loci are parallel and independent. We provide three lines of evidence which show that these circuits interact and, therefore, comprise a single integrated system. Firtly, siphon and gill stimulation evoked similar excitatory responses in the central gill motor neurones. Secondly, the GWR habituated by repetitive stimulation at one locus was dishabituated by stimulation of the other locus. Thirdly, transfer of habituation occurred. Although the transfer was seen neurally at the level of central gill motor neurones, transfer of habituation also occurred after the CNS was removed. Therefore, the neuronal circuits mediating the reflexes evoked at the siphon and gill interact within both the CNS and PNS. The PNS is largely responsible for mediating this gill behaviour that is based on such interactions, while the CNS provides suppressive and facilitatory plasticity to these responses to enable Aplysia to better adapt to a changing environment.

scholarly journals Suppression of Thyroarytenoid Muscle Responses during Repeated Air Pressure Stimulation of the Laryngeal Mucosa in Awake Humans

2005 ◽  
Vol 114 (4) ◽  
pp. 264-270 ◽  
Author(s):  
Pamela Reed Kearney ◽  
Eric A. Mann ◽  
Christopher J. Poletto ◽  
Christy L. Ludlow
Keyword(s):  
Air Pressure ◽  
Repeated Presentation ◽  
Repeated Stimulation ◽  
Laryngeal Mucosa ◽  
Posterior Cricoarytenoid Muscle ◽  
Interstimulus Intervals ◽  
Posterior Cricoarytenoid ◽  
Muscle Responses ◽  
Thyroarytenoid Muscle ◽  
Stimulation Of

Repeated stimulation of the laryngeal mucosa occurs during speech. Single stimuli, however, can elicit the laryngeal adductor response (LAR). Our hypothesis was that the LAR to repeated rapid air pressure stimuli is centrally suppressed in humans. Hookedwire electrodes were inserted into the thyroarytenoid and cricothyroid muscles on both sides and into the posterior cricoarytenoid muscle on one side. Pairs of air puff stimuli were presented to the mucosa over the arytenoids at pressure levels three times threshold with interstimulus intervals from 250 to 5,000 ms. Bilateral thyroarytenoid responses occurred at around 150 ms to more than 70% of the initial stimuli. With repeated presentation at intervals of 2 seconds or less, the percent occurrence decreased to less than 40% and response amplitudes were reduced by 50%. Central suppression of adductor responses to repeated air puff stimuli may allow speakers to produce voice without eliciting reflexive spasms that could disrupt speech.

Suppression of gill withdrawal reflex behaviours in Aplysia: the role of acetylcholine

1990 ◽  
Vol 68 (11) ◽  
pp. 1407-1413
Author(s):  
David Cawthorpe ◽  
Ken Lukowiak
Keyword(s):  
Tactile Stimulation ◽  
Aplysia Californica ◽  
Withdrawal Reflex ◽  
Stimulation Of

Acetylcholine (ACh) dissolved in seawater and perfused through the isolated gill of the Aplysia californica produced suppression of the gill withdrawal reflex (GWR) evoked by tactile stimulation of the gill. This suppression was reversible upon washout and was blocked by co-perfusion of curare and α-bungarotoxin. Co-perfusion of atropine did not block the suppression of the GWR produced by ACh. We concluded that the suppressive effects produced by perfusion of ACh through the gill occur as a result of the action of ACh at the nicotinic-like receptors. The role of ACh suppression in the mediation of gill reflex behaviours is discussed.Key words: Aplysia, gill withdrawal reflex, suppression, acetylcholine.

Contribution of individual mechanoreceptor sensory neurons to defensive gill-withdrawal reflex in Aplysia

1978 ◽  
Vol 41 (2) ◽  
pp. 418-431 ◽  
Author(s):  
J. H. Byrne ◽  
V. F. Castellucci ◽  
E. R. Kandel
Keyword(s):  
Motor Neuron ◽  
Sensory Neuron ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Tactile Stimulation ◽  
Sensory Cell ◽  
Divalent Cations ◽  
Plastic Properties ◽  
Withdrawal Reflex ◽  
Stimulation Of

1. To evaluate the contribution which mechanoreceptor sensory neurons make to the defensive gill-withdrawal reflex we developed an isolated reflex preparation. We then reduced this isolated reflex to a microcircuit (consisting of a single sensory cell and single motor cell) so as to causally relate the contribution of individual cells to the expression and plastic properties of the behavior. 2. Mechanoreceptor neurons make significant contributions to the amplitude and duration of the complex PSP in the motor neurons. A single spike in a sensory neuron produces an EPSP in the motor neuron which accounts for 7-36% of the complex EPSP produced by weak tactile stimulation of the skin. 3. More than 50% of the synaptic input to the gill motor neurons appears to be monosynaptic. Perfusing the ganglion with solutions of high divalent cations reduced the motor neurons' complex PSP by only 40%. 4. The population response of the mechanoreceptors to a point stimulus can be simulated by repetitively firing a single sensory neuron. Firing a single sensory cell discharges the motor neuron and produces a gill contraction similar to that produced by a natural stimulus. 5. Mechanoreceptors make monosynaptic connections onto gill motor neurons which decrement with repeated stimulation paralleling the decrement of the complex PSP to punctate tactile stimulation of the skin. 6. The results indicate that the known neural elements may quantitatively account for most of the expression of the behavior and its short-term habituation.

scholarly journals Operant conditioning of aerial respiratory behaviour in Lymnaea stagnalis

1996 ◽  
Vol 199 (3) ◽  
pp. 683-691 ◽  
Author(s):  
K Lukowiak ◽  
E Ringseis ◽  
G Spencer ◽  
W Wildering ◽  
N Syed
Keyword(s):  
Operant Conditioning ◽  
Tactile Stimulation ◽  
Direct Evidence ◽  
Lymnaea Stagnalis ◽  
Freshwater Snail ◽  
Withdrawal Reflex ◽  
Before And After ◽  
Opening And Closing ◽  
Stimulation Paradigm ◽  
Stimulation Of

In this study, we operantly conditioned the aerial respiratory behaviour of the freshwater snail Lymnaea stagnalis. Aerial respiration in Lymnaea stagnalis is accomplished by the spontaneous opening and closing of its respiratory orifice, the pneumostome, at the water surface. Weak tactile stimulation of the pneumostome area, when the pneumostome is open, evoked only the pneumostome closure response, which is one aspect of the escape-withdrawal reflex. Pneumostome stimulation resulted in its closure and the termination of aerial respiratory activity. A contingent tactile stimulation paradigm was used to operantly condition the animals. Stimulation of the pneumostome whenever the animal attempted to breathe resulted in significantly fewer attempts to open the pneumostome as training progressed. The latency of the first breath (subsequent to stimulation), the number of breaths and the total breathing time were measured before and after each training period. Significant, quantifiable changes in these behavioural parameters were observed only in the operant conditioning group animals. Control animals receiving tactile stimulation to their pneumostome not contingent upon pneumostome opening movements (yoked controls) or those that were physically prevented from surfacing to breathe (hypoxic controls), did not exhibit significant changes in these behavioural parameters. Our data provide the first direct evidence for operant conditioning of respiration in any animal.

Control of feeding motor output by paracerebral neurons in brain of Pleurobranchaea californica

1982 ◽  
Vol 47 (5) ◽  
pp. 885-908 ◽  
Author(s):  
R. Gillette ◽  
M. P. Kovac ◽  
W. J. Davis
Keyword(s):  
Feeding Behavior ◽  
Action Potentials ◽  
Tactile Stimulation ◽  
Natural Food ◽  
Buccal Ganglion ◽  
Pleurobranchaea Californica ◽  
Feeding Rhythm ◽  
Intracellular Stimulation ◽  
Motor Rhythm ◽  
Stimulation Of

1. A population of interneurons that control feeding behavior in the mollusk Pleurobranchaea has been analyzed by dye injection and intracellular stimulation/recording in whole animals and reduced preparations. The population consists of 12-16 somata distributed in two bilaterally symmetrical groups on the anterior edge of the cerebropleural ganglion (brain). On the basis of their position adjacent to the cerebral lobes, these cells have been named paracerebral neurons (PCNs). This study concerns pme subset pf [MCs. the large, phasic ones, which have the strongest effect on the feeding rhythm (21). 2. Each PCN sends a descending axon via the ipsilateral cerebrobuccal connective to the buccal ganglion. Axon branches have not been detected in other brain or buccal nerves and hence the PCNs appear to be interneurons. 3. In whole-animal preparations, tonic intracellular depolarization of the PNCs causes them to discharge cyclic bursts of action potentials interrupted by a characteristic hyperpolarization. In all specimens that exhibit feeding behavior, the interburst hyperpolarization is invariably accompanied by radula closure and the beginning of proboscis retraction (the "bite"). No other behavorial effect of PCN stimulation has been observed. 4. In whole-animal preparations, the PCNs are excited by food and tactile stimulation of the oral veil, rhinophores, and tentacles. When such stimuli induce feeding the PCNs discharge in the same bursting pattern seen during tonic PCN depolarization, with the cyclic interburst hyperpolarization phase locked to the bit. When specimens egest an unpalatable object by cyclic buccal movements, however, the PCNs are silent. The PCNs therefore exhibit properties expected of behaviorally specific "command" neurons for feeding. 5. Silencing one or two PCNs by hyperpolarization may weaken but does not prevent feeding induced by natural food stimuli. Single PCNs therefore can be sufficient but are not necessary to induction of feeding behavior. Instead the PCNs presumably operate as a population to control feeding. 6. In isolated nervous system preparations tonic extracellular stimulation of the stomatogastric nerve of the buccal ganglion elicits a cyclic motor rhythm that is similar in general features to the PNC-induced motor rhythm. Bursts of PCN action potentials intercalated at the normal phase position in this cycle intensify the buccal rhythm. Bursts of PCN impulses intercalated at abnormal phase positions reset the buccal rhythm. The PCNs, therefore, also exhibit properties expected of pattern-generator elements and/or coordinating neurons for the buccal rhythm. 7. The PCNs are recruited into activity when the buccal motor rhythm is elicited by stomatogastric nerve stimulation or stimulation of the reidentifiable ventral white cell. The functional synergy between the PCNs and the buccal rhythm is therefore reciprocal. 8...

Complex dynamics resulting from repeated stimulation of nonlinear oscillators at a fixed phase

1987 ◽  
Vol 125 (2-3) ◽  
pp. 119-122 ◽  
Author(s):  
John Lewis ◽  
Manjit Bachoo ◽  
Leon Glass ◽  
Canio Polosa
Keyword(s):  
Complex Dynamics ◽  
Nonlinear Oscillators ◽  
Repeated Stimulation ◽  
Fixed Phase ◽  
Stimulation Of
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