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.

CNS control of the PNS-mediated gill withdrawal reflex and its habituation

1977 ◽  
Vol 55 (6) ◽  
pp. 1252-1262 ◽  
Author(s):  
Ken Lukowiak
Keyword(s):  
Nervous System ◽  
Motor Neurons ◽  
Neural Mechanisms ◽  
Abdominal Ganglion ◽  
Synaptic Efficacy ◽  
Motor Pathways ◽  
Withdrawal Reflex ◽  
Neural Processes ◽  
Ultimate Cause ◽  
Cns Control

Removal of the branchial (Br) nerve input to the gill significantly reduced the latency and increased the amplitude of the gill withdrawal reflex evoked by siphon stimulation. Further, after Br removal repeated siphon stimulation which previously resulted in habituation now resulted in facilitation of the reflex. However, the synaptic input to gill motor neurons in the abdominal ganglion continued to decrement as before. In preparations without the peripheral nervous system (PNS), removal of Br did not produce similar results. The gill withdrawal reflex and its habituation are mediated by the PNS, but the CNS exerts facilitatory and suppressive control. Thus, changes in synaptic efficacy to gill motor neurons in the abdominal ganglion are not the ultimate cause of gill reflex habituation. Habituation is the result of adaptive neural processes which occur together in the abdominal ganglion, the PNS, and the peripheral terminations of the central motor pathways to the gill. Therefore, in any analysis of the underlying neural mechanisms of habituation all these loci must be included and taken into account.

Dopamine modulation of gill reflex behavior in Aplysia

1979 ◽  
Vol 57 (3) ◽  
pp. 329-332 ◽  
Author(s):  
Peter Ruben ◽  
Ken Lukowiak
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Neuron ◽  
Peripheral Nervous System ◽  
Motor Neurons ◽  
Withdrawal Reflex ◽  
Dopaminergic Pathway ◽  
The Central Nervous System ◽  
Dopamine Modulation

We have studied the effects of dopamine on the gill withdrawal reflex evoked by tactile siphon stimulation in the margine mollusc Aplysia. Physiological concentrations of dopamine (diluted in seawater) were perfused through the gill during siphon stimulation series. The amplitude of the reflex was potentiated by dopamine and habituation of the reflex was prevented. This occurred with no change in the activity evoked in central motor neurons. These results lead us to conclude that the dopaminergic motor neuron L9 is modulating habituation in the periphery and that the central nervous system facilitatory control of the peripheral nervous system may act via a dopaminergic pathway.

Excitatory and inhibitory roles of central ganglia in initiation of the insect ecdysis behavioural sequence

2000 ◽  
Vol 203 (8) ◽  
pp. 1329-1340 ◽  
Author(s):  
D. Zitnan ◽  
M.E. Adams
Keyword(s):  
Neural Network ◽  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Abdominal Ganglion ◽  
Suboesophageal Ganglion ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
Inka Cells ◽  
Behavioural Sequence

Insects shed their old cuticle by performing the ecdysis behavioural sequence. To activate each subunit of this set of programmed behaviours in Manduca sexta, specific central ganglia are targeted by pre-ecdysis-triggering (PETH) and ecdysis-triggering (ETH) hormones secreted from Inka cells. PETH and ETH act on each abdominal ganglion to initiate, within a few minutes, pre-ecdysis I and II, respectively. Shortly thereafter, ETH targets the tritocerebrum and suboesophageal ganglion to activate the ecdysis neural network in abdominal ganglia through the elevation of cyclic GMP (cGMP) levels. However, the onset of ecdysis behaviour is delayed by inhibitory factor(s) from the cephalic and thoracic ganglia. The switch from pre-ecdysis to ecdysis is controlled by an independent clock in each abdominal ganglion and is considerably accelerated after removal of the head and thorax. Eclosion hormone (EH) appears to be one of the central signals inducing elevation of cGMP levels and ecdysis, but these actions are quite variable and usually restricted to anterior ganglia. EH treatment of desheathed ganglia also elicits strong production of cGMP in intact ganglia, suggesting that this induction occurs via the release of additional downstream factors. Our data suggest that the initiation of pre-ecdysis and the transition to ecdysis are regulated by stimulatory and inhibitory factors released within the central nervous system after the initial actions of PETH and ETH.

Modeling and Simulation of the Central Nervous System Control with Generic Fuzzy Models

SIMULATION ◽  
2003 ◽  
Vol 79 (11) ◽  
pp. 648-669 ◽  
Author(s):  
Angela Nebot ◽  
Francisco Mugica ◽  
François E. Cellier ◽  
Montserrat Vallverdú
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Modeling And Simulation ◽  
System Control ◽  
Fuzzy Models ◽  
The Central Nervous System ◽  
Central Nervous System Control

Central nervous system control of airway tone in guinea pigs: the role of histamine

1988 ◽  
Vol 65 (5) ◽  
pp. 2024-2029 ◽  
Author(s):  
P. J. Mauser ◽  
N. H. Edelman ◽  
R. W. Chapman
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Guinea Pigs ◽  
Lung Compliance ◽  
System Control ◽  
The Central Nervous System ◽  
Dose Dependent Decrease ◽  
Airway Tone ◽  
Dynamic Lung Compliance ◽  
H1 Antagonist

The central nervous system (CNS) plays an important role in the reflex control of bronchomotor tone, but the relevant neurotransmitters and neuromodulators have not been identified. In this study we have investigated the effect of histamine. Anesthetized male guinea pigs were prepared with a chronically implanted intracerebroventricular (icv) cannula and instrumented for the measurement of pulmonary resistance (RL), dynamic lung compliance (Cdyn), tidal volume (VT), respiratory rate (f), blood pressure (BP), and heart rate (HR). Administration of histamine (2-30 micrograms) icv caused a significant (P less than 0.05) reduction of Cdyn with no change in RL, VT, and f. At a dose of 100 micrograms icv, histamine caused an increase in RL (202 +/- 78%), a reduction of Cdyn (77 +/- 9%), an increase in f (181 +/- 64%), and a reduction of VT (53 +/- 18%). There were no changes in BP and HR after 100 micrograms of icv histamine. In contrast, intravenous administration of histamine (0.1-2 micrograms/kg) caused a dose-dependent decrease in Cdyn and increase in RL that was associated with tachypnea at each bronchoconstrictor dose. Intravenous histamine (2 micrograms/kg) produced a fall in BP and an increase in HR. The bronchoconstrictor responses to icv histamine were completely blocked by vagotomy and significantly reduced by atropine (0.1 mg/kg iv), whereas vagotomy and atropine did not block the bronchospasm due to intravenous histamine. Additional studies indicated that the pulmonary responses due to icv histamine (100 micrograms) were blocked by pretreatment with the H1-antagonist chlorpheniramine (1 and 10 micrograms, icv). These data indicate that histamine may serve a CNS neurotransmitter function in reflex bronchoconstriction in guinea pigs.

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.

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