The role of glutamate in swim initiation in the medicinal leech

Thorogood, Maria Stella E.; Brodfuehrer, Peter D.

doi:10.1007/bf02211024

Cited by 18 publications

(12 citation statements)

References 34 publications

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“…Neurons Tr1, SE1, and R3b1 initiate swimming (Brodfuehrer and Friesen, 1986a,b,c;Thorogood and Brodfuehrer 1995;Shaw and Kristan, 1997;Esch et al, 2002), whereas neurons SIN1 and Tr2 terminate swimming O'Gara and Friesen, 1995). The firing of neuron R3b1 (Esch et al, 2002) elicits both swimming and crawling or a hybrid behavior (similar to that shown in Fig.…”

Section: Flow Of Leech Behavioral Decisions As a First-order Markov Pmentioning

confidence: 58%

Statistics of Decision Making in the Leech

García‐Pérez¹,

Mazzoni²,

Zoccolan³

et al. 2005

J. Neurosci.

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Animals continuously decide among different behaviors, but, even in invertebrates, the mechanisms underlying choice and decision are unknown. In this article, leech spontaneous behavior was tracked and quantified for up to 12 h. We obtained a statistical characterization, in space and time domains, of the decision processes underlying selection of behavior in the leech. We found that the spatial distribution of leech position in a uniform environment is isotropic (the same in all directions), but this isotropy is broken in the presence of localized external stimuli. In the time domain, transitions among behaviors can be described by a Markov process, the structure of which (allowed states and transitions) is highly conserved across individuals. Finally, a wide range of recurrent, deterministic motifs was identified in the apparently irregular and unstructured exploratory behavior. These results provide a rigorous description of the inner dynamics that control the spontaneous and continuous flow of behavioral decisions in the leech.

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Section: Flow Of Leech Behavioral Decisions As a First-order Markov Pmentioning

confidence: 58%

Statistics of Decision Making in the Leech

García‐Pérez¹,

Mazzoni²,

Zoccolan³

et al. 2005

J. Neurosci.

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“…Not only were networks' bursts suppressed, but also single neuron's bursts (Figure 7), supporting the finding that the single neuron behavior depends on the global correlation (Figure 4). The prominent effect of APV was unexpected in leech networks, as most of the known glutamate receptors in the leech are non-NMDA [37], [38]. However, when we applied the selective antagonist APV (see Methods) we always obtained a clear reduction of the bursting activity (Figure 6A, blue trace), suggesting that NMDA receptors are present in the leech ganglion [39].…”

Section: Discussionmentioning

confidence: 89%

On the Dynamics of the Spontaneous Activity in Neuronal Networks

et al. 2007

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Most neuronal networks, even in the absence of external stimuli, produce spontaneous bursts of spikes separated by periods of reduced activity. The origin and functional role of these neuronal events are still unclear. The present work shows that the spontaneous activity of two very different networks, intact leech ganglia and dissociated cultures of rat hippocampal neurons, share several features. Indeed, in both networks: i) the inter-spike intervals distribution of the spontaneous firing of single neurons is either regular or periodic or bursting, with the fraction of bursting neurons depending on the network activity; ii) bursts of spontaneous spikes have the same broad distributions of size and duration; iii) the degree of correlated activity increases with the bin width, and the power spectrum of the network firing rate has a 1/f behavior at low frequencies, indicating the existence of long-range temporal correlations; iv) the activity of excitatory synaptic pathways mediated by NMDA receptors is necessary for the onset of the long-range correlations and for the presence of large bursts; v) blockage of inhibitory synaptic pathways mediated by GABAA receptors causes instead an increase in the correlation among neurons and leads to a burst distribution composed only of very small and very large bursts. These results suggest that the spontaneous electrical activity in neuronal networks with different architectures and functions can have very similar properties and common dynamics.

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“…1) was caused by 5-HT receptors located in these cells, because it was unaffected by blocking glutamatergic and cholinergic excitatory synaptic transmission ( Fig. 3; Burgin and Szczupak, 1998;Thorogood and Brodfuehrer, 1995). The [Ca 2ϩ ] i increase was exclusively due to Ca 2ϩ influx, since it was abolished in Ca 2ϩ -free solution (Fig.…”

Section: ؉ ] I Increase In P and N1 Neuronsmentioning

confidence: 91%

Ca²⁺ influx into identified leech neurons induced by 5‐hydroxytryptamine

Dierkes

Schlue

2004

J. Neurobiol.

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The role of 5-hydroxytryptamine (5-HT, serotonin) in the control of leech behavior is well established and has been analyzed extensively on the cellular level; however, hitherto little is known about the effect of 5-HT on the cytosolic free calcium concentration ([Ca(2+)](i)) in leech neurons. As [Ca(2+)](i) plays a pivotal role in numerous cellular processes, we investigated the effect of 5-HT on [Ca(2+)](i) (measured by Fura-2) in identified leech neurons under different experimental conditions, such as changed extracellular ion composition and blockade of excitatory synaptic transmission. In pressure (P), lateral nociceptive (N1), and Leydig neurons, 5-HT induced a [Ca(2+)](i) increase which was predominantly due to Ca(2+) influx since it was abolished in Ca(2+)-free solution. The 5-HT-induced Ca(2+) influx occurred only if the cells depolarized sufficiently, indicating that it was mediated by voltage-dependent Ca(2+) channels. In P and N1 neurons, the membrane depolarization was due to Na(+) influx through cation channels coupled to 5-HT receptors, whereby the dose-dependency suggests an involvement in excitatory synaptic transmission. In Leydig neurons, 5-HT receptor-coupled cation channels seem to be absent. In these cells, the membrane depolarization activating the voltage-dependent Ca(2+) channels was evoked by 5-HT-triggered excitatory glutamatergic input. In Retzius, anterior pagoda (AP), annulus erector (AE), and median nociceptive (N2) neurons, 5-HT had no effect on [Ca(2+)](i).

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The role of glutamate in swim initiation in the medicinal leech

Cited by 18 publications

References 34 publications

Statistics of Decision Making in the Leech

Statistics of Decision Making in the Leech

On the Dynamics of the Spontaneous Activity in Neuronal Networks

Ca²⁺ influx into identified leech neurons induced by 5‐hydroxytryptamine

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The role of glutamate in swim initiation in the medicinal leech

Cited by 18 publications

References 34 publications

Statistics of Decision Making in the Leech

Statistics of Decision Making in the Leech

On the Dynamics of the Spontaneous Activity in Neuronal Networks

Ca2+ influx into identified leech neurons induced by 5‐hydroxytryptamine

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Product

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Ca²⁺ influx into identified leech neurons induced by 5‐hydroxytryptamine