Presynaptic Facilitation by Neuropeptide Signaling Mediates Odor-Driven Food Search

The temporal spacing within flights of Franklin's gulls (Larus pipixcan) was studied. The extent to which gulls formed flocks was related to the time of day and also the apparent destination of the flight. In the morning, gulls departing from a colony toward foraging sites tended not to form flocks if food resources could be located predictably. Where food resources were the least predictable, gulls departing in the morning did form flocks. An intermediate tendency to form flocks occurred for morning departures toward food sources of intermediate predictability. Arriving gulls that fed en route to the colonies had lower temporal clumping than those that flew directly to the colony. Similarly, direct flights of gulls departing toward the evening roost were characterized by high temporal clumping. The highest degree of temporal clumping occurred in flights of gulls between traditional food sites. These findings support the hypothesis that some kinds of flocking in Franklin's gulls are related to increasing the success of foraging individuals. The tendency for flights toward foraging sites whose locations were unpredictable to be somewhat dispersed suggests that flocks of intermediate density provide the greatest benefits during food search.

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Presynaptic Inhibition, Presynaptic Facilitation, and the Molecular Logic of Second-Messenger Systems

Molecular and Cellular Aspects of the Drug Addictions ◽

10.1007/978-1-4613-8817-3_6 ◽

1989 ◽

pp. 159-197

Author(s):

Andrea Volterra ◽

Steven A. Siegelbaum ◽

J. David Sweatt ◽

Eric R. Kandel

Keyword(s):

Presynaptic Inhibition ◽

Second Messenger ◽

Molecular Logic ◽

Second Messenger Systems ◽

Presynaptic Facilitation

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An essential role of acetylcholine-glutamate synergy at habenular synapses in nicotine dependence

eLife ◽

10.7554/elife.11396 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 29

Author(s):

Silke Frahm ◽

Beatriz Antolin-Fontes ◽

Andreas Görlich ◽

Johannes-Friedrich Zander ◽

Gudrun Ahnert-Hilger ◽

...

Keyword(s):

Synaptic Vesicles ◽

Critical Role ◽

Conditioned Reward ◽

Quantal Size ◽

Medial Habenula ◽

Vesicular Transporters ◽

Circuit Function ◽

And Behavior ◽

Presynaptic Facilitation

A great deal of interest has been focused recently on the habenula and its critical role in aversion, negative-reward and drug dependence. Using a conditional mouse model of the ACh-synthesizing enzyme choline acetyltransferase (Chat), we report that local elimination of acetylcholine (ACh) in medial habenula (MHb) neurons alters glutamate corelease and presynaptic facilitation. Electron microscopy and immuno-isolation analyses revealed colocalization of ACh and glutamate vesicular transporters in synaptic vesicles (SVs) in the central IPN. Glutamate reuptake in SVs prepared from the IPN was increased by ACh, indicating vesicular synergy. Mice lacking CHAT in habenular neurons were insensitive to nicotine-conditioned reward and withdrawal. These data demonstrate that ACh controls the quantal size and release frequency of glutamate at habenular synapses, and suggest that the synergistic functions of ACh and glutamate may be generally important for modulation of cholinergic circuit function and behavior.

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Activity-dependent enhancement of presynaptic facilitation provides a cellular mechanism for the temporal specificity of classical conditioning in Aplysia.

Learning & Memory ◽

10.1101/lm.1.4.243 ◽

1994 ◽

Vol 1 (4) ◽

pp. 243-257

Author(s):

G A Clark ◽

R D Hawkins ◽

E R Kandel

Keyword(s):

Action Potential ◽

Classical Conditioning ◽

Sensory Neurons ◽

Cell Activity ◽

Critical Time ◽

Ionic Currents ◽

Temporal Specificity ◽

The Us ◽

Activity Dependent ◽

Presynaptic Facilitation

A hallmark of many forms of classical conditioning is a precise temporal specificity: Learning is optimal when the conditioned stimulus (CS) slightly precedes the unconditioned stimulus (US), but the learning is degraded at longer or backward intervals, consistent with the notion that conditioning involves learning about predictive relationships in the environment. To further examine the cellular mechanisms contributing to the temporal specificity of classical conditioning of the siphon-withdrawal response in Aplysia, we paired action potential activity in siphon sensory neurons (the neural CS) with tail nerve shock (the US) at three critical time points. We found that CS-US pairings at short (0.5 sec) forward intervals produced greater synaptic facilitation at sensorimotor connections than did either 0.5-sec backward pairings or longer (5 sec) forward pairings, as reflected in a differential increase in both the amplitude and rate of rise of the synaptic potential. In the same preparations, forward pairings also differentially reduced the sensory neuron afterhyperpolarization relative to backward pairings, suggesting that changes in synaptic efficacy were accompanied by temporally specific changes in ionic currents in the sensory neurons. Additional experiments demonstrated that short forward pairings of sensory cell activity and restricted applications of the neuromodulatory transmitter serotonin (normally released by the US) differentially enhanced action potential broadening in siphon sensory neurons, relative to backward pairings. Taken together, these results suggest that temporally specific synaptic enhancement engages both spike-width-dependent and spike-width-independent facilitatory processes and that activity-dependent enhancement of presynaptic facilitation may contribute to both the CS-US sequence and proximity requirements of conditioning.

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