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Changes in frequency of spontaneous oscillations in procerebrum correlate to behavioural choice in terrestrial snails.

Samarova E, Balaban P - Front Cell Neurosci (2009)

Bottom Line: In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation.No significant difference in responses to 5% and 20% cineole was noted.Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency) or approach (increase in frequency) to the source of odor.

View Article: PubMed Central - PubMed

Affiliation: Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science Moscow, Russia.

ABSTRACT
The aim of our study was to understand functional significance of spontaneous oscillations of local field potential in the olfactory brain lobe of terrestrial snail, the procerebrum (PC). We compared changes in frequency of oscillations in semi-intact preparations from snails trained to percept the same conditioned odor as positive (associated with food reinforcement) or negative (associated with noxious reinforcement). In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation. In in vitro preparations from naïve snails, a similar decrease in frequency of the PC oscillations to odor presentation was observed. Changes in frequency of the oscillations to cineole presentations in the "aversive" group of snails (demonstrating withdrawal) were much more pronounced than in naïve snails. No significant difference in responses to 5% and 20% cineole was noted. Changes in the spontaneous oscillations frequency in the snails trained to respond with positive reaction (approach) to cineole depended on the concentration of the applied odor, and these responses were qualitatively similar to responses of other groups during the first 10 s of responses to odor, but significantly different (increase in PC oscillations frequency) from the responses of the aversively trained and naïve snails in the interval 11-30 s, which corresponds to the end of the tentacle withdrawal and timing of decision making (approach or escape) in the free behaving snails. Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency) or approach (increase in frequency) to the source of odor.

No MeSH data available.


Related in: MedlinePlus

Averaged changes of the oscillatory rhythm recorded in vitro in the procerebrum of naïve snails in response to odor application. (A) Changes in the amplitude of the procerebral oscillations in response to the cineole application in 5% (n = 5) and (B) 20% (n = 6) concentrations. (C) Changes in the frequency of the procerebral oscillations in response to cineole application in 5% (n = 5) and (D) 20% (n = 6) concentrations. Vertical bars indicate the standard error of the mean. Statistical significance here and on further figures was calculated in relation to the mean of the frequency or amplitude for 20 s before odor application taken as 100%. * p < 0.05, ** p < 0.01, *** p < 0.001, ANOVA, Dunn's method. (E,F) The response of the procerebrum, MtC3, MtC1 neurons and the cerebro-buccal connective to 5% (E) and 20% (F) cineole application to the nose–brain preparation of naïve snail. Only one example is shown, traces below here and on further figures show part of the response at another time scale. (E) A decrease in the amplitude and frequency of the procerebrum oscillations was observed in semi-intact preparation of the naïve snail. No depolarization in MtC1 neuron after odor presentation was noted. Moderate intensity reaction of MtC3 neuron to cineole was observed. (F) A decrease in the amplitude and frequency of PC oscillations was observed in semi-intact preparation of the naïve snail in response to 20% cineole application. Depolarization in MtC1 neuron after odor presentation is evident.
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Figure 4: Averaged changes of the oscillatory rhythm recorded in vitro in the procerebrum of naïve snails in response to odor application. (A) Changes in the amplitude of the procerebral oscillations in response to the cineole application in 5% (n = 5) and (B) 20% (n = 6) concentrations. (C) Changes in the frequency of the procerebral oscillations in response to cineole application in 5% (n = 5) and (D) 20% (n = 6) concentrations. Vertical bars indicate the standard error of the mean. Statistical significance here and on further figures was calculated in relation to the mean of the frequency or amplitude for 20 s before odor application taken as 100%. * p < 0.05, ** p < 0.01, *** p < 0.001, ANOVA, Dunn's method. (E,F) The response of the procerebrum, MtC3, MtC1 neurons and the cerebro-buccal connective to 5% (E) and 20% (F) cineole application to the nose–brain preparation of naïve snail. Only one example is shown, traces below here and on further figures show part of the response at another time scale. (E) A decrease in the amplitude and frequency of the procerebrum oscillations was observed in semi-intact preparation of the naïve snail. No depolarization in MtC1 neuron after odor presentation was noted. Moderate intensity reaction of MtC3 neuron to cineole was observed. (F) A decrease in the amplitude and frequency of PC oscillations was observed in semi-intact preparation of the naïve snail in response to 20% cineole application. Depolarization in MtC1 neuron after odor presentation is evident.

Mentions: Changes in amplitude and frequency of the procerebral oscillations after cineole application were calculated in percentages of the mean before (40 s) odor application. Average amplitude of the oscillatory rhythm of the PC in naïve snails in vitro increased during the 21–30 and 31–40 s time intervals after the 5% cineole application, and was significantly higher in comparison to the baseline. In this case, increase of the amplitude of the procerebral oscillations to a 5% cineole application was 7% (from 100.7 ± 1.44% to 107.28 ± 2.26%) in the 21–30 s time interval and 9% (from 100.7 ± 1.44% to 109.47 ± 2.88%) in the 31–40 s time interval (Figure 4A). No significant changes of the amplitude of the oscillations were observed during the first 20 s after the odor application to the semi-intact preparation; however the tendency of the amplitude of the oscillations to decrease was obvious (Figure 4A).


Changes in frequency of spontaneous oscillations in procerebrum correlate to behavioural choice in terrestrial snails.

Samarova E, Balaban P - Front Cell Neurosci (2009)

Averaged changes of the oscillatory rhythm recorded in vitro in the procerebrum of naïve snails in response to odor application. (A) Changes in the amplitude of the procerebral oscillations in response to the cineole application in 5% (n = 5) and (B) 20% (n = 6) concentrations. (C) Changes in the frequency of the procerebral oscillations in response to cineole application in 5% (n = 5) and (D) 20% (n = 6) concentrations. Vertical bars indicate the standard error of the mean. Statistical significance here and on further figures was calculated in relation to the mean of the frequency or amplitude for 20 s before odor application taken as 100%. * p < 0.05, ** p < 0.01, *** p < 0.001, ANOVA, Dunn's method. (E,F) The response of the procerebrum, MtC3, MtC1 neurons and the cerebro-buccal connective to 5% (E) and 20% (F) cineole application to the nose–brain preparation of naïve snail. Only one example is shown, traces below here and on further figures show part of the response at another time scale. (E) A decrease in the amplitude and frequency of the procerebrum oscillations was observed in semi-intact preparation of the naïve snail. No depolarization in MtC1 neuron after odor presentation was noted. Moderate intensity reaction of MtC3 neuron to cineole was observed. (F) A decrease in the amplitude and frequency of PC oscillations was observed in semi-intact preparation of the naïve snail in response to 20% cineole application. Depolarization in MtC1 neuron after odor presentation is evident.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742667&req=5

Figure 4: Averaged changes of the oscillatory rhythm recorded in vitro in the procerebrum of naïve snails in response to odor application. (A) Changes in the amplitude of the procerebral oscillations in response to the cineole application in 5% (n = 5) and (B) 20% (n = 6) concentrations. (C) Changes in the frequency of the procerebral oscillations in response to cineole application in 5% (n = 5) and (D) 20% (n = 6) concentrations. Vertical bars indicate the standard error of the mean. Statistical significance here and on further figures was calculated in relation to the mean of the frequency or amplitude for 20 s before odor application taken as 100%. * p < 0.05, ** p < 0.01, *** p < 0.001, ANOVA, Dunn's method. (E,F) The response of the procerebrum, MtC3, MtC1 neurons and the cerebro-buccal connective to 5% (E) and 20% (F) cineole application to the nose–brain preparation of naïve snail. Only one example is shown, traces below here and on further figures show part of the response at another time scale. (E) A decrease in the amplitude and frequency of the procerebrum oscillations was observed in semi-intact preparation of the naïve snail. No depolarization in MtC1 neuron after odor presentation was noted. Moderate intensity reaction of MtC3 neuron to cineole was observed. (F) A decrease in the amplitude and frequency of PC oscillations was observed in semi-intact preparation of the naïve snail in response to 20% cineole application. Depolarization in MtC1 neuron after odor presentation is evident.
Mentions: Changes in amplitude and frequency of the procerebral oscillations after cineole application were calculated in percentages of the mean before (40 s) odor application. Average amplitude of the oscillatory rhythm of the PC in naïve snails in vitro increased during the 21–30 and 31–40 s time intervals after the 5% cineole application, and was significantly higher in comparison to the baseline. In this case, increase of the amplitude of the procerebral oscillations to a 5% cineole application was 7% (from 100.7 ± 1.44% to 107.28 ± 2.26%) in the 21–30 s time interval and 9% (from 100.7 ± 1.44% to 109.47 ± 2.88%) in the 31–40 s time interval (Figure 4A). No significant changes of the amplitude of the oscillations were observed during the first 20 s after the odor application to the semi-intact preparation; however the tendency of the amplitude of the oscillations to decrease was obvious (Figure 4A).

Bottom Line: In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation.No significant difference in responses to 5% and 20% cineole was noted.Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency) or approach (increase in frequency) to the source of odor.

View Article: PubMed Central - PubMed

Affiliation: Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science Moscow, Russia.

ABSTRACT
The aim of our study was to understand functional significance of spontaneous oscillations of local field potential in the olfactory brain lobe of terrestrial snail, the procerebrum (PC). We compared changes in frequency of oscillations in semi-intact preparations from snails trained to percept the same conditioned odor as positive (associated with food reinforcement) or negative (associated with noxious reinforcement). In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation. In in vitro preparations from naïve snails, a similar decrease in frequency of the PC oscillations to odor presentation was observed. Changes in frequency of the oscillations to cineole presentations in the "aversive" group of snails (demonstrating withdrawal) were much more pronounced than in naïve snails. No significant difference in responses to 5% and 20% cineole was noted. Changes in the spontaneous oscillations frequency in the snails trained to respond with positive reaction (approach) to cineole depended on the concentration of the applied odor, and these responses were qualitatively similar to responses of other groups during the first 10 s of responses to odor, but significantly different (increase in PC oscillations frequency) from the responses of the aversively trained and naïve snails in the interval 11-30 s, which corresponds to the end of the tentacle withdrawal and timing of decision making (approach or escape) in the free behaving snails. Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency) or approach (increase in frequency) to the source of odor.

No MeSH data available.


Related in: MedlinePlus