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Optogenetic dissection of dopamine subpopulations in Drosophila reveals interplay between reward and aversion
Title
Optogenetic dissection of dopamine subpopulations in Drosophila reveals interplay between reward and aversion.
Creator
Alshakarchi, Zainab, Duboue, Erik, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
Dopamine is an essential component in the neural pathway for attractive and aversive behavior. Dopaminergic (DA) neurons are known to have a key role in neurotransmission which can result in the modulation of different behaviors as well as the manifestation of different mental health disorders. Drosophila share similar genetics that are associated with several neurodegenerative diseases and disorders in humans. Furthermore, previous studies have shown conservation of DA neurons between humans...
Show moreDopamine is an essential component in the neural pathway for attractive and aversive behavior. Dopaminergic (DA) neurons are known to have a key role in neurotransmission which can result in the modulation of different behaviors as well as the manifestation of different mental health disorders. Drosophila share similar genetics that are associated with several neurodegenerative diseases and disorders in humans. Furthermore, previous studies have shown conservation of DA neurons between humans and Drosophila which facilitate research using Drosophila as a model organism. In this study, we initially developed and tested a novel optogenetics system, which targeted neurons with spatial specificity, that activated or inhibited neurons through channelrhodopsin microbial opsins that are sensitive to red light. This system was then used to investigate the DA subsets that mediate attractive and aversive behavior. The activation of PPL1 clusters mostly resulted in aversive behavior as aligned with the literature, however activation of clusters with output neurons (PPL1 & PAM) concluded with different results.
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Date Issued
2021
PURL
http://purl.flvc.org/fau/fd/FA00013868
Subject Headings
Drosophila, Dopaminergic Neurons, Optogenetics
Format
Document (PDF)
EFFECTS OF OPTOGENETICALLY STIMULATING THE REUNIENS NUCLEUS DURING SLEEP IN A NOVEL ATTENTIONAL SET-SHIFTING TASK
Title
EFFECTS OF OPTOGENETICALLY STIMULATING THE REUNIENS NUCLEUS DURING SLEEP IN A NOVEL ATTENTIONAL SET-SHIFTING TASK.
Creator
Yarden, Ori Simon, Varela, Carmen, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
Sparse thalamocortical cell population synchronicity during sleep spindle oscillations has been hypothesized to promote the integration of hippocampal memory information into associated neocortical representations 1. We asked the question of whether sparse or rhythmic activity in thalamocortical cells of the reuniens nucleus influence memory consolidation and cognitive flexibility during learning after sleep. For this study, I designed a novel attentional set-shifting task and incorporated...
Show moreSparse thalamocortical cell population synchronicity during sleep spindle oscillations has been hypothesized to promote the integration of hippocampal memory information into associated neocortical representations 1. We asked the question of whether sparse or rhythmic activity in thalamocortical cells of the reuniens nucleus influence memory consolidation and cognitive flexibility during learning after sleep. For this study, I designed a novel attentional set-shifting task and incorporated optogenetics with closed-loop stimulation in sleeping rats to investigate the effects of sparse (nonrhythmic) or rhythmic spindle-like (~10Hz) activity in thalamic cells of the reuniens nucleus on learning and cognitive flexibility. We show that, as predicted, post-sleep setshifting performance improved after sleep with non-rhythmic optogenetic stimulation in the thalamic nucleus reuniens relative to rhythmic optogenetic stimulation. While both non-rhythmic and rhythmic optogenetic stimulation led to an increase in perseverative errors, only non-rhythmic optogenetic stimulation showed effects of learning from errors, which correlated with sleep, and which ultimately had a net benefit in set-shifting performance compared to rhythmic optogenetic stimulation and the control group.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013632
Subject Headings
Optogenetics, Thalamic Nuclei, Sleep, Learning
Format
Document (PDF)
OPTOGENETICALLY DISRUPTING THE THALAMIC SPINDLE OSCILLATION DURING SLEEP IMPAIRS COGNITIVE FLEXIBILITY
Title
OPTOGENETICALLY DISRUPTING THE THALAMIC SPINDLE OSCILLATION DURING SLEEP IMPAIRS COGNITIVE FLEXIBILITY.
Creator
Yarden, Ori Simon, Varela, Carmen, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description
A hypothesized model of spindle organization of thalamic and hippocampal spike dynamics (Figure 1) suggests that sparsity operates in spindles as an essential component of thalamic activity that could be contributing to flexibility in learning (Varela & Wilson, 2020). We asked the question of whether sparse spindle-like (10Hz non-rhythmic) or 10Hz rhythmic activity in thalamic cells of the reuniens nucleus influence cognitive flexibility during learning after sleep. By comparing the two...
Show moreA hypothesized model of spindle organization of thalamic and hippocampal spike dynamics (Figure 1) suggests that sparsity operates in spindles as an essential component of thalamic activity that could be contributing to flexibility in learning (Varela & Wilson, 2020). We asked the question of whether sparse spindle-like (10Hz non-rhythmic) or 10Hz rhythmic activity in thalamic cells of the reuniens nucleus influence cognitive flexibility during learning after sleep. By comparing the two stimulation protocols (“nonrhythmic” and “rhythmic”), we tested if disrupting the characteristic sparsity reveals any changes in flexibility during learning after sleep. Results showed that sleep accompanied 10Hz rhythmic optogenetic stimulation of thalamic nucleus reuniens impaired rule-switching (or set-shifting) performance and disrupted the sleep enhancing rule-switch associated increase in vicarious trial and error (VTE), which we used as a metric for deliberation. We found that rule-switching was associated with a subsequent increase in VTE, as were incorrect choices, and when rats subsequently made correct choices. Instead, stimulating against the endogenous thalamocortical spindle oscillation (i.e. sleep accompanied 10Hz rhythmic optogenetic stimulation) resulted in a significant disruption in post-sleep performance and VTE during, but not prior to, rule-switching. Lastly, optogenetic 10Hz stimulation of the thalamic nucleus reuniens did not affect sleeping or waking behavior during the sleep box session but it did show a clear though nonsignificant increase in waking head velocities; thus, changes in cognitive flexibility and VTE cannot be explained by any changes in sleep itself, but rather due to the after-effects the specific patterns of 10Hz optogenetic stimulation in thalamic nucleus reuniens applied during sleep had on cognition.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014275
Subject Headings
Optogenetics, Midline Thalamic Nuclei, Sleep
Format
Document (PDF)
The Dynamic pH Landscape At The Drosophila NMJ Synaptic Cleft And Its Implication In Neurotransmission
Title
The Dynamic pH Landscape At The Drosophila NMJ Synaptic Cleft And Its Implication In Neurotransmission.
Creator
Hernandez, Roberto X., Macleod, Gregory T., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
The intricate processes governing cellular pH and its impact on protein and cellular function have been extensively explored. However, our understanding of the pH fluctuations that occur during routine cellular activities and their potential to modulate cell function remains, particularly within the highly dynamic pH landscape of a synapse. Investigating the scale, directionality, and temporal characteristics of these activity-dependent pH fluctuations at synapses is of paramount interest, as...
Show moreThe intricate processes governing cellular pH and its impact on protein and cellular function have been extensively explored. However, our understanding of the pH fluctuations that occur during routine cellular activities and their potential to modulate cell function remains, particularly within the highly dynamic pH landscape of a synapse. Investigating the scale, directionality, and temporal characteristics of these activity-dependent pH fluctuations at synapses is of paramount interest, as it carries profound implications for neurotransmitter release and signal transduction. Employing both empirical and computational modeling methods, our research explores the dynamic pH environment within the synaptic cleft of Drosophila glutamatergic motor neuron Ib terminals during synaptic activity and reveals its significance in modulating neurotransmission. Contrary to popular belief, we discovered that these terminals undergo activity-dependent extracellular alkalinization in response to both single action potentials and burst stimulation. This surprising phenomenon was also observed at the mouse calyx of Held. We found activity-dependent alkalinization to be predominantly driven by Ca2+ movement across the postsynaptic membrane, and by targeting pH indicators to subcellular domains, we identified alkalinization to primarily occur within the cleft.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014346
Subject Headings
Neurotransmission, Drosophila, Hydrogen-Ion Concentration, Motor Neurons, Optogenetics
Format
Document (PDF)