scholarly journals Modularity and neural coding from a brainstem synaptic wiring diagram

2020 ◽  
Author(s):  
Ashwin Vishwanathan ◽  
Alexandro D. Ramirez ◽  
Jingpeng Wu ◽  
Alex Sood ◽  
Runzhe Yang ◽  
...  
Keyword(s):  
Eye Movement ◽  
Neural Activity ◽  
Calcium Imaging ◽  
Neural Coding ◽  
Clustering Algorithms ◽  
Recurrent Network ◽  
Electron Microscopic ◽  
Wiring Diagram ◽  
Larval Zebrafish ◽  
Vertebrate Brain

AbstractNeuronal wiring diagrams reconstructed from electron microscopic images are enabling new ways of attacking neuroscience questions. We address two central issues, modularity and neural coding, by reconstructing and analyzing a wiring diagram from a larval zebrafish brainstem. We identified a recurrently connected “center” within the 3000-node graph, and applied graph clustering algorithms to divide the center into two modules with stronger connectivity within than between modules. Outgoing connection patterns and registration to maps of neural activity suggested the modules were specialized for body and eye movements. The eye movement module further subdivided into two submodules corresponding to the control of the two eyes. We constructed a recurrent network model of the eye movement module with connection strengths estimated from synapse numbers. Neural activity in the model replicated the statistics of eye position encoding across multiple populations of neurons as observed by calcium imaging. Our findings show that synapse-level wiring diagrams can be used to extract structural modules with interpretable functions in the vertebrate brain, and can be related to the encoding of computational variables important for behavior. We also show through a potential synapse formalism that these modeling successes require true synaptic connectivity; connectivity inferred from arbor overlap is insufficient.

scholarly journals Percolation in the resting zebrafish habenula

2018 ◽  
Author(s):  
Suryadi ◽  
Ruey-Kuang Cheng ◽  
Suresh Jesuthasan ◽  
Lock Yue Chew
Keyword(s):  
Calcium Imaging ◽  
The Other ◽  
Behavioural Flexibility ◽  
Spatial Correlations ◽  
Sensory Stimuli ◽  
Two Photon ◽  
Larval Zebrafish ◽  
Vertebrate Brain ◽  
Evolutionarily Conserved ◽  
Neuronal Avalanches

AbstractThe habenula is an evolutionarily conserved structure of the vertebrate brain that is essential for behavioural flexibility and mood control. It is spontaneously active and is able to access diverse states when the animal is exposed to sensory stimuli or reward. Here we analyze two-photon calcium imaging time-series of the habenula of larval zebrafish and find that percolation occurs, indicating the presence of long-range spatial correlations within each side of the habenula, with percolation occurring independently in each side. On the other hand, the analysis of neuronal avalanches suggests that the system is subcritical, implying that the flexibility in its dynamics may result from other dynamical processes.

The Zebrafish Visual System: From Circuits to Behavior

2019 ◽  
Vol 5 (1) ◽  
pp. 269-293 ◽  
Author(s):  
Johann H. Bollmann
Keyword(s):  
Visual System ◽  
Neural Activity ◽  
Visual Information ◽  
Ganglion Cells ◽  
Larval Zebrafish ◽  
Vertebrate Brain ◽  
Visuomotor Transformations ◽  
Behavioral Needs ◽  
The Brain ◽  
Processing Steps

Visual stimuli can evoke complex behavioral responses, but the underlying streams of neural activity in mammalian brains are difficult to follow because of their size. Here, I review the visual system of zebrafish larvae, highlighting where recent experimental evidence has localized the functional steps of visuomotor transformations to specific brain areas. The retina of a larva encodes behaviorally relevant visual information in neural activity distributed across feature-selective ganglion cells such that signals representing distinct stimulus properties arrive in different areas or layers of the brain. Motor centers in the hindbrain encode motor variables that are precisely tuned to behavioral needs within a given stimulus setting. Owing to rapid technological progress, larval zebrafish provide unique opportunities for obtaining a comprehensive understanding of the intermediate processing steps occurring between visual and motor centers, revealing how visuomotor transformations are implemented in a vertebrate brain.

scholarly journals Manipulating neural activity and sleep-dependent memory consolidation

Neuroforum ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Maryam Ghorbani ◽  
Lisa Marshall
Keyword(s):  
Eye Movement ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Nrem Sleep ◽  
Neural Oscillations ◽  
Rapid Eye Movement ◽  
Hippocampus Dependent Memory

AbstractSleep contributes actively to the consolidation of many forms of memory. This review describes the neural oscillations of non-rapid eye movement (NREM) sleep, the structures underlying these oscillations and their relation to hippocampus-dependent memory consolidation. A main focus lies on the relation between inter- and intraregional interactions and their electrophysiological representation. Methods for modulating neural oscillations with the intent of affecting memory consolidation are presented.

scholarly journals Neural Components of Reading Revealed by Distributed and Symbolic Computational Models

2020 ◽  
Vol 1 (4) ◽  
pp. 381-401
Author(s):  
Ryan Staples ◽  
William W. Graves
Keyword(s):  
Neural Activity ◽  
Neural Coding ◽  
Computational Models ◽  
Ann Model ◽  
Distributed Representations ◽  
Neural Data ◽  
Cognitive Components ◽  
Components Of Reading ◽  
Artificial Neural Network Ann ◽  
Models Of Reading

Determining how the cognitive components of reading—orthographic, phonological, and semantic representations—are instantiated in the brain has been a long-standing goal of psychology and human cognitive neuroscience. The two most prominent computational models of reading instantiate different cognitive processes, implying different neural processes. Artificial neural network (ANN) models of reading posit nonsymbolic, distributed representations. The dual-route cascaded (DRC) model instead suggests two routes of processing, one representing symbolic rules of spelling–to–sound correspondence, the other representing orthographic and phonological lexicons. These models are not adjudicated by behavioral data and have never before been directly compared in terms of neural plausibility. We used representational similarity analysis to compare the predictions of these models to neural data from participants reading aloud. Both the ANN and DRC model representations corresponded to neural activity. However, the ANN model representations correlated to more reading-relevant areas of cortex. When contributions from the DRC model were statistically controlled, partial correlations revealed that the ANN model accounted for significant variance in the neural data. The opposite analysis, examining the variance explained by the DRC model with contributions from the ANN model factored out, revealed no correspondence to neural activity. Our results suggest that ANNs trained using distributed representations provide a better correspondence between cognitive and neural coding. Additionally, this framework provides a principled approach for comparing computational models of cognitive function to gain insight into neural representations.

scholarly journals Short-term Effects of Vagus Nerve Stimulation on Learning and Evoked Activity in Auditory Cortex

2019 ◽  
Author(s):  
Jesyin Lai ◽  
Stephen V. David
Keyword(s):  
Auditory Cortex ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Neural Activity ◽  
Neural Plasticity ◽  
Neural Coding ◽  
Vagus Nerve Stimulation ◽  
Primary Auditory Cortex ◽  
Long Term Effects ◽  
Tone Frequency

ABSTRACTChronic vagus nerve stimulation (VNS) can facilitate learning of sensory and motor behaviors. VNS is believed to trigger release of neuromodulators, including norepinephrine and acetylcholine, which can mediate cortical plasticity associated with learning. Most previous work has studied effects of VNS over many days, and less is known about how acute VNS influences neural coding and behavior over the shorter term. To explore this question, we measured effects of VNS on learning of an auditory discrimination over 1-2 days. Ferrets implanted with cuff electrodes on the vagus nerve were trained by classical conditioning on a tone frequency-reward association. One tone was associated with reward while another tone, was not. The frequencies and reward associations of the tones were changed every two days, requiring learning of a new relationship. When the tones (both rewarded and non-rewarded) were paired with VNS, rates of learning increased on the first day following a change in reward association. To examine VNS effects on auditory coding, we recorded single- and multi-unit neural activity in primary auditory cortex (A1) of passively listening animals following brief periods of VNS (20 trials/session) paired with tones. Because afferent VNS induces changes in pupil size associated with fluctuations in neuromodulation, we also measured pupil during recordings. After pairing VNS with a neuron’s best-frequency (BF) tone, responses in a subpopulation of neurons were reduced. Pairing with an off-BF tone or performing VNS during the inter-trial interval had no effect on responses. We separated the change in A1 activity into two components, one that could be predicted by fluctuations in pupil and one that persisted after VNS and was not accounted for by pupil. The BF-specific reduction in neural responses remained, even after regressing out changes that could be explained by pupil. In addition, the size of VNS-mediated changes in pupil predicted the magnitude of persistent changes in the neural response. This interaction suggests that changes in neuromodulation associated with arousal gate the long-term effects of VNS on neural activity. Taken together, these results support a role for VNS in auditory learning and help establish VNS as a tool to facilitate neural plasticity.

scholarly journals Connectome to behaviour: modelling Caenorhabditis elegans at cellular resolution

2018 ◽  
Vol 373 (1758) ◽  
pp. 20170366 ◽  
Author(s):  
Stephen D. Larson ◽  
Padraig Gleeson ◽  
André E. X. Brown
Keyword(s):  
Caenorhabditis Elegans ◽  
Neural Activity ◽  
Multiscale Simulations ◽  
Theme Issue ◽  
Wiring Diagram ◽  
C Elegans ◽  
Behaviour Modelling ◽  
Cellular Resolution ◽  
The Mind

It has been 30 years since the ‘mind of the worm’ was published in Philosophical Transactions B (White et al . 1986 Phil. Trans. R. Soc. Lond. B 314 , 1–340). Predicting Caenorhabditis elegans ' behaviour from its wiring diagram has been an enduring challenge since then. This special theme issue of Philosophical Transactions B combines research from neuroscientists, physicists, mathematicians and engineers to discuss advances in neural activity imaging, behaviour quantification and multiscale simulations, and how they are bringing the goal of whole-animal modelling at cellular resolution within reach. This article is part of a discussion meeting issue ‘Connectome to behaviour: modelling C. elegans at cellular resolution’.

scholarly journals Optical imaging of the ventral medullary surface across sleep-wake states

1999 ◽  
Vol 277 (4) ◽  
pp. R1239-R1245 ◽  
Author(s):  
C. A. Richard ◽  
D. M. Rector ◽  
R. K. Harper ◽  
R. M. Harper
Keyword(s):  
Standard Deviation ◽  
Optical Imaging ◽  
Spontaneous Activity ◽  
Eye Movement ◽  
Rem Sleep ◽  
Neural Activity ◽  
Sleep Onset ◽  
Quiet Sleep ◽  
Ventral Medullary Surface ◽  
Wavelength Light

We hypothesized that spontaneous activity declines over widespread areas of the cat ventral medullary surface (VMS) during rapid eye movement (REM) sleep. We assessed neural and hemodynamic activity, measured as changes in reflected 660- and 560-nm wavelength light, from the VMS during sleep and waking states in five adult, unrestrained cats and in two control cats. Relative to quiet sleep, overall activity declined, and variability, assessed by standard deviation, increased by 25% during REM sleep. Variability in activity during waking also increased by 45% over quiet sleep, but mean activity was unchanged. REM sleep onset was preceded by a reduction in the hemodynamic signal from 5 to 60 s before neural activity decline. The activity decline during REM sleep, previously noted in the goat rostral VMS, extends to intermediate VMS areas of the cat and differs from most neural sites, such as the cortex, hippocampus, and thalamus, which increase activity during REM sleep. The activity decline during REM sleep has the potential to modify VMS responsiveness to baroreceptor and chemoreceptor challenges during the REM state.

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