scholarly journals Rod-cone signal interference in the retina shapes perception in primates

2019 ◽  
Author(s):  
Adree Songco-Aguas ◽  
William N Grimes ◽  
Fred Rieke
Keyword(s):  
Neural Circuits ◽  
Human Vision ◽  
Signal Interference ◽  
High Contrast ◽  
Behavioral Differences ◽  
Genetic Manipulations ◽  
Electrophysiological Recordings ◽  
Fundamental Goal ◽  
Cone Signal ◽  
Human Primate

AbstractLinking the activity of neurons, circuits and synapses to human behavior is a fundamental goal of neuroscience. Meeting this goal is challenging, in part because behavior, particularly perception, often masks the complexity of the underlying neural circuits, and in part because of the significant behavioral differences between primates and animals like mice and flies in which genetic manipulations are relatively common. Here we relate circuit-level processing of rod and cone signals in the non-human primate retina to a known break in the normal seamlessness of human vision – a surprising inability to see high contrast flickering lights under specific conditions. We use electrophysiological recordings and perceptual experiments to identify key mechanisms that shape the retinal integration of rod- and cone-generated retinal signals. We incorporate these mechanistic insights into a predictive model that accurately captures the cancellation of rod- and cone-mediated responses and can explain the perceptual insensitivity to flicker.

Dynamic shifts of the contrast-response function

1997 ◽  
Vol 14 (3) ◽  
pp. 577-587 ◽  
Author(s):  
Jonathan D. Victor ◽  
Mary M. Conte ◽  
Keith P. Purpura
Keyword(s):  
Gain Control ◽  
Human Vision ◽  
High Contrast ◽  
Contrast Level ◽  
Low Contrast ◽  
Contrast Gain ◽  
Contrast Response Function ◽  
Stimuli Response ◽  
Response Phase ◽  
Contrast Response

AbstractWe recorded visual evoked potentials in response to square-wave contrast-reversal checkerboards undergoing a transition in the mean contrast level. Checkerboards were modulated at 4.22 Hz (8.45-Hz reversal rate). After each set of 16 cycles of reversals, stimulus contrast abruptly switched between a “high” contrast level (0.06 to 1.0) to a “low” contrast level (0.03 to 0.5). Higher contrasts attenuated responses to lower contrasts by up to a factor of 2 during the period immediately following the contrast change. Contrast-response functions derived from the initial second following a conditioning contrast shifted by a factor of 2–4 along the contrast axis. For low-contrast stimuli, response phase was an advancing function of the contrast level in the immediately preceding second. For high-contrast stimuli, response phase was independent of the prior contrast history. Steady stimulation for periods as long as 1 min produced only minor effects on response amplitude, and no detectable effects on response phase. These observations delineate the dynamics of a contrast gain control in human vision.

Orientation Specificity and Spatial Selectivity in Human Vision

Perception ◽  
1973 ◽  
Vol 2 (1) ◽  
pp. 53-60 ◽  
Author(s):  
J A Movshon ◽  
C Blakemore
Keyword(s):  
Spatial Frequency ◽  
Human Visual System ◽  
Human Vision ◽  
Orientation Tuning ◽  
High Contrast ◽  
Vertical Grating ◽  
Spatial Frequencies ◽  
High Contrast Grating ◽  
Orientation Specificity ◽  
Adaptation Method

An adaptation method is used to determine the orientation specificity of channels sensitive to different spatial frequencies in the human visual system. Comparison between different frequencies is made possible by a data transformation in which orientational effects are expressed in terms of equivalent contrast (the contrast of a vertical grating producing the same adaptational effect as a high-contrast grating of a given orientation). It is shown that, despite great variances in the range of orientations affected by adaptation at different spatial frequencies (±10° to ±50°), the half-width at half-amplitude of the orientation channels does not vary systematically as a function of spatial frequency over the range tested (2·5 to 20 cycles deg−1). Two subjects were used and they showed significantly different orientation tuning across the range of spatial frequencies. The results are discussed with reference to previous determinations of orientation specificity, and to related psychophysical and neurophysiological phenomena.

scholarly journals Imaging Voltage with Microbial Rhodopsins

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiao Min Zhang ◽  
Tatsushi Yokoyama ◽  
Masayuki Sakamoto
Keyword(s):  
Membrane Potential ◽  
Brain Function ◽  
Critical Parameter ◽  
Neural Circuits ◽  
Superior Performance ◽  
Neuronal Dynamics ◽  
Spatiotemporal Resolution ◽  
Invasive Approach ◽  
Electrophysiological Recordings ◽  
Genetic Specificity

Membrane potential is the critical parameter that reflects the excitability of a neuron, and it is usually measured by electrophysiological recordings with electrodes. However, this is an invasive approach that is constrained by the problems of lacking spatial resolution and genetic specificity. Recently, the development of a variety of fluorescent probes has made it possible to measure the activity of individual cells with high spatiotemporal resolution. The adaptation of this technique to image electrical activity in neurons has become an informative method to study neural circuits. Genetically encoded voltage indicators (GEVIs) can be used with superior performance to accurately target specific genetic populations and reveal neuronal dynamics on a millisecond scale. Microbial rhodopsins are commonly used as optogenetic actuators to manipulate neuronal activities and to explore the circuit mechanisms of brain function, but they also can be used as fluorescent voltage indicators. In this review, we summarize recent advances in the design and the application of rhodopsin-based GEVIs.

scholarly journals Simultaneous optogenetic manipulation and calcium imaging in freely movingC. elegans

2013 ◽  
Author(s):  
Frederick B. Shipley ◽  
Christopher M. Clark ◽  
Mark J. Alkema ◽  
Andrew M. Leifer
Keyword(s):  
Neural Activity ◽  
Calcium Imaging ◽  
Neural Circuits ◽  
Neural Response ◽  
Sensory Stimuli ◽  
Systems Neuroscience ◽  
C Elegans ◽  
Fundamental Goal ◽  
Freely Moving ◽  
Interneuron Activity

A fundamental goal of systems neuroscience is to probe the dynamics of neural activity that drive behavior. Here we present an instrument to simultaneously manipulate neural activity via Channelrhodopsin, monitor neural response via GCaMP3, and observes behavior in freely moving C. elegans. We use the instrument to directly observe the relation between sensory stimuli, interneuron activity and locomotion in the mechanosensory circuit. Now published as: Front Neural Circuits 8:28, doi:10.3389/fncir.2014.00028

scholarly journals Calsyntenin-3 interacts with both α- and β-neurexins in the regulation of excitatory synaptic innervation in specific Schaffer collateral pathways

2020 ◽  
Vol 295 (27) ◽  
pp. 9244-9262 ◽  
Author(s):  
Hyeonho Kim ◽  
Dongwook Kim ◽  
Jinhu Kim ◽  
Hee-Yoon Lee ◽  
Dongseok Park ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Conditional Knockout ◽  
Stratum Radiatum ◽  
Excitatory Synapses ◽  
Schaffer Collateral ◽  
Ca1 Neurons ◽  
Electrophysiological Recordings ◽  
Presynaptic Differentiation ◽  
Collateral Pathways

Calsyntenin-3 (Clstn3) is a postsynaptic adhesion molecule that induces presynaptic differentiation via presynaptic neurexins (Nrxns), but whether Nrxns directly bind to Clstn3 has been a matter of debate. Here, using LC–MS/MS–based protein analysis, confocal microscopy, RNAscope assays, and electrophysiological recordings, we show that β-Nrxns directly interact via their LNS domain with Clstn3 and Clstn3 cadherin domains. Expression of splice site 4 (SS4) insert–positive β-Nrxn variants, but not insert–negative variants, reversed the impaired Clstn3 synaptogenic activity observed in Nrxn-deficient neurons. Consistently, Clstn3 selectively formed complexes with SS4–positive Nrxns in vivo. Neuron-specific Clstn3 deletion caused significant reductions in number of excitatory synaptic inputs. Moreover, expression of Clstn3 cadherin domains in CA1 neurons of Clstn3 conditional knockout mice rescued structural deficits in excitatory synapses, especially within the stratum radiatum layer. Collectively, our results suggest that Clstn3 links to SS4–positive Nrxns to induce presynaptic differentiation and orchestrate excitatory synapse development in specific hippocampal neural circuits, including Schaffer collateral afferents.

scholarly journals Distinct sources of deterministic and stochastic components of action timing decisions in rodent frontal cortex

2016 ◽  
Author(s):  
Masayoshi Murakami ◽  
Hanan Shteingart ◽  
Yonatan Loewenstein ◽  
Zachary F. Mainen
Keyword(s):  
Frontal Cortex ◽  
Neural Circuits ◽  
Internal State ◽  
Theoretical Models ◽  
Neural Dynamics ◽  
Stochastic Choice ◽  
Electrophysiological Recordings ◽  
Timing Decisions ◽  
Action Timing ◽  
Differential Coding

SUMMARYThe selection and timing of actions are subject to determinate influences such as sensory cues and internal state as well as to effectively stochastic variability. Although stochastic choice mechanisms are assumed by many theoretical models, their origin and mechanisms remain poorly understood. Here we investigated this issue by studying how neural circuits in the frontal cortex determine action timing in rats performing a waiting task. Electrophysiological recordings from two regions necessary for this behavior, medial prefrontal cortex (mPFC) and secondary motor cortex (M2), revealed an unexpected functional dissociation. Both areas encoded deterministic biases in action timing, but only M2 neurons reflected stochastic trial-by-trial fluctuations. This differential coding was reflected in distinct timescales of neural dynamics in the two frontal cortical areas. These results suggest a two-stage model in which stochastic components of action timing decisions are injected by circuits downstream of those carrying deterministic bias signals.

scholarly journals A model of flexible motor sequencing through thalamic control of cortical dynamics

2019 ◽  
Author(s):  
Laureline Logiaco ◽  
L.F. Abbott ◽  
Sean Escola
Keyword(s):  
Basal Ganglia ◽  
Neural Circuits ◽  
Activity Patterns ◽  
Thalamic Neurons ◽  
Cortical Dynamics ◽  
Sustained Activity ◽  
Electrophysiological Recordings ◽  
Complex Motor ◽  
Output Neurons ◽  
Noise Robust

AbstractThe mechanisms by which neural circuits generate an extensible library of motor motifs and flexibly string them into arbitrary sequences are unclear. We developed a model in which inhibitory basal ganglia output neurons project to thalamic units that are themselves bidirectionally connected to a recurrent cortical network. During movement sequences, electrophysiological recordings of basal ganglia output neurons show sustained activity patterns that switch at the boundaries between motifs. Thus, we model these inhibitory patterns as silencing some thalamic neurons while leaving others disinhibited and free to interact with cortex during specific motifs. We show that a small number of disinhibited thalamic neurons can control cortical dynamics to generate specific motor output in a noise robust way. If the thalamic units associated with each motif are segregated, many motor outputs can be learned without interference and then combined in arbitrary orders for the flexible production of long and complex motor sequences.

scholarly journals Tracing cortical circuits in humans and non-human primates from high resolution connectomic, transcriptomic, and temporal dimensions

2021 ◽  
Author(s):  
Christine J. Charvet ◽  
Kwadwo Ofori ◽  
Christine Baucum ◽  
Jianli Sun ◽  
Melinda S. Modrell ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Resolution ◽  
Human Brain ◽  
Frontal Cortex ◽  
Neural Circuits ◽  
Human Cognition ◽  
Biological Organization ◽  
Brain Connectome ◽  
Temporal Dimensions ◽  
Human Primate

AbstractThe neural circuits that support human cognition are a topic of enduring interest. Yet, the lack of tools available to map human brain circuits has precluded our ability to trace the human and non-human primate connectome. We harnessed high-resolution connectomic, anatomic, and transcriptomic data to investigate the evolution and development of frontal cortex circuitry. We applied machine learning to RNA sequencing data to find corresponding ages between humans and macaques and to compare the development of circuits across species. We transcriptionally defined neural circuits by testing for associations between gene expression and white matter maturation. We then considered transcriptional and structural growth to test whether frontal cortex circuit maturation is unusually extended in humans relative to other species. We also considered gene expression and high-resolution diffusion MR tractography of adult brains to test for cross-species variation in frontal cortex circuits. We found that frontal cortex circuitry development is extended in primates, and concomitant with an expansion in cortico-cortical pathways compared with mice in adulthood. Importantly, we found that these parameters varied relatively little across humans and studied primates. These data identify a surprising collection of conserved features in frontal cortex circuits across humans and Old World monkeys. Our work demonstrates that integrating transcriptional and connectomic data across temporal dimensions is a robust approach to trace the evolution of brain connectomics in primates.Significance StatementWe lack appropriate tools to visualize the human brain connectome. We develop new approaches to study connections in the human and non-human primate brains. The integration of transcription with structure offers an unprecedented opportunity to study circuitry evolution. Our integrative approach finds corresponding ages across species and transcriptionally defines neural circuits. We used this information to test for variation in circuit maturation across species and found a surprising constellation of similar features in frontal cortex neural circuits across humans and primates. Integrating across scales of biological organization expands the repertoire of tools available to study connections in primates, which opens new avenues to study connections in health and diseases of the human brain.

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