scholarly journals Bidirectional encoding of motion contrast in the mouse superior colliculus

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jad Barchini ◽  
Xuefeng Shi ◽  
Hui Chen ◽  
Jianhua Cang
Keyword(s):  
Superior Colliculus ◽  
Temporal Frequency ◽  
Visual Saliency ◽  
Visual Scene ◽  
Inhibitory Neurons ◽  
Feature Representations ◽  
Neuronal Populations ◽  
Orientation Contrast ◽  
Motion Contrast ◽  
Superficial Lamina

Detection of salient objects in the visual scene is a vital aspect of an animal’s interactions with its environment. Here, we show that neurons in the mouse superior colliculus (SC) encode visual saliency by detecting motion contrast between stimulus center and surround. Excitatory neurons in the most superficial lamina of the SC are contextually modulated, monotonically increasing their response from suppression by the same-direction surround to maximal potentiation by an oppositely-moving surround. The degree of this potentiation declines with depth in the SC. Inhibitory neurons are suppressed by any surround at all depths. These response modulations in both neuronal populations are much more prominent to direction contrast than to phase, temporal frequency, or static orientation contrast, suggesting feature-specific saliency encoding in the mouse SC. Together, our findings provide evidence supporting locally generated feature representations in the SC, and lay the foundations towards a mechanistic and evolutionary understanding of their emergence.

scholarly journals Orientation Tuning, But Not Direction Selectivity, Is Invariant to Temporal Frequency in Primary Visual Cortex

2005 ◽  
Vol 94 (2) ◽  
pp. 1336-1345 ◽  
Author(s):  
Bartlett D. Moore ◽  
Henry J. Alitto ◽  
W. Martin Usrey
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimulus ◽  
Visual Processing ◽  
Cortical Neurons ◽  
Temporal Frequency ◽  
Direction Selectivity ◽  
Orientation Tuning ◽  
Orientation Contrast ◽  
Wide Range

The activity of neurons in primary visual cortex is influenced by the orientation, contrast, and temporal frequency of a visual stimulus. This raises the question of how these stimulus properties interact to shape neuronal responses. While past studies have shown that the bandwidth of orientation tuning is invariant to stimulus contrast, the influence of temporal frequency on orientation-tuning bandwidth is unknown. Here, we investigate the influence of temporal frequency on orientation tuning and direction selectivity in area 17 of ferret visual cortex. For both simple cells and complex cells, measures of orientation-tuning bandwidth (half-width at half-maximum response) are ∼20–25° across a wide range of temporal frequencies. Thus cortical neurons display temporal-frequency invariant orientation tuning. In contrast, direction selectivity is typically reduced, and occasionally reverses, at nonpreferred temporal frequencies. These results show that the mechanisms contributing to the generation of orientation tuning and direction selectivity are differentially affected by the temporal frequency of a visual stimulus and support the notion that stability of orientation tuning is an important aspect of visual processing.

scholarly journals A Systematic Evaluation of Interneuron Morphology Representations for Cell Type Discrimination

2020 ◽  
Vol 18 (4) ◽  
pp. 591-609 ◽  
Author(s):  
Sophie Laturnus ◽  
Dmitry Kobak ◽  
Philipp Berens
Keyword(s):  
Cell Types ◽  
Bipolar Cells ◽  
Machine Learning Algorithms ◽  
Feature Representation ◽  
Inhibitory Neurons ◽  
Systematic Evaluation ◽  
Two Dimensional ◽  
Feature Representations ◽  
Density Maps ◽  
The Difference

Abstract Quantitative analysis of neuronal morphologies usually begins with choosing a particular feature representation in order to make individual morphologies amenable to standard statistics tools and machine learning algorithms. Many different feature representations have been suggested in the literature, ranging from density maps to intersection profiles, but they have never been compared side by side. Here we performed a systematic comparison of various representations, measuring how well they were able to capture the difference between known morphological cell types. For our benchmarking effort, we used several curated data sets consisting of mouse retinal bipolar cells and cortical inhibitory neurons. We found that the best performing feature representations were two-dimensional density maps, two-dimensional persistence images and morphometric statistics, which continued to perform well even when neurons were only partially traced. Combining these feature representations together led to further performance increases suggesting that they captured non-redundant information. The same representations performed well in an unsupervised setting, implying that they can be suitable for dimensionality reduction or clustering.

scholarly journals Identification of Subpallial Neuronal Populations Across Zebrafish Larval Stages that Express Molecular Markers for the Striatum

2021 ◽  
Author(s):  
Vernie Aguda ◽  
Helen Chasiotis ◽  
Indira Riadi ◽  
Tod Rogers Thiele
Keyword(s):  
Substance P ◽  
Anterior Commissure ◽  
Inhibitory Neurons ◽  
Molecular Profile ◽  
Striatal Neurons ◽  
Indirect Pathway ◽  
Larval Stages ◽  
Neuronal Populations ◽  
Larval Zebrafish ◽  
Precursor Peptide

Striatal neurons within the basal ganglia play a central role in vertebrate action selection; however, their location in larval zebrafish is not well defined. We assayed for conserved striatal markers in the zebrafish subpallium using fluorescent in situ hybridization (FISH) and immunohistochemistry. Whole mount FISH revealed an inhibitory neuronal cluster rostral to the anterior commissure that expresses tac1, the gene that encodes the precursor peptide for substance P. This molecular profile is shared by mammalian striatal direct pathway neurons. A second partially overlapping population of inhibitory neurons was identified that expresses penka, the gene that encodes the precursor peptide for enkephalin. This molecular profile is shared by striatal indirect pathway neurons. Immunostaining for substance P and enkephalin confirmed the presence of these peptides in the subpallium as well as the presence of dopaminergic innervation. The tac1 and penka populations were both found to increase linearly across larval stages. Together, these findings support the existence of a striatal homologue in larval zebrafish that grows to match the development and increasing behavioural complexity of the organism.

scholarly journals A Disinhibitory Circuit for Contextual Modulation in Primary Visual Cortex

2020 ◽  
Author(s):  
Andreas J. Keller ◽  
Mario Dipoppa ◽  
Morgane M. Roth ◽  
Matthew S. Caudill ◽  
Alessandro Ingrosso ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Vasoactive Intestinal Peptide ◽  
Primary Visual Cortex ◽  
Computational Modelling ◽  
Visual Scene ◽  
Inhibitory Neurons ◽  
Contextual Modulation ◽  
Sensory Stimuli ◽  
Excitatory Neurons ◽  
Mouse Visual Cortex

Context guides perception by influencing the saliency of sensory stimuli. Accordingly, in visual cortex, responses to a stimulus are modulated by context, the visual scene surrounding the stimulus. Responses are suppressed when stimulus and surround are similar but not when they differ. The mechanisms that remove suppression when stimulus and surround differ remain unclear. Here we use optical recordings, manipulations, and computational modelling to show that a disinhibitory circuit consisting of vasoactive-intestinal-peptide-expressing (VIP) and somatostatin-expressing (SOM) inhibitory neurons modulates responses in mouse visual cortex depending on the similarity between stimulus and surround. When the stimulus and the surround are similar, VIP neurons are inactive and SOM neurons suppress excitatory neurons. However, when the stimulus and the surround differ, VIP neurons are active, thereby inhibiting SOM neurons and relieving excitatory neurons from suppression. We have identified a canonical cortical disinhibitory circuit which contributes to contextual modulation and may regulate perceptual saliency.

scholarly journals Naturalistic coding of working memory in primate prefrontal cortex

2020 ◽  
Author(s):  
Megan Roussy ◽  
Rogelio Luna ◽  
Lyndon Duong ◽  
Benjamin Corrigan ◽  
Roberto A. Gulli ◽  
...  
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Memory Performance ◽  
Memory Function ◽  
Nmda Receptor Antagonist ◽  
Inhibitory Neurons ◽  
Natural Behavior ◽  
Neuronal Populations ◽  
Memory Representations ◽  
Decoding Accuracy

SummaryThe primate lateral prefrontal cortex (LPFC) is considered fundamental for temporarily maintaining and manipulating mental representations that serve behavior, a cognitive function known as working memory1. Studies in non-human primates have shown that LPFC lesions impair working memory2 and that LPFC neuronal activity encodes working memory representations3. However, such studies have used simple displays and constrained gaze while subjects held information in working memory3, which put into question their ethological validity4,5. Currently, it remains unclear whether LPFC microcircuits can support working memory function during natural behavior. We tested macaque monkeys in a working memory navigation task in a life-like virtual environment while their gaze was unconstrained. We show that LPFC neuronal populations robustly encode working memory representations in these conditions. Furthermore, low doses of the NMDA receptor antagonist, ketamine, impaired working memory performance while sparing perceptual and motor skills. Ketamine decreased the firing of narrow spiking inhibitory interneurons and increased the firing of broad spiking cells reducing population decoding accuracy for remembered locations. Our results show that primate LPFC generates robust neural codes for working memory in naturalistic settings and that such codes rely upon a fine balance between the activation of excitatory and inhibitory neurons.

Commissural Excitation and Inhibition by the Superior Colliculus in Tectoreticular Neurons Projecting to Omnipause Neuron and Inhibitory Burst Neuron Regions

2005 ◽  
Vol 94 (3) ◽  
pp. 1707-1726 ◽  
Author(s):  
M. Takahashi ◽  
Y. Sugiuchi ◽  
Y. Izawa ◽  
Y. Shinoda
Keyword(s):  
Superior Colliculus ◽  
Inhibitory Neurons ◽  
Functional Roles ◽  
Commissural Neurons ◽  
Burst Neuron ◽  
Electrophysiological Studies ◽  
Disynaptic Inhibition ◽  
Forel's Field H ◽  
Commissural Connections ◽  
Stimulation Of

Previous electrophysiological studies have shown that the commissural connections between the two superior colliculi are mainly inhibitory with fewer excitatory connections. However, the functional roles of the commissural connections are not well understood, so we sought to clarify the physiology of tectal commissural excitation and inhibition of tectoreticular neurons (TRNs) in the “fixation ” and “saccade ” zones of the superior colliculus (SC). By recording intracellular potentials, we identified TRNs by their antidromic responses to stimulation of the omnipause neuron (OPN) and inhibitory burst neuron (IBN) regions and analyzed the effects of stimulation of the contralateral SC on these TRNs in anesthetized cats. TRNs in the caudal SC (saccade neurons) projected to the IBN region, and received mono- or disynaptic inhibition from the entire rostrocaudal extent of the contralateral SC. In contrast, TRNs in the rostral SC projected to the OPN or IBN region and received monosynaptic excitation from the most rostral level of the contralateral SC, and mono- or disynaptic inhibition from its entire rostrocaudal extent. Among the rostral TRNs with commissural excitation, IBN-projecting TRNs also projected to Forel's field H (vertical gaze center), suggesting that they were most likely saccade neurons related to vertical saccades. In contrast, TRNs projecting only to the OPN region were most likely fixation neurons. Most putative inhibitory neurons in the rostral SC had multiple axon branches throughout the rostrocaudal extent of the contralateral SC, whereas excitatory commissural neurons, most of which were rostral TRNs, distributed terminals to a discrete region in the rostral SC.

scholarly journals Superior colliculus encodes visual saliency before the primary visual cortex

2017 ◽  
Vol 114 (35) ◽  
pp. 9451-9456 ◽  
Author(s):  
Brian J. White ◽  
Janis Y. Kan ◽  
Ron Levy ◽  
Laurent Itti ◽  
Douglas P. Munoz
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Visual Saliency ◽  
Saliency Map ◽  
Stimulus Onset ◽  
Brain Areas ◽  
V1 Neurons ◽  
Processing Stream

Models of visual attention postulate the existence of a bottom-up saliency map that is formed early in the visual processing stream. Although studies have reported evidence of a saliency map in various cortical brain areas, determining the contribution of phylogenetically older pathways is crucial to understanding its origin. Here, we compared saliency coding from neurons in two early gateways into the visual system: the primary visual cortex (V1) and the evolutionarily older superior colliculus (SC). We found that, while the response latency to visual stimulus onset was earlier for V1 neurons than superior colliculus superficial visual-layer neurons (SCs), the saliency representation emerged earlier in SCs than in V1. Because the dominant input to the SCs arises from V1, these relative timings are consistent with the hypothesis that SCs neurons pool the inputs from multiple V1 neurons to form a feature-agnostic saliency map, which may then be relayed to other brain areas.

Neuronal responses to orientation and motion contrast in cat striate cortex

1999 ◽  
Vol 16 (3) ◽  
pp. 587-600 ◽  
Author(s):  
SABINE KASTNER ◽  
HANS-CHRISTOPH NOTHDURFT ◽  
IVAN N. PIGAREV
Keyword(s):  
Striate Cortex ◽  
Coherent Motion ◽  
Neuronal Responses ◽  
Physiological Basis ◽  
Orientation Contrast ◽  
Motion Contrast ◽  
Striate Neurons ◽  
The Mean ◽  
Adult Cats ◽  
Main Effects

Responses of striate neurons to line textures were investigated in anesthetized and paralyzed adult cats. Light bars centered over the excitatory receptive field (RF) were presented with different texture surrounds composed of many similar bars. In two test series, responses of 169 neurons to textures with orientation contrast (surrounding bars orthogonal to the center bar) or motion contrast (surrounding bars moving opposite to the center bar) were compared to the responses to the corresponding uniform texture conditions (all lines parallel, coherent motion) and to the center bar alone. In the majority of neurons center bar responses were suppressed by the texture surrounds. Two main effects were found. Some neurons were generally suppressed by either texture surround. Other neurons were less suppressed by texture displaying orientation or motion (i.e. feature) contrast than by the respective uniform texture, so that their responses to orientation or motion contrast appeared to be relatively enhanced (preference for feature contrast). General suppression was obtained in 33% of neurons tested for orientation and in 19% of neurons tested for motion. Preference for orientation or motion contrast was obtained in 22% and 34% of the neurons, respectively, and was also seen in the mean response of the population. One hundred nineteen neurons were studied in both orientation and motion tests. General suppression was correlated across the orientation and motion dimension, but not preference for feature contrast. We also distinguished modulatory effects from end-zones and flanks using butterfly-configured texture patterns. Both regions contributed to the generally suppressive effects. Preference for orientation or motion contrast was not generated from either end-zones or flanks exclusively. Neurons with preference for feature contrast may form the physiological basis of the perceptual saliency of pop-out elements in line textures. If so, pop-out of motion and pop-out of orientation would be encoded in different pools of neurons at the level of striate cortex.

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