scholarly journals Emergence of Direction Selectivity at the Convergence of Thalamo-Cortical Synapses in Visual Cortex

2018 ◽  
Author(s):  
Anthony D Lien ◽  
Massimo Scanziani
Keyword(s):  
Visual Cortex ◽  
Cortical Neurons ◽  
De Novo ◽  
Visual Stimulation ◽  
Direction Selectivity ◽  
Cellular Mechanisms ◽  
Motion Direction ◽  
Thalamic Neurons ◽  
Response Diversity ◽  
Time Courses

AbstractDetecting the direction of an object’s motion is essential for our representation of the visual environment. Visual cortex is one of the main stages in the mammalian nervous system where motion direction may be computed de novo. Experiments and theories indicate that cortical neurons respond selectively to motion direction by combining inputs that provide information about distinct spatial locations with distinct time-delays. Despite the importance of this spatiotemporal offset for direction selectivity its origin and cellular mechanisms are not fully understood. We show that ~80+/−10 thalamic neurons responding with distinct time-courses to stimuli in distinct locations contribute to the excitation of mouse visual cortical neurons during visual stimulation. Integration of thalamic inputs with the appropriate spatiotemporal offset provides cortical neurons with the primordial bias for direction selectivity. These data show how cortical neurons selectively combine the spatiotemporal response diversity of thalamic neurons to extract fundamental features of the visual world.

scholarly journals 3-5 Hz membrane potential oscillations decrease the gain of neurons in visual cortex

2016 ◽  
Author(s):  
Michael C. Einstein ◽  
Pierre-Olivier Polack ◽  
Peyman Golshani
Keyword(s):  
Visual Cortex ◽  
Membrane Potential ◽  
Sensory Processing ◽  
Cortical Neurons ◽  
Visual Stimulation ◽  
Cellular Mechanisms ◽  
Potential Oscillations ◽  
Subthreshold Oscillations ◽  
Excitatory Neurons ◽  
Membrane Potential Oscillations

ABSTRACTGain modulation is a computational mechanism critical for sensory processing. Yet, the cellular mechanisms that decrease the gain of cortical neurons are unclear. To test if low frequency subthreshold oscillations could reduce neuronal gain during wakefulness, we measured the membrane potential of primary visual cortex (V1) layer 2/3 excitatory, parvalbumin-positive (PV+), and somatostatin-positive (SOM+) neurons in awake mice during passive visual stimulation and sensory discrimination tasks. We found prominent 3-5 Hz membrane potential oscillations that reduced the gain of excitatory neurons but not the gain of PV+ and SOM+ interneurons, which oscillated synchronously with excitatory neurons and fired strongly at the peak of de polarizations. 3-5 Hz oscillation prevalence and timing were strongly modulated by visual input and the animal’s behavior al response, suggesting that these oscillations are triggered to adjust sensory responses for specific behavioral contexts. Therefore, these findings reveal a novel gain reduction mechanism that adapts sensory processing to behavior.

scholarly journals Mechanisms of Direction Selectivity in Cat Primary Visual Cortex as Revealed by Visual Adaptation

2010 ◽  
Vol 104 (5) ◽  
pp. 2615-2623 ◽  
Author(s):  
Nicholas J. Priebe ◽  
Ilan Lampl ◽  
David Ferster
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Cortical Neurons ◽  
Visual Stimulation ◽  
Direction Selectivity ◽  
Dependent Manner ◽  
Visual Responses ◽  
Null Direction ◽  
Simple Cells ◽  
Complex Cells

In contrast to neurons of the lateral geniculate nucleus (LGN), neurons in the primary visual cortex (V1) are selective for the direction of visual motion. Cortical direction selectivity could emerge from the spatiotemporal configuration of inputs from thalamic cells, from intracortical inhibitory interactions, or from a combination of thalamic and intracortical interactions. To distinguish between these possibilities, we studied the effect of adaptation (prolonged visual stimulation) on the direction selectivity of intracellularly recorded cortical neurons. It is known that adaptation selectively reduces the responses of cortical neurons, while largely sparing the afferent LGN input. Adaptation can therefore be used as a tool to dissect the relative contribution of afferent and intracortical interactions to the generation of direction selectivity. In both simple and complex cells, adaptation caused a hyperpolarization of the resting membrane potential (−2.5 mV, simple cells, −0.95 mV complex cells). In simple cells, adaptation in either direction only slightly reduced the visually evoked depolarization; this reduction was similar for preferred and null directions. In complex cells, adaptation strongly reduced visual responses in a direction-dependent manner: the reduction was largest when the stimulus direction matched that of the adapting motion. As a result, adaptation caused changes in the direction selectivity of complex cells: direction selectivity was reduced after preferred direction adaptation and increased after null direction adaptation. Because adaptation in the null direction enhanced direction selectivity rather than reduced it, it seems unlikely that inhibition from the null direction is the primary mechanism for creating direction selectivity.

scholarly journals Motion/direction-sensitive thalamic neurons project extensively to the middle layers of primary visual cortex

2021 ◽  
Author(s):  
Jun Zhuang ◽  
Yun Wang ◽  
Naveen D Ouellette ◽  
Emily Turschak ◽  
Rylan Larsen ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Population Level ◽  
Middle Layer ◽  
Current View ◽  
Motion Direction ◽  
Thalamic Neurons ◽  
Novel Approach ◽  
Single Axon

The motion/direction-sensitive and location-sensitive neurons are two major functional types in mouse visual thalamus that project to the primary visual cortex (V1). It has been proposed that the motion/direction-sensitive neurons mainly target the superficial layers in V1, in contrast to the location-sensitive neurons which mainly target the middle layers. Here, by imaging calcium activities of motion/direction-sensitive and location-sensitive axons in V1, we find no evidence for these cell-type specific laminar biases at population level. Furthermore, using a novel approach to reconstruct single-axon structures with identified in vivo response types, we show that, at single-axon level, the motion/direction-sensitive axons have middle layer preferences and project more densely to the middle layers than the location-sensitive axons. Overall, our results demonstrate that Motion/direction-sensitive thalamic neurons project extensively to the middle layers of V1, challenging the current view of the thalamocortical organizations in the mouse visual system.

scholarly journals Neural selectivity for visual motion in macaque area V3A

2020 ◽  
Author(s):  
Nardin Nakhla ◽  
Yavar Korkian ◽  
Matthew R. Krause ◽  
Christopher C. Pack
Keyword(s):  
Visual Cortex ◽  
Optic Flow ◽  
Functional Role ◽  
Visual Motion ◽  
Flow Patterns ◽  
Brain Regions ◽  
Direction Selectivity ◽  
Motion Processing ◽  
Imaging Studies ◽  
Motion Direction

AbstractThe processing of visual motion is carried out by dedicated pathways in the primate brain. These pathways originate with populations of direction-selective neurons in the primary visual cortex, which project to dorsal structures like the middle temporal (MT) and medial superior temporal (MST) areas. Anatomical and imaging studies have suggested that area V3A might also be specialized for motion processing, but there have been very few studies of single-neuron direction selectivity in this area. We have therefore performed electrophysiological recordings from V3A neurons in two macaque monkeys (one male and one female) and measured responses to a large battery of motion stimuli that includes translation motion, as well as more complex optic flow patterns. For comparison, we simultaneously recorded the responses of MT neurons to the same stimuli. Surprisingly, we find that overall levels of direction selectivity are similar in V3A and MT and moreover that the population of V3A neurons exhibits somewhat greater selectivity for optic flow patterns. These results suggest that V3A should be considered as part of the motion processing machinery of the visual cortex, in both human and non-human primates.Significance statementAlthough area V3A is frequently the target of anatomy and imaging studies, little is known about its functional role in processing visual stimuli. Its contribution to motion processing has been particularly unclear, with different studies yielding different conclusions. We report a detailed study of direction selectivity in V3A. Our results show that single V3A neurons are, on average, as capable of representing motion direction as are neurons in well-known structures like MT. Moreover, we identify a possible specialization for V3A neurons in representing complex optic flow, which has previously been thought to emerge in higher-order brain regions. Thus it appears that V3A is well-suited to a functional role in motion processing.

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.

Direction Selectivity of Neurons in the Striate Cortex Increases as Stimulus Contrast Is Decreased

2006 ◽  
Vol 95 (4) ◽  
pp. 2705-2712 ◽  
Author(s):  
Matthew R. Peterson ◽  
Baowang Li ◽  
Ralph D. Freeman
Keyword(s):  
Visual Cortex ◽  
Cortical Neurons ◽  
Striate Cortex ◽  
Human Subjects ◽  
Response Characteristic ◽  
Direction Selectivity ◽  
Integration Time ◽  
Stimulus Contrast ◽  
Cortical Cells ◽  
Moving Stimulus

Various properties of external scenes are integrated during the transmission of information along central visual pathways. One basic property concerns the sensitivity to direction of a moving stimulus. This direction selectivity (DS) is a fundamental response characteristic of neurons in the visual cortex. We have conducted a neurophysiological study of cells in the visual cortex to determine how DS is affected by changes in stimulus contrast. Previous work shows that a neuron integration time is increased at low contrasts, causing temporal changes of response properties. This leads to the prediction that DS should change with stimulus contrast. However, the change could be in a counterintuitive direction, i.e., DS could increase with reduced contrast. This possibility is of intrinsic interest but it is also of potential relevance to recent behavioral work in which human subjects exhibit increased DS as contrast is reduced. Our neurophysiological results are consistent with this finding, i.e., the degree of DS of cortical neurons is inversely related to stimulus contrast. Temporal phase differences of inputs to cortical cells may account for this result.

scholarly journals Erasing motion: Scrambling direction selectivity in visual cortex during saccades

2021 ◽  
Author(s):  
Satoru K Miura ◽  
Massimo Scanziani
Keyword(s):  
Visual Cortex ◽  
External World ◽  
Direction Selectivity ◽  
Efference Copy ◽  
Visual Input ◽  
Visual Scene ◽  
General Mechanism ◽  
Motion Direction ◽  
Sensory Cortices ◽  
Evoked Activity

A prominent feature of sensory processing is the ability to distinguish whether the activation of the sensory periphery is caused by changes in the external world or by the animal's own actions. Saccades, rapid eye movements executed by animals across phyla, cause the visual scene to momentarily shift on the retina. The mechanisms by which visual systems differentiate between motion of the visual scene induced by saccades from motion due to changes in the external world are not fully understood. Here, we discovered that in mouse primary visual cortex (V1), the two types of motion evoke distinct patterns of activity across the population of neurons. As a result, a decoder of motion direction trained on the response to motion in the external world fails to generalize when tested on the response to saccades that induce similar motion on the retina. This is because during saccades, V1 combines the visual input with a strong non-visual input arriving from the pulvinar nucleus of the thalamus. This non-visual input is an efference copy - a copy of the oculomotor command that differs depending on the direction of the saccades. Silencing the pulvinar prevented the non-visual input from reaching V1, such that the pattern of activity in V1 was now similar no matter whether the motion was generated in the external world or by saccades. Thus, the pulvinar input to V1 ensures differential responses to the external and self-generated motion and may prevent downstream areas from extracting motion information about visual stimulus shifts generated by saccades. Changing the pattern of evoked activity through an efference copy may be a general mechanism that enables sensory cortices in mammals to distinguish between external and self-generated stimuli.

Motion direction signals in the primary visual cortex of cat and monkey

2001 ◽  
Vol 18 (4) ◽  
pp. 501-516 ◽  
Author(s):  
WILSON S. GEISLER ◽  
DUANE G. ALBRECHT ◽  
ALISON M. CRANE ◽  
LAWRENCE STERN
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Spatial Orientation ◽  
Cortical Neurons ◽  
Image Feature ◽  
Motion Direction ◽  
Parallel Motion ◽  
Tuning Function

When an image feature moves with sufficient speed it should become smeared across space, due to temporal integration in the visual system, effectively creating a spatial motion pattern that is oriented in the direction of the motion. Recent psychophysical evidence shows that such “motion streak signals” exist in the human visual system. In this study, we report neurophysiological evidence that these motion streak signals also exist in the primary visual cortex of cat and monkey. Single neuron responses were recorded for two kinds of moving stimuli: single spots presented at different velocities and drifting plaid patterns presented at different spatial and temporal frequencies. Measurements were made for motion perpendicular to the spatial orientation of the receptive field (“perpendicular motion”) and for motion parallel to the spatial orientation of the receptive field (“parallel motion”). For moving spot stimuli, as the speed increases, the ratio of the responses to parallel versus perpendicular motion increases, and above some critical speed, the response to parallel motion exceeds the response to perpendicular motion. For moving plaid patterns, the average temporal tuning function is approximately the same for both parallel motion and perpendicular motion; in contrast, the spatial tuning function is quite different for parallel motion and perpendicular motion (band pass for the former and low pass for the latter). In general, the responses to spots and plaids are consistent with the conventional model of cortical neurons with one rather surprising exception: Many cortical neurons appear to be direction selective for parallel motion. We propose a simple explanation for “parallel motion direction selectivity” and discuss its implications for the motion streak hypothesis. Taken as a whole, we find that the measured response properties of cortical neurons to moving spot and plaid patterns agree with the recent psychophysics and support the hypothesis that motion streak signals are present in V1.

scholarly journals Categorically distinct types of receptive fields in early visual cortex

2016 ◽  
Vol 115 (5) ◽  
pp. 2556-2576 ◽  
Author(s):  
Vargha Talebi ◽  
Curtis L. Baker
Keyword(s):  
Visual Cortex ◽  
System Identification ◽  
Cortical Neurons ◽  
Temporal Dynamics ◽  
High Reliability ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Natural Image ◽  
Visual Responses ◽  
Neurophysiological Studies

In the visual cortex, distinct types of neurons have been identified based on cellular morphology, response to injected current, or expression of specific markers, but neurophysiological studies have revealed visual receptive field (RF) properties that appear to be on a continuum, with only two generally recognized classes: simple and complex. Most previous studies have characterized visual responses of neurons using stereotyped stimuli such as bars, gratings, or white noise and simple system identification approaches (e.g., reverse correlation). Here we estimate visual RF models of cortical neurons using visually rich natural image stimuli and regularized regression system identification methods and characterize their spatial tuning, temporal dynamics, spatiotemporal behavior, and spiking properties. We quantitatively demonstrate the existence of three functionally distinct categories of simple cells, distinguished by their degree of orientation selectivity (isotropic or oriented) and the nature of their output nonlinearity (expansive or compressive). In addition, these three types have differing average values of several other properties. Cells with nonoriented RFs tend to have smaller RFs, shorter response durations, no direction selectivity, and high reliability. Orientation-selective neurons with an expansive output nonlinearity have Gabor-like RFs, lower spontaneous activity and responsivity, and spiking responses with higher sparseness. Oriented RFs with a compressive nonlinearity are spatially nondescript and tend to show longer response latency. Our findings indicate multiple physiologically defined types of RFs beyond the simple/complex dichotomy, suggesting that cortical neurons may have more specialized functional roles rather than lying on a multidimensional continuum.

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