A fully computable model of bottom-up and top-down processing in high-level visual cortex

Top-down spatial attention enhances cortical representations of behaviorally relevant visual information and increases the precision of perceptual reports. However, little is known about the relative precision of top-down attentional modulations in different visual areas, especially compared to the highly precise stimulus-driven responses that are observed in early visual cortex. For example, the precision of attentional modulations in early visual areas may be limited by the relatively coarse spatial selectivity and the anatomical connectivity of the areas in prefrontal cortex that generate and relay the top-down signals. Here, we used fMRI and human participants to assess the precision of bottom-up spatial representations evoked by high contrast stimuli across the visual hierarchy. Then, we examined the relative precision of top-down attentional modulations in the absence of spatially-specific bottom-up drive. While V1 showed the largest relative difference between the precision of top-down attentional modulations and the precision of bottom-up modulations, mid-level areas such as V4 showed relatively smaller differences between the precision of top-down and bottom-up modulations. Overall, this interaction between visual areas (e.g. V1 vs V4) and the relative precision of top-down and bottom-up modulations suggests that the precision of top-down attentional modulations is limited by the representational fidelity of areas that generate and relay top-down feedback signals.

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Neural modulation of a realistic layered-microcircuit model of visual cortex based on bottom-up and top-down signals

Neuroscience Research ◽

10.1016/j.neures.2010.07.1684 ◽

2010 ◽

Vol 68 ◽

pp. e380

Author(s):

Tomoki Fukai ◽

Nobuhiko Wagatsuma ◽

Tobias C. Potjans ◽

Markus Diesmann

Keyword(s):

Visual Cortex ◽

Top Down ◽

Bottom Up ◽

Neural Modulation

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Bottom-up saliency and top-down learning in the primary visual cortex of monkeys

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1803854115 ◽

2018 ◽

Vol 115 (41) ◽

pp. 10499-10504 ◽

Cited By ~ 14

Author(s):

Yin Yan ◽

Li Zhaoping ◽

Wu Li

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Detection Task ◽

Late Response ◽

Late Component ◽

Neuronal Responses ◽

Top Down ◽

Bottom Up ◽

Response Component ◽

Orientation Contrast

Early sensory cortex is better known for representing sensory inputs but less for the effect of its responses on behavior. Here we explore the behavioral correlates of neuronal responses in primary visual cortex (V1) in a task to detect a uniquely oriented bar—the orientation singleton—in a background of uniformly oriented bars. This singleton is salient or inconspicuous when the orientation contrast between the singleton and background bars is sufficiently large or small, respectively. Using implanted microelectrodes, we measured V1 activities while monkeys were trained to quickly saccade to the singleton. A neuron’s responses to the singleton within its receptive field had an early and a late component, both increased with the orientation contrast. The early component started from the outset of neuronal responses; it remained unchanged before and after training on the singleton detection. The late component started ∼40 ms after the early one; it emerged and evolved with practicing the detection task. Training increased the behavioral accuracy and speed of singleton detection and increased the amount of information in the late response component about a singleton’s presence or absence. Furthermore, for a given singleton, faster detection performance was associated with higher V1 responses; training increased this behavioral–neural correlate in the early V1 responses but decreased it in the late V1 responses. Therefore, V1’s early responses are directly linked with behavior and represent the bottom-up saliency signals. Learning strengthens this link, likely serving as the basis for making the detection task more reflexive and less top-down driven.

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Signatures of top-down and bottom-up effects on visual perception measured intracranially from human visual cortex

Frontiers in Human Neuroscience ◽

10.3389/conf.fnhum.2011.207.00073 ◽

2011 ◽

Vol 5 ◽

Author(s):

Melloni Lucia

Keyword(s):

Visual Cortex ◽

Visual Perception ◽

Top Down ◽

Bottom Up ◽

Human Visual Cortex

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Characterization of Feedback Neurons in the High-Level Visual Cortical Areas That Project Directly to the Primary Visual Cortex in the Cat

Frontiers in Neuroanatomy ◽

10.3389/fnana.2020.616465 ◽

2021 ◽

Vol 14 ◽

Author(s):

Huijun Pan ◽

Shen Zhang ◽

Deng Pan ◽

Zheng Ye ◽

Hao Yu ◽

...

Keyword(s):

Information Processing ◽

Visual Cortex ◽

Primary Visual Cortex ◽

Visual Information ◽

Higher Order ◽

Top Down ◽

Cortical Areas ◽

Area 21A ◽

High Level ◽

Visual Cortical

Previous studies indicate that top-down influence plays a critical role in visual information processing and perceptual detection. However, the substrate that carries top-down influence remains poorly understood. Using a combined technique of retrograde neuronal tracing and immunofluorescent double labeling, we characterized the distribution and cell type of feedback neurons in cat’s high-level visual cortical areas that send direct connections to the primary visual cortex (V1: area 17). Our results showed: (1) the high-level visual cortex of area 21a at the ventral stream and PMLS area at the dorsal stream have a similar proportion of feedback neurons back projecting to the V1 area, (2) the distribution of feedback neurons in the higher-order visual area 21a and PMLS was significantly denser than in the intermediate visual cortex of area 19 and 18, (3) feedback neurons in all observed high-level visual cortex were found in layer II–III, IV, V, and VI, with a higher proportion in layer II–III, V, and VI than in layer IV, and (4) most feedback neurons were CaMKII-positive excitatory neurons, and few of them were identified as inhibitory GABAergic neurons. These results may argue against the segregation of ventral and dorsal streams during visual information processing, and support “reverse hierarchy theory” or interactive model proposing that recurrent connections between V1 and higher-order visual areas constitute the functional circuits that mediate visual perception. Also, the corticocortical feedback neurons from high-level visual cortical areas to the V1 area are mostly excitatory in nature.

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Opposing Influence of Top-down and Bottom-up Input on Excitatory Layer 2/3 Neurons in Mouse Primary Visual Cortex

Neuron ◽

10.1016/j.neuron.2020.09.024 ◽

2020 ◽

Vol 108 (6) ◽

pp. 1194-1206.e5 ◽

Cited By ~ 1

Author(s):

Rebecca Jordan ◽

Georg B. Keller

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Top Down ◽

Bottom Up ◽

Layer 2

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Orphan Implementations of Public Policy for Conflict-Oriented Issues

Administrative Culture ◽

10.32994/hk.v21i2.269 ◽

2021 ◽

Vol 21 (2) ◽

pp. 43-63

Author(s):

Shulamith Gertel Groome

Keyword(s):

Public Policy ◽

Decision Making ◽

Public Interest ◽

Policy Process ◽

Frame Of Reference ◽

Limited Resources ◽

Top Down ◽

Bottom Up ◽

Field Level ◽

High Level

This paper aims to broaden our understanding of public policy characterized by issues of non-consensus. The idea of flexible, independent administrative decision-making for a conflict-oriented policy-type is addressed in terms of chronological constructions of policy process. Distributions of limited resources are a source of public contention likely to draw ambiguous high-level policy decisions that lack practical administrative directives. Conflicting institutional, professional and stakeholder influences, at various levels of policy processes, illuminate circumstances fostering implementations incongruent with politically motivated macro-declarations. Yet, this does not necessarily represent failed policy. A reevaluation of administrative systems, by critical deconstruction of the dominant top-down discourse, provides a frame of reference for valid divergent implementations. A conceptual progression from field-level interpretation and adaptation of macro policy, initiatory orphan implementations emerge as policy itself. This revised bottom-up modality of the policy process implies a working balance of combined outputs, providing equitable outcome to serve largescale public interest.

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