scholarly journals Transmission of spiking-rate information through layered networks: the role of recurrent and feedback connections

2007 ◽  
Vol 8 (S2) ◽  
Author(s):  
Anthony N Burkitt ◽  
Chris Trengove
Keyword(s):  
Layered Networks ◽  
Rate Information ◽  
Feedback Connections

Effects of Feedback Projections From Area 18 Layers 2/3 to Area 17 Layers 2/3 in the Cat Visual Cortex

1999 ◽  
Vol 82 (5) ◽  
pp. 2667-2675 ◽  
Author(s):  
Susana Martinez-Conde ◽  
Javier Cudeiro ◽  
Kenneth L. Grieve ◽  
Rosa Rodriguez ◽  
Casto Rivadulla ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Small Region ◽  
Orientation Tuning ◽  
Area 17 ◽  
Visual Responses ◽  
Area 18 ◽  
Cat Visual Cortex ◽  
Effects Of Feedback ◽  
Feedback Connections

In the absence of a direct geniculate input, area 17 cells in the cat are nevertheless able to respond to visual stimuli because of feedback connections from area 18. Anatomic studies have shown that, in the cat visual cortex, layer 5 of area 18 projects to layer 5 of area 17, and layers 2/3 of area 18 project to layers 2/3 of area 17. What is the specific role of these connections? Previous studies have examined the effect of area 18 layer 5 blockade on cells in area 17 layer 5. Here we examine whether the feedback connections from layers 2/3 of area 18 influence the orientation tuning and velocity tuning of cells in layers 2/3 of area 17. Experiments were carried out in anesthetized and paralyzed cats. We blocked reversibly a small region (300 μm radius) in layers 2/3 of area 18 by iontophoretic application of GABA and recorded simultaneously from cells in layers 2/3 of area 17 while stimulating with oriented sweeping bars. Area 17 cells showed either enhanced or suppressed visual responses to sweeping bars of various orientations and velocities during area 18 blockade. For most area 17 cells, orientation bandwidths remained unaltered, and we never observed visual responses during blockade that were absent completely in the preblockade condition. This suggests that area 18 layers 2/3 modulate visual responses in area 17 layers 2/3 without fundamentally altering their specificity.

Role of Feedback Connections in Central Visual Processing

2020 ◽  
Vol 6 (1) ◽  
pp. 313-334
Author(s):  
Farran Briggs
Keyword(s):  
Visual Processing ◽  
Physiological Response ◽  
Functional Role ◽  
Functional Roles ◽  
Vision Science ◽  
The Core ◽  
Feedback Circuits ◽  
Corticothalamic Feedback ◽  
Feedback Connections

The physiological response properties of neurons in the visual system are inherited mainly from feedforward inputs. Interestingly, feedback inputs often outnumber feedforward inputs. Although they are numerous, feedback connections are weaker, slower, and considered to be modulatory, in contrast to fast, high-efficacy feedforward connections. Accordingly, the functional role of feedback in visual processing has remained a fundamental mystery in vision science. At the core of this mystery are questions about whether feedback circuits regulate spatial receptive field properties versus temporal responses among target neurons, or whether feedback serves a more global role in arousal or attention. These proposed functions are not mutually exclusive, and there is compelling evidence to support multiple functional roles for feedback. In this review, the role of feedback in vision will be explored mainly from the perspective of corticothalamic feedback. Further generalized principles of feedback applicable to corticocortical connections will also be considered.

scholarly journals Gestalts at threshold could reveal Gestalts as predictions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thiago Leiros Costa ◽  
Johan Wagemans
Keyword(s):  
Predictive Processing ◽  
Top Down ◽  
Visual Neurons ◽  
Chance Performance ◽  
Response Profile ◽  
Early Visual Cortex ◽  
Feedback Connections ◽  
And Control ◽  
Contrast Response

AbstractWe review and revisit the predictive processing inspired “Gestalts as predictions” hypothesis. The study of Gestalt phenomena at and below threshold can help clarify the role of higher-order object selective areas and feedback connections in mid-level vision. In two psychophysical experiments assessing manipulations of contrast and configurality we showed that: (1) Gestalt phenomena are robust against saliency manipulations across the psychometric function even below threshold (with the accuracy gains and higher saliency associated with Gestalts being present even around chance performance); and (2) peak differences between Gestalt and control conditions happened around the time where responses to Gestalts are starting to saturate (mimicking the differential contrast response profile of striate vs. extra-striate visual neurons). In addition, Gestalts are associated with steeper psychometric functions in all experiments. We propose that these results reflect the differential engagement of object-selective areas in Gestalt phenomena and of information- or percept-based processing, as opposed to energy- or stimulus-based processing, more generally. In addition, the presence of nonlinearities in the psychometric functions suggest differential top-down modulation of the early visual cortex. We treat this as a proof of principle study, illustrating that classic psychophysics can help assess possible involvement of hierarchical predictive processing in Gestalt phenomena.

scholarly journals LITERASI INFORMASI PETANI NANAS DALAM MENINGKATKAN PRODUKTIVITAS PERTANIAN DI DESA TANGKIT BARU KEC. SUNGAI GELAM KAB. MUARO JAMBI

2020 ◽  
Vol 26 (01) ◽  
pp. 173-206
Author(s):  
Andi Junudu ◽  
Muhammad Rum ◽  
Wenny Dastina
Keyword(s):  
Secondary School ◽  
Qualitative Method ◽  
Flow Model ◽  
Information Access ◽  
Data Presentation ◽  
Analysis Technique ◽  
Rate Information ◽  
Locating Information ◽  
The Village

This article discusses the pineapple farmer’s literacy in improving agricultural productivity in the Tangkit Baru Village. The Purpose of this article was to explore the literacy level of farmer information by default of The International Federation of Library Association and Literacy (IFLA). The writing employed a descriptive qualitative method with a sampling approach. The data analysis technique used is the flow model of data reduction, data presentation and deduction scheme. The results proved that the pineapple farmers’ literacy in the village of Tangkit Baru in good category, with increased productivity. The default IFLA information literation component suggest, (information access) is obtained through socialization among farmers, as well as through generations; then at the rate (information evaluation), farmers know the variety of plants, the inhibitory factors dof locating information, and the ability to compare the information accordingly are evaluated so that information can be useful; and (use of information), farmers apply information through experimentation and information obtained, disseminated and communicated to create coexistence. The pineapple farmers in the Tangkit Baru village at the average level of secondary school are able to work well, because of the important information literacy role of their communities. Which, of course, the pineapple productivity will increase as well as minimize the damage to the farmland.

scholarly journals The Visual Callosal Connection: A Connection Like Any Other?

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Kerstin E. Schmidt
Keyword(s):  
Hierarchical Level ◽  
Similar Response ◽  
Callosal Connections ◽  
Visual Areas ◽  
Main Action ◽  
Functional Topography ◽  
Multiplicative Shift ◽  
Neuronal Groups ◽  
Feedback Connections

Recent work about the role of visual callosal connections in ferrets and cats is reviewed, and morphological and functional homologies between the lateral intrinsic and callosal network in early visual areas are discussed. Both networks selectively link distributed neuronal groups with similar response properties, and the actions exerted by callosal input reflect the functional topography of those networks. This supports the notion that callosal connections perpetuate the function of the lateral intrahemispheric circuit onto the other hemisphere. Reversible deactivation studies indicate that the main action of visual callosal input is a multiplicative shift of responses rather than a changing response selectivity. Both the gain of that action and its excitatory-inhibitory balance seem to be dynamically adapted to the feedforward drive by the visual stimulus onto primary visual cortex. Taken together anatomical and functional evidence from corticocortical and lateral circuits further leads to the conclusion that visual callosal connections share more features with lateral intrahemispheric connections on the same hierarchical level and less with feedback connections. I propose that experimental results about the callosal circuit in early visual areas can be interpreted with respect to lateral connectivity in general.

The influence of conflict monitoring on meta-reasoning and response times in a base rate task

2018 ◽  
Vol 71 (12) ◽  
pp. 2548-2561 ◽  
Author(s):  
Marin Dujmović ◽  
Pavle Valerjev
Keyword(s):  
Response Times ◽  
Conflict Detection ◽  
Base Rate ◽  
Dual Process ◽  
Conflict Monitoring ◽  
Metacognitive Processes ◽  
Rate Information ◽  
Rate Ratios ◽  
The Impact

We examined the role of conflict monitoring processes in forming metacognitive judgements of confidence while performing base rate tasks. Recently proposed models of dual-process reasoning, as well as research, have shown that conflict detection might represent a link between Type 1 and Type 2 processing. Conflict detection has also been shown to affect metacognitive processes in reasoning tasks. By varying base rate probability and congruence, we generated base rate tasks of four distinct levels of congruence. The results of two experiments showed that participants were slower and less confident in conflict conditions regardless of their response. However, there were two distinct subsets of participants with different levels of sensitivity to conflict which resulted in different patterns of results when using low base rate ratios. In-depth analyses showed that the impact of base rate information in the formation of metacognitive judgements depended on congruence and response type. Base rate information was a more salient cue for metacognitive processes when responding according to base rates compared with responding according to belief. There is evidence that base rate information may serve as a direct cue for metacognition, independent of fluency.

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