scholarly journals Neural coding of action planning: visual processing or visual memory?

2016 ◽  
Vol 16 (12) ◽  
pp. 23
Author(s):  
Simona Monaco ◽  
Elisa Pellencin ◽  
Malfatti Giulia ◽  
Turella Luca
2011 ◽  
Vol 17 (4) ◽  
pp. 449-456 ◽  
Author(s):  
AM Smerbeck ◽  
J Parrish ◽  
D Serafin ◽  
EA Yeh ◽  
B Weinstock-Guttman ◽  
...  

Background: Children with multiple sclerosis (MS) can suffer significant cognitive deficits. This study investigates the sensitivity and validity in pediatric MS of two visual processing tests borrowed from the adult literature, the Brief Visuospatial Memory Test-Revised (BVMTR) and the Symbol Digit Modalities Test (SDMT). Objective: To test the hypothesis that visual processing is disproportionately impacted in pediatric MS by comparing performance with that of healthy controls on the BVMTR and SDMT. Methods: We studied 88 participants (43 MS, 45 controls) using a neuropsychological assessment battery including measures of intelligence, language, visual memory, and processing speed. Patients and demographically matched controls were compared to determine which tests are most sensitive in pediatric MS. Results: Statistically significant differences were found between the MS and control groups on BVMTR Total Learning ( t (84) = 4.04, p < 0.001, d = 0.87), BVMTR Delayed Recall ( t (84) = 4.45, p < 0.001, d = 0.96), and SDMT ( t (38) = 2.19, p = 0.035, d = 0.69). No significant differences were found between groups on confrontation naming or general intellectual ability. Validity coefficients exploring correlation between BVMTR, SDMT, and disease characteristics were consistent with the adult literature. Conclusions: This study found that BVMTR and SDMT may be useful in assessing children and adolescents with MS.


2018 ◽  
Author(s):  
Simona Monaco ◽  
Giulia Malfatti ◽  
Alessandro Zendron ◽  
Elisa Pellencin ◽  
Luca Turella

AbstractPredictions of upcoming movements are based on several types of neural signals that span the visual, somatosensory, motor and cognitive system. Thus far, pre-movement signals have been investigated while participants viewed the object to be acted upon. Here, we studied the contribution of information other than vision to the classification of preparatory signals for action, even in absence of online visual information. We used functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis (MVPA) to test whether the neural signals evoked by visual, memory-based and somato-motor information can be reliably used to predict upcoming actions in areas of the dorsal and ventral visual stream during the preparatory phase preceding the action, while participants were lying still. Nineteen human participants (nine women) performed one of two actions towards an object with their eyes open or closed. Despite the well-known role of ventral stream areas in visual recognition tasks and the specialization of dorsal stream areas in somato-motor processes, we decoded action intention in areas of both streams based on visual, memory-based and somato-motor signals. Interestingly, we could reliably decode action intention in absence of visual information based on neural activity evoked when visual information was available, and vice-versa. Our results show a similar visual, memory and somato-motor representation of action planning in dorsal and ventral visual stream areas that allows predicting action intention across domains, regardless of the availability of visual information.


2018 ◽  
Author(s):  
Karolina Socha ◽  
Matt Whiteway ◽  
Daniel A. Butts ◽  
Vincent Bonin

SummaryVisual motion is a ubiquitous component of animals’ sensory experience and its encoding is critical for navigation and movement. Yet its impact on behavior and neural coding is not well understood. Combining pupillometry with cellular calcium imaging measurements of thalamocortical axons in awake behaving mice, we examined the impact of arousal and behavioral state on encoding of visual motion in the visual thalamus. We discovered that back-to-front visual motions elicits a robust behavioral response that shapes tunings of visual thalamic responses. Consistent with an arousal mechanism, the effects were pronounced during stillness and weak or absent during locomotor activity and under anesthesia. The impact on neuronal tuning was specific, biasing population response patterns in favor of back-to-front motion. The potent influence of visual motion on behavioral state dynamically affect sensory coding at early visual processing stages. Further research is required to reveal the circuitry and function of this novel mechanism.


2021 ◽  
Author(s):  
Guozhang Chen ◽  
Franz Scherr ◽  
Wolfgang Maass

AbstractThe neocortex is a network of rather stereotypical cortical microcircuits that share an exquisite genetically encoded architecture: Neurons of a fairly large number of different types are distributed over several layers (laminae), with specific probabilities of synaptic connections that depend on the neuron types involved and their spatial locations. Most available knowledge about this structure has been compiled into a detailed model [Billeh et al., 2020] for a generic cortical microcircuit in the primary visual cortex, consisting of 51,978 neurons of 111 different types. We add a noise model to the network that is based on experimental data, and analyze the results of network computations that can be extracted by projection neurons on layer 5. We show that the resulting model acquires through alignment of its synaptic weights via gradient descent training the capability to carry out a number of demanding visual processing tasks. Furthermore, this weight-alignment induces specific neural coding features in the microcircuit model that match those found in the living brain: High dimensional neural codes with an arguably close to optimal power-law decay of explained variance of PCA components, specific relations between signal- and noise-coding dimensions, and network dynamics in a critical regime. Hence these important features of neural coding and dynamics of cortical microcircuits in the brain are likely to emerge from aspects of their genetically encoded architecture that are captured by this data-based model in combination with learning processes. In addition, the model throws new light on the relation between visual processing capabilities and details of neural coding.


2019 ◽  
Author(s):  
Evan Cesanek ◽  
Jordan A. Taylor ◽  
Fulvio Domini

AbstractVisual perception often fails to recover the veridical 3D shape of objects in the environment due to ambiguity and variability in the available depth cues. However, we rely heavily on 3D shape estimates when planning movements, for example reaching to pick up an object from a slanted surface. Given the wide variety of distortions that can affect 3D perception, how do our actions remain accurate across different environments? One hypothesis is that the visuomotor system performs selective filtering of 3D information to minimize distortions. Indeed, some studies have found that actions appear to preferentially target stereo information when it is put in conflict with texture information. However, since these studies analyze averages over multiple trials, this apparent preference could be produced by sensorimotor adaptation. In Experiment 1, we create a set of cue-conflict stimuli where one available depth cue is affected by a constant bias. Sensory feedback rapidly aligns the motor output with physical reality in just a few trials, which can make it seem as if action planning selectively relies on the reinforced cue—yet no change in the relative influences of the cues is necessary to eliminate the constant errors. In contrast, when one depth cue becomes less correlated with physical reality, variable movement errors will occur, causing canonical adaptation to fail as the opposite error corrections cancel out. As a result, canonical adaptation cannot explain the preference for stereo found in studies with variable errors. However, Experiment 2 shows that persistent errors can produce a novel form of adaptation that gradually reduces the relative influence of an unreliable depth cue. These findings show that grasp control processes are continuously modified based on sensory feedback to compensate for both biases and noise in 3D visual processing, rather than having a hardwired preference for one type of depth information.


2020 ◽  
Vol 35 (6) ◽  
pp. 1044-1044
Author(s):  
Leonard S ◽  
Hall T

Abstract Objective Extant literature supports the “Two-Stream Hypothesis” of visual processing including a ventral stream (connecting the occipital lobe to the temporal lobe) and a dorsal stream (connecting the occipital lobe to the parietal lobe), but is not traditionally believed to involve the frontal lobe. Method “Eddie”, a healthy 14-year-old male, sustained a penetrating brain injury by accidentally lodging a pool cue through his right orbital bones and piercing his right frontal lobe through to the skull. He was ambulatory, awake, and alert on arrival to the ED, with a laceration, swelling, and bleeding of the eyelid. A cranial CT revealed a complex orbital roof fracture, injury to the orbit, and right frontal contusions. Eddie underwent a right supraorbital craniotomy with repair of the orbital roof fracture and debridement of bony fragments. Post-operative MRI revealed right frontal parenchymal edema and patchy areas of contusion. Results Neuropsychological evaluation revealed a robust cognitive reserve including verbal skills, working memory, processing speed, and word reading skills in the high average. Eddie demonstrated significant discrepancies in visually mediated skills including relatively weaker visual–spatial skills (24 standard score (SS) points lower than verbal skills), fluid reasoning with visual problem-solving (30 SS points lower than verbal skills), low average judgment of line orientation, and a discrepancy between verbal and visual memory. He also demonstrated mild difficulties consistent with his right orbito-frontal injury including weaknesses regarding impulsivity, self-monitoring, planning, and task approach. Conclusions The current case demonstrates possible involvement of the frontal lobe in the visual processing pathways.


2011 ◽  
Vol 366 (1571) ◽  
pp. 1702-1725 ◽  
Author(s):  
Michael A. Webster ◽  
Donald I. A. MacLeod

The appearance of faces can be strongly affected by the characteristics of faces viewed previously. These perceptual after-effects reflect processes of sensory adaptation that are found throughout the visual system, but which have been considered only relatively recently in the context of higher level perceptual judgements. In this review, we explore the consequences of adaptation for human face perception, and the implications of adaptation for understanding the neural-coding schemes underlying the visual representation of faces. The properties of face after-effects suggest that they, in part, reflect response changes at high and possibly face-specific levels of visual processing. Yet, the form of the after-effects and the norm-based codes that they point to show many parallels with the adaptations and functional organization that are thought to underlie the encoding of perceptual attributes like colour. The nature and basis for human colour vision have been studied extensively, and we draw on ideas and principles that have been developed to account for norms and normalization in colour vision to consider potential similarities and differences in the representation and adaptation of faces.


2013 ◽  
Vol 4 ◽  
Author(s):  
Webb Barbara ◽  
Mangan Michael ◽  
Ardin Paul

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