Edge Assignment in Cells of Monkey Area V2

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 187-187
Author(s):  
H Zhou ◽  
H Friedman ◽  
R von der Heydt
Keyword(s):  
Visual Perception ◽  
Local Contrast ◽  
Cortical Processing ◽  
Neural Basis ◽  
Left Edge ◽  
Area V2 ◽  
The Right ◽  
Figure Preference ◽  
Response Field ◽  
Identical Edge

One of the processes of visual perception is to organise 2-D images into figure and ground, assigning the borders to the figure. We have studied the neural basis of this phenomenon. We recorded from orientation-selective cells of areas V1 and V2 in the awake, fixating monkey. A square (typically 4 deg) of uniform colour or gray was displayed in a uniform surround field (11 deg) of different colour or gray. The square was much larger than the response fields of the cells studied. Its orientation and colour were optimised for each cell. In interleaved tests, we centred two opposite edges of the square in the RF, and also reversed the colours of square and surround, resulting in four different display combinations. Flipping edges and colours produced pairs of displays with an identical edge in the response field, but the figure on opposite sides. The display was static for each period of fixation, and mean spike numbers per second were measured. Many cells were selective for the sign of local contrast. In V2 we found cells that were highly discriminative for the direction of the figure, eg responding 10 times more to the left edge of a gray square with white surround than to the right edge of a white square with gray surround. In some cells, this discrimination was nearly independent of the figure size. The response could either be independent of local contrast (general edge assignment), or conditional on figure colour (joint assignment of edge and colour). We have observed direction-of-figure preference also in V1, but with smaller discrimination ratios. We conclude that figural edge assignment is part of early cortical processing.

Emotional Reactivity to Visual Content as Revealed by ERP Component Clustering

2015 ◽  
Vol 29 (4) ◽  
pp. 135-146 ◽  
Author(s):  
Miroslaw Wyczesany ◽  
Szczepan J. Grzybowski ◽  
Jan Kaiser
Keyword(s):  
Emotional Reactivity ◽  
Brain Activity ◽  
Affective State ◽  
Occipital Lobe ◽  
Stimulus Onset ◽  
Emotional States ◽  
Neural Basis ◽  
Temporoparietal Junction ◽  
The Right ◽  
The Impact

Abstract. In the study, the neural basis of emotional reactivity was investigated. Reactivity was operationalized as the impact of emotional pictures on the self-reported ongoing affective state. It was used to divide the subjects into high- and low-responders groups. Independent sources of brain activity were identified, localized with the DIPFIT method, and clustered across subjects to analyse the visual evoked potentials to affective pictures. Four of the identified clusters revealed effects of reactivity. The earliest two started about 120 ms from the stimulus onset and were located in the occipital lobe and the right temporoparietal junction. Another two with a latency of 200 ms were found in the orbitofrontal and the right dorsolateral cortices. Additionally, differences in pre-stimulus alpha level over the visual cortex were observed between the groups. The attentional modulation of perceptual processes is proposed as an early source of emotional reactivity, which forms an automatic mechanism of affective control. The role of top-down processes in affective appraisal and, finally, the experience of ongoing emotional states is also discussed.

scholarly journals Causal modulation of right hemisphere fronto-parietal phase synchrony with Transcranial Magnetic Stimulation during a conscious visual detection task

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chloé Stengel ◽  
Marine Vernet ◽  
Julià L. Amengual ◽  
Antoni Valero-Cabré
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Visual Perception ◽  
Frequency Band ◽  
Magnetic Stimulation ◽  
Visual Detection ◽  
Detection Task ◽  
Oscillatory Activity ◽  
Top Down ◽  
The Right ◽  
High Beta

AbstractCorrelational evidence in non-human primates has reported increases of fronto-parietal high-beta (22–30 Hz) synchrony during the top-down allocation of visuo-spatial attention. But may inter-regional synchronization at this specific frequency band provide a causal mechanism by which top-down attentional processes facilitate conscious visual perception? To address this question, we analyzed electroencephalographic (EEG) signals from a group of healthy participants who performed a conscious visual detection task while we delivered brief (4 pulses) rhythmic (30 Hz) or random bursts of Transcranial Magnetic Stimulation (TMS) to the right Frontal Eye Field (FEF) prior to the onset of a lateralized target. We report increases of inter-regional synchronization in the high-beta band (25–35 Hz) between the electrode closest to the stimulated region (the right FEF) and right parietal EEG leads, and increases of local inter-trial coherence within the same frequency band over bilateral parietal EEG contacts, both driven by rhythmic but not random TMS patterns. Such increases were accompained by improvements of conscious visual sensitivity for left visual targets in the rhythmic but not the random TMS condition. These outcomes suggest that high-beta inter-regional synchrony can be modulated non-invasively and that high-beta oscillatory activity across the right dorsal fronto-parietal network may contribute to the facilitation of conscious visual perception. Our work supports future applications of non-invasive brain stimulation to restore impaired visually-guided behaviors by operating on top-down attentional modulatory mechanisms.

scholarly journals Effects of behavioural activation on the neural circuit related to intrinsic motivation

BJPsych Open ◽  
2018 ◽  
Vol 4 (5) ◽  
pp. 317-323 ◽  
Author(s):  
Asako Mori ◽  
Yasumasa Okamoto ◽  
Go Okada ◽  
Koki Takagaki ◽  
Masahiro Takamura ◽  
...  
Keyword(s):  
Intrinsic Motivation ◽  
Neural Circuit ◽  
Intervention Group ◽  
Behavioural Activation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Neural Basis ◽  
Efficient Treatment ◽  
The Right ◽  
Magnetic Resonance Imaging Scanning

BackgroundBehavioural activation is an efficient treatment for depression and can improve intrinsic motivation. Previous studies have revealed that the frontostriatal circuit is involved in intrinsic motivation; however, there are no data on how behavioural activation affects the frontostriatal circuit.AimsWe aimed to investigate behavioural activation-related changes in the frontostriatal circuit.MethodFifty-nine individuals with subthreshold depression were randomly assigned to either the intervention or non-intervention group. The intervention group received five weekly behavioural activation sessions. The participants underwent functional magnetic resonance imaging scanning on two separate occasions while performing a stopwatch task based on intrinsic motivation. We investigated changes in neural activity and functional connectivity after behavioural activation.ResultsAfter behavioural activation, the intervention group had increased activation and connectivity in the frontostriatal region compared with the non-intervention group. The increased activation in the right middle frontal gyrus was correlated with an improvement of subjective sensitivity to environmental rewards.ConclusionsBehavioural activation-related changes to the frontostriatal circuit advance our understanding of psychotherapy-induced improvements in the neural basis of intrinsic motivation.Declaration of interestNone.

Microsurgically generated discontinuities provoke heritable changes in cellular handedness of a ciliate, Stylonychia mytilus

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 337-356
Author(s):  
X.B. Shi ◽  
Z.I. Qiu ◽  
W. He ◽  
J. Frankel
Keyword(s):  
Large Scale ◽  
Mirror Image ◽  
The Other ◽  
Left Edge ◽  
Left Handed ◽  
Specific Manner ◽  
The Right ◽  
Anteroposterior Polarity ◽  
Posterior Anterior ◽  
Stylonychia Mytilus

Stylonychia mytilus is a dorsoventrally flattened ciliate with compound ciliary structures arranged in a specific manner on the cell surface. In mirror-image (MI) doublets of this ciliate, two nearly complete sets of ciliary structures are arrayed side-by-side, one in a normal or ‘right-handed’ (RH) arrangement, the other in a reversed or ‘left-handed’ (LH) arrangement. MI-doublets exist in two forms, one with the RH component on the right, the LH component on the left, and feeding structures near the center (‘buccal-adjoining MI-doublet’); the other with the RH component on the left, the LH component on the right, and feeding structures on the lateral edges (‘buccal-opposing MI-doublet’). We describe an operation that can generate either type of MI-doublet. This operation interchanges large anterior and posterior regions of the cell, transposing the original posterior region anteriorly (P—A) and the original anterior region posteriorly (A—P), while retaining the original anteroposterior polarity of each region. Two sets of new ciliary structures then are formed in mirror-image arrangement, with the set in the P—A region oriented normally and the set in the A—P region undergoing a reversal of polarity along its anteroposterior axis. This sometimes creates end-to-end MI forms, but more commonly produces side-by-side MI-doublets through a folding together of the P—A and A—P regions. This folding occurs because one lateral edge of the cell had been removed during the operation; if the left edge was removed, the complex folds to the left and forms a buccal-adjoining MI-doublet, whereas if the right edge was removed, the complex folds to the right and forms a buccal-opposing MI-doublet. Both types can reorganize and later divide true-to-type, although the ‘buccal-opposing’ type is by far the more stable of the two. The generation of mirror-image forms is dependent on the prior abnormal juxtaposition of regions from opposite ends of the cell, and involves a coordinated respecification of large-scale organization. We interpret this response to be a consequence of intercalation of missing intervening positional values in the zone of posterior-anterior abutment.

2. Description of a Sliding Scale for Facilitating the Use of the Moist-bulb Hygrometer.

1851 ◽  
Vol 2 ◽  
pp. 13
Author(s):  
James Dalmahoy
Keyword(s):  
Dew Point ◽  
Left Edge ◽  
Sliding Scale ◽  
The Right

The instrument described in the paper is made of German silver, and is about a foot in length, andof an inch in breadth; along the middle of it there is a groove for a slider. On the right edge of the groove is engraved a scale of inches, and on the left the degrees of temperature from 0° to 85° Fahrenheit, each being placed exactly opposite that point of the scale of inches which measures the corresponding tension of vapour. On the left edge of the slider is engraved a scale of equal parts, eachof an inch; on the right edge, and having the same zero, is a vernier, applicable to the scale of inches. The lines on these scales are ten times larger than those which the symbols in the dew-point formula represent, but their numerical designations are not changed.

scholarly journals The Interaction Between Caudate Nucleus and Regions Within the Theory of Mind Network as a Neural Basis for Social Intelligence

2021 ◽  
Vol 15 ◽  
Author(s):  
Mikhail Votinov ◽  
Artem Myznikov ◽  
Maya Zheltyakova ◽  
Ruslan Masharipov ◽  
Alexander Korotkov ◽  
...  
Keyword(s):  
Theory Of Mind ◽  
Caudate Nucleus ◽  
Cognitive Processes ◽  
Social Intelligence ◽  
Functional Integration ◽  
Mental States ◽  
Neural Basis ◽  
Caudate Nuclei ◽  
Structural Peculiarity ◽  
The Right

The organization of socio-cognitive processes is a multifaceted problem for which many sophisticated concepts have been proposed. One of these concepts is social intelligence (SI), i.e., the set of abilities that allow successful interaction with other people. The theory of mind (ToM) human brain network is a good candidate for the neural substrate underlying SI since it is involved in inferring the mental states of others and ourselves and predicting or explaining others’ actions. However, the relationship of ToM to SI remains poorly explored. Our recent research revealed an association between the gray matter volume of the caudate nucleus and the degree of SI as measured by the Guilford-Sullivan test. It led us to question whether this structural peculiarity is reflected in changes to the integration of the caudate with other areas of the brain associated with socio-cognitive processes, including the ToM system. We conducted seed-based functional connectivity (FC) analysis of resting-state fMRI data for 42 subjects with the caudate as a region of interest. We found that the scores of the Guilford-Sullivan test were positively correlated with the FC between seeds in the right caudate head and two clusters located within the right superior temporal gyrus and bilateral precuneus. Both regions are known to be nodes of the ToM network. Thus, the current study demonstrates that the SI level is associated with the degree of functional integration between the ToM network and the caudate nuclei.

The Structural Language Network

2017 ◽  
Author(s):  
Angela D. Friederici ◽  
Noam Chomsky
Keyword(s):  
White Matter ◽  
Language Processing ◽  
Sentence Processing ◽  
Information Transfer ◽  
Right Hemisphere ◽  
Brain Regions ◽  
Neural Basis ◽  
Fiber Tracts ◽  
White Matter Fiber Tracts ◽  
The Right

An adequate description of the neural basis of language processing must consider the entire network both with respect to its structural white matter connections and the functional connectivities between the different brain regions as the information has to be sent between different language-related regions distributed across the temporal and frontal cortex. This chapter discusses the white matter fiber bundles that connect the language-relevant regions. The chapter is broken into three sections. In the first, we look at the white matter fiber tracts connecting the language-relevant regions in the frontal and temporal cortices; in the second, the ventral and dorsal pathways in the right hemisphere that connect temporal and frontal regions; and finally in the third, the two syntax-relevant and (at least) one semantic-relevant neuroanatomically-defined networks that sentence processing is based on. From this discussion, it becomes clear that online language processing requires information transfer via the long-range white matter fiber pathways that connect the language-relevant brain regions within each hemisphere and between hemispheres.

scholarly journals The neural representation of facial-emotion categories reflects conceptual structure

2019 ◽  
Vol 116 (32) ◽  
pp. 15861-15870 ◽  
Author(s):  
Jeffrey A. Brooks ◽  
Junichi Chikazoe ◽  
Norihiro Sadato ◽  
Jonathan B. Freeman
Keyword(s):  
Individual Differences ◽  
Emotion Perception ◽  
Conceptual Structure ◽  
Neural Representation ◽  
Facial Emotion ◽  
Neural Basis ◽  
Concept Knowledge ◽  
Cross Cultural Differences ◽  
Specific Emotion ◽  
The Right

Humans reliably categorize configurations of facial actions into specific emotion categories, leading some to argue that this process is invariant between individuals and cultures. However, growing behavioral evidence suggests that factors such as emotion-concept knowledge may shape the way emotions are visually perceived, leading to variability—rather than universality—in facial-emotion perception. Understanding variability in emotion perception is only emerging, and the neural basis of any impact from the structure of emotion-concept knowledge remains unknown. In a neuroimaging study, we used a representational similarity analysis (RSA) approach to measure the correspondence between the conceptual, perceptual, and neural representational structures of the six emotion categories Anger, Disgust, Fear, Happiness, Sadness, and Surprise. We found that subjects exhibited individual differences in their conceptual structure of emotions, which predicted their own unique perceptual structure. When viewing faces, the representational structure of multivoxel patterns in the right fusiform gyrus was significantly predicted by a subject’s unique conceptual structure, even when controlling for potential physical similarity in the faces themselves. Finally, cross-cultural differences in emotion perception were also observed, which could be explained by individual differences in conceptual structure. Our results suggest that the representational structure of emotion expressions in visual face-processing regions may be shaped by idiosyncratic conceptual understanding of emotion categories.

Graffiti and perceived neighborhood safety: a neuroimaging study

2019 ◽  
Vol 37 (1) ◽  
pp. 69-81
Author(s):  
Russell James ◽  
Michael O’Boyle
Keyword(s):  
Negative Impact ◽  
Parahippocampal Gyrus ◽  
Neural Basis ◽  
Neighborhood Safety ◽  
Content Type ◽  
Perceived Safety ◽  
Photographic Images ◽  
Neuroimaging Study ◽  
The Right ◽  
Perceived Neighborhood Safety

Purpose The purpose of this paper is to uncover the neural basis underlying the negative impact of graffiti on evaluations of neighborhood safety. Design/methodology/approach While in a functional magnetic resonance imaging scanner, participants rated the perceived safety of neighborhood scenes shown in photographic images. Some scenes were systematically altered to include graffiti, surveillance cameras or framed public art. Findings Consistent with previous research, the average safety rating for each scene including graffiti was significantly lower than for every other non-graffiti scene presented. The powerful salience of graffiti (as demonstrated by increased activation of the left fusiform gyrus) accompanied a decreased salience of other built environment scene elements (as demonstrated by reduced activation in the right parahippocampal gyrus). It appears as though the presence of graffiti causes the cognitive impact of other scene elements to fade. This redirection of cognitive focus may help to explain the dominant impact of graffiti on neighborhood safety evaluations. Practical implications Because of these basic perceptual tendencies, graffiti will necessarily dominate neighborhood safety evaluations. In any attempts to improve neighborhood safety evaluations, combating graffiti should be accorded a position of great importance, in keeping with these cognitive realities. Originality/value This is the first neuroimaging study of graffiti and perceived neighborhood safety.

Multi-Item Discriminability Pattern to Faces in Developmental Prosopagnosia Reveals Distinct Mechanisms of Face Processing

2019 ◽  
Vol 30 (5) ◽  
pp. 2986-2996
Author(s):  
Xue Tian ◽  
Ruosi Wang ◽  
Yuanfang Zhao ◽  
Zonglei Zhen ◽  
Yiying Song ◽  
...  
Keyword(s):  
Face Processing ◽  
Alternative Hypothesis ◽  
Normal Population ◽  
Imaging Study ◽  
Multiple Sources ◽  
Neural Basis ◽  
Face Area ◽  
Normal Individuals ◽  
The Face ◽  
The Right

Abstract Previous studies have shown that individuals with developmental prosopagnosia (DP) show specific deficits in face processing. However, the mechanism underlying the deficits remains largely unknown. One hypothesis suggests that DP shares the same mechanism as normal population, though their faces processing is disproportionally impaired. An alternative hypothesis emphasizes a qualitatively different mechanism of DP processing faces. To test these hypotheses, we instructed DP and normal individuals to perceive faces and objects. Instead of calculating accuracy averaging across stimulus items, we used the discrimination accuracy for each item to construct a multi-item discriminability pattern. We found DP’s discriminability pattern was less similar to that of normal individuals when perceiving faces than perceiving objects, suggesting that DP has qualitatively different mechanism in representing faces. A functional magnetic resonance imaging study was conducted to reveal the neural basis and found that multi-voxel activation patterns for faces in the right fusiform face area and occipital face area of DP were deviated away from the mean activation pattern of normal individuals. Further, the face representation was more heterogeneous in DP, suggesting that deficits of DP may come from multiple sources. In short, our study provides the first direct evidence that DP processes faces qualitatively different from normal population.

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