32 Generating sequences of multiple saccadic eye movements allows us to search our 33 environment... more 32 Generating sequences of multiple saccadic eye movements allows us to search our 33 environment quickly and efficiently. Although the frontal eye field cortex (FEF) has been 34 linked to target selection and making saccades, little is known about its role in the control 35 and performance of the sequences of saccades made during self-guided visual search. We 36 recorded from FEF cells while monkeys searched for a target embedded in natural scenes, 37 and examined the degree to which cells with visual and visuo-movement activity showed 38 evidence of target selection for future saccades. We found that for about half of these 39 cells, activity during the fixation period between saccades predicted the next saccade in a 40 sequence at an early time that precluded selection based upon current visual input to a 41 cell’s response field. In addition to predicting the next saccade, activity during the 42 fixation prior to two successive saccades also predicted the direction and goal of t...
When we search for visual objects, the features of those objects bias our attention across the vi... more When we search for visual objects, the features of those objects bias our attention across the visual landscape (feature-based attention). The brain uses these top-down cues to select eye movement targets (spatial selection). The frontal eye field (FEF) is a prefrontal brain region implicated in selecting eye movements and is thought to reflect feature-based attention and spatial selection. Here, we study how FEF facilitates attention and selection in complex natural scenes. We ask whether FEF neurons facilitate feature-based attention by representing search-relevant visual features, or whether they are primarily involved in selecting eye movement targets in space. We show that search-relevant visual features are weakly predictive of gaze in natural scenes and additionally have no significant influence on FEF activity. Instead, FEF activity appears to primarily correlate with the direction of the upcoming eye movement. Our result demonstrates a concrete need for better models of nat...
Generating sequences of multiple saccadic eye movements allows us to search our environment quick... more Generating sequences of multiple saccadic eye movements allows us to search our environment quickly and efficiently. Although the frontal eye field cortex (FEF) has been linked to target selection and making saccades, little is known about its role in the control and performance of the sequences of saccades made during self-guided visual search. We recorded from FEF cells while monkeys searched for a target embedded in natural scenes and examined the degree to which cells with visual and visuo-movement activity showed evidence of target selection for future saccades. We found that for about half of these cells, activity during the fixation period between saccades predicted the next saccade in a sequence at an early time that precluded selection based on current visual input to a cell's response field. In addition to predicting the next saccade, activity during the fixation prior to two successive saccades also predicted the direction and goal of the second saccade in the sequenc...
The frontal eye field (FEF) plays a central role in saccade selection and execution. Using artifi... more The frontal eye field (FEF) plays a central role in saccade selection and execution. Using artificial stimuli, many studies have shown that the activity of neurons in the FEF is affected by both visually salient stimuli in a neuron's receptive field and upcoming saccades in a certain direction. However, the extent to which visual and motor information is represented in the FEF in the context of the cluttered natural scenes we encounter during everyday life has not been explored. Here, we model the activities of neurons in the FEF, recorded while monkeys were searching natural scenes, using both visual and saccade information. We compare the contribution of bottom-up visual saliency (based on low-level features such as brightness, orientation, and color) and saccade direction. We find that, while saliency is correlated with the activities of some neurons, this relationship is ultimately driven by activities related to movement. Although bottom-up visual saliency contributes to the choice of saccade targets, it does not appear that FEF neurons actively encode the kind of saliency posited by popular saliency map theories. Instead, our results emphasize the FEF's role in the stages of saccade planning directly related to movement generation.
Social norms regulate behavior, and changes in norms have a great impact on society. In most mode... more Social norms regulate behavior, and changes in norms have a great impact on society. In most modern societies, norms change through interpersonal communication and persuasive messages found in media. Here, we examined the neural basis of persuasion-induced changes in attitude toward and away from norms using fMRI. We measured brain activity while human participants were exposed to persuasive messages directed toward specific norms. Persuasion directed toward social norms specifically activated a set of brain regions including temporal poles, temporo-parietal junction, and medial prefrontal cortex. Beyond these regions, when successful, persuasion away from an accepted norm specifically recruited the left middle temporal and supramarginal gyri. Furthermore, in combination with data from a separate attitude-rating task, we found that left supramarginal gyrus activity represented participant attitude toward norms and tracked the persuasion-induced attitude changes that were away from agreement. Social norms are the rules governing acceptable behavior within a group 1-3. They regulate individual behavior as internalized beliefs and through external interpersonal sanctions, and they regulate important social phenomena such as cooperation, collective action, and social order 2,4,5. Importantly, norms are not fixed but dynamically changing within a society 3,6. These changes can occur because factors such as the natural environment, group composition, or economic systems fluctuate 7,8. In modern societies, persuasive communication plays an important role in how norms change. While virtually all people agree on some norms such as 'murder is wrong' , agreement with many other norms varies person to person. When questioning a norm gains significant traction within a society, proponents and critics often attempt to sway others to their respective positions with personal dialog, through television, and over the internet 2,6,9,10. Indeed, verbal persuasion has been a factor in the abolition of racial segregation through the civil-rights movement, new attitudes against public smoking, and the ongoing changes across some parts of the world with regard to same-sex marriage 7,11,12. How much people agree with a norm can be influenced by persuasion, and this process is critical to group-level reinforcement/emergence or weakening/abolition of norms. Recent studies in social science have begun to investigate how this process unfolds in the context of communication in social networks 7,13 , but a biological explanation at the individual brain level is still lacking. Recent studies have assessed various norm-related cognitive processes and clarified their neural correlates. Norm compliance/adaptation has been associated with the right dorsolateral prefrontal cortex (dLPFC), ventromedial prefrontal cortex (vMPFC), and insula 14-16. Moral judgment has been associated with the dorsomedial prefrontal cortex (dMPFC), posterior cingulate cortex, the temporo-parietal junction (TPJ), vMPFC, and the striatum 17-19. Additionally, recognition of social equality has been associated with the activity in the vMPFC, striatum, and insula 20,21. However, these studies presupposed fixed norms/moral-standards, and therefore did not assess how norms themselves 'change'. Other recent studies have assessed the neural basis of persuasion in the context of product advertisement or health promotion 22-27. These studies showed that the dMPFC, vMPFC, inferior frontal gyrus (IFG) and dLPFC play a pivotal role in attitude change through persuasion. However, social norms were not targeted, and whether changing attitudes toward social norms requires any additional brain regions is unknown. Thus, neuroscience studies of social norms have never assessed how norms change, while those of persuasion-induced attitude change have not targeted norms.
Macaques were trained on a WCST analogue with two dimensions (color and shape). In each trial ani... more Macaques were trained on a WCST analogue with two dimensions (color and shape). In each trial animals chose one of three stimuli that matched the sample according to the currently reinforced matching dimension. No cues were given as to the currently correct matching rule. Whenever performance reached a criterion, the rule was switched unannounced. After animals learned the task, we made bilateral lesions to orbitofrontal (OFC), principal sulcus (PS), superior-dorsolateral parts of the prefrontal cortex, or to the anterior cingulate sulcus (ACS). None of the lesions impaired control matching tasks. However, OFC, PS and ACS groups achieved significantly fewer rule-shifts per day in the WCST task. Further, different cognitive components of the task were impaired after these three lesions including more fragile rule memory in PS group, reduced sensitivity to positive feedback in OFC group, and quick immature responses in ACS group. Thus a distributed network supports flexible task performance.
The frontal eye field (FEF) plays a central role in saccade selection and execution. Using artifi... more The frontal eye field (FEF) plays a central role in saccade selection and execution. Using artificial stimuli, many studies have shown that the activity of neurons in the FEF is affected by both visually salient stimuli in a neuron's receptive field and upcoming saccades in a certain direction. However, the extent to which visual and motor information is represented in the FEF in the context of the cluttered natural scenes we encounter during everyday life has not been explored. Here, we model the activities of neurons in the FEF, recorded while monkeys were searching natural scenes, using both visual and saccade information. We compare the contribution of bottom-up visual saliency (based on low-level features such as brightness, orientation, and color) and saccade direction. We find that, while saliency is correlated with the activities of some neurons, this relationship is ultimately driven by activities related to movement. Although bottom-up visual saliency contributes to the choice of saccade targets, it does not appear that FEF neurons actively encode the kind of saliency posited by popular saliency map theories. Instead, our results emphasize the FEF's role in the stages of saccade planning directly related to movement generation.
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