scholarly journals Model-based fMRI reveals co-existing specific and generalized concept representations

2020 ◽  
Author(s):  
Caitlin R. Bowman ◽  
Takako Iwashita ◽  
Dagmar Zeithamova
Keyword(s):  
Prefrontal Cortex ◽  
Parietal Cortex ◽  
Inferior Frontal Gyrus ◽  
Ventromedial Prefrontal Cortex ◽  
Central Tendency ◽  
Single Task ◽  
Categorization Task ◽  
Multiple Levels ◽  
Concept Representations ◽  
The Right

AbstractThere has been a long-standing debate about whether categories are represented by individual category members (exemplars) or by the central tendency abstracted from individual members (prototypes). Across neuroimaging studies, there has been neural evidence for either exemplar representations or prototype representations, but not both. In the present study, we asked whether it is possible for individuals to form multiple types of category representations within a single task. We designed a categorization task to promote both exemplar and prototype representations, and we tracked their formation across learning. We found evidence for co-existing prototype and exemplar representations in brain in regions that aligned with previous studies: prototypes in ventromedial prefrontal cortex and anterior hippocampus and exemplars in inferior frontal gyrus and lateral parietal cortex. These findings show that, under the right circumstances, individuals may form representations at multiple levels of specificity, potentially facilitating a broad range of future memory-based decisions.

scholarly journals Tracking prototype and exemplar representations in the brain across learning

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Caitlin R Bowman ◽  
Takako Iwashita ◽  
Dagmar Zeithamova
Keyword(s):  
Prefrontal Cortex ◽  
Inferior Frontal Gyrus ◽  
Brain Regions ◽  
Ventromedial Prefrontal Cortex ◽  
Central Tendency ◽  
Final Test ◽  
Single Task ◽  
Multiple Levels ◽  
The Right ◽  
The Brain

There is a long-standing debate about whether categories are represented by individual category members (exemplars) or by the central tendency abstracted from individual members (prototypes). Neuroimaging studies have shown neural evidence for either exemplar representations or prototype representations, but not both. Presently, we asked whether it is possible for multiple types of category representations to exist within a single task. We designed a categorization task to promote both exemplar and prototype representations and tracked their formation across learning. We found only prototype correlates during the final test. However, interim tests interspersed throughout learning showed prototype and exemplar representations across distinct brain regions that aligned with previous studies: prototypes in ventromedial prefrontal cortex and anterior hippocampus and exemplars in inferior frontal gyrus and lateral parietal cortex. These findings indicate that, under the right circumstances, individuals may form representations at multiple levels of specificity, potentially facilitating a broad range of future decisions.

scholarly journals Connections of the Human Orbitofrontal Cortex and Inferior Frontal Gyrus

2020 ◽  
Vol 30 (11) ◽  
pp. 5830-5843 ◽  
Author(s):  
Chih-Chin Heather Hsu ◽  
Edmund T Rolls ◽  
Chu-Chung Huang ◽  
Shin Tai Chong ◽  
Chun-Yi Zac Lo ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Anterior Cingulate Cortex ◽  
Orbitofrontal Cortex ◽  
Inferior Frontal Gyrus ◽  
Cingulate Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Anterior Cingulate ◽  
Inferior Parietal Cortex ◽  
Temporal Pole ◽  
The Right

Abstract The direct connections of the orbitofrontal cortex (OFC) were traced with diffusion tractography imaging and statistical analysis in 50 humans, to help understand better its roles in emotion and its disorders. The medial OFC and ventromedial prefrontal cortex have direct connections with the pregenual and subgenual parts of the anterior cingulate cortex; all of which are reward-related areas. The lateral OFC (OFClat) and its closely connected right inferior frontal gyrus (rIFG) have direct connections with the supracallosal anterior cingulate cortex; all of which are punishment or nonreward-related areas. The OFClat and rIFG also have direct connections with the right supramarginal gyrus and inferior parietal cortex, and with some premotor cortical areas, which may provide outputs for the OFClat and rIFG. Another key finding is that the ventromedial prefrontal cortex shares with the medial OFC especially strong outputs to the nucleus accumbens and olfactory tubercle, which comprise the ventral striatum, whereas the other regions have more widespread outputs to the striatum. Direct connections of the OFC and IFG were with especially the temporal pole part of the temporal lobe. The left IFG, which includes Broca’s area, has direct connections with the left angular and supramarginal gyri.

Age differences in ventromedial prefrontal cortex functional connectivity during socioemotional content processing

2020 ◽  
Vol 48 (7) ◽  
pp. 1-19
Author(s):  
Ryan T. Daley ◽  
Holly J. Bowen ◽  
Eric C. Fields ◽  
Angela Gutchess ◽  
Elizabeth A. Kensinger
Keyword(s):  
Prefrontal Cortex ◽  
Functional Connectivity ◽  
Inferior Frontal Gyrus ◽  
Age Groups ◽  
Emotional Content ◽  
Ventromedial Prefrontal Cortex ◽  
Anterior Cingulate ◽  
Supramarginal Gyrus ◽  
Age Related ◽  
Content Processing

Self-relevance effects are often confounded by the presence of emotional content, rendering it difficult to determine how brain networks functionally connected to the ventromedial prefrontal cortex (vmPFC) are affected by the independent contributions of self-relevance and emotion. This difficulty is complicated by age-related changes in functional connectivity between the vmPFC and other default mode network regions, and regions typically associated with externally oriented networks. We asked groups of younger and older adults to imagine placing emotional and neutral objects in their home or a stranger's home. An age-invariant vmPFC cluster showed increased activation for self-relevant and emotional content processing. Functional connectivity analyses revealed age × self-relevance interactions in vmPFC connectivity with the anterior cingulate cortex. There were also age × emotion interactions in vmPFC functional connectivity with the anterior insula, orbitofrontal gyrus, inferior frontal gyrus, and supramarginal gyrus. Interactions occurred in regions with the greatest differences between the age groups, as revealed by conjunction analyses. Implications of the findings are discussed.

The Role of the Right Prefrontal Cortex in Self-evaluation of the Face: A Functional Magnetic Resonance Imaging Study

2008 ◽  
Vol 20 (2) ◽  
pp. 342-355 ◽  
Author(s):  
Tomoyo Morita ◽  
Shoji Itakura ◽  
Daisuke N. Saito ◽  
Satoshi Nakashita ◽  
Tokiko Harada ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Face Recognition ◽  
Inferior Frontal Gyrus ◽  
Video Recording ◽  
Imaging Study ◽  
The Self ◽  
Anterior Cingulate ◽  
Precentral Gyrus ◽  
Self Evaluation ◽  
The Right

Individuals can experience negative emotions (e.g., embarrassment) accompanying self-evaluation immediately after recognizing their own facial image, especially if it deviates strongly from their mental representation of ideals or standards. The aim of this study was to identify the cortical regions involved in self-recognition and self-evaluation along with self-conscious emotions. To increase the range of emotions accompanying self-evaluation, we used facial feedback images chosen from a video recording, some of which deviated significantly from normal images. In total, 19 participants were asked to rate images of their own face (SELF) and those of others (OTHERS) according to how photogenic they appeared to be. After scanning the images, the participants rated how embarrassed they felt upon viewing each face. As the photogenic scores decreased, the embarrassment ratings dramatically increased for the participant's own face compared with those of others. The SELF versus OTHERS contrast significantly increased the activation of the right prefrontal cortex, bilateral insular cortex, anterior cingulate cortex, and bilateral occipital cortex. Within the right prefrontal cortex, activity in the right precentral gyrus reflected the trait of awareness of observable aspects of the self; this provided strong evidence that the right precentral gyrus is specifically involved in self-face recognition. By contrast, activity in the anterior region, which is located in the right middle inferior frontal gyrus, was modulated by the extent of embarrassment. This finding suggests that the right middle inferior frontal gyrus is engaged in self-evaluation preceded by self-face recognition based on the relevance to a standard self.

scholarly journals Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

2016 ◽  
Vol 113 (52) ◽  
pp. E8492-E8501 ◽  
Author(s):  
Roland G. Benoit ◽  
Daniel J. Davies ◽  
Michael C. Anderson
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Episodic Simulation ◽  
Dorsolateral Prefrontal ◽  
Future Events ◽  
The Right ◽  
Development Of Anxiety ◽  
The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

scholarly journals Who Comes First? The Role of the Prefrontal and Parietal Cortex in Cognitive Control

2005 ◽  
Vol 17 (9) ◽  
pp. 1367-1375 ◽  
Author(s):  
Marcel Brass ◽  
Markus Ullsperger ◽  
Thomas R. Knoesche ◽  
D. Yves von Cramon ◽  
Natalie A. Phillips
Keyword(s):  
Prefrontal Cortex ◽  
Cognitive Control ◽  
Parietal Cortex ◽  
Inferior Frontal Gyrus ◽  
Event Related Potentials ◽  
Brain Regions ◽  
High Temporal Resolution ◽  
Cortical Region ◽  
Task Set ◽  
Related Potentials

Cognitive control processes enable us to adjust our behavior to changing environmental demands. Although neuropsychological studies suggest that the critical cortical region for cognitive control is the prefrontal cortex, neuro-imaging studies have emphasized the interplay of prefrontal and parietal cortices. This raises the fundamental question about the different contributions of prefrontal and parietal areas in cognitive control. It was assumed that the prefrontal cortex biases processing in posterior brain regions. This assumption leads to the hypothesis that neural activity in the prefrontal cortex should precede parietal activity in cognitive control. The present study tested this assumption by combining results from functional magnetic resonance imaging (fMRI) providing high spatial resolution and event-related potentials (ERPs) to gain high temporal resolution. We collected ERP data using a modified task-switching paradigm. In this paradigm, a situation where the same task was indicated by two different cues was compared with a situation where two cues indicated different tasks. Only the latter condition required updating of the task set. Task-set updating was associated with a midline negative ERP deflection peaking around 470 msec. We placed dipoles in regions activated in a previous fMRI study that used the same paradigm (left inferior frontal junction, right inferior frontal gyrus, right parietal cortex) and fitted their directions and magnitudes to the ERP effect. The frontal dipoles contributed to the ERP effect earlier than the parietal dipole, providing support for the view that the prefrontal cortex is involved in updating of general task representations and biases relevant stimulus-response associations in the parietal cortex.

scholarly journals Daily and Intermittent Smoking Decrease Gray Matter Volume and Concentrations of Glutamate, Creatine, Myo-Inositol and N-acetylaspartate in the Prefrontal Cortex

2020 ◽  
Author(s):  
Paul Faulkner ◽  
Susanna Lucini Paioni ◽  
Petya Kozhuharova ◽  
Natasza Orlov ◽  
David J. Lythgoe ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Gray Matter ◽  
Smoking Status ◽  
Inferior Frontal Gyrus ◽  
Gray Matter Volume ◽  
Structural Mri ◽  
Resonance Spectroscopy ◽  
Matter Volume ◽  
The Right

AbstractCigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because non-daily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 non-smokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent 1H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural MRI to determine whole-brain gray matter volume. Compared to non-smokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of prefrontal metabolites and structure did not differ between daily and intermittent smokers. Finally, medial prefrontal metabolite concentrations and right inferior frontal gray matter volume were positively correlated, but these relationships were not influenced by smoking status. This study provides the first evidence that both daily and intermittent smoking are associated with low concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol, and low gray matter volume in the prefrontal cortex. Future tobacco cessation efforts should not ignore potential deleterious effects of intermittent smoking by considering only daily smokers. Finally, because low glutamate concentrations hinder cessation, treatments that can normalize tonic levels of prefrontal glutamate, such as N-acetylcysteine, may help intermittent and daily smokers to quit.

scholarly journals 0307 Gray Matter Volume Correlates of Psychomotor Vigilance Speed During Sleep Deprivation

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A116-A116
Author(s):  
C E Meinhausen ◽  
J R Vanuk ◽  
M A Grandner ◽  
W D Killgore
Keyword(s):  
Prefrontal Cortex ◽  
Sleep Deprivation ◽  
Gray Matter ◽  
Inferior Frontal Gyrus ◽  
Gray Matter Volume ◽  
Sleep Loss ◽  
Grey Matter Volume ◽  
Matter Volume ◽  
The Right ◽  
Psychomotor Vigilance

Abstract Introduction Sleep deprivation has often been associated with decreased cognitive control, including deficits in the ability to sustain attention. Psychomotor vigilance speed slows following a period of fatigue, and can lead to disastrous results in daily life. In order to determine the brain areas correlated with reduced psychomotor vigilance speed, as a result of diminished sleep, a voxel-based morphometry analysis was performed prior to a period of monitored sleep deprivation. The mean speed of response time during the final 17 hours of a 29-hour sleep deprivation was then measured with the Psychomotor Vigilance Test (PVT), a reaction-timed task that measures the speed participants respond to a visual stimulus. Methods 45 healthy individuals (male=23 female=22) between the ages of 20-43 years (M=25.4 SD=5.6) participated in the study. Structural neuroimaging data were collected using a T3 magnetic resonance imaging scanner following a typical night’s sleep. Mean PVT speed was monitored with an hourly 10-minute PVT assessment during a monitored overnight sleep deprivation session. Speed was defined as the reciprocal of reaction time (1/RT). Results PVT speed was negatively correlated with grey matter volume (P<.05 FWE-corrected) in the prefrontal cortex, specifically the right posterior inferior frontal gyrus (p=.030; MNI coordinates = 36, 12, 26). Conclusion Our findings indicate that gray matter within the right posterior inferior frontal gyrus is greater in individuals who are more vulnerable to slowing of PVT responses during an overnight period of sleep deprivation. These findings suggest that inter-individual differences in the ability to sustain psychomotor vigilance during sleep loss may be related to increased gray matter in the right lateral prefrontal cortex and could have implications for understanding the neurobiological substrates of vulnerability and resilience to sleep loss. Support  

Characterization of Empathy Deficits following Prefrontal Brain Damage: The Role of the Right Ventromedial Prefrontal Cortex

2003 ◽  
Vol 15 (3) ◽  
pp. 324-337 ◽  
Author(s):  
S. G. Shamay-Tsoory ◽  
R. Tomer ◽  
B. D. Berger ◽  
J. Aharon-Peretz
Keyword(s):  
Prefrontal Cortex ◽  
Brain Damage ◽  
Cognitive Flexibility ◽  
Right Hemisphere ◽  
Ventromedial Prefrontal Cortex ◽  
Fundamental Aspect ◽  
Affect Recognition ◽  
Healthy Controls ◽  
Empathic Response ◽  
The Right

Impaired empathic response has been described in patients following brain injury, suggesting that empathy may be a fundamental aspect of the social behavior disturbed by brain damage. However, the neuroanatomical basis of impaired empathy has not been studied in detail. The empathic response of patients with localized lesions in the prefrontal cortex (n = 25) was compared to responses of patients with posterior (n = 17) and healthy control subjects (n = 19). To examine the cognitive processes that underlie the empathic ability, the relationships between empathy scores and the performance on tasks that assess processes of cognitive flexibility, affect recognition, and theory of mind (TOM) were also examined. Patients with prefrontal lesions, particularly when their damage included the ventromedial prefrontal cortex, were significantly impaired in empathy as compared to patients with posterior lesions and healthy controls. However, among patients with posterior lesions, those with damage to the right hemisphere were impaired, whereas those with left posterior lesions displayed empathy levels similar to healthy controls. Seven of nine patients with the most profound empathy deficit had a right ventromedial lesion. A differential pattern regarding the relationships between empathy and cognitive performance was also found: Whereas among patients with dorsolateral prefrontal damage empathy was related to cognitive flexibility but not to TOM and affect recognition, empathy scores in patients with ventromedial lesions were related to TOM but not to cognitive flexibility. Our findings suggest that prefrontal structures play an important part in a network mediating the empathic response and specifically that the right ventromedial cortex has a unique role in integrating cognition and affect to produce the empathic response.

scholarly journals Task- and Experience-dependent Cortical Selectivity to Features Informative for Categorization

2014 ◽  
Vol 26 (2) ◽  
pp. 319-333 ◽  
Author(s):  
Marieke van der Linden ◽  
Joost Wegman ◽  
Guillén Fernández
Keyword(s):  
Color Change ◽  
Inferior Frontal Gyrus ◽  
Categorization Task ◽  
Enhanced Sensitivity ◽  
Electrophysiological Recordings ◽  
Cortical Responses ◽  
Occipitotemporal Cortex ◽  
Human Participants ◽  
The Right ◽  
Fmri Adaptation

In this study, we bridge the gap between monkey electrophysiological recordings that showed selective responses to informative features and human fMRI data that demonstrated increased and selective responses to trained objects. Human participants trained with computer-generated fish stimuli. For each participant, two features of the fish were informative for category membership and two features were uninformative. After training, participants showed higher perceptual sensitivity to the informative dimensions. An fMRI adaptation paradigm revealed that during categorization the right inferior frontal gyrus and occipitotemporal cortex were selectively responsive to the informative features. These selective cortical responses were experience dependent; they were not present for the entire trained object, but specific for those features that were informative for categorization. Responses in the inferior frontal gyrus showed category selectivity. Moreover, selectivity to the informative features correlated with performance on the categorization task during scanning. This all suggests that the frontal cortex is involved in actively categorizing objects and that it uses informative features to do so while ignoring those features that do not contribute category information. Occipitotemporal cortex also showed selectivity to the informative features during the categorization task. Interestingly, this area showed a positive correlation of performance during training and selectivity to the informative features and a negative correlation with selectivity to the uninformative features. This indicates that training enhanced sensitivity to trained items and decreased sensitivity to uninformative features. The absence of sensitivity for informative features during a color change detection task indicates that there is a strong component of task-related processing of these features.

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