scholarly journals Measures of repetition suppression in the Fusiform Face Area are inflated by co-occurring effects of statistically learned visual associations

2019 ◽  
Author(s):  
Sophie-Marie Rostalski ◽  
Catarina Amado ◽  
Gyula Kovács ◽  
Daniel Feuerriegel

AbstractRepeated presentation of a stimulus leads to reductions in measures of neural responses. This phenomenon, termed repetition suppression (RS), has recently been conceptualized using models based on predictive coding, which describe RS as due to expectations that are weighted toward recently-seen stimuli. To evaluate these models, researchers have manipulated the likelihood of stimulus repetition within experiments. They have reported findings that are inconsistent across hemodynamic and electrophysiological measures, and difficult to interpret as clear support or refutation of predictive coding models. We instead investigated a different type of expectation effect that is apparent in stimulus repetition experiments: the difference in one’s ability to predict the identity of repeated, compared to unrepeated, stimuli. In previous experiments that presented pairs of repeated or alternating images, once participants had seen the first stimulus image in a pair, they could form specific expectations about the repeated stimulus image. However they could not form such expectations for the alternating image, which was often randomly chosen from a large stimulus set. To assess the contribution of stimulus predictability effects to previously observed RS, we measured BOLD signals while presenting pairs of repeated and alternating faces. This was done in contexts whereby stimuli in alternating trials were either i.) predictable through statistically learned associations between pairs of stimuli or ii.) chosen randomly and therefore unpredictable. We found that RS in the right FFA was much larger in trials with unpredictable compared to predictable alternating faces. This was primarily due to unpredictable alternating stimuli evoking larger BOLD signals than predictable alternating stimuli. We show that imbalances in stimulus predictability across repeated and alternating trials can greatly inflate measures of RS, or even mimic RS effects. Our findings also indicate that stimulus-specific expectations, as described by predictive coding models, may account for a sizeable portion of observed RS effects.


2017 ◽  
Author(s):  
Travis Meyer ◽  
Nicole C. Rust

AbstractOur visual memory percepts of whether we have encountered specific objects or scenes before are hypothesized to manifest as decrements in neural responses in inferotemporal cortex (IT) with stimulus repetition. To evaluate this proposal, we recorded IT neural responses as two monkeys performed a single-exposure visual memory task designed to measure the rates of forgetting with time. We found that a weighted linear read-out of IT was a better predictor of the monkeys’ forgetting rates and reaction time patterns than a strict instantiation of the repetition suppression hypothesis, expressed as a total spike count scheme. Behavioral predictions could be attributed to visual memory signals that were reflected as repetition suppression and were intermingled with visual selectivity, but only when combined across the most sensitive neurons.



2017 ◽  
Author(s):  
Matthew F. Tang ◽  
Cooper A. Smout ◽  
Ehsan Arabzadeh ◽  
Jason B. Mattingley

AbstractPredictive coding theories argue that recent experience establishes expectations in the brain that generate prediction errors when violated. Prediction errors provide a possible explanation for repetition suppression, where evoked neural activity is attenuated across repeated presentations of the same stimulus. The predictive coding account argues repetition suppression arises because repeated stimuli are expected, whereas non-repeated stimuli are unexpected and thus elicit larger neural responses. Here we employed electroencephalography in humans to test the predictive coding account of repetition suppression by presenting sequences of visual gratings with orientations that were expected either to repeat or change in separate blocks of trials. We applied multivariate forward modelling to determine how orientation selectivity was affected by repetition and prediction. Unexpected stimuli were associated with significantly enhanced orientation selectivity, whereas selectivity was unaffected for repeated stimuli. Our results suggest that repetition suppression and expectation have separable effects on neural representations of visual feature information.



2020 ◽  
Author(s):  
Stephen J. Gotts ◽  
Shawn C. Milleville ◽  
Alex Martin

SummaryStimulus identification commonly improves with repetition over long delays (“repetition priming”), whereas neural activity commonly decreases (“repetition suppression”). Multiple models have been proposed to explain this brain-behavior relationship, predicting alterations in functional and/or effective connectivity (Synchrony and Predictive Coding models), in the latency of neural responses (Facilitation model), and in the relative similarity of neural representations (Sharpening model). Here, we test these predictions with fMRI during overt and covert naming of repeated and novel objects. While we find partial support for predictions of the Facilitation and Sharpening models in the left fusiform gyrus and left frontal cortex, the strongest support was observed for the Synchrony model, with increased coupling between right temporoparietal and anterior cingulate cortex for repeated objects that correlated with priming magnitude across participants. Despite overlap with regions showing repetition suppression, increased coupling and repetition suppression varied independently, establishing that they follow from distinct mechanisms.HighlightsTested four prominent neural models of repetition suppression and long-term primingConnectivity analyses supported Synchrony model but not Predictive Coding modelTiming, spatial similarity of responses partially support Facilitation, SharpeningRepetition suppression was independent of coupling, implying distinct mechanismseTOCGotts et al. test four prominent neural models of repetition suppression and behavioral priming. They show that the model with the most support is the Synchrony model: a whole-brain connectivity analysis revealed that temporoparietal cortex has increased coupling with anterior cingulate cortex following repetition, particularly for strongly primed objects.



2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stephen J. Gotts ◽  
Shawn C. Milleville ◽  
Alex Martin

AbstractStimulus identification commonly improves with repetition over long delays (“repetition priming”), whereas neural activity commonly decreases (“repetition suppression”). Multiple models have been proposed to explain this brain-behavior relationship, predicting alterations in functional and/or effective connectivity (Synchrony and Predictive Coding models), in the latency of neural responses (Facilitation model), and in the relative similarity of neural representations (Sharpening model). Here, we test these predictions with fMRI during overt and covert naming of repeated and novel objects. While we find partial support for predictions of the Facilitation and Sharpening models in the left fusiform gyrus and left frontal cortex, the data were most consistent with the Synchrony model, with increased coupling between right temporoparietal and anterior cingulate cortex for repeated objects that correlated with priming magnitude across participants. Increased coupling and repetition suppression varied independently, each explaining unique variance in priming and requiring modifications of all current models.



2019 ◽  
Author(s):  
Jon Walbrin ◽  
Ioana Mihai ◽  
Julia Landsiedel ◽  
Kami Koldewyn

AbstractRecent evidence demonstrates that a region of the posterior superior temporal sulcus (pSTS) is selective to visually observed social interactions in adults. In contrast, we know comparatively little about neural responses to social interactions in children. Here, we used fMRI to ask whether the pSTS would be ‘tuned’ to social interactions in children at all, and if so, how selectivity might differ from adults. This was investigated not only in the pSTS, but also in socially-tuned regions in neighbouring temporal cortex: extrastriate body area (EBA), face-selective STS (STS-F), fusiform face area (FFA), and temporo-parietal junction (TPJ-M).Both children and adults showed selectivity to social interaction within right pSTS, while only adults showed selectivity on the left. Adults also showed both more focal and greater selectivity than children (6–12 years) bilaterally. Exploratory sub-group analyses showed that younger children (6–8 years), but not older children (9-12), are less selective than adults on the right, while there was a developmental trend (adults > older > younger) in left pSTS. These results suggest that, over development, the neural response to social interactions is characterized by increasingly more selective, more focal and more bilateral pSTS responses, a process that likely continues into adolescence.HighlightsChildren show less interaction selectivity in the pSTS than adultsAdults show bilateral pSTS selectivity, while children are more right-lateralizedExploratory findings suggest interaction selectivity in pSTS is more focally tuned in adults



eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Matthew F Tang ◽  
Cooper A Smout ◽  
Ehsan Arabzadeh ◽  
Jason B Mattingley

Predictive coding theories argue that recent experience establishes expectations in the brain that generate prediction errors when violated. Prediction errors provide a possible explanation for repetition suppression, where evoked neural activity is attenuated across repeated presentations of the same stimulus. The predictive coding account argues repetition suppression arises because repeated stimuli are expected, whereas non-repeated stimuli are unexpected and thus elicit larger neural responses. Here, we employed electroencephalography in humans to test the predictive coding account of repetition suppression by presenting sequences of visual gratings with orientations that were expected either to repeat or change in separate blocks of trials. We applied multivariate forward modelling to determine how orientation selectivity was affected by repetition and prediction. Unexpected stimuli were associated with significantly enhanced orientation selectivity, whereas selectivity was unaffected for repeated stimuli. Our results suggest that repetition suppression and expectation have separable effects on neural representations of visual feature information.



1999 ◽  
Vol 4 (1) ◽  
pp. 6-7
Author(s):  
James J. Mangraviti

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.



2020 ◽  
Vol 6 (2) ◽  
pp. 187-197
Author(s):  
Nurlaila Suci Rahayu Rais ◽  
Dedeh Apriyani ◽  
Gito Gardjito

Monitoring of warehouse inventory data processing is an important thing for companies. PT Talaga mulya indah is still manual using paper media, causing problems that have an effect on existing information, namely: problems with data processing of incoming and outgoing goods. And the difference between data on the amount of stock of goods available with physical data, often occurs inputting data more than once for the same item, searching for available data, and making reports so that it impedes companies in monitoring inventory of existing stock of goods. Which aims to create a system that can provide updated information to facilitate the warehouse admin in making inventory reports, and reduce errors in input by means of integrated control. In this study, the authors used the data collection method used in this analysis using the method of observation, interviews, and literature review (literature study). For analysis using the PIECES analysis method. Furthermore, the system design used is UML (Unified Modeling Language). The results of this study are expected to produce the right data in the process of monitoring inventory data processing, also can provide the right information and make it easier to control the overall availability of goods.



2013 ◽  
Vol 3 (2) ◽  
pp. 438-473
Author(s):  
M. Heri Fadoil

Abstract: Abdul Karim Soroush judges that religious rule is incorrect assessment of the application of Islamic jurisprudence. In a religious society, Islamic jurisprudence obtains the right to govern. It is, of course, necessary to establish a kind of Islamic jurisprudence-based religious rule. Soroush firmly rejects it because such interpretation is too narrow. As for democracy, Soroush argues that the system used is not necessarily equal to that of the Western. On the contrary, Ayatollah Khomeini’s thoughts on religious rule are reflected in the so called wilayat al-faqih. It is a religious scholar-based government. Democracy, according to him, is the values of Islam itself, which is able to represent the level of a system to bring to the country’s progress. Principally, there are some similarities between the ideas of Ayatollah Khomeini and those of Abdul Karim Soroush in term of religiosity. They assume that it is able to sustain the religious system of government. The difference between both lies on the application of religiosity itself. Ayatollah Khomeini applies the concept of a religious scholar-based government, while Abdul Karim Soroush rejects the institutionalization of religion in the government or state.Keywords: Governance, democracy, Abdul Karim Soroush, Ayatollah Khomeini



Author(s):  
Anne Phillips

No one wants to be treated like an object, regarded as an item of property, or put up for sale. Yet many people frame personal autonomy in terms of self-ownership, representing themselves as property owners with the right to do as they wish with their bodies. Others do not use the language of property, but are similarly insistent on the rights of free individuals to decide for themselves whether to engage in commercial transactions for sex, reproduction, or organ sales. Drawing on analyses of rape, surrogacy, and markets in human organs, this book challenges notions of freedom based on ownership of our bodies and argues against the normalization of markets in bodily services and parts. The book explores the risks associated with metaphors of property and the reasons why the commodification of the body remains problematic. The book asks what is wrong with thinking of oneself as the owner of one's body? What is wrong with making our bodies available for rent or sale? What, if anything, is the difference between markets in sex, reproduction, or human body parts, and the other markets we commonly applaud? The book contends that body markets occupy the outer edges of a continuum that is, in some way, a feature of all labor markets. But it also emphasizes that we all have bodies, and considers the implications of this otherwise banal fact for equality. Bodies remind us of shared vulnerability, alerting us to the common experience of living as embodied beings in the same world. Examining the complex issue of body exceptionalism, the book demonstrates that treating the body as property makes human equality harder to comprehend.



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