Conceptual Object Representations Research Articles

Classifier categories reflect but do not affect conceptual organization.

Do we structure object-related conceptual information according to real-world sensorimotor experience, or can it also be shaped by linguistic information? This study investigates whether a feature of language coded in grammar-numeral classifiers-affects the conceptual representation of objects. We compared speakers of Mandarin (a classifier language) with speakers of Dutch (a language without classifiers) on how they judged object similarity in 4 studies. In the first 3 studies, participants had to rate how similar a target object was to 4 comparison objects, 1 of which shared a classifier with the target. Objects were presented as either words or pictures. Overall, the target object was always rated as most similar to the object with the shared classifier, but this was the case regardless of the language of the participant. In a final study using a successive pile-sorting task, we also found that the underlying object concepts were similar for speakers of Mandarin and Dutch. Speakers of a nonclassifier language are therefore sensitive to the same conceptual similarities that underlie classifier systems in a classifier language. Classifier systems may therefore reflect conceptual structure, rather than shape it. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Untangling featural and conceptual object representations

How are visual inputs transformed into conceptual representations by the human visual system? The contents of human perception, such as objects presented on a visual display, can reliably be decoded from voxel activation patterns in fMRI, and in evoked sensor activations in MEG and EEG. A prevailing question is the extent to which brain activation associated with object categories is due to statistical regularities of visual features within object categories. Here, we assessed the contribution of mid-level features to conceptual category decoding using EEG and a novel fast periodic decoding paradigm. Our study used a stimulus set consisting of intact objects from the animate (e.g., fish) and inanimate categories (e.g., chair) and scrambled versions of the same objects that were unrecognizable and preserved their visual features (Long et al., 2018). By presenting the images at different periodic rates, we biased processing to different levels of the visual hierarchy. We found that scrambled objects and their intact counterparts elicited similar patterns of activation, which could be used to decode the conceptual category (animate or inanimate), even for the unrecognizable scrambled objects. Animacy decoding for the scrambled objects, however, was only possible at the slowest periodic presentation rate. Animacy decoding for intact objects was faster, more robust, and could be achieved at faster presentation rates. Our results confirm that the mid-level visual features preserved in the scrambled objects contribute to animacy decoding, but also demonstrate that the dynamics vary markedly for intact versus scrambled objects. Our findings suggest a complex interplay between visual feature coding and categorical representations that is mediated by the visual system’s capacity to use image features to resolve a recognisable object.

Electrophysiological study of action-affordance priming between object names

If our central representation of an object is defined through embodied experience, we might expect access to action affordances to be privileged over more abstract concepts. We used event-related potentials to examine the relative time course of access to affordances. Written object names were primed with the name of an object sharing the same affordance as the target (e.g. precision-grip: “grape” primed by “tweezers”) or the same taxonomic category (e.g. fruit: “grape” primed by “apple”). N200 latencies, related to go/nogo semantic category decisions on target words, revealed no difference in facilitation provided by affordance and semantic priming. However, separate analyses of ERPs for go and nogo trials showed that semantic priming led to earlier activation during go trials (around 430 ms), and affordance priming led to earlier activation during nogo trials (around 180 ms). While affordances appear to be peripheral to the conceptual representation of objects, they do lead to direct motor preparation.

The temporal evolution of conceptual object representations revealed through models of behavior, semantics and deep neural networks

Visual object representations are commonly thought to emerge rapidly, yet it has remained unclear to what extent early brain responses reflect purely low-level visual features of these objects and how strongly those features contribute to later categorical or conceptual representations. Here, we aimed to estimate a lower temporal bound for the emergence of conceptual representations by defining two criteria that characterize such representations: 1) conceptual object representations should generalize across different exemplars of the same object, and 2) these representations should reflect high-level behavioral judgments. To test these criteria, we compared magnetoencephalography (MEG) recordings between two groups of participants (n = 16 per group) exposed to different exemplar images of the same object concepts. Further, we disentangled low-level from high-level MEG responses by estimating the unique and shared contribution of models of behavioral judgments, semantics, and different layers of deep neural networks of visual object processing. We find that 1) both generalization across exemplars as well as generalization of object-related signals across time increase after 150 ms, peaking around 230 ms; 2) representations specific to behavioral judgments emerged rapidly, peaking around 160 ms. Collectively, these results suggest a lower bound for the emergence of conceptual object representations around 150 ms following stimulus onset.

Neural representations of novel objects associated with olfactory experience

Object conceptual knowledge comprises information related to several motor and sensory modalities (e.g. for tools, how they look like, how to manipulate them). Whether and to which extent conceptual object knowledge is represented in the same sensory and motor systems recruited during object-specific learning experience is still a controversial question. A direct approach to assess the experience-dependence of conceptual object representations is based on training with novel objects. The present study extended previous research, which focused mainly on the role of manipulation experience for tool-like stimuli, by considering sensory experience only. Specifically, we examined the impact of experience in the non-dominant olfactory modality on the neural representation of novel objects. Sixteen healthy participants visually explored a set of novel objects during the training phase while for each object an odor (e.g., peppermint) was presented (olfactory-visual training). As control conditions, a second set of objects was only visually explored (visual-only training), and a third set was not part of the training. In a post-training fMRI session, participants performed an old/new task with pictures of objects associated with olfactory-visual and visual-only training (old) and no training objects (new). Although we did not find any evidence of activations in primary olfactory areas, the processing of olfactory-visual versus visual-only training objects elicited greater activation in the right anterior hippocampus, a region included in the extended olfactory network. This finding is discussed in terms of different functional roles of the hippocampus in olfactory processes.

Multisensory Interactions between Auditory and Haptic Object Recognition

Object manipulation produces characteristic sounds and causes specific haptic sensations that facilitate the recognition of the manipulated object. To identify the neural correlates of audio-haptic binding of object features, healthy volunteers underwent functional magnetic resonance imaging while they matched a target object to a sample object within and across audition and touch. By introducing a delay between the presentation of sample and target stimuli, it was possible to dissociate haptic-to-auditory and auditory-to-haptic matching. We hypothesized that only semantically coherent auditory and haptic object features activate cortical regions that host unified conceptual object representations. The left fusiform gyrus (FG) and posterior superior temporal sulcus (pSTS) showed increased activation during crossmodal matching of semantically congruent but not incongruent object stimuli. In the FG, this effect was found for haptic-to-auditory and auditory-to-haptic matching, whereas the pSTS only displayed a crossmodal matching effect for congruent auditory targets. Auditory and somatosensory association cortices showed increased activity during crossmodal object matching which was, however, independent of semantic congruency. Together, the results show multisensory interactions at different hierarchical stages of auditory and haptic object processing. Object-specific crossmodal interactions culminate in the left FG, which may provide a higher order convergence zone for conceptual object knowledge.

Neuronal correlates of repetition priming of familiar and unfamiliar visual objects: evidence from fMRI and MEG

Event Abstract Back to Event Neuronal correlates of repetition priming of familiar and unfamiliar visual objects: evidence from fMRI and MEG Uwe Friese1*, Benjamin Rahm2, Jochen Kaiser2 and Thomas Gruber1 1 University of Osnabrück, Germany 2 Gutenberg University, Germany Visual object recognition has been studied with various neuroimaging approaches including methods based on hemodynamic brain responses and electrophysiological measures. A common finding is the attenuation of brain activity during the processing of repeated stimuli in distributed cortical regions – a phenomenon often called repetition suppression. Due to differences in measuring modalities, experimental tasks, and procedures it is, however, difficult to compare previously published results directly. We conducted identical experiments with MEG and fMRI, respectively. Participants were repeatedly confronted with images of familiar and unfamiliar objects. Familiarity and repetition modulated fMRI-BOLD activity most prominently in bilateral occipito-temporal regions including the fusiform cortices. These regions have been associated with the processing of conceptual object representations in numerous fMRI studies. In the MEG study, we focused on the analysis of induced gamma band activity (iGBA) since synchronized oscillations in the gamma band range play an important role for the integration of distributed object representations. Source localization of iGBA revealed effects of familiarity and repetition in occipital and parietal cortex areas, partially overlapping with occipital regions found in the fMRI study. Both, the suppression of the BOLD signal and of iGBA are interpreted as a “sharpening” within cortical object representations which results in more efficient stimulus processing (i.e. priming). Our results demonstrate that while some overlap occurred for fMRI-BOLD and MEG-iGBA, each of the two methods might be sensitive to differential aspects of visual object processing. Keywords: fMRI, Memory Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Neural Bases of Memory and Learning Citation: Friese U, Rahm B, Kaiser J and Gruber T (2011). Neuronal correlates of repetition priming of familiar and unfamiliar visual objects: evidence from fMRI and MEG. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00421 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Uwe Friese, University of Osnabrück, Osnabrück, Germany, ufriese@uos.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Uwe Friese Benjamin Rahm Jochen Kaiser Thomas Gruber Google Uwe Friese Benjamin Rahm Jochen Kaiser Thomas Gruber Google Scholar Uwe Friese Benjamin Rahm Jochen Kaiser Thomas Gruber PubMed Uwe Friese Benjamin Rahm Jochen Kaiser Thomas Gruber Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effect of lamotrigine on cognition in children with epilepsy

<h3>Abstract</h3> Colour is a defining feature of many objects, playing a crucial role in our ability to rapidly recognise things in the world around us and make categorical distinctions. For example, colour is a vital cue when distinguishing lemons from limes or blackberries from raspberries. That means our representation of many objects includes key colour-related information. The question addressed here is whether the neural representation activated by <i>knowing</i> that something is red is the same as that activated when we <i>actually see</i> something red, particularly in regard to timing. We addressed this question using neural timeseries (magnetoencephalography, MEG) data to contrast real colour perception and implied object colour activation. We applied multivariate pattern analysis (MVPA) to focus, in particular, on the temporal dynamics of these processes. Male and female human participants (N=18) viewed isoluminant red and green shapes and grey-scale, luminance-matched pictures of fruits and vegetables that are red (e.g., tomato) or green (e.g., kiwifruit) in nature. We show that the brain activation pattern evoked by real colour perception is similar to implied colour activation, but that this pattern is instantiated at a later time. Similarly, participants were faster at categorising the colour of an abstract shape than they were at categorising the typical colour of grey-scale objects. Together, these results demonstrate that a common colour representation can be triggered by activating object representations from memory and perceiving colours. We show here that the key difference between these processes lies in the time it takes to access the common colour representation. <h3>Significance Statement</h3> Colour is a defining feature of objects and is vital to rapidly recognise and categorise things in our environment. In the current study, we recorded neural data to contrast the <i>timecourse</i> of colour representations when evoked by colour perception versus object-colour activation. We found that the neural representation for coloured shapes is similar to that of grey-scale images of objects that are associated with a colour (e.g., red for a tomato). However, the common colour representation is activated later when accessed via object-colour knowledge in comparison to colour perception, consistent with the idea that they are evoked when the object representation is accessed. These results highlight the critical role of perceptual features such as colour in conceptual object representations.

Quantitative perceptual representation of prepositional semantics

In this paper we concentrate on spatial prepositions, more specifically we are interested here in projective prepositions (eg. “in front of”, “to the left of”) which have in the past been treated as semantically uninteresting. We demonstrate that projective prepositions are in fact problematic and demand more attention than they have so far been afforded; after summarising the important components of their meaning, we review the deficiencies of past and current approaches to the decoding problem; that is, predicting what a locative expression used in a particular situation conveys. Finally we present our own approach. Motivated by the shortcomings of contemporary work, we integrate elements of Lang's conceptual representation of objects' perceptual and dimensional characteristics, and the potential field model of object proximity that originated in manipulator and mobile robot path-finding.