Biology subjects

Matic, K.

Publications and source records attributed to Matic, K..

4 recordsLinked to original sources

bioRxiv2026

Clutter does not affect the spatial tuning of * category representations in human object-selective cortex *

Natural vision is frequently impaired when the visual field is crowded with multiple competing objects. One common interpretation of this clutter interference is that large receptive fields in high-level visual cortex make it hard to separate objects from their surround. This view predicts less interference for spatially localized representations; therefore, classifiers trained under clutter might rely more on such localized representations. Here we tested this by measuring participants brain signals with fMRI while they viewed objects presented either alone or within cluttered arrays. Consistent with prior work, category decoding accuracy was significantly reduced in clutter. However, classifiers trained directly on cluttered displays were not spatially more localized. Instead, they generalized robustly across spatial positions, comparable to classifiers trained on isolated objects. This finding challenges the idea that clutter preferentially disrupts position-tolerant representations.

neuroscience↗

bioRxiv2025

Visual working memory representations of naturalistic images in early visual cortex are not sensory-like

For a long time, working memory was considered to reflect sustained activity in prefrontal and parietal areas. This has been challenged by the "sensory recruitment model" according to which sensory areas are involved in maintaining working memory representations. The main support for this comes from the finding that working memory contents can be decoded from early sensory areas during memory delay periods. However, the availability of stimulus-related information in sensory regions does not reveal whether this information is encoded in a sensory format, i.e. in the same way as sensory stimuli. Alternatively, working memory contents could be encoded in independent formats or even potentially undergo dynamic changes throughout the delay. Here, we test this question directly by requiring participants to briefly memorise naturalistic object-scenes. We directly compared the way early visual regions encoded the contents during perception and working memory maintenance. As in previous studies, we found robust stimulus-related information in early visual cortex throughout the delay. However, despite continuously robust information, the encoding of memory contents in the later delay period did not occur in the same format as during pure perception. Thus, despite the fact that sensory areas have working-memory-related information, the format of this information is not strictly sensory-like throughout the delay.

neuroscience↗

bioRxiv2024

Temporal dynamics and readout latency in perception and iconic memory

Following the offset of complex visual stimuli, rich stimulus information remains briefly available to the observer, reflecting a rapidly decaying iconic memory trace. Traditionally, iconic memory decay is assumed to begin with stimulus offset. Instead, here we found that available information begins decaying already when cues are presented in the final stage of stimulus presentation. Using closely spaced ("micro-timed") readout cues and a theoretical model of information availability, we observed that a cue has to be presented around 10-30 milliseconds before stimulus offset in order to access the full sensory information. We suggest that this does not reflect an early loss in sensory encoding, but instead it is a consequence of a latency in the processing of the cue which postpones the readout of the sensory representation by 10-30 milliseconds. Our analysis also shows that spatial proximity of items in complex arrays impacts sensory representation during both perceptual encoding and initial memory decay. Overall, these results provide a theoretical and empirical characterization of the readout from visual representations, and offer a detailed insight into the transition from perception into iconic memory.

neuroscience↗

bioRxiv2019

Prospective and retrospective contributions to intention awareness in voluntary action

Spontaneous, voluntary actions are often accompanied by motor intentions, that is the experience of \"being about to move\". The emergence of this experience is contentiously discussed, culminating in two opposing views of motor intention. While prospective theorists hold that an intention to move genuinely precedes the action, retrospective theorists suggest that an intention is reconstructed only after action execution. As such, both theories offer radically different predictions about the possibility of voluntary control over action intention. We assess here the respective contributions of prospective and retrospective factors in motor intention awareness in a real-time EEG setup. Participants performed self-paced movements with intermittent interruption by cues, signalling to either move or not to move. Cues were triggered by a brain-computer interface upon detection of either the presence or absence of a readiness potential (RP), a signal known to precede self-paced voluntary actions. Subsequently, participants reported their intention to move at the time of the cue. We found that participants were more likely to report an intention to move when the cue was followed by a movement than no movement, highlighting the effect of retrospection on awareness of intention. Interestingly, however, an intention to move was also more frequently reported when the cue was elicited by an RP, compared to when no RP was present, suggesting that awareness of intention is also informed by motor preparation processes, congruent with prospective theories. Overall, our findings show that intention awareness in voluntary action relies on both prospective and retrospective components, and we describe here how these two factors are dynamically integrated over time.

neuroscience↗