Biology subjects

Aliko, S.

Publications and source records attributed to Aliko, S..

4 recordsLinked to original sources

bioRxiv2025

Situation Models in the Brain are Used to Resolve Word References

Resolving the meaning of a pronoun requires retrieving information about a unique individual (a referent) from many remembered experiences and inferences throughout sensory and cognitive modalities, from vision and audition to episodic memory and social cognition. Here, we hypothesize that the functional neuroanatomy of pronoun interpretation involves interaction across distributed neural networks, during which each referent activates its own unique sensorimotor neural fingerprint associated with these experiences. To test this hypothesis, we collected fMRI data from 20 people watching a full-length movie, and developed a 3D branched convolutional neural network to distinguish movie characters from the fMRI signal across distributed sensorimotor regions. The same model distinguished the characters referenced by pronouns, using these same sensorimotor regions, supplemented by the hippocampus, precuneus, and medial prefrontal cortices. This work has far-reaching implications for understanding the relations among the many domains and modalities of neural representation required for ecological language comprehension. In particular, the demonstration that situation models, implemented in distributed sensory-motor and association cortices, are involved in resolving reference, suggests a whole brain distribution for language processing.

neuroscience↗

bioRxiv2023

The entire brain, more or less is at work: 'Language regions' are artefacts of averaging

Models of the neurobiology of language suggest that a small number of anatomically fixed brain regions are responsible for language functioning. This derives from centuries of aphasia studies and decades of neuroimaging. The latter rely on thresholded measures of central tendency applied to activity patterns from heterogeneous stimuli. We hypothesised that these methods obscure the whole brain distribution of regions supporting language. Specifically, language regions are connectivity hubs, coordinating varying peripheral activity that averages out following thresholding. We tested this with neuroimaging meta-analyses and movie-fMRI. Results show that words localise to language regions when averaged but are distributed throughout the brain when examining specific linguistic representations. These language regions are partially connectivity hubs that are spatiotemporally dynamic, making connections with [~]40% of the brain periphery outside those regions, and only appearing in the aggregate over time. Hub-periphery connections encode linguistic representations, not the language regions alone. Results replicate with audiobook-fMRI. Finally, intracranial neuronal recordings support findings, showing language regions are hub-like, with linguistic representations decodable throughout the brain. Together, these four studies suggest that language regions are artefacts of averaging heterogeneous language representations. Instead, they are connectivity hubs coordinating whole-brain distributed network representations, suggesting why their damage results in aphasia.

neuroscience↗

bioRxiv2020

Reorganization of the neurobiology of language after sentence overlearning

There is a widespread assumption that there are a static set of language regions in the brain. Yet, people still regularly produce familiar formulaic expressions when those regions are severely damaged. This suggests that the neurobiology of language varies with the extent of word sequence learning and might not be fixed. We test the hypothesis that perceiving sentences is mostly supported by sensorimotor regions involved in speech production and not language regions after overlearning. Twelve participants underwent two sessions of behavioural testing and functional magnetic resonance imaging (fMRI), separated by 15 days. During this period, they repeated two sentences 30 times each, twice a day. In both fMRI sessions, participants passively listened to those two sentences and novel sentences. Lastly, they spoke novel sentences. Behavioural results confirm that participants overlearned sentences. Correspondingly, there was an increase or recruitment of sensorimotor regions involved in sentence production and a reduction in activity or inactivity for overlearned sentences in regions involved in listening to novel sentences. The global network organization of the brain changed by [~]45%, mostly through lost connectivity. Thus, there was a profound reorganization of the neurobiology of speech perception after overlearning towards sensorimotor regions not considered in most contemporary models and away from the language regions posited by those models. These same sensorimotor regions are generally preserved in aphasia and Alzheimers disease, perhaps explaining residual abilities with formulaic language. These and other results warrant reconsidering static neurobiological models of language.

neuroscience↗

bioRxiv2020

A 'Naturalistic Neuroimaging Database' for understanding the brain using ecological stimuli

Neuroimaging has advanced our understanding of human psychology using reductionist stimuli that often do not resemble information the brain naturally encounters. It has improved our understanding of the network organization of the brain mostly through analyses of resting-state data for which the functions of networks cannot be verifiably labelled. We make a Naturalistic Neuroimaging Database (NNDb v1.0) publically available to allow for a more complete understanding of the brain under more ecological conditions during which networks can be labelled. Eighty-six participants underwent behavioural testing and watched one of 10 full-length movies while functional magnetic resonance imaging was acquired. Resulting timeseries data are shown to be of high quality, with good signal-to-noise ratio, few outliers and low movement. Data-driven functional analyses provide further evidence of data quality. They also demonstrate accurate timeseries/movie alignment and how movie annotations might be used to label networks. The NNDb can be used to answer questions previously unaddressed with standard neuroimaging approaches, progressing our knowledge of how the brain works in the real world.

neuroscience↗