Hippocampal representations switch from errors to predictions during acquisition of predictive associations

Aitken, Fraser; Kok, Peter

doi:10.1101/2021.09.21.461228

Cited by 4 publications

(3 citation statements)

References 110 publications

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“…Despite the expectation cues not affecting perception, they did induce stimulus-specific templates in the deep layers of the early visual cortex, in line with previous work 38 . Strikingly, this effect was reliable even in those who were not aware of the cue-stimulus relationship, which suggests that the brain can generate sensory expectations based on statistical relationships that are learnt outside of conscious awareness 71 (Aitken & Kok, 2022). The finding that stimulus-specific deep layer activity might not be sufficient to generate a conscious percept seems in conflict with theories that emphasise the importance of deep layer activity in generating conscious percepts 72,73 .…”

Section: Discussionmentioning

confidence: 99%

Perceptual expectations and false percepts generate stimulus-specific activity in distinct layers of the early visual cortex

Haarsma

Deveci

Corbin

et al. 2022

Preprint

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Popular theories suggest that hallucinations arise through excessive top-down perceptual expectations, whereas others have emphasised the role of spontaneous bottom-up activity. These theories make different predictions about how input and feedback layers in sensory regions contribute to hallucinations. Here, we used layer-specific fMRI to interrogate neural activity underlying hallucinations - high confidence false percepts - and perceptual expectations while healthy participants (N=25) performed a perceptual discrimination task. We found that false percepts were related to stimulus-like activity in the middle input layers of V2. On the other hand, perceptual expectations activated the deep feedback layers of V2, without influencing perception. The prevalence of high confidence false percepts was related to everyday hallucination severity, confirming their ecological validity. These results reveal that hallucinations can arise through spontaneous stimulus-specific activity in the input layers of the visual cortex, independent of top-down perceptual expectations.

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Section: Discussionmentioning

confidence: 99%

Perceptual expectations and false percepts generate stimulus-specific activity in distinct layers of the early visual cortex

Haarsma

Deveci

Corbin

et al. 2022

Preprint

Self Cite

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“…Third, our scope was limited to the temporal domain, and questions arise regarding potential differences between brain regions. Internal predictions have been generally associated with the hippocampus (Aitken & Kok, 2022; de Lange et al, 2018; Hindy et al, 2016; Stachenfeld et al, 2017), which has a location that challenges EEG sensitivity. Further studies should employ more spatially sensitive techniques.…”

Section: Discussionmentioning

confidence: 99%

Top-down specific preparatory activations for Selective Attention and Perceptual Expectations

Peñalver

López-García

González-García

et al. 2022

Preprint

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SummaryProactive cognition brain models are mainstream nowadays. Within these, preparation is understood as an endogenous, top-down function that takes place prior to the actual perception of a stimulus and improves subsequent behavior. Neuroimaging has uncovered the existence of such preparatory activity in different cognitive domains, however no research to date has sought to uncover their potential similarities and differences. Two of these domains, often confounded in the literature, are Selective Attention (information relevance) and Perceptual Expectation (information probability). We used EEG to characterize the mechanisms that support preparation in Attention and Expectation. In different blocks, participants were cued to the relevance or to the probability of target categories, faces vs. names in a gender discrimination task. Multivariate Pattern (MVPA) and Representational Similarity Analyses (RSA) during the preparation window showed that both manipulations led to a significant, ramping-up prediction of the relevant or expected target category. However, classifiers trained on data from one condition did not generalize to the other, indicating the existence of different anticipatory neural patterns. Further analyses pointed to a differential involvement of specific frequency bands in each condition. Finally, a Canonical Template Tracking procedure showed that there was stronger perceptual reinstatement for Attention than for Expectation. Overall, results indicate that preparation during attention and expectation acts through different, although partially overlapping, neural mechanisms. These findings have important implications for current models of brain functioning, as they are a first step towards characterizing and dissociating the neural mechanisms involved in top-down anticipatory processing.

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“…A number of studies have decoded visual content that is predicted on the basis of simple auditory cues from hippocampal BOLD patterns (Aitken and Kok, 2021;Kok et al, 2020;Kok and Turk-Browne, 2018). Predicted visual content can also be decoded from hippocampus when that prediction is triggered by auditory cues on the basis of semantic knowledge.…”

Section: Auditory Sequences and Predictionsmentioning

confidence: 99%

The hearing hippocampus

Billig¹,

Lad²,

Sedley³

et al. 2022

Preprint

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The hippocampus has a well-established role in spatial and episodic memory but a broader function has been proposed including aspects of perception and relational processing. Neural bases of sound analysis have been described in the pathway to auditory cortex, but wider networks supporting auditory cognition are still being established. We review what is known about the role of the hippocampus in processing auditory information, and how the hippocampus itself is shaped by sound. In examining imaging, recording, and lesion studies in species from rodents to humans, we uncover a hierarchy of hippocampal responses to sound including during passive exposure, active listening, and the learning of associations between sounds and other stimuli. We describe how the hippocampus' connectivity and computational architecture allow it to track and manipulate auditory information – whether in the form of speech, music, or environmental, emotional, or phantom sounds. Functional and structural correlates of auditory experience are also identified. The extent of auditory-hippocampal interactions is consistent with the view that the hippocampus makes broad contributions to perception and cognition, beyond spatial and episodic memory. More deeply understanding these interactions may unlock applications including entraining hippocampal rhythms to support cognition, and intervening in links between hearing loss and dementia.

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Hippocampal representations switch from errors to predictions during acquisition of predictive associations

Cited by 4 publications

References 110 publications

Perceptual expectations and false percepts generate stimulus-specific activity in distinct layers of the early visual cortex

Perceptual expectations and false percepts generate stimulus-specific activity in distinct layers of the early visual cortex

Top-down specific preparatory activations for Selective Attention and Perceptual Expectations

The hearing hippocampus

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