Fundamental constraints on distinguishing reality from imagination

Опубликована: Июль 1, 2021

Humans are voracious imaginers, with internal simulations supporting memory, planning and decision-making. Because the neural mechanisms imagination overlap those perception, a foundational question is how reality kept apart. Traditional psychology experiments struggle to investigate this issue as subjects can rapidly learn that real stimuli in play. Here we capitalised on ability conduct large-scale, one-trial-per-participant psychophysics via online platforms combined computational modelling neuroimaging perceptual monitoring failures general population. We find striking evidence for subjective intermixing of – both behaviourally neurally. Our data best explained by model evaluates total strength intermixed imagined perceived signals against “reality threshold” determine whether it reflects reality. These findings suggest not separate, nor intention imagine used identity discount self-generated signals. Instead, judgment based intensity intermixture between A consequence account predicts when virtual or strong enough, they become indistinguishable from

Язык: Английский

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Sensory processing in humans and mice fluctuates between external and internal modes

PLoS Biology, Год журнала: 2023, Номер 21(12), С. e3002410 - e3002410

Опубликована: Дек. 8, 2023

Perception is known to cycle through periods of enhanced and reduced sensitivity external information. Here, we asked whether such slow fluctuations arise as a noise-related epiphenomenon limited processing capacity or, alternatively, represent structured mechanism perceptual inference. Using 2 large-scale datasets, found that humans mice alternate between externally internally oriented modes sensory analysis. During mode, perception aligns more closely with the information, whereas internal mode characterized by biases toward history. Computational modeling indicated dynamic changes in are enabled interlinked factors: (i) integration subsequent inputs over time (ii) antiphase oscillations impact information versus predictions provided We propose between-mode generate unambiguous error signals enable optimal inference volatile environments.

Язык: Английский

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Expectation Cues and False Percepts Generate Stimulus-Specific Activity in Distinct Layers of the Early Visual Cortex

Journal of Neuroscience, Год журнала: 2023, Номер 43(47), С. 7946 - 7957

Опубликована: Сен. 22, 2023

Perception has been proposed to result from the integration of feedforward sensory signals with internally generated feedback signals. Feedback are believed play an important role in driving false percepts, that is, seeing things not actually there. Feedforward and influences on perception can be studied using layer-specific fMRI, which we used here interrogate neural activity underlying high-confidence percepts while healthy human participants (

Язык: Английский

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Uncovering the Role of the Early Visual Cortex in Visual Mental Imagery

Опубликована: Фев. 29, 2024

The question of whether the early visual cortex (EVC) is involved in mental imagery remains a topic debate. In this paper, I propose that inconsistency findings can be explained by unique challenges associated with investigating EVC activity during imagery. During perception, processes low-level features which means highly sensitive to variation details. If has same role imagery, any change details image would lead corresponding changes activity. Within context, should not ‘active’ but how its relates specific properties. Studies using methods are reveal recruit similar ways as perception. However, all images contain high level Therefore, end considering more nuanced view states EVC, does mean it always so.

Язык: Английский

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Neural Substrates of Visual Perception and Working Memory: Two Sides of the Same Coin or Two Different Coins?

Frontiers in Neural Circuits, Год журнала: 2021, Номер 15

Опубликована: Ноя. 26, 2021

Visual perception occurs when a set of physical signals emanating from the environment enter visual system and brain interprets such as percept. working memory produces maintains mental representation percept while corresponding to that are not available. Early studies in humans non-human primates demonstrated lesions prefrontal cortex impair performance during tasks but perceptual tasks. These attributed fundamental role lesser cortex. Indeed, single cell recording have found neurons lateral macaques encode representations via persistent firing, validating results lesion studies. However, other reported some areas parietal temporal lobe—classically associated with perception—similarly firing. This prompted line enquiry about associative cortices perception. Here, we review evidence neuron macaque monkeys examining across different hierarchy link them same We conclude early both ventral (V1-V2-V4) dorsal (V1-V3-MT) pathways mainly signals. On hand, downstream V4 MT contain subpopulations and/or Differences cortical architecture (neuronal types, layer composition, synaptic density distribution) may be linked differential encoding between higher association areas.

Язык: Английский

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A metacognitive account of phenomenal force

Mind & Language, Год журнала: 2022, Номер 38(4), С. 1081 - 1101

Опубликована: Сен. 5, 2022

According to phenomenal conservatism or dogmatism, perceptual experiences can give us immediate justification for beliefs about the external world in virtue of having a distinctive kind character—namely force. I present three cases show that force is neither pervasive among nor exclusive experiences. The plausibility such calls out explanation. argue contrary long‐held assumption, separate, non‐perceptual state generated by some metacognitive mechanisms monitor one's first‐order mental processes and states. This new account advances our understanding nature

Язык: Английский

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The epistemic insignificance of phenomenal force

Philosophy and Phenomenological Research, Год журнала: 2023, Номер 109(1), С. 55 - 76

Опубликована: Авг. 29, 2023

Abstract Does phenomenal force, the distinctive phenomenology attributed to perceptual experience, really form an integral part of latter? If not, what implications does it have for justification? In this paper, I first argue a metacognitive account, according which force constitutes separate, state. This account opens up previously unexplored path challenging conservatism or dogmatism, has been prominent theory justification over past two decades. Moreover, investigate several alternative possibilities in might still be deemed as significant, but ultimately demonstrate that its epistemic role remains marginal at best.

Язык: Английский

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Vividness of Visual Imagery Supported by Intrinsic Structural-Functional Brain Network Dynamics

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Март 5, 2024

Abstract Vividness of visual imagery is subject to individual variability, a phenomenon with largely unexplored neurobiological underpinnings. By analyzing data from 273 participants we explored the link between structural-functional organization brain connectomes and reported intensity (measured VVIQ-2). Employing graph theory analyses investigated both structural (DTI) functional (rs-fMRI) within network regions often implicated in imagery. Our results indicate relationship increased local efficiency clustering coefficients connectome individuals who experience more vivid Increased were mirrored increases left inferior temporal regions, region frequently identified as critical hub literature. Furthermore, found have lower levels global their connectome. We propose that clarity are optimized by characterized heightened localized information transfer interconnectedness. Conversely, an excessively globally integrated might dilute specific neural activity crucial for generating images, leading less locally concentrated resource allocation key involved vividness.

Язык: Английский

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Introspective psychophysics for the study of subjective experience

Cerebral Cortex, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 21, 2024

Abstract Studying subjective experience is hard. We believe that pain not identical to nociception, nor pleasure a computational reward signal, fear the activation of “threat circuitry”. Unfortunately, introspective self-reports offer our best bet for accessing experience, but many still introspection “unreliable” and “unverifiable”. But which introspection’s faults do we find most damning? Is it provides imperfect access brain processes (e.g. perception, memory)? That objectively verifiable? hard isolate from non-subjective processing capacity? Here, I argue none these prevents us building meaningful, impactful psychophysical research program treats as valid empirical target through precisely characterizing relationships among environmental variables, behavior, self-reported phenomenology. Following recent similar calls by Peters (Towards canonical computations generating phenomenal experience. 2022. Neurosci Biobehav Rev: 142, 104903), Kammerer Frankish (What forms could systems take? A programme. 2023. J Conscious Stud 30:13–48), Fleming (Metacognitive psychophysics in humans, animals, AI. 30:113–128), “introspective psychophysics” thus apparent features, bugs—just noise distortions linking environment behavior inspired Fechner’s over 150 years ago. This next generation will establish powerful tool testing precise explanatory models phenomenology across dimensions—urgency, emotion, clarity, vividness, confidence, more.

Язык: Английский

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The vividness of visualisations and autistic trait expression are not strongly associated

Consciousness and Cognition, Год журнала: 2025, Номер 129, С. 103821 - 103821

Опубликована: Фев. 4, 2025

A minority of people (Aphantasics) report an inability to visualise. Aphantasia has been linked Autism - a neurodevelopmental condition affecting social interactions. There is risk circular logic informing proposed links, as the most popular metric autistic traits, Autism-Spectrum Quotient (AQ), Imagination subscale with items relating directly and indirectly imagery. We tested for inter-relationships between imagery vividness ratings expression using metrics that do not encompass subscale. also conducted hierarchical linear regression analyses assess contributions different AQ scores inter-relationships. Only in our highest-powered study (N = 308) were we able detect weak inter-relationship imagery, independent suggest only should exist, many describe themselves visual thinkers who have strong

Язык: Английский

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