scholarly journals Fractals in Action: An fMRI study on the Generation of new Hierarchical Levels in Motor Sequences

2017 ◽  
Author(s):  
Mauricio J.D. Martins ◽  
Roberta Bianco ◽  
Daniela Sammler ◽  
Arno Villringer

AbstractGeneration of hierarchical structures, such as the embedding of subordinate elements into larger structures, is a core feature of human cognition. Discrimination of well-formed hierarchies is thought to rely on lateral prefrontal cortex (PFC). However, the brain bases underlying the active generation of new hierarchical levels remain poorly understood. Here, we created a new motor paradigm to isolate this active generative process. In fMRI, participants planned and performed (identical) movement sequences based on three previously learned rules: (1) a hierarchical ‘fractal’ rule that involved generation of new levels, (2) a linear ‘iterative’ rule adding items to existing hierarchical levels, and (3) simple ‘repetition’. We found that generation of new hierarchical levels (using the fractal rule) activated a bilateral motor planning-and imagery network, but did not involve lateral PFC. Conversely, adding items to existing hierarchical levels required M1 directly during execution. These results show that the generation of new hierarchical levels can be achieved without involvement of putative domain-general systems such as those ascribed to lateral PFC. We hypothesize that these systems might be important to parse hierarchical sequences in a multi-domain fashion but not necessarily to generate new hierarchical levels.

2021 ◽  
pp. 221-286
Author(s):  
Michael A. Arbib

The atmosphere of a building is the pervading mood it provides, and can be considered a non-Gibsonian affordance. Atmosphere may frame our experience of a building, but over time our perception of the atmosphere may change. This chapter explores atmosphere in relation to motivation and emotion and the role of the limbic system of the brain. Emotion builds on a set of primordial emotions, but human cognition adds subtlety and supports aesthetic emotions. Paintings by Turner and Constable are examined to take the reader beyond the phenomenology of atmosphere and to explore the idea that the artist “inverts” vision. A visual pathway judges the emerging sketch; a visuomotor pathway updates the sketch. In iterating the process, the sketch changes, but so too will the mental image. An fMRI study of architects observing images of “contemplative” building grounds a critique that suggests challenges for designing further experiments. A crucial obstacle is the distance between cog/neuroscience experiments that seek to isolate the influence of a few key variables and the whole-person experience of using and contemplating a building in all its varied complexity.


NeuroImage ◽  
2000 ◽  
Vol 11 (5) ◽  
pp. S49
Author(s):  
D.L. Harrington ◽  
L.A. Mead ◽  
A.R. Mayer ◽  
K.Y. Haaland ◽  
S.M. Rao

2011 ◽  
Vol 33 (8) ◽  
pp. 1780-1791 ◽  
Author(s):  
Andrea Ginestroni ◽  
Stefano Diciotti ◽  
Paolo Cecchi ◽  
Ilaria Pesaresi ◽  
Carlo Tessa ◽  
...  

2017 ◽  
Vol 38 (6) ◽  
pp. 3025-3038 ◽  
Author(s):  
Anna Zilverstand ◽  
Bettina Sorger ◽  
Anita Kaemingk ◽  
Rainer Goebel

2018 ◽  
Author(s):  
Andrea E. Martin

Hierarchical structure and compositionality imbue human language with unparalleled expressive power and set it apart from other perception-action systems. However, neither formal nor neurobiological models account for how these defining computational properties might arise in a physiological system. I attempt to reconcile hierarchy and compositionality with principles from cell assembly computation in neuroscience; the result is an emerging theory of how the brain could convert distributed perceptual representations into hierarchical structures across multiple timescales while representing interpretable incremental stages of (de)compositional meaning. The model's architecture - a multidimensional coordinate system based on neurophysiological models of sensory processing - proposes that a manifold of neural trajectories encodes sensory, motor, and abstract linguistic states. Gain modulation, including inhibition, tunes the path in the manifold in accordance with behavior, and is how latent structure is inferred. As a consequence, predictive information about upcoming sensory input during production and comprehension is available without a separate operation. The proposed processing mechanism is synthesized from current models of neural entrainment to speech, concepts from systems neuroscience and category theory, and a symbolic-connectionist computational model that uses time and rhythm to structure information. I build on evidence from cognitive neuroscience and computational modeling that suggests a formal and mechanistic alignment between structure building and neural oscillations, and moves towards unifying basic insights from linguistics and psycholinguistics with the currency of neural computation.


2019 ◽  
Author(s):  
Jeffrey N. Chiang ◽  
Yujia Peng ◽  
Hongjing Lu ◽  
Keith J. Holyoak ◽  
Martin M. Monti

AbstractThe ability to generate and process semantic relations is central to many aspects of human cognition. Theorists have long debated whether such relations are coded as atomistic links in a semantic network, or as distributed patterns over some core set of abstract relations. The form and content of the conceptual and neural representations of semantic relations remains to be empirically established. The present study combined computational modeling and neuroimaging to investigate the representation and comparison of abstract semantic relations in the brain. By using sequential presentation of verbal analogies, we decoupled the neural activity associated with encoding the representation of the first-order semantic relation between words in a pair from that associated with the second-order comparison of two relations. We tested alternative computational models of relational similarity in order to distinguish between rival accounts of how semantic relations are coded and compared in the brain. Analyses of neural similarity patterns supported the hypothesis that semantic relations are coded, in the parietal cortex, as distributed representations over a pool of abstract relations specified in a theory-based taxonomy. These representations, in turn, provide the immediate inputs to the process of analogical comparison, which draws on a broad frontoparietal network. This study sheds light not only on the form of relation representations but also on their specific content.SignificanceRelations provide basic building blocks for language and thought. For the past half century, cognitive scientists exploring human semantic memory have sought to identify the code for relations. In a neuroimaging paradigm, we tested alternative computational models of relation processing that predict patterns of neural similarity during distinct phases of analogical reasoning. The findings allowed us to draw inferences not only about the form of relation representations, but also about their specific content. The core of these distributed representations is based on a relatively small number of abstract relation types specified in a theory-based taxonomy. This study helps to resolve a longstanding debate concerning the nature of the conceptual and neural code for semantic relations in the mind and brain.


Neurology ◽  
2017 ◽  
Vol 88 (7) ◽  
pp. 685-691 ◽  
Author(s):  
Brett L. Foster ◽  
Josef Parvizi

Background:The posteromedial cortex (PMC) is a collective term for an anatomically heterogeneous area of the brain constituting a core node of the human default mode network (DMN), which is engaged during internally focused subjective cognition such as autobiographical memory.Methods:We explored the effects of causal perturbations of PMC with direct electric brain stimulation (EBS) during presurgical epilepsy monitoring with intracranial EEG electrodes.Results:Data were collected from 885 stimulations in 25 patients implanted with intracranial electrodes across the PMC. While EBS of regions immediately dorsal or ventral to the PMC reliably produced somatomotor or visual effects, respectively, we found no observable behavioral or subjectively reported effects when sites within the boundaries of PMC were electrically perturbed. In each patient, null effects of PMC stimulation were observed for sites in which intracranial recordings had clearly demonstrated electrophysiologic responses during autobiographical recall.Conclusions:Direct electric modulation of the human PMC produced null effects when standard functional mapping methods were used. More sophisticated stimulation paradigms (e.g., EBS during experimental cognitive tests) will be required for testing the causal contribution of PMC to human cognition and subjective experience. Nonetheless, our findings suggest that some extant theories of PMC and DMN contribution to human awareness and subjective conscious states require cautious re-examination.


Author(s):  
Georg Northoff

Some recent philosophical discussions consider whether the brain is best understood as an open or closed system. This issue has major epistemic consequences akin to the scepticism engendered by the famous Cartesian demon. Specifically, one and the same empirical theory of brain function, predictive coding, entailing a prediction model of brain, have been associated with contradictory views of the brain as either open (Clark, 2012, 2013) or closed (Hohwy, 2013, 2014). Based on recent empirical evidence, the present paper argues that contrary to appearances, these views of the brain are compatible with one another. I suggest that there are two main forms of neural activity in the brain, one of which can be characterized as open, and the other as closed. Stimulus-induced activity, because it relies on predictive coding is indeed closed to the world, which entails that in certain respects, the brain is an inferentially secluded and self-evidencing system. In contrast, the brain’s resting state or spontaneous activity is best taken as open because it is a world-evidencing system that allows for the brain’s neural activity to align with the statistically-based spatiotemporal structure of objects and events in the world. This model requires an important caveat, however. Due to its statistically-based nature, the resting state’s alignment to the world comes in degrees. In extreme cases, the degree of alignment can be extremely low, resulting in a resting state that is barely if at all aligned to the world. This is for instance the case in schizophrenia. Clinical symptoms such as delusions and hallucinations in schizophrenics are indicative of the fundamental delicateness of the alignment between the brain’s resting-state and the world’s phenomena. Nevertheless, I argue that so long as we are dealing with a well-functioning brain, the more dire epistemic implications of predictive coding can be forestalled. That the brain is in part a self-evidencing system does not yield any generalizable reason to worry that human cognition is out of step with the real world. Instead, the brain is aligned to the world accounting for “world-brain relation” that mitigates sceptistic worries.


Author(s):  
Nihal Toros Ntapiapis ◽  
Çağla Özkardeşler

Given increasing knowledge about how consumers communicate with texts, our understanding of how brain processes information remains relatively limited. Besides that, in today's world, advancing neuroscience-related technology and developments have changed the understanding of consumer behavior. In this regard, in the 1990s, consumer neuroscience and neuromarketing concepts were revealed. This new concept has brought a multi-disciplinary approach and new perceptions of human cognition and behavior. For measuring consumer behaviors through a new alternative method, research has started combining traditional marketing researches with these new methods. This chapter explores how typeface knowledge from the brain functions using neuroscience technology and the importance neurosciences methodologies have for readability research. Moreover, this chapter will evaluate how typefaces affect the purchase decision of the consumers and offer an integrative literature review.


2018 ◽  
pp. 230-240

While MRI became a standard workhorse in neurology/neurosurgery within a few years of installation of the first MRI unit, fMRI, in spite of being a powerful imaging tool, remains primarily a research tool, even though the first fMRI study was published 25 years ago. Scientifically, fMRI has made a major impact, judging by the number of PubMed citations and publications in high-impact journals. In cognitive neuroscience, fMRI is the most commonly used imaging technique in published peer-reviewed articles. fMRI is used clinically for preoperative brain mapping in neurosurgery to delineate the proximity of the lesion (tumor) to eloquent areas of the brain, with the aim of achieving adequate tumor resection with minimal functional damage to the brain. fMRI connectivity and activation maps have identified altered activation patterns and resting-state networks in psychiatric disorders like schizophrenia, bipolar disorder, autism, and Alzheimer’s disease, but fMRI is still not a standard diagnostic procedure in psychiatry. Diffusion imaging technique is being used for triaging stroke patients who are likely to respond to stroke therapy (embolectomy and/or clot lysis). Meanwhile, major collaborative fMRI studies are in progress in many institutions to collect normative data on connectivity, activation response, and behavioral response as well as correlation among them. Studies focused on specific neuropsychiatric disorders also have been initiated by the National Institutes of Health. All this is a reflection of the huge potential application of fMRI in clinical practice envisioned by the scientific community.


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