scholarly journals Predicting speech from a cortical hierarchy of event-based time scales

2021 ◽  
Vol 7 (49) ◽  
Author(s):  
Lea-Maria Schmitt ◽  
Julia Erb ◽  
Sarah Tune ◽  
Anna U. Rysop ◽  
Gesa Hartwigsen ◽  
...  
Keyword(s):  
Time Scales ◽  
Cortical Hierarchy ◽  
Event Based

scholarly journals Event-Based Quantum Mechanics: A Context for the Emergence of Classical Information

2019 ◽  
Author(s):  
Ignazio Licata ◽  
Leonardo Chiatti
Keyword(s):  
Hilbert Space ◽  
Quantum Mechanics ◽  
Quantum Computing ◽  
Time Scales ◽  
Quantum Jumps ◽  
Classical Information ◽  
Primary Element ◽  
Informational Constraint ◽  
Event Based ◽  
Physical Quantities

This paper explores an event-based version of quantum mechanics which differs from the commonly accepted one, even though the usual elements of quantum formalism, e.g., the Hilbert space, are maintained. This version introduces as primary element the occurrence of micro-events induced by usual physical (mechanical, electromagnetic and so on) interactions. These micro-events correspond to state reductions and are identified with quantum jumps, already introduced by Bohr in his atomic model and experimentally well established today. Macroscopic bodies are defined as clusters of jumps; the emergence of classicality thus becomes understandable and time honoured paradoxes can be solved. In particular, we discuss the cat paradox in this context. Quantum jumps are described as temporal localizations of physical quantities; if the information associated with these localizations has to be finite, two time scales spontaneously appear: an upper cosmological scale and a lower scale of elementary "particles''. This allows the interpretation of the Bekenstein limit like a particular informational constraint on the manifestation of a micro-event in the cosmos it belongs. The topic appears relevant in relation to recent discussions on possible spatiotemporal constraints on quantum computing.

scholarly journals Event-Based Quantum Mechanics: A Context for the Emergence of Classical Information

2019 ◽  
Author(s):  
Ignazio Licata ◽  
Leonardo Chiatti
Keyword(s):  
Hilbert Space ◽  
Quantum Mechanics ◽  
Quantum Computing ◽  
Time Scales ◽  
Quantum Jumps ◽  
Classical Information ◽  
Primary Element ◽  
Informational Constraint ◽  
Event Based ◽  
Physical Quantities

This paper explores an event-based version of quantum mechanics which differs from the commonly accepted one, even though the usual elements of quantum formalism, e.g., the Hilbert space, are mantained. This version introduces as primary element the occurrence of micro-events induced by usual physical (mechanical, electromagnetic and so on) interactions. These micro-events correspond to state reductions and are identified with quantum jumps, already introduced by Bohr in his atomic model and experimentally well established today. Macroscopic bodies are defined as clusters of jumps; the emergence of classicality thus becomes understandable and time honoured paradoxes can be solved. In particular, we discuss the cat paradox in this context. Quantum jumps are described as temporal localizations of physical quantities; if the information associated with these localizations has to be finite, two time scales spontaneously appear: an upper cosmological scale and a lower scale of elementary "particles". This allows the interpretation of the Bekenstein limit like a particular informational constraint on the manifestation of a micro-event in the cosmos to which it belongs. The topic appears relevant in relation to recent discussions on possible spatiotemporal constraints on quantum computing.

scholarly journals Event-Based Quantum Mechanics: A Context for the Emergence of Classical Information

Symmetry ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 181 ◽  
Author(s):  
Ignazio Licata ◽  
Leonardo Chiatti
Keyword(s):  
Hilbert Space ◽  
Quantum Mechanics ◽  
Quantum Computing ◽  
Time Scales ◽  
Quantum Jumps ◽  
Classical Information ◽  
Primary Element ◽  
Informational Constraint ◽  
Event Based ◽  
Physical Quantities

This paper explores an event-based version of quantum mechanics which differs from the commonly accepted one, even though the usual elements of quantum formalism, e.g., the Hilbert space, are maintained. This version introduces as primary element the occurrence of micro-events induced by usual physical (mechanical, electromagnetic and so on) interactions. These micro-events correspond to state reductions and are identified with quantum jumps, already introduced by Bohr in his atomic model and experimentally well established today. Macroscopic bodies are defined as clusters of jumps; the emergence of classicality thus becomes understandable and time honoured paradoxes can be solved. In particular, we discuss the cat paradox in this context. Quantum jumps are described as temporal localizations of physical quantities; if the information associated with these localizations has to be finite, two time scales spontaneously appear: an upper cosmological scale and a lower scale of elementary “particles”. This allows the interpretation of the Bekenstein limit like a particular informational constraint on the manifestation of a micro-event in the cosmos it belongs. The topic appears relevant in relation to recent discussions on possible spatiotemporal constraints on quantum computing.

scholarly journals Predicting speech from a cortical hierarchy of event-based timescales

2020 ◽  
Author(s):  
Lea-Maria Schmitt ◽  
Julia Erb ◽  
Sarah Tune ◽  
Anna Rysop ◽  
Gesa Hartwigsen ◽  
...  
Keyword(s):  
Language Comprehension ◽  
Network Architecture ◽  
Neural Coding ◽  
Computationally Efficient ◽  
Top Down ◽  
Coding Scheme ◽  
Model Based ◽  
Neural Processes ◽  
Cortical Hierarchy ◽  
Event Based

AbstractHow can anticipatory neural processes structure the temporal unfolding of context in our natural environment? We here provide evidence for a neural coding scheme that sparsely updates contextual representations at the boundary of events and gives rise to a hierarchical, multi-layered organization of predictive language comprehension. Training artificial neural networks to predict the next word in a story at five stacked timescales and then using model-based functional MRI, we observe a sparse, event-based “surprisal hierarchy”.The hierarchy evolved along a temporo-parietal pathway, with model-based surprisal at longest timescales represented in inferior parietal regions. Along this hierarchy, surprisal at any given timescale gated bottom-up and top-down connectivity to neighbouring timescales. In contrast, surprisal derived from a continuously updated context influenced temporo-parietal activity only at short timescales. Representing context in the form of increasingly coarse events constitutes a network architecture for making predictions that is both computationally efficient and semantically rich.

scholarly journals Processing of Auditory Novelty Across the Cortical Hierarchy: An Intracranial Electrophysiology Study

2018 ◽  
Author(s):  
Kirill V. Nourski ◽  
Mitchell Steinschneider ◽  
Ariane E. Rhone ◽  
Hiroto Kawasaki ◽  
Matthew A. Howard ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Time Scales ◽  
Information Flow ◽  
Novelty Detection ◽  
Predictive Coding ◽  
Cortical Activation ◽  
Multiple Time Scales ◽  
Neurosurgical Patients ◽  
Cortical Hierarchy ◽  
High Gamma

AbstractUnder the predictive coding hypothesis, specific spatiotemporal patterns of cortical activation are postulated to occur during sensory processing as expectations generate feedback predictions and prediction errors generate feedforward signals. Establishing experimental evidence for this information flow within cortical hierarchy has been difficult, especially in humans, due to spatial and temporal limitations of non-invasive measures of cortical activity. This study investigated cortical responses to auditory novelty using the local/global deviant paradigm, which engages the hierarchical network underlying auditory predictive coding over short (‘local deviance’; LD) and long (‘global deviance’; GD) time scales. Electrocorticographic responses to auditory stimuli were obtained in neurosurgical patients from regions of interest (ROIs) including auditory, auditory-related and prefrontal cortex. LD and GD effects were assayed in averaged evoked potential (AEP) and high gamma (70-150 Hz) signals, the former likely dominated by local synaptic currents and the latter largely reflecting local spiking activity. AEP LD effects were distributed across all ROIs, with greatest percentage of significant sites in core and non-core auditory cortex. High gamma LD effects were localized primarily to auditory cortex in the superior temporal plane and on the lateral surface of the superior temporal gyrus (STG). LD effects exhibited progressively longer latencies in core, non-core, auditory-related and prefrontal cortices, consistent with feedforward signaling. The spatial distribution of AEP GD effects overlapped that of LD effects, but high gamma GD effects were more restricted to non-core areas. High gamma GD effects had shortest latencies in STG and preceded AEP GD effects in most ROIs. This latency profile, along with the paucity of high gamma GD effects in the superior temporal plane, suggest that the STG plays a prominent role in initiating novelty detection signals over long time scales. Thus, the data demonstrate distinct patterns of information flow in human cortex associated with auditory novelty detection over multiple time scales.

LVSEM: Past Present and Future

1990 ◽  
Vol 48 (1) ◽  
pp. 364-365
Author(s):  
James B. Pawley
Keyword(s):  
Field Emission ◽  
Line Width ◽  
Time Scales ◽  
Silicon Oxide ◽  
Beam Current ◽  
High Brightness ◽  
High Beam ◽  
Fixed Charges ◽  
Beam Voltage ◽  
Deposited Metal

Past: In 1960 Thornley published the first description of SEM studies carried out at low beam voltage (LVSEM, 1-5 kV). The aim was to reduce charging on insulators but increased contrast and difficulties with low beam current and frozen biological specimens were also noted. These disadvantages prevented widespread use of LVSEM except by a few enthusiasts such as Boyde. An exception was its use in connection with studies in which biological specimens were dissected in the SEM as this process destroyed the conducting films and produced charging unless LVSEM was used.In the 1980’s field emission (FE) SEM’s came into more common use. The high brightness and smaller energy spread characteristic of the FE-SEM’s greatly reduced the practical resolution penalty associated with LVSEM and the number of investigators taking advantage of the technique rapidly expanded; led by those studying semiconductors. In semiconductor research, the SEM is used to measure the line-width of the deposited metal conductors and of the features of the photo-resist used to form them. In addition, the SEM is used to measure the surface potentials of operating circuits with sub-micrometer resolution and on pico-second time scales. Because high beam voltages destroy semiconductors by injecting fixed charges into silicon oxide insulators, these studies must be performed using LVSEM where the beam does not penetrate so far.

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