scholarly journals Direct brain recordings reveal continuous encoding of structure in random stimuli

2021 ◽  
Author(s):  
Julian Fuhrer ◽  
Kyrre Glette ◽  
Jugoslav Ivanovic ◽  
Pal Gunnar Larsson ◽  
Tristan Andres Bekinschtein ◽  
...  

The brain excels at processing sensory input, even in rich or chaotic environments. Mounting evidence attributes this to the creation of sophisticated internal models of the environment that draw on statistical structures in the unfolding sensory input. Understanding how and where this modeling takes place is a core question in statistical learning. It is unknown how this modeling applies to random sensory signals. Here, we identify conditional relations, through transitional probabilities, as an implicit structure supporting the encoding of a random auditory stream. We evaluate this representation using intracranial electroencephalography recordings by applying information-theoretical principles to high-frequency activity (75-145 Hz). We demonstrate how the brain continuously encodes conditional relations between random stimuli in a network outside of the auditory system following a hierarchical organization including temporal, frontal and hippocampal regions. Our results highlight that hierarchically organized brain areas continuously attempt to order incoming information by maintaining a probabilistic representation of the sensory input, even under random stimuli presentation.

2002 ◽  
Vol 87 (4) ◽  
pp. 2137-2148 ◽  
Author(s):  
Sean M. O'Connor ◽  
Rune W. Berg ◽  
David Kleinfeld

We tested if coherent signaling between the sensory vibrissa areas of cerebellum and neocortex in rats was enhanced as they whisked in air. Whisking was accompanied by 5- to 15-Hz oscillations in the mystatial electromyogram, a measure of vibrissa position, and by 5- to 20-Hz oscillations in the differentially recorded local field potential (∇LFP) within the vibrissa area of cerebellum and within the ∇LFP of primary sensory cortex. We observed that only 10% of the activity in either cerebellum or sensory neocortex was significantly phase-locked to rhythmic motion of the vibrissae; the extent of this modulation is in agreement with the results from previous single-unit measurements in sensory neocortex. In addition, we found that 40% of the activity in the vibrissa areas of cerebellum and neocortex was significantly coherent during periods of whisking. The relatively high level of coherence between these two brain areas, in comparison with their relatively low coherence with whisking per se, implies that the vibrissa areas of cerebellum and neocortex communicate in a manner that is incommensurate with whisking. To the extent that the vibrissa areas of cerebellum and neocortex communicate over the same frequency band as that used by whisking, these areas must multiplex electrical activity that is internal to the brain with activity that is that phase-locked to vibrissa sensory input.


2016 ◽  
Vol 116 (6) ◽  
pp. 2497-2512 ◽  
Author(s):  
Anne Kösem ◽  
Anahita Basirat ◽  
Leila Azizi ◽  
Virginie van Wassenhove

During speech listening, the brain parses a continuous acoustic stream of information into computational units (e.g., syllables or words) necessary for speech comprehension. Recent neuroscientific hypotheses have proposed that neural oscillations contribute to speech parsing, but whether they do so on the basis of acoustic cues (bottom-up acoustic parsing) or as a function of available linguistic representations (top-down linguistic parsing) is unknown. In this magnetoencephalography study, we contrasted acoustic and linguistic parsing using bistable speech sequences. While listening to the speech sequences, participants were asked to maintain one of the two possible speech percepts through volitional control. We predicted that the tracking of speech dynamics by neural oscillations would not only follow the acoustic properties but also shift in time according to the participant's conscious speech percept. Our results show that the latency of high-frequency activity (specifically, beta and gamma bands) varied as a function of the perceptual report. In contrast, the phase of low-frequency oscillations was not strongly affected by top-down control. Whereas changes in low-frequency neural oscillations were compatible with the encoding of prelexical segmentation cues, high-frequency activity specifically informed on an individual's conscious speech percept.


2016 ◽  
Author(s):  
K. Kessler ◽  
R. A. Seymour ◽  
G. Rippon

AbstractAlthough atypical social behaviour remains a key characterisation of ASD, the presence of sensory and perceptual abnormalities has been given a more central role in recent classification changes. An understanding of the origins of such aberrations could thus prove a fruitful focus for ASD research. Early neurocognitive models of ASD suggested that the study of high frequency activity in the brain as a measure of cortical connectivity might provide the key to understanding the neural correlates of sensory and perceptual deviations in ASD. As our review shows, the findings from subsequent research have been inconsistent, with a lack of agreement about the nature of any high frequency disturbances in ASD brains. Based on the application of new techniques using more sophisticated measures of brain synchronisation, direction of information flow, and invoking the coupling between high and low frequency bands, we propose a framework which could reconcile apparently conflicting findings in this area and would be consistent both with emerging neurocognitive models of autism and with the heterogeneity of the condition.HighlightsSensory and perceptual aberrations are becoming a core feature of the ASD symptom prolife.Brain oscillations and functional connectivity are consistently affected in ASD.Relationships (coupling) between high and low frequencies are also deficient.Novel framework proposes the ASD brain is marked by local dysregulation and reduced top-down connectivityThe ASD brain’s ability to predict stimuli and events in the environment may be affectedThis may underlie perceptual sensitives and cascade into social processing deficits in ASD


2018 ◽  
Vol 10 (3) ◽  
pp. 6-13 ◽  
Author(s):  
N. D. Sorokina ◽  
S. S. Pertsov ◽  
G. V. Selitsky

Recent studies show that the brain gamma activity includes both the gamma rhythm (standard EEG) and high frequency (100-1000 Hz) as well as super-high (>1000 Hz) frequency oscillations, as recorded by electrocorticography. As reported in the literature, the high-frequency oscillations (80-500 Hz) are highly informative markers of an epileptic focus. In this review, we analyze features of high-frequency activity associated with the epileptiform activity, and its relation to the seizure onset range. Further study of high-frequency bioelectric activity of the brain is of interest to researchers and clinicians, and may improve the EEG differential diagnosis of epilepsy.


2021 ◽  
Author(s):  
Salman E Qasim ◽  
Uma Rani Mohan ◽  
Joel M Stein ◽  
Joshua Jacobs

Emotional events are often easier to recall, and comprise our most valuable memories. Here, as subjects performed a memory task in which they recalled emotional stimuli more readily than neutral stimuli, we used direct brain recording and stimulation in the hippocampus and amygdala to identify how the brain prioritizes emotional information for memory encoding. High-frequency activity (HFA), a correlate of local neuronal spiking, increased in both hippocampus and amygdala when subjects successfully encoded emotionally arousing stimuli. Direct electrical stimulation applied to these regions during encoding decreased HFA and selectively impaired retrieval for emotional stimuli. Finally, depressed subjects' memory was biased more by valence than arousal, and they exhibited a congruent increase in HFA as a function of valence. Our findings thus provide evidence that emotional stimuli up-regulate activity in the amygdala--hippocampus circuit to enhance memory for emotional information, and suggest that targeted modulation of this circuit alters emotional memory processes.


2017 ◽  
Author(s):  
Erik Johan Wiersma

The human brain processes a wide variety of inputs and does so either consciously or subconsciously. According to the Global Workspace theory, conscious processing involves broadcasting of information to several regions of the brain and subconscious processing involves more localized processing. This theoretical paper aims to expand on some of the aspects of the Global Workspace theory: how the properties of incoming information result in it being processed subconsciously or consciously; why processing can be either be sustained or short-lived; how the Global Workspace theory may apply both to real-time sensory input as well as to internally retained information. This paper proposes that: familiar input which does not elicit intense emotions becomes processed subconsciously and such processing can be continuous and sustained; input that elicits relatively intense emotions is subjected to highly sustainable conscious processing; input can also undergo meta-conscious processing. Such processing is not very sustainable but can exert control over other cognitive processes. This paper also discusses possible benefits of regulating cognitive processes this way.


2020 ◽  
Vol 44 (3) ◽  
pp. 241-249
Author(s):  
Yoshiaki Omura

While a visiting Professor at the University of Paris, VI (formerly Sorvonne) more than 40 years ago, the Author became very good friends with Dr. Paul Nogier who periodically gave seminars and workshops in Paris. After the author diagnosed his cervical problem & offered him simple help, Dr. Nogier asked the Author to present lectures and demonstrations on the effects of ear stimulation, namely the effects of acupuncture & electrical stimulation of the ear lobules. It is only now, in 2019 that we have discovered 2–5 minute high frequency stimulation of the ear lobule inhibits cancer activity for 1– 4 hours post stimulation. Although the procedure is extremely simple. First take optimal dose of Vitamin D3, which has the most essential 10 unique beneficial factors required for every human cell activity. Next, apply high frequency stimulation to ear lobule while the worst ear lobule is held by all fingers with vibrator directly touching the surface of the worst ear lobule, preferably after patient repeatedly takes optimal dose of Vitamin D3. When the worst ear lobule is held between thumb & index fingers and applying mechanical stimulation of 250 ~ 500 mechanical vibration/second for 2 ~ 5 minutes using an electrical vibrator, there is rapid disappearance of cancer activity in both the brain and rest of the body for short time duration 1 ~ 4 hours. The effect often increases by additional pressure by holding fingers. As of May 2019, the Author found that many people from various regions of the world developed early stages of multiple cancers. For evaluation of this study, U. S. patented Bi-Digital O-Ring Test (BDORT) was used which was developed by the Author while doing his Graduate experimental physics research at Colombia University. BDORT was found to be most essential for determining the beneficial effects as well as harmful effects of any substance or treatment. Using BDORT, Author was the first to recognize severe increasing mid-backache was an early sign of pancreatic cancer of President of New York State Board of Medicine after top pain specialists failed to detect the cause after 3 years of effort, while the BDORT showed early stages of cancer whereas conventional X-Ray of the pancreas did not show any cancer image until 2 months after Author detected with BDORT. For example, the optimal dose of the banana is usually about 2.0 - 2.5 millimeters cross section of the banana. A whole banana is more than 50 ~ 100 times the optimal dose. Any substance eaten in more than 25 times of its optimal dose becomes highly toxic and creates DNA mutations which can cause multiple malignancies in the presence of strong electro-magnetic field. With standard medication given by doctor, patients often become sick and they are unable to reduce body weight, unless medication is reduced or completely stopped. When the amount of zinc is very high, DNA often becomes unstable and multiple cancers can grow rapidly in the presence of strong electromagnetic field. Large amount of Vitamin C from regular orange or orange juice inhibit the most important Vitamin D3 effects. At least 3 kinds of low Vitamin C oranges will not inhibit Vitamin D3. Since B12 particularly methyl cobalamin which is a red small tablet is known to improve brain circulation very significantly we examined its effect within 20 seconds of oral intake we found the following very significant changes. Acetylcholine in both sides of the brain often increases over 4,500 ng. Longevity gene Sirtuin 1 level increases significantly for short time of few hours. Thymosin α1 and Thymosinβ4 both increase to over 1500 ng from 20 ng or less.


Author(s):  
Armin Schnider

What diseases cause confabulations and which are the brain areas whose damage is responsible? This chapter reviews the causes, both historic and present, of confabulations and deduces the anatomo-clinical relationships for the four forms of confabulation in the following disorders: alcoholic Korsakoff syndrome, traumatic brain injury, rupture of an anterior communicating artery aneurysm, posterior circulation stroke, herpes and limbic encephalitis, hypoxic brain damage, degenerative dementia, tumours, schizophrenia, and syphilis. Overall, clinically relevant confabulation is rare. Some aetiologies have become more important over time, others have virtually disappeared. While confabulations seem to be more frequent after anterior brain damage, only one form has a distinct anatomical basis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zekun Xu ◽  
Eric Laber ◽  
Ana-Maria Staicu ◽  
B. Duncan X. Lascelles

AbstractOsteoarthritis (OA) is a chronic condition often associated with pain, affecting approximately fourteen percent of the population, and increasing in prevalence. A globally aging population have made treating OA-associated pain as well as maintaining mobility and activity a public health priority. OA affects all mammals, and the use of spontaneous animal models is one promising approach for improving translational pain research and the development of effective treatment strategies. Accelerometers are a common tool for collecting high-frequency activity data on animals to study the effects of treatment on pain related activity patterns. There has recently been increasing interest in their use to understand treatment effects in human pain conditions. However, activity patterns vary widely across subjects; furthermore, the effects of treatment may manifest in higher or lower activity counts or in subtler ways like changes in the frequency of certain types of activities. We use a zero inflated Poisson hidden semi-Markov model to characterize activity patterns and subsequently derive estimators of the treatment effect in terms of changes in activity levels or frequency of activity type. We demonstrate the application of our model, and its advance over traditional analysis methods, using data from a naturally occurring feline OA-associated pain model.


2021 ◽  
Author(s):  
Saskia Haegens ◽  
Yagna J. Pathak ◽  
Elliot H. Smith ◽  
Charles B. Mikell ◽  
Garrett P. Banks ◽  
...  

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