scholarly journals Effects of Spatial Memory Processing on Hippocampal Ripples

2021 ◽  
Vol 12 ◽  
Author(s):  
Daniel Lachner-Piza ◽  
Lukas Kunz ◽  
Armin Brandt ◽  
Matthias Dümpelmann ◽  
Aljoscha Thomschewski ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Brain Activity ◽  
Spatial Navigation ◽  
Brain Regions ◽  
Interictal Spikes ◽  
Navigation Task ◽  
Brain Functions ◽  
Before And After ◽  
Surgical Evaluation ◽  
Oscillatory Brain Activity

Human High-Frequency-Oscillations (HFO) in the ripple band are oscillatory brain activity in the frequency range between 80 and 250 Hz. HFOs may comprise different subgroups that either play a role in physiologic or pathologic brain functions. An exact differentiation between physiologic and pathologic HFOs would help elucidate their relevance for cognitive and epileptogenic brain mechanisms, but the criteria for differentiating between physiologic and pathologic HFOs remain controversial. In particular, the separation of pathologic HFOs from physiologic HFOs could improve the identification of epileptogenic brain regions during the pre-surgical evaluation of epilepsy patients. In this study, we performed intracranial electroencephalography recordings from the hippocampus of epilepsy patients before, during, and after the patients completed a spatial navigation task. We isolated hippocampal ripples from the recordings and categorized the ripples into the putative pathologic group iesRipples, when they coincided with interictal spikes, and the putative physiologic group isolRipples, when they did not coincide with interictal spikes. We found that the occurrence of isolRipples significantly decreased during the task as compared to periods before and after the task. The rate of iesRipples was not modulated by the task. In patients who completed the spatial navigation task on two consecutive days, we furthermore examined the occurrence of ripples in the intervening night. We found that the rate of ripples that coincided with sleep spindles and were therefore putatively physiologic correlated with the performance improvement on the spatial navigation task, whereas the rate of all ripples did not show this relationship. Together, our results suggest that the differentiation of HFOs into putative physiologic and pathologic subgroups may help identify their role for spatial memory and memory consolidation processes. Conversely, excluding putative physiologic HFOs from putative pathologic HFOs may improve the HFO-based identification of epileptogenic brain regions in future studies.

scholarly journals Between Thought and Expression, a Magnetoencephalography Study of the “Tip-of-the-Tongue” Phenomenon

2014 ◽  
Vol 26 (10) ◽  
pp. 2210-2223 ◽  
Author(s):  
Karmen Resnik ◽  
David Bradbury ◽  
Gareth R. Barnes ◽  
Alex P. Leff
Keyword(s):  
Brain Activity ◽  
Brain Regions ◽  
Temporal Region ◽  
Speech Output ◽  
Proper Nouns ◽  
Confrontation Naming ◽  
Beta Power ◽  
Oscillatory Brain Activity ◽  
Language Areas ◽  
Tip Of The Tongue

“Tip-of-the-tongue” (TOT) is the phenomenon associated with the inaccessibility of a known word from memory. It is universally experienced, increases in frequency with age, and is most common for proper nouns. It is a good model for the symptom of anomia experienced much more frequently by some aphasic patients following brain injury. Here, we induced the TOT state in older participants while they underwent brain scanning with magnetoencephalography to investigate the changes in oscillatory brain activity associated with failed retrieval of known words. Using confrontation naming of pictures of celebrities, we successfully induced the TOT state in 29% of trials and contrasted it with two other states: “Know” where the participants both correctly recognized the celebrity's face and retrieved their name and “Don't Know” when the participants did not recognize the celebrity. We wished to test Levelt's influential model of speech output by carrying out two analyses, one epoching the data to the point in time when the picture was displayed and the other looking back in time from when the participants first articulated their responses. Our main findings supported the components of Levelt's model, but not their serial activation over time as both semantic and motor areas were identified in both analyses. We also found enduring decreases in the alpha frequency band in the left ventral temporal region during the TOT state, suggesting ongoing semantic search. Finally, we identified reduced beta power in classical peri-sylvian language areas for the TOT condition, suggesting that brain regions that encode linguistic memories are also involved in their attempted retrieval.

scholarly journals Understanding the neurological mechanism involved in enhanced memory recall task following binaural beat: a pilot study

2021 ◽  
Author(s):  
Muhammad Danish Mujib ◽  
Muhammad Abul Hasan ◽  
Saad Ahmed Qazi ◽  
Aleksandra Vuckovic
Keyword(s):  
Short Term Memory ◽  
Brain Activity ◽  
Digit Span ◽  
Memory Task ◽  
Neural Mechanism ◽  
Alpha Power ◽  
Before And After ◽  
Gamma Power ◽  
Group A ◽  
Oscillatory Brain Activity

AbstractBinaural beat (BB) is a promising technique for memory improvement in elderly or people with neurological conditions. However, the related modulation of cortical networks followed by behavioral changes has not been investigated. The objective of this study is to establish a relationship between BB oscillatory brain activity evoked by stimulation and a behavioral response in a short term memory task. Three Groups A, B, and C of 20 participants each received alpha (10 Hz), beta (14 Hz), and gamma (30 Hz) BB, respectively, for 15 min. Their EEG was recorded in pre, during, and post BB states. Participants performed a digit span test before and after a BB session. A significant increase in the cognitive score was found only for Group A while a significant decrease in reaction time was noted for Groups A and C. Group A had a significant decrease of theta and increase of alpha power, and a significant increase of theta and decrease of gamma imaginary coherence (ICH) post BB. Group C had a significant increase in theta and gamma power accompanied by the increase of theta and gamma ICH post BB. The effectiveness of BB depends on the frequency of stimulation. A putative neural mechanism involves an increase in theta ICH in parieto-frontal and interhemispheric frontal networks.

scholarly journals Towards personalized rTMS in tinnitus: reliability of individualized stimulation protocols in behavioral and electrophysiological responses

2021 ◽  
Author(s):  
Stefan Schoisswohl ◽  
Berthold Langguth ◽  
Tobias Hebel ◽  
Mohamed A. Abdelnaim ◽  
Gregor Volberg ◽  
...  
Keyword(s):  
Repetitive Transcranial Magnetic Stimulation ◽  
Brain Activity ◽  
Clinical Effectiveness ◽  
Individual Variability ◽  
Group Level ◽  
Non Invasive ◽  
Electrophysiological Responses ◽  
Before And After ◽  
Oscillatory Brain Activity ◽  
Test Retest Reliability

AbstractBackgroundRepetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation tool potentially modulating pathological brain activity. Its clinical effectiveness is hampered by varying results and characterized by inter-individual variability in treatment responses. RTMS individualization might constitute a useful strategy to overcome this variability. A precondition for this approach would be that repeatedly applied protocols result in reliable effects. The condition tinnitus provides the advantage of immediate behavioral consequences (tinnitus loudness changes) after interventions and thus offers an excellent model to exemplify TMS personalization.ObjectiveThe aim was to investigate the test-retest reliability of short rTMS stimulations in modifying tinnitus loudness and oscillatory brain activity as well as to examine the feasibility of rTMS individualization in tinnitus.MethodsThree short verum (1Hz, 10Hz, 20Hz; 200 pulses) and one sham (0.1Hz; 20 pulses) rTMS protocol were administered on two different days in 22 tinnitus patients. Before and after each protocol, oscillatory brain activity was recorded with electroencephalography (EEG) together with behavioral tinnitus loudness ratings. Stimulation responders were identified via consistent and sham-superior behavioral or electrophysiological responses according to the prevalent neurophysiological models for tinnitus.ResultsIt was feasible to identify individualized rTMS protocols featuring reliable tinnitus loudness changes (55% responder), alpha increases (91% responder) and gamma decreases (100% responder) respectively. Contrary, test-retest correlation analyses per protocol on a group-level were not significant neither for behavioral nor for electrophysiological effects. No associations between behavioral and EEG responses were given.ConclusionRTMS individualization via behavioral and electrophysiological data in tinnitus can be considered as a feasible approach to overcome low reliability on group-level. The present results open the discussion favoring personalization utilizing neurophysiological markers rather than behavioral responses. These insights are not only useful for the rTMS treatment of tinnitus but also for neuromodulation interventions in other pathologies as our results suggest that the individualization of stimulation protocols is feasible despite absent group-level reliability.

scholarly journals Pathfinder: open source software for analyzing spatial navigation search strategies

2019 ◽  
Author(s):  
Matthew B. Cooke ◽  
Timothy P. O’Leary ◽  
Phelan Harris ◽  
Richard E. Brown ◽  
Jason S. Snyder
Keyword(s):  
Spatial Memory ◽  
Open Source ◽  
Water Maze ◽  
Spatial Navigation ◽  
Brain Regions ◽  
Search Strategies ◽  
Sensory Stimuli ◽  
Data Files ◽  
Spatial Water Maze ◽  
Goal Directed Behavior

AbstractSpatial navigation is a universal behavior that varies depending on goals, experience and available sensory stimuli. Spatial navigational tasks are routinely used to study learning, memory and goal-directed behavior, in both animals and humans. One popular paradigm for testing spatial memory is the Morris water maze, where subjects learn the location of a hidden platform that offers escape from a pool of water. Researchers typically express learning as a function of the latency to escape, though this reveals little about the underlying navigational strategies. Recently, a number of studies have begun to classify water maze search strategies in order to clarify the precise spatial and mnemonic functions of different brain regions, and to identify which aspects of spatial memory are disrupted in disease models. However, despite their usefulness, strategy analyses have not been widely adopted due to the lack of software to automate analyses. To address this need we developed Pathfinder, an open source application for analyzing spatial navigation behaviors. In a representative dataset, we show that Pathfinder effectively characterizes the development of highly-specific spatial search strategies as male and female mice learn a standard spatial water maze. Pathfinder can read data files from commercially- and freely-available software packages, is optimized for classifying search strategies in water maze paradigms, but can also be used to analyze 2D navigation by other species, and in other tasks, as long as timestamped xy coordinates are available. Pathfinder is simple to use, can automatically determine pool and platform geometry, generates heat maps, analyzes navigation with respect to multiple goal locations, and can be updated to accommodate future developments in spatial behavioral analyses. Given these features, Pathfinder may be a useful tool for studying how navigational strategies are regulated by the environment, depend on specific neural circuits, and are altered by pathology.

scholarly journals Quetiapine Ameliorates Anxiety-Like Behavior and Cognitive Impairments in Stressed Rats: Implications for the Treatment of Posttraumatic Stress Disorder

2010 ◽  
pp. 263-271 ◽  
Author(s):  
H-N Wang ◽  
Y Peng ◽  
Q-R Tan ◽  
Y-C Chen ◽  
R-G Zhang ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Traumatic Stress ◽  
Stress Disorder ◽  
Cognitive Impairments ◽  
Brain Regions ◽  
Protective Effects ◽  
Post Traumatic Stress ◽  
Memory Impairments ◽  
Before And After ◽  
Behavior Learning

The purpose of this study was to determine preventive and protective effects of chronic orally administration with quetiapine (QUE) against anxiety-like behavior and cognitive impairments in rats exposed to the enhanced single prolonged stress (ESPS), an animal model that is used to study post-traumatic stress disorder (PTSD), and to detect changes in the expression of cortical phosphorylated p44/42 extracellular-regulated protein kinase (pERK1/2). Before or after exposure to ESPS paradigm, consisting of 2-h constraint, 20-min forced swimming, etherinduced loss of consciousness, and an electric foot shock, rats were given orally QUE (10 mg/kg daily) for 14 days. Animals were then tested in the open field (OF), elevated plus-maze (EPM), and Morris water maze (MWM). Brains were removed for immunohistochemical staining of pERK1/2. ESPS exposure resulted in pronounced anxiety-like behavior compared to unexposed animals. ESPS-exposed animals also displayed marked learning and spatial memory impairments. However, QUE treatment (both before and after ESPS exposure) significantly ameliorated anxiety-like behavior, learning and spatial memory impairments. ESPS also markedly reduced the expression of pERK1/2 in the prefrontal cortex, medial amygdala nucleus, and cingulate gyrus. Both before and after ESPS exposure QUE treatments significantly elevated the reduced pERK1/2 expression in the three brain regions. QUE has preventive and protective effects against stress-associated symptoms and the changes in pERK1/2 functions may be associated with the pathophysiology of traumatic stress and the therapeutic efficacy of anti-PTSD therapy.

scholarly journals Blue Light Stimulates Cognitive Brain Activity in Visually Blind Individuals

2013 ◽  
Vol 25 (12) ◽  
pp. 2072-2085 ◽  
Author(s):  
Gilles Vandewalle ◽  
Olivier Collignon ◽  
Joseph T. Hull ◽  
Véronique Daneault ◽  
Geneviève Albouy ◽  
...  
Keyword(s):  
Blue Light ◽  
Ganglion Cells ◽  
Brain Activity ◽  
Memory Task ◽  
Brain Regions ◽  
Human Cognition ◽  
Brain Functions ◽  
And Performance ◽  
Blind Individuals ◽  
The Impact

Light regulates multiple non-image-forming (or nonvisual) circadian, neuroendocrine, and neurobehavioral functions, via outputs from intrinsically photosensitive retinal ganglion cells (ipRGCs). Exposure to light directly enhances alertness and performance, so light is an important regulator of wakefulness and cognition. The roles of rods, cones, and ipRGCs in the impact of light on cognitive brain functions remain unclear, however. A small percentage of blind individuals retain non-image-forming photoreception and offer a unique opportunity to investigate light impacts in the absence of conscious vision, presumably through ipRGCs. Here, we show that three such patients were able to choose nonrandomly about the presence of light despite their complete lack of sight. Furthermore, 2 sec of blue light modified EEG activity when administered simultaneously to auditory stimulations. fMRI further showed that, during an auditory working memory task, less than a minute of blue light triggered the recruitment of supplemental prefrontal and thalamic brain regions involved in alertness and cognition regulation as well as key areas of the default mode network. These results, which have to be considered as a proof of concept, show that non-image-forming photoreception triggers some awareness for light and can have a more rapid impact on human cognition than previously understood, if brain processing is actively engaged. Furthermore, light stimulates higher cognitive brain activity, independently of vision, and engages supplemental brain areas to perform an ongoing cognitive process. To our knowledge, our results constitute the first indication that ipRGC signaling may rapidly affect fundamental cerebral organization, so that it could potentially participate to the regulation of numerous aspects of human brain function.

scholarly journals Pathfinder: open source software for analyzing spatial navigation search strategies

F1000Research ◽  
2020 ◽  
Vol 8 ◽  
pp. 1521
Author(s):  
Matthew B. Cooke ◽  
Timothy P. O'Leary ◽  
Phelan Harris ◽  
Ricky Ma ◽  
Richard E. Brown ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Open Source ◽  
Water Maze ◽  
Spatial Navigation ◽  
Brain Regions ◽  
Search Strategies ◽  
Sensory Stimuli ◽  
Data Files ◽  
Spatial Water Maze ◽  
Goal Directed Behavior

Spatial navigation is a universal behavior that varies depending on goals, experience and available sensory stimuli. Spatial navigational tasks are routinely used to study learning, memory and goal-directed behavior, in both animals and humans. One popular paradigm for testing spatial memory is the Morris water maze, where subjects learn the location of a hidden platform that offers escape from a pool of water. Researchers typically express learning as a function of the latency to escape, though this reveals little about the underlying navigational strategies. Recently, a number of studies have begun to classify water maze search strategies in order to clarify the precise spatial and mnemonic functions of different brain regions, and to identify which aspects of spatial memory are disrupted in disease models. However, despite their usefulness, strategy analyses have not been widely adopted due to the lack of software to automate analyses. To address this need we developed Pathfinder, an open source application for analyzing spatial navigation behaviors. In a representative dataset, we show that Pathfinder effectively characterizes the development of highly-specific spatial search strategies as male and female mice learn a standard spatial water maze. Pathfinder can read data files from commercially- and freely-available software packages, is optimized for classifying search strategies in water maze paradigms, and can also be used to analyze 2D navigation by other species, and in other tasks, as long as timestamped xy coordinates are available. Pathfinder is simple to use, can automatically determine pool and platform geometry, generates heat maps, analyzes navigation with respect to multiple goal locations, and can be updated to accommodate future developments in spatial behavioral analyses. Given these features, Pathfinder may be a useful tool for studying how navigational strategies are regulated by the environment, depend on specific neural circuits, and are altered by pathology.

scholarly journals Are alpha-band oscillations a default dynamic of the human visual brain, or a product of ongoing visual processes?

2020 ◽  
Author(s):  
Wiremu Hohaia ◽  
Blake W. Saurels ◽  
Alan Johnston ◽  
Kielan Yarrow ◽  
Derek H. Arnold
Keyword(s):  
Cognitive Neuroscience ◽  
Brain Activity ◽  
Brain Regions ◽  
Radial Motion ◽  
Alpha Band ◽  
Alpha Oscillations ◽  
Brain Waves ◽  
Visual Processes ◽  
Before And After ◽  
Eyes Open

AbstractOne of the seminal findings of cognitive neuroscience is that the power of alpha-band (∼10 Hz) brain waves, in occipital regions, increases when people close their eyes. This has encouraged the view that alpha oscillations are a default dynamic, to which the visual brain returns in the absence of input. Accordingly, we might be unable to increase the power of alpha oscillations when the eyes are closed, above the level that would usually ensue. Here we report counter evidence. We used electroencephalography (EEG) to record brain activity when people had their eyes open and closed, before and after they had adapted to radial motion. The increase in the power of alpha oscillations when people closed their eyes was enhanced by adaptation to a broad range of radial motion speeds. This effect was greatest for 10Hz motion, but robust for other frequencies, and specifically for 7.5Hz. This last observation is important, as it rules against an ongoing entrainment of activity, at the adaptation frequency, as an explanation for our results. Instead, our data show that visual processes remain active when people close their eyes, and these can be modulated by adaptation to increase the power of alpha oscillations in occipital brain regions.

Sign in / Sign up

Export Citation Format

Share Document