scholarly journals Stimulus dependence of theta rhythmic activity in primate V1 and its potential relevance for visual perception

2021 ◽  
Author(s):  
Prasakti Tenri Fanyiwi ◽  
Beshoy Agayby ◽  
Ricardo Kienitz ◽  
Marcus Haag ◽  
Michael C. Schmid
Keyword(s):  
Visual Perception ◽  
Visual Stimulus ◽  
Neural Activity ◽  
Temporal Dynamics ◽  
Reaction Times ◽  
Rhythmic Activity ◽  
Peak Frequency ◽  
Theta Oscillations ◽  
Theta Power ◽  
Fixational Eye Movements

AbstractA growing body of psychophysical research reports theta (3-8 Hz) rhythmic fluctuations in visual perception that are often attributed to an attentional sampling mechanism arising from theta rhythmic neural activity in mid- to high-level cortical association areas. However, it remains unclear to what extent such neuronal theta oscillations might already emerge at early sensory cortex like the primary visual cortex (V1), e.g. from the stimulus filter properties of neurons. To address this question, we recorded multi-unit neural activity from V1 of two macaque monkeys viewing a static visual stimulus with variable sizes, orientations and contrasts. We found that among the visually responsive electrode sites, more than 50 % showed a spectral peak at theta frequencies. Theta power varied with varying basic stimulus properties. Within each of these stimulus property domains (e.g. size), there was usually a single stimulus value that induced the strongest theta activity. In addition to these variations in theta power, the peak frequency of theta oscillations increased with increasing stimulus size and also changed depending on the stimulus position in the visual field. Further analysis confirmed that this neural theta rhythm was indeed stimulus-induced and did not arise from small fixational eye movements (microsaccades). When the monkeys performed a detection task of a target embedded in a theta-generating visual stimulus, reaction times also tended to fluctuate at the same theta frequency as the one observed in the neural activity. The present study shows that a highly stimulus-dependent neuronal theta oscillation can be elicited in V1 that appears to influence the temporal dynamics of visual perception.

scholarly journals Inhibitory Control in the Absence of Awareness: Interactions Between Frontal and Motor Cortex Oscillations Mediate Implicitly Learned Responses

2021 ◽  
Vol 15 ◽  
Author(s):  
Silvia L. Isabella ◽  
J. Allan Cheyne ◽  
Douglas Cheyne
Keyword(s):  
Cognitive Control ◽  
Pupil Diameter ◽  
Reaction Times ◽  
Brain Regions ◽  
Cognitive Effort ◽  
Theta Activity ◽  
Theta Oscillations ◽  
Response Preparation ◽  
Experimental Conditions ◽  
Theta Power

Cognitive control of action is associated with conscious effort and is hypothesised to be reflected by increased frontal theta activity. However, the functional role of these increases in theta power, and how they contribute to cognitive control remains unknown. We conducted an MEG study to test the hypothesis that frontal theta oscillations interact with sensorimotor signals in order to produce controlled behaviour, and that the strength of these interactions will vary with the amount of control required. We measured neuromagnetic activity in 16 healthy adults performing a response inhibition (Go/Switch) task, known from previous work to modulate cognitive control requirements using hidden patterns of Go and Switch cues. Learning was confirmed by reduced reaction times (RT) to patterned compared to random Switch cues. Concurrent measures of pupil diameter revealed changes in subjective cognitive effort with stimulus probability, even in the absence of measurable behavioural differences, revealing instances of covert variations in cognitive effort. Significant theta oscillations were found in five frontal brain regions, with theta power in the right middle frontal and right premotor cortices parametrically increasing with cognitive effort. Similar increases in oscillatory power were also observed in motor cortical gamma, suggesting an interaction. Right middle frontal and right precentral theta activity predicted changes in pupil diameter across all experimental conditions, demonstrating a close relationship between frontal theta increases and cognitive control. Although no theta-gamma cross-frequency coupling was found, long-range theta phase coherence among the five significant sources between bilateral middle frontal, right inferior frontal, and bilateral premotor areas was found, thus providing a mechanism for the relay of cognitive control between frontal and motor areas via theta signalling. Furthermore, this provides the first evidence for the sensitivity of frontal theta oscillations to implicit motor learning and its effects on cognitive load. More generally these results present a possible a mechanism for this frontal theta network to coordinate response preparation, inhibition and execution.

Medial Prefrontal Theta Oscillations Track the Time Course of Interference during Selective Memory Retrieval

2014 ◽  
Vol 26 (4) ◽  
pp. 777-791 ◽  
Author(s):  
Catarina S. Ferreira ◽  
Alejandra Marful ◽  
Tobias Staudigl ◽  
Teresa Bajo ◽  
Simon Hanslmayr
Keyword(s):  
Memory Retrieval ◽  
Time Course ◽  
Retrieval Practice ◽  
Temporal Dynamics ◽  
Theta Oscillations ◽  
Theta Power ◽  
Fine Grained ◽  
Retrieval Condition ◽  
Induced Forgetting ◽  
Noncompetitive Condition

Memory retrieval is often challenged by other irrelevant competing memories that cause interference. This phenomenon is typically studied with the retrieval practice paradigm in which a category cue (e.g., Fruits) is presented together with an item-specific cue (e.g., Or::). Presentation of the category cue usually induces interference by reactivating competing memories (e.g., Banana, Apple, etc.), which is thought to be solved by means of inhibition, leading to retrieval-induced forgetting of these competing memories. Previous studies associated interference with an increase in medial prefrontal theta band (4–8 Hz) oscillations, but these studies could not disentangle the interference from the inhibition processes. We here used a retrieval practice procedure in which the category cue was presented before the item-specific cue to disentangle the interference from the inhibition signal. Furthermore, a competitive retrieval condition was contrasted with a noncompetitive condition. At a behavioral level, retrieval-induced forgetting was found in the competitive but not in the noncompetitive condition. At a neural level, presentation of the category cue elicited higher levels of theta power in the competitive condition, when compared with the noncompetitive retrieval condition. Importantly, this difference was localized to the ACC, which has been associated with the detection and mediation of interference. Additionally, theta power decreased upon presentation of the item-specific cue, and this difference was related to later forgetting. Our results therefore disentangle, for the first time, interference and inhibition in episodic memory retrieval and suggest that theta oscillations track the fine-grained temporal dynamics of interference during competitive memory retrieval.

Theta Oscillations and Human Navigation: A Magnetoencephalography Study

2002 ◽  
Vol 14 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Dráulio B. de Araújo ◽  
Oswaldo Baffa ◽  
Ronald T. Wakai
Keyword(s):  
Virtual Reality ◽  
Theta Rhythm ◽  
Motor Task ◽  
Spatiotemporal Analysis ◽  
Peak Frequency ◽  
Theta Oscillations ◽  
Theta Power ◽  
Knowing That ◽  
Starting Point ◽  
Passive Viewing

Magnetoencephalography (MEG) was used to study alpha and theta activity while subjects navigated through a computer-generated virtual reality town. The subjects were first allowed to explore the environment freely. They then had to navigate from a starting point to a destination, knowing that an obstruction would appear at one of several possible locations along the main route and force them to take a detour. Spatiotemporal analysis of the theta and alpha bands were performed (1) prior to the start of navigation, (2) from the start of navigation until the obstruction was encountered, (3) during the time subjects were contemplating a detour and were not navigating, and (4) from the resumption of navigation until the destination was reached. In all subjects, theta power was strongest during the two periods of navigation. The peak frequency of the oscillations was approximately 3.7 Hz. Control studies consisted of a motor task similar to that required for navigation, passive viewing of a tour through the same virtual reality town, and a mental concentration task. No consistent increases in theta power were seen in the MEG during any of the control tasks. The results suggest an association between theta rhythm and the performance of navigational tasks in humans.

Some Factors Affecting Reaction Times to Auditory Stimuli in Mental Patients

1954 ◽  
Vol 100 (419) ◽  
pp. 462-477 ◽  
Author(s):  
K. R. L. Hall ◽  
E. Stride
Keyword(s):  
Reaction Time ◽  
Visual Perception ◽  
Visual Stimuli ◽  
Reaction Times ◽  
Auditory Stimuli ◽  
Factors Affecting ◽  
Mental Patients ◽  
Personal Equation ◽  
Work Up

A number of studies on reaction time (R.T.) latency to visual and auditory stimuli in psychotic patients has been reported since the first investigations on the personal equation were carried out. The general trends from the work up to 1943 are well summarized by Hunt (1944), while Granger's (1953) review of “Personality and visual perception” contains a summary of the studies on R.T. to visual stimuli.

scholarly journals Familiarity affects the same event-related brain potential components in note readers and non-note readers

2018 ◽  
Vol 1 ◽  
pp. 205920431877823 ◽  
Author(s):  
Linda Becker
Keyword(s):  
Visual Perception ◽  
Neural Plasticity ◽  
Visual Processing ◽  
Music Perception ◽  
Reaction Times ◽  
Future Research ◽  
Familiarity Effect ◽  
Professional Musicians ◽  
Brain Potential ◽  
Cognitive Domains

Musical expertise can lead to neural plasticity in specific cognitive domains (e.g., in auditory music perception). However, not much is known about whether the visual perception of simple musical symbols (e.g., notes) already differs between musicians and non-musicians. This was the aim of the present study. Therefore, the Familiarity Effect (FE) – an effect which occurs quite early during visual processing and which is based on prior knowledge or expertise – was investigated. The FE describes the phenomenon that it is easier to find an unfamiliar element (e.g., a mirrored eighth note) in familiar elements (e.g., normally oriented eighth notes) than to find a familiar element in a background of unfamiliar elements. It was examined whether the strength of the FE for eighth notes differs between note readers and non-note readers. Furthermore, it was investigated at which component of the event-related brain potential (ERP) the FE occurs. Stimuli that consisted of either eighth notes or vertically mirrored eighth notes were presented to the participants (28 note readers, 19 non-note readers). A target element was embedded in half of the trials. Reaction times, sensitivity, and three ERP components (the N1, N2p, and P3) were recorded. For both the note readers and the non-note readers, strong FEs were found in the behavioral data. However, no differences in the strength of the FE between groups were found. Furthermore, for both groups, the FE was found for the same ERP components (target-absent trials – N1 latency; target-present trials – N2p latency, N2p amplitude, P3 amplitude). It is concluded that the early visual perception of eighth note symbols does not differ between note readers and non-note readers. However, future research is needed to verify this for more complex musical stimuli and for professional musicians.

The Effects of Ethyl Alcohol on a Driver's Driving Skill, Visual Perception, Risk Acceptance, Choice Reaction Times and Information Processing Rates

1974 ◽  
Vol 18 (2) ◽  
pp. 116-116
Author(s):  
Helmut T. Zwahlen
Keyword(s):  
Information Processing ◽  
Standard Deviation ◽  
Visual Perception ◽  
Reaction Times ◽  
Driving Skill ◽  
Alcohol Condition ◽  
The Mean ◽  
Risk Acceptance ◽  
Standard Deviations ◽  
Choice Reaction Times

Twelve subjects (20–37 years old) were tested in the laboratory and eleven out of these were also tested in a car in the field, first under a no alcohol condition and then under an alcohol condition (approximately 0.10% BAC). In the laboratory the subjects simple and choice reaction times for two uncertainty modes were measured and their information processing rates (3 bits unsertainty) were determined. In the field the subjects driving skill for driving through a gap with 20 inches total clearance at 20 MPH was measured, as well as their static visual perceptual capabilities and risk acceptance decisions for a 46 feet viewing distance using psychophysical experimental methods. Based upon the driving skill measure (standard deviation of centerline deviations in the gap), the mean of the psychometric visual gap perception function and the mean of the psychometric gap risk acceptance function, the “Safety Distance” and the “Driver Safety Index” (DSI) were obtained. Based upon a statistical analysis of the data we may conclude first that the effects of alcohol (approximately 0.10% BAC) vary widely from one subject to another (slighthly improved performance to highly impaired performance) and that the changes in the group averages of the means and standard deviations of the psychometric visual perception and risk acceptance functions, the driving skill distributions, the “Safety Distances” and the DSI's for the subjects (although all changes in the group averages are in the expected direction) are statistically not significant (α = .05). Second, the group average of the means of the choice reaction times for the subjects increased by 5% under the alcohol condition (statistically significant, α = .05), but more important the group average of the standard deviations of the choice reaction times for the subjects increased by 23% (statistically significant, α = .05). The group average of the information processing rates for the subjects decreased by 3% (statistically not significant, α = .05) under the alcohol condition. A system model in which the system demands on the driver are represented in terms of choice reaction times is used to demonstrate that the increase in performance variability (expressed by the standard deviation of choice reaction times) under the influence of alcohol provides a much better explanation for the higher accident involvement than the historically most frequently used rather small increase in average performance (expressed by the mean of choice reaction times).

Rhythmic Activity and Individual Variability in Recognition Memory: Theta Oscillations Correlate with Performance whereas Alpha Oscillations Correlate with ERPs

2017 ◽  
Vol 29 (1) ◽  
pp. 183-202 ◽  
Author(s):  
Yvonne Y. Chen ◽  
Jeremy B. Caplan
Keyword(s):  
Individual Differences ◽  
Recognition Memory ◽  
Memory Task ◽  
Rhythmic Activity ◽  
Individual Variability ◽  
Theta Oscillations ◽  
Alpha Oscillations ◽  
Alpha Oscillation ◽  
Familiarity And Recollection ◽  
Visual Inattention

During study trials of a recognition memory task, alpha (∼10 Hz) oscillations decrease, and concurrently, theta (4–8 Hz) oscillations increase when later memory is successful versus unsuccessful (subsequent memory effect). Likewise, at test, reduced alpha and increased theta activity are associated with successful memory (retrieval success effect). Here we take an individual-differences approach to test three hypotheses about theta and alpha oscillations in verbal, old/new recognition, measuring the difference in oscillations between hit trials and miss trials. First, we test the hypothesis that theta and alpha oscillations have a moderately mutually exclusive relationship; but no support for this hypothesis was found. Second, we test the hypothesis that theta oscillations explain not only memory effects within participants, but also individual differences. Supporting this prediction, durations of theta (but not alpha) oscillations at study and at test correlated significantly with d′ across participants. Third, we test the hypothesis that theta and alpha oscillations reflect familiarity and recollection processes by comparing oscillation measures to ERPs that are implicated in familiarity and recollection. The alpha-oscillation effects correlated with some ERP measures, but inversely, suggesting that the actions of alpha oscillations on memory processes are distinct from the roles of familiarity- and recollection-linked ERP signals. The theta-oscillation measures, despite differentiating hits from misses, did not correlate with any ERP measure; thus, theta oscillations may reflect elaborative processes not tapped by recollection-related ERPs. Our findings are consistent with alpha oscillations reflecting visual inattention, which can modulate memory, and with theta oscillations supporting recognition memory in ways that complement the most commonly studied ERPs.

scholarly journals Author Correction: Individual alpha peak frequency is slower in schizophrenia and related to deficits in visual perception and cognition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ian S. Ramsay ◽  
Peter A. Lynn ◽  
Brandon Schermitzler ◽  
Scott R. Sponheim
Keyword(s):  
Visual Perception ◽  
Peak Frequency ◽  
Alpha Peak

scholarly journals Circadian modulation of neurons and astrocytes controls synaptic plasticity in hippocampal area CA1

2019 ◽  
Author(s):  
John P. McCauley ◽  
Maurice A. Petroccione ◽  
Lianna Y. D’Brant ◽  
Gabrielle C. Todd ◽  
Nurat Affinnih ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Temporal Dynamics ◽  
Rhythmic Activity ◽  
Surface Expression ◽  
Receptor Activation ◽  
Cellular Mechanisms ◽  
Functional Changes ◽  
Area Ca1 ◽  
Hippocampal Area

SummaryMost animal species operate according to a 24-hour period set by the suprachiasmatic nucleus (SCN) of the hypothalamus. The rhythmic activity of the SCN is known to modulate hippocampal-dependent memory processes, but the molecular and cellular mechanisms that account for this effect remain largely unknown. Here, we show that there are cell-type specific structural and functional changes that occur with circadian rhythmicity in neurons and astrocytes in hippocampal area CA1. Pyramidal neurons change the surface expression of NMDA receptors, whereas astrocytes change their proximity to synapses. Together, these phenomena alter glutamate clearance, receptor activation and integration of temporally clustered excitatory synaptic inputs, ultimately shaping hippocampal-dependent learningin vivo. We identify corticosterone as a key contributor to changes in synaptic strength. These findings identify important mechanisms through which neurons and astrocytes modify the molecular composition and structure of the synaptic environment, contribute to the local storage of information in the hippocampus and alter the temporal dynamics of cognitive processing.

scholarly journals Functional but not obligatory link between microsaccades and neural modulation by covert spatial attention

2021 ◽  
Author(s):  
Baiwei Liu ◽  
Anna C Nobre ◽  
Freek van Ede
Keyword(s):  
Spatial Attention ◽  
Neural Activity ◽  
Alpha Activity ◽  
Spatial Modulation ◽  
Fixational Eye Movements ◽  
Neural Modulation ◽  
Gaze Behaviour ◽  
Eeg Alpha ◽  
Eeg Alpha Activity ◽  
Spatial Modulations

Covert spatial attention is associated with spatially specific modulation of neural activity as well as with directional biases in fixational eye-movements known as microsaccades. Recently, this link has been suggested to be obligatory, such that modulation of neural activity by covert spatial attention occurs only when paired with microsaccades toward the attended location. Here we revisited this link between microsaccades and neural modulation by covert spatial attention in humans. We investigated spatial modulation of 8-12 Hz EEG alpha activity and microsaccades in a context with no incentive for overt gaze behaviour: when attention is directed internally within the spatial layout of visual working memory. In line with a common attentional origin, we show that spatial modulations of alpha activity and microsaccades co-vary: alpha lateralisation is stronger in trials with microsaccades toward compared to away from the memorised location of the to-be-attended item and occurs earlier in trials with earlier microsaccades toward this item. Critically, however, trials without attention-driven microsaccades nevertheless showed clear spatial modulation of alpha activity - comparable to the neural modulation observed in trials with attention-driven microsaccades. Thus, directional biases in microsaccades are correlated with neural signatures of covert spatial attention, but they are not a prerequisite for neural modulation by covert spatial attention to be manifest.

Sign in / Sign up

Export Citation Format

Share Document