Slow and fast rhythms generated in the cerebral cortex of the anesthetized mouse

2011 ◽  
Vol 106 (6) ◽  
pp. 2910-2921 ◽  
Author(s):  
Marcel Ruiz-Mejias ◽  
Laura Ciria-Suarez ◽  
Maurizio Mattia ◽  
Maria V. Sanchez-Vives
Keyword(s):  
Cerebral Cortex ◽  
Prefrontal Cortex ◽  
Firing Rate ◽  
Oscillatory Activity ◽  
State Transitions ◽  
Population Activity ◽  
Cortical Areas ◽  
Up States ◽  
High Gamma ◽  
Up And Down States

A characterization of the oscillatory activity in the cerebral cortex of the mouse was realized under ketamine anesthesia. Bilateral recordings were obtained from deep layers of primary visual, somatosensory, motor, and medial prefrontal cortex. A slow oscillatory activity consisting of up and down states was detected, the average frequency being 0.97 Hz in all areas. Different parameters of the oscillation were estimated across cortical areas, including duration of up and down states and their variability, speed of state transitions, and population firing rate. Similar values were obtained for all areas except for prefrontal cortex, which showed significant faster down-to-up state transitions, higher firing rate during up states, and more regular cycles. The wave propagation patterns in the anteroposterior axis in motor cortex and the mediolateral axis in visual cortex were studied with multielectrode recordings, yielding speed values between 8 and 93 mm/s. The firing of single units was analyzed with respect to the population activity. The most common pattern was that of neurons firing in >90% of the up states with 1–6 spikes. Finally, fast rhythms (beta, low gamma, and high gamma) were analyzed, all of them showing significantly larger power during up states than in down states. Prefrontal cortex exhibited significantly larger power in both beta and gamma bands (up to 1 order of magnitude larger in the case of high gamma) than the rest of the cortical areas. This study allows us to carry out interareal comparisons and provides a baseline to compare against cortical emerging activity from genetically altered animals.

scholarly journals Routing information flow by separate neural synchrony frequencies allows for “functionally labeled lines” in higher primate cortex

2019 ◽  
Vol 116 (25) ◽  
pp. 12506-12515 ◽  
Author(s):  
Mohammad Bagher Khamechian ◽  
Vladislav Kozyrev ◽  
Stefan Treue ◽  
Moein Esghaei ◽  
Mohammad Reza Daliri
Keyword(s):  
Information Flow ◽  
Information Transfer ◽  
Sensory Information ◽  
Spike Timing ◽  
Oscillatory Activity ◽  
Attention Task ◽  
Cortical Areas ◽  
High Gamma ◽  
Ventral Pathway ◽  
Visual Cortical

Efficient transfer of sensory information to higher (motor or associative) areas in primate visual cortical areas is crucial for transforming sensory input into behavioral actions. Dynamically increasing the level of coordination between single neurons has been suggested as an important contributor to this efficiency. We propose that differences between the functional coordination in different visual pathways might be used to unambiguously identify the source of input to the higher areas, ensuring a proper routing of the information flow. Here we determined the level of coordination between neurons in area MT in macaque visual cortex in a visual attention task via the strength of synchronization between the neurons’ spike timing relative to the phase of oscillatory activities in local field potentials. In contrast to reports on the ventral visual pathway, we observed the synchrony of spikes only in the range of high gamma (180 to 220 Hz), rather than gamma (40 to 70 Hz) (as reported previously) to predict the animal’s reaction speed. This supports a mechanistic role of the phase of high-gamma oscillatory activity in dynamically modulating the efficiency of neuronal information transfer. In addition, for inputs to higher cortical areas converging from the dorsal and ventral pathway, the distinct frequency bands of these inputs can be leveraged to preserve the identity of the input source. In this way source-specific oscillatory activity in primate cortex can serve to establish and maintain “functionally labeled lines” for dynamically adjusting cortical information transfer and multiplexing converging sensory signals.

Neural Ensemble Coding during Working Memory Task in Rat Prefrontal Cortex

2011 ◽  
Vol 467-469 ◽  
pp. 1291-1296
Author(s):  
Wen Wen Bai ◽  
Xin Tian
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Firing Rate ◽  
Memory Task ◽  
Neural Population ◽  
Average Firing Rate ◽  
Population Activity ◽  
Ensemble Coding ◽  
Neural Ensemble ◽  
Ensemble Activity

Working memory is one of important cognitive functions and recent studies demonstrate that prefrontal cortex plays an important role in working memory. But the issue that how neural activity encodes during working memory task is still a question that lies at the heart of cognitive neuroscience. The aim of this study is to investigate neural ensemble coding mechanism via average firing rate during working memory task. Neural population activity was measured simultaneously from multiple electrodes placed in prefrontal cortex while rats were performing a working memory task in Y-maze. Then the original data was filtered by a high-pass filtering, spike detection and spike sorting, spatio-temporal trains of neural population were ultimately obtained. Then, the average firing rates were computed in a selected window (500ms) with a moving step (125ms). The results showed that the average firing rate were higher during workinig memory task, along with obvious ensemble activity. Conclusion: The results indicate that the working memory information is encoded with neural ensemble activity.

scholarly journals Synaptophysin gene expression in schizophrenia

2000 ◽  
Vol 176 (3) ◽  
pp. 236-242 ◽  
Author(s):  
Sharon L. Eastwood ◽  
Nigel J. Cairns ◽  
Paul J. Harrison
Keyword(s):  
Gene Expression ◽  
Cerebral Cortex ◽  
Prefrontal Cortex ◽  
Messenger Rna ◽  
Regional Distribution ◽  
Anterior Cingulate ◽  
Cortical Areas ◽  
Dorsolateral Prefrontal ◽  
Synaptic Pathology

BackgroundDecreased expression of proteins such as synaptophysin in the hippocampus and prefrontal cortex in schizophrenia is suggestive of synaptic pathology. However, the overall profile of changes is unclear.AimsTo investigate synaptophysin gene expression in the cerebral cortex in schizophrenia.MethodThe dorsolateral prefrontal (Brodmann area [BA] 9/46), anterior cingulate (BA 24), superior temporal (BA 22) and occipital (BA 17) cortex were studied in two series of brains, totalling 19 cases and 19 controls. Synaptophysin was measured by immunoautoradiography and immunoblotting. Synaptophysin messenger RNA (m RNA) was measured using in situ hybridisation.ResultsSynaptophysin was unchanged in schizophrenia, except for a reduction in BA 17 of one brain series. Synaptophysin mRNA was decreased in BA 17, and in BA 22 in the women with schizophrenia. No alterations were seen in BA 9/46.ConclusionsSynaptophysin expression is decreased in some cortical areas in schizophrenia. The alterations affect the mRNA more than the protein, and have an unexpected regional distribution. The characteristics of the implied synaptic pathology remain to be determined.

scholarly journals Stereotyped large amplitude cortical LFP events can be clustered and reveal precisely ordered phase-locking in neuronal populations

2019 ◽  
Author(s):  
Catalin C. Mitelut ◽  
Martin A. Spacek ◽  
Allen W. Chan ◽  
Tim H. Murphy ◽  
Nicholas V. Swindale
Keyword(s):  
Visual Cortex ◽  
Barrel Cortex ◽  
Slow Wave Sleep ◽  
Current Source ◽  
Field Potential ◽  
State Transitions ◽  
Stimulus Processing ◽  
Cortical Areas ◽  
Up States ◽  
Firing Order

AbstractDuring quiet wakefulness, slow-wave sleep and anesthesia, mammalian cortex exhibits a synchronised state during which transient changes in the local field potential (LFP) accompany periods of increased single neuron firing, known as UP-states. While UP-state genesis is still debated (Crunelli and Hughes, 2010) such transitions may constitute the default activity pattern of the entire cortex (Neske, 2016). Recent findings of preserved firing order between UP-state transitions and stimulus processing in high-firing rate (>2Hz) rat auditory and barrel cortex neurons (Luczak et al., 2015) support this hypothesis. Yet it is unknown whether UP-states are homogeneous and whether neurons with firing rates <2Hz in visual cortex or other species exhibit spiking order. Using extracellular recordings during anesthetized states in cat visual cortex and mouse visual, auditory and barrel cortex, we show that UP-states can be tracked and clustered based on the shape of the LFP waveform. We show that LFP event clusters (LECs) have current-source-density profiles that are common across different recordings or animals and using simultaneous electrophysiology and widefield voltage and calcium imaging in mouse we confirm that LEC transitions are cortex-wide phenomena. Individual LEC events can be resolved in time to within 1 – 4 ms and they elicit synchronous firing of over 75% of recorded neurons with most neurons synchronizing their firing to within ±5 – 15 ms relative LECs. Firing order of different neurons during LEC events was preserved over periods of ~30 minutes enabling future studies of UP-state transitions and firing order with near millisecond precision.Significant StatementDuring sleep and anesthetic states mammalian cortex undergoes substantial changes from awake active states. Recent studies show that single neurons in some cortical areas in rats undergo increased spiking during sleep and anesthetic states (called UP-state transitions) with some neurons firing in an order similar to awake states. This suggests that sensory processing may be similar across all states and that firing order is important for stimulus processing. Yet UP-state transitions remain poorly understood and it is unclear whether firing order is present in other cortical areas or species. Here we describe multiple classes of UP-state transitions and show most neurons in visual cortex in cats and visual, barrel and auditory cortex in mice exhibit firing order during such transitions.

scholarly journals Synchronous spiking associated with high gamma oscillations in prefrontal cortex exerts top-down control over a 5Hz-rhythmic modulation of spiking in locus coeruleus

2020 ◽  
Author(s):  
Nelson K. Totah ◽  
Nikos K. Logothetis ◽  
Oxana Eschenko
Keyword(s):  
Prefrontal Cortex ◽  
Locus Coeruleus ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Neuronal Population ◽  
Excitatory Input ◽  
Top Down ◽  
Population Activity ◽  
Oscillation Analysis ◽  
High Gamma

AbstractThe brainstem noradrenergic locus coeruleus (LC) is reciprocally connected with the prefrontal cortex (PFC). Strong coupling between LC spiking and depolarizing phase of slow (1 – 2 Hz) waves in the PFC field potentials during sleep and anesthesia suggests that the LC drives cortical state transition. Reciprocal LC-PFC connectivity should also allow interactions in the opposing (top-down) direction, but prior work has only studied prefrontal control over LC activity using direct electrical (or optogenetic) stimulation paradigms. Here, we describe the physiological characteristics of naturally occurring top-down prefrontal-coerulear interactions. Specifically, we recorded LC multi-unit activity (MUA) simultaneously with PFC single unit and local field potential (LFP) activity in urethane-anesthetized rats. We observed cross-regional coupling between the phase of ~5 Hz oscillations in LC population spike rate and the power of PFC LFP oscillations within the high Gamma (hGamma) range (60 – 200 Hz). Specifically, transient increases in PFC hGamma power preceded peaks in the ~5 Hz LC-MUA oscillation. Analysis of cross-regional transfer entropy demonstrated that the PFC hGamma transients were predictive of a transient increase in LC-MUA. A ~29 msec delay between these signals was consistent with the conduction velocity from the PFC to the LC. Finally, we showed that PFC hGamma transients are associated with synchronized spiking of a subset (27%) of PFC single units. Our data suggest that, PFC hGamma transients may indicate the timing of the top-down excitatory input to LC, at least under conditions when LC neuronal population activity fluctuates rhythmically at ~5 Hz. Synchronized PFC neuronal spiking that occurs during hGamma transients may provide a previously unknown mode of top-down control over the LC.

Temperature Modulation of Slow and Fast Cortical Rhythms

2010 ◽  
Vol 103 (3) ◽  
pp. 1253-1261 ◽  
Author(s):  
R. Reig ◽  
M. Mattia ◽  
A. Compte ◽  
C. Belmonte ◽  
M. V. Sanchez-Vives
Keyword(s):  
Firing Rate ◽  
Field Potential ◽  
Cortical Network ◽  
Network Activity ◽  
Local Network ◽  
Temperature Modulation ◽  
Moderate Increase ◽  
Control Mechanisms ◽  
Up States ◽  
Up And Down States

In the local cortical network, spontaneous emergent activity self-organizes in rhythmic patterns. These rhythms include a slow one (<1 Hz), consisting in alternation of up and down states, and also faster rhythms (10–80 Hz) generated during up states. Varying the temperature in the bath between 26 and 41°C resulted in a strong modulation of the emergent network activity. Up states became shorter for warmer temperatures and longer with cooling, whereas down states were shortest at physiological (36–37°C) temperature. The firing rate during up states was robustly modulated by temperature, increasing with higher temperatures. The sparse firing rate during down states hardly varied with temperature, thus resulting in a progressive merging of up and down states for temperatures around 30°C. Below 30°C and down to 26°C the firing lost rhythmicity, becoming progressively continuous. The slope of the down-to-up transitions, which reflects the speed of recruitment of the local network, was progressively steeper for higher temperatures, whereas wave-propagation speed exhibited only a moderate increase. Fast rhythms were particularly sensitive to temperature. Broadband high-frequency fluctuations in the local field potential were maximal for recordings at 36–38°C. Overall, we found that maintaining cortical slices at physiological temperature is critical for the generated activity to be analogous to that in vivo. We also demonstrate that changes in activity with temperature were not secondary to oxygenation changes. Temperature variation sets the in vitro cortical network at different functional regimes, allowing the exploration of network activity generation and control mechanisms.

scholarly journals Monkey prefrontal neurons during Sternberg task performance: full contents of working memory or most recent item?

2017 ◽  
Vol 117 (6) ◽  
pp. 2269-2281 ◽  
Author(s):  
R. O. Konecky ◽  
M. A. Smith ◽  
C. R. Olson
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Firing Rate ◽  
Dorsolateral Prefrontal Cortex ◽  
Memory Task ◽  
Delay Period ◽  
Population Activity ◽  
Storage Mechanism ◽  
Dorsolateral Prefrontal ◽  
Recent Item

To explore the brain mechanisms underlying multi-item working memory, we monitored the activity of neurons in the dorsolateral prefrontal cortex while macaque monkeys performed spatial and chromatic versions of a Sternberg working-memory task. Each trial required holding three sequentially presented samples in working memory so as to identify a subsequent probe matching one of them. The monkeys were able to recall all three samples at levels well above chance, exhibiting modest load and recency effects. Prefrontal neurons signaled the identity of each sample during the delay period immediately following its presentation. However, as each new sample was presented, the representation of antecedent samples became weak and shifted to an anomalous code. A linear classifier operating on the basis of population activity during the final delay period was able to perform at approximately the level of the monkeys on trials requiring recall of the third sample but showed a falloff in performance on trials requiring recall of the first or second sample much steeper than observed in the monkeys. We conclude that delay-period activity in the prefrontal cortex robustly represented only the most recent item. The monkeys apparently based performance of this classic working-memory task on some storage mechanism in addition to the prefrontal delay-period firing rate. Possibilities include delay-period activity in areas outside the prefrontal cortex and changes within the prefrontal cortex not manifest at the level of the firing rate. NEW & NOTEWORTHY It has long been thought that items held in working memory are encoded by delay-period activity in the dorsolateral prefrontal cortex. Here we describe evidence contrary to that view. In monkeys performing a serial multi-item working memory task, dorsolateral prefrontal neurons encode almost exclusively the identity of the sample presented most recently. Information about earlier samples must be encoded outside the prefrontal cortex or represented within the prefrontal cortex in a cryptic code.

Brain State–Dependency of Coherent Oscillatory Activity in the Cerebral Cortex and Basal Ganglia of the Rat

2004 ◽  
Vol 92 (4) ◽  
pp. 2122-2136 ◽  
Author(s):  
Peter J. Magill ◽  
Andrew Sharott ◽  
J. Paul Bolam ◽  
Peter Brown
Keyword(s):  
Cerebral Cortex ◽  
Basal Ganglia ◽  
Functional Organization ◽  
Cortical Activation ◽  
Partial Coherence ◽  
Oscillatory Activity ◽  
Brain State ◽  
Population Activity ◽  
State Dependency ◽  
State Frequency

The nature of the coupling between neuronal assemblies in the cerebral cortex and basal ganglia (BG) is poorly understood. We tested the hypothesis that coherent population activity is dependent on brain state, frequency range, and/or BG nucleus using data from simultaneous recordings of electrocorticogram (ECoG) and BG local field potentials (LFPs) in anesthetized rats. The coherence between ECoG and LFPs simultaneously recorded from subthalamic nucleus (STN), globus pallidus (GP), and substantia nigra pars reticulata (SNr) was largely confined to slow- (∼1 Hz) and spindle- (7–12 Hz) frequency oscillations during slow-wave activity (SWA). In contrast, during cortical activation, coherence was mostly restricted to high-frequency oscillations (15–60 Hz). The coherence between ECoG and LFPs also depended on BG recording site. Partial coherence analyses showed that, during SWA, STN and SNr shared the same temporal coupling with cortex, thereby forming a single functional axis. Cortex was also tightly, but independently, correlated with GP in a separate functional axis. During activation, STN, GP, and, to a lesser extent, SNr shared the same coherence with cortex as part of one functional axis. In addition, GP formed a second, independently coherent loop with cortex. These data suggest that coherent oscillatory activity is present at the level of LFPs recorded in cortico-basal ganglia circuits, and that synchronized population activity is dynamically organized according to brain state, frequency, and nucleus. These attributes further suggest that synchronized activity should be considered as one of a number of candidate mechanisms underlying the functional organization of these brain circuits.

Neuronal Activity of Mitral-Tufted Cells in Awake Rats During Passive and Active Odorant Stimulation

2008 ◽  
Vol 100 (1) ◽  
pp. 422-430 ◽  
Author(s):  
Romulo A. Fuentes ◽  
Marcelo I. Aguilar ◽  
María L. Aylwin ◽  
Pedro E. Maldonado
Keyword(s):  
Firing Rate ◽  
Strong Dependence ◽  
Field Potential ◽  
Temporal Patterns ◽  
Neuronal Population ◽  
Oscillatory Activity ◽  
Population Activity ◽  
Oscillatory Power ◽  
Rhythmic Discharge ◽  
Excitatory Responses

Odorants induce specific modulation of mitral/tufted (MT) cells' firing rate in the mammalian olfactory bulb (OB), inducing temporal patterns of neuronal discharge embedded in an oscillatory local field potential (LFP). While most studies have examined anesthetized animals, little is known about the firing rate and temporal patterns of OB single units and population activity in awake behaving mammals. We examined the firing rate and oscillatory activity of MT cells and LFP signals in behaving rats during two olfactory tasks: passive exposure (PE) and two-alternative (TA) choice discrimination. MT inhibitory responses are predominant in the TA task (76.5%), whereas MT excitatory responses predominate in the PE task (59.2%). Rhythmic discharge in the 12- to 100-Hz range was found in 79.0 and 68.9% of MT cells during PE and TA tasks, respectively. Most odorants presented in PE task increase rhythmic discharges at frequencies >50 Hz, whereas in TA, one of four odorants produced a modest increment <40 Hz. LFP oscillations were clearly modulated by odorants during the TA task, increasing their oscillatory power at frequencies centered at 20 Hz and decreasing power at frequencies >50 Hz. Our results indicate that firing rate responses of MT cells in awake animals are behaviorally modulated with inhibition being a prominent feature of this modulation. The occurrence of oscillatory patterns in single- and multiunitary discharge is also related to stimulation and behavioral context, while the oscillatory patterns of the neuronal population showed a strong dependence on odorant stimulation.

scholarly journals Gradual progression from sensory to task-related processing in cerebral cortex

2017 ◽  
Author(s):  
Scott L. Brincat ◽  
Markus Siegel ◽  
Constantin von Nicolai ◽  
Earl K. Miller
Keyword(s):  
Cerebral Cortex ◽  
Prefrontal Cortex ◽  
Neural Population ◽  
Population Activity ◽  
Shape Information ◽  
Sensory Inputs ◽  
Neural Representations ◽  
Cortical Hierarchy ◽  
Multiple Levels ◽  
Neural Population Activity

AbstractSomewhere along the cortical hierarchy, behaviorally relevant information is distilled from raw sensory inputs. We examined how this transformation progresses along multiple levels of the hierarchy by comparing neural representations in visual, temporal, parietal, and frontal cortices in monkeys categorizing across three visual domains (shape, motion direction, color). Representations in visual areas MT and V4 were tightly linked to external sensory inputs. In contrast, lateral prefrontal cortex (PFC) largely represented the abstracted behavioral relevance of stimuli (task rule, motion category, color category). Intermediate-level areas—posterior inferotemporal (PIT), lateral intraparietal (LIP), and frontal eye fields (FEF)—exhibited mixed representations. While the distribution of sensory information across areas aligned well with classical functional divisions—MT carried stronger motion information, V4 and PIT carried stronger color and shape information—categorical abstraction did not, suggesting these areas may participate in different networks for stimulus-driven and cognitive functions. Paralleling these representational differences, the dimensionality of neural population activity decreased progressively from sensory to intermediate to frontal cortex. This shows how raw sensory representations are transformed into behaviorally relevant abstractions and suggests that the dimensionality of neural activity in higher cortical regions may be specific to their current task.Significance statementThe earliest stages of processing in cerebral cortex reflect a relatively faithful copy of sensory inputs, but intelligent behavior requires abstracting behaviorally relevant concepts and categories. We examined how this transformation progresses through multiple levels of the cortical hierarchy by comparing neural representations in six cortical areas in monkeys categorizing across three visual domains. We found that categorical abstraction occurred in a gradual fashion across the cortical hierarchy and reached an apex in prefrontal cortex. Categorical coding did not respect classical models of large-scale cortical organization. The dimensionality of neural population activity was reduced in parallel with these representational changes. Our results shed light on how raw sensory inputs are transformed into behaviorally relevant abstractions.

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