scholarly journals Visual Thalamocortical Mechanisms of Waking State Dependent Activity and Alpha Oscillations

2021 ◽  
Author(s):  
Dennis B. Nestvogel ◽  
David A. McCormick
Keyword(s):  
Cortical Activation ◽  
List Type ◽  
Visual Thalamus ◽  
State Dependent ◽  
Dependent Activity ◽  
Alpha Oscillation ◽  
Recurrent Activity ◽  
The Brain ◽  
Lp Cells ◽  
Awake Animal

SummaryThe brain exhibits distinct patterns of recurrent activity closely related to the behavioral state of the animal. The neural mechanisms that underlie state-dependent activity in the awake animal are incompletely understood. Here, we demonstrate that two types of state-dependent activity - rapid arousal/movement related signals and a 3-5 Hz alpha-like rhythm - in the primary visual cortex (V1) of mice strongly correlate with activity in the visual thalamus. Inactivation of V1 does not interrupt arousal/movement related signals in most visual thalamic neurons, but it abolishes the 3-5 Hz oscillation. Silencing of the visual thalamus similarly eradicates the alpha-like rhythm and perturbs arousal/movement-related activation in V1. Finally, we observed that whisker movement or locomotion is not required for rapid increases in cortical activation. Our results indicate that thalamocortical interactions together with cell-intrinsic properties of thalamocortical cells play a crucial role in shaping state-dependent activity in V1 of the awake animal.HighlightsWhisker movements correlate with rapid synaptic activation in V1 and visual thalamusSilencing of V1 does not abolish movement related activation in most dLGN or LP cellsSilencing of visual thalamus strongly reduces movement related activation in V1Thalamocortical interactions generate state-dependent alpha frequency oscillationVisual thalamic cells exhibit LTS firing during alpha oscillation in the awake mouse

scholarly journals Activation State-Dependent Substrate Gating in Ca2+/Calmodulin-Dependent Protein Kinase II

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
D. E. Johnson ◽  
A. Hudmon
Keyword(s):  
Protein Kinase ◽  
Catalytic Domain ◽  
Intrinsic Property ◽  
Dependent Protein Kinase ◽  
Calcium Calmodulin Dependent ◽  
State Dependent ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
Substrate Phosphorylation ◽  
The Brain

Calcium/calmodulin-dependent protein kinase II (CaMKII) is highly concentrated in the brain where its activation by the Ca2+sensor CaM, multivalent structure, and complex autoregulatory features make it an ideal translator of Ca2+signals created by different patterns of neuronal activity. We provide direct evidence that graded levels of kinase activity and extent of T287(T286αisoform) autophosphorylation drive changes in catalytic output and substrate selectivity. The catalytic domains of CaMKII phosphorylate purified PSDs much more effectively when tethered together in the holoenzyme versus individual subunits. Using multisubstrate SPOT arrays, high-affinity substrates are preferentially phosphorylated with limited subunit activity per holoenzyme, whereas multiple subunits or maximal subunit activation is required for intermediate- and low-affinity, weak substrates, respectively. Using a monomeric form of CaMKII to control T287autophosphorylation, we demonstrate that increased Ca2+/CaM-dependent activity for all substrates tested, with the extent of weak, low-affinity substrate phosphorylation governed by the extent of T287autophosphorylation. Our data suggest T287autophosphorylation regulates substrate gating, an intrinsic property of the catalytic domain, which is amplified within the multivalent architecture of the CaMKII holoenzyme.

Effects of the DAT 3’UTR VNTR Genotype on Brain Function in Healthy Subjects and Patients with Schizophrenia

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
D.P. Prata ◽  
A. Mechelli ◽  
C. Fu ◽  
M. Picchioni ◽  
F. Kane ◽  
...  
Keyword(s):  
Verbal Fluency ◽  
Diagnostic Group ◽  
Cortical Activation ◽  
Anterior Cingulate ◽  
List Type ◽  
Type Number ◽  
Cortical Function ◽  
Repeat Allele ◽  
Word Generation ◽  
Brain Responses

Aims:To examine the effect of a polymorphism in the Dopamine Transporter (DAT) gene on brain activation during executive function and, for the first time:1.determine the extent to which this is altered in schizophrenia and2.use a verbal fluency paradigm.This is relevant since:1.DAT plays a key role in the regulation of dopamine, which modulates cortical activation during cognitive tasks and2.a disruption of dopamine function is a fundamental pathophysiological feature of schizophrenia.Method:Functional magnetic resonance imaging was used to measure whole-brain responses during overt verbal fluency in 85 subjects: 44 healthy volunteers and 41 DSM-IV schizophrenia patients. Main effects of genotype and diagnostic group on activation and their interaction were estimated using an ANOVA in SPM5.Results:The 10-repeat allele of the 3'UTR VNTR was associated with greater activation than the 9-repeat allele in the left (Z=4.8; FWEp=0.005) and right (Z=4.2; FWEp=0.057) anterior insula and with decreased activation in the rostral anterior cingulate (Z=4.3 FWEp=0.04) during word generation (versus baseline). These effects were irrespective of diagnostic group but generally more marked in patients. There were also strong trends for groupxgenotype interactions in the left middle frontal gyrus and the left nucleus accumbens. Analysis was controlled for task performance, IQ, antipsychotic medication, psychopathology and demographics.Conclusion:Cortical function during executive tasks is normally modulated by variation in the DAT gene, effect which is dependent on the brain region. DAT's effect may be altered in schizophrenia patients, which may reflect altered central dopamine function.

FC29-02 - Is prenatal exposure to alcohol a factor which re-program the brain?

2011 ◽  
Vol 26 (S2) ◽  
pp. 1978-1978
Author(s):  
J.H. Sliwowska
Keyword(s):  
Prenatal Exposure ◽  
Hpa Axis ◽  
Alcohol Exposure ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Ovariectomized Rats ◽  
List Type ◽  
Depression And Anxiety ◽  
Hpg Axis ◽  
The Brain

IntroductionFetal programming refers to the concept that early environmental factors, including prenatal exposure to stress and drugs, can permanently organize or imprint physiological and behavioural systems and increase vulnerability to disorders such as depression and anxiety later in life.AimsIs prenatal exposure to alcohol a factor which re-programs the brain?ObjectivesEffects of prenatal alcohol exposure (PAE) on:1)the hypothalamus-pituitary-adrenal (HPA) axis;2)the hypothalamus-pituitary-gonadal (HPG) axis;3)serotonergic (5-HT) system and4)adult hippocampal neurogenesis are presented.MethodsOffspring from prenatal ethanol (PAE), pair-fed (PF) and ad lib-fed control (C) dams are studied across the development or in adulthood. Immunocytochemistry and in situ hybridization techniques are used.ResultsIn term of the HPA axis: PAE alters the balance of mineralocorticoids/glucocorticoids (MRs/GRs) receptor levels in the hippocampus of adult females. In the case of the HPG axis: PAE delays puberty and changes hormonal profiles in males and females. PAE also decreases numbers of 5-HT-immunoreactive neurons in the dorsal raphe nucleus of the brainstem in ovariectomized rats and estradiol and progesterone modulate those effects. Finally, in adult PAE males, but not females stress-induced decrease in neurogenesis is altered.ConclusionsIn our animal model PAE re-programs the brain. Effects of PAE are long-lasting, affect HPA and HPG axes, 5-HT system and adult hippocampal neurogenesis and if seen in humans could contribute to increased vulnerability to depression and anxiety.

Hippocampus Retains the Periodicity of Gamma Stimulation In Vivo

2002 ◽  
Vol 88 (5) ◽  
pp. 2349-2354 ◽  
Author(s):  
J. E. Mikkonen ◽  
T. Grönfors ◽  
J. J. Chrobak ◽  
M. Penttonen
Keyword(s):  
Information Acquisition ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Short Term ◽  
Ca1 Pyramidal Cells ◽  
State Dependent ◽  
Hippocampal Ca1 ◽  
Oscillatory Rhythms ◽  
The Brain

Several behavioral state dependent oscillatory rhythms have been identified in the brain. Of these neuronal rhythms, gamma (20–70 Hz) oscillations are prominent in the activated brain and are associated with various behavioral functions ranging from sensory binding to memory. Hippocampal gamma oscillations represent a widely studied band of frequencies co-occurring with information acquisition. However, induction of specific gamma frequencies within the hippocampal neuronal network has not been satisfactorily established. Using both in vivo intracellular and extracellular recordings from anesthetized rats, we show that hippocampal CA1 pyramidal cells can discharge at frequencies determined by the preceding gamma stimulation, provided that the gamma is introduced in theta cycles, as occurs in vivo. The dynamic short-term alterations in the oscillatory discharge described in this paper may serve as a coding mechanism in cortical neuronal networks.

Greater Movement-Related Cortical Potential During Human Eccentric Versus Concentric Muscle Contractions

2001 ◽  
Vol 86 (4) ◽  
pp. 1764-1772 ◽  
Author(s):  
Yin Fang ◽  
Vlodek Siemionow ◽  
Vinod Sahgal ◽  
Fuqin Xiong ◽  
Guang H. Yue
Keyword(s):  
Muscle Activation ◽  
Onset Time ◽  
Muscle Contractions ◽  
Elbow Flexor ◽  
Movement Planning ◽  
Cortical Activation ◽  
Cortical Potential ◽  
Eeg Signals ◽  
Muscle Actions ◽  
The Brain

Despite abundant evidence that different nervous system control strategies may exist for human concentric and eccentric muscle contractions, no data are available to indicate that the brain signal differs for eccentric versus concentric muscle actions. The purpose of this study was to evaluate electroencephalography (EEG)-derived movement-related cortical potential (MRCP) and to determine whether the level of MRCP-measured cortical activation differs between the two types of muscle activities. Eight healthy subjects performed 50 voluntary eccentric and 50 voluntary concentric elbow flexor contractions against a load equal to 10% body weight. Surface EEG signals from four scalp locations overlying sensorimotor-related cortical areas in the frontal and parietal lobes were measured along with kinetic and kinematic information from the muscle and joint. MRCP was derived from the EEG signals of the eccentric and concentric muscle contractions. Although the elbow flexor muscle activation (EMG) was lower during eccentric than concentric actions, the amplitude of two major MRCP components—one related to movement planning and execution and the other associated with feedback signals from the peripheral systems—was significantly greater for eccentric than for concentric actions. The MRCP onset time for the eccentric task occurred earlier than that for the concentric task. The greater cortical signal for eccentric muscle actions suggests that the brain probably plans and programs eccentric movements differently from concentric muscle tasks.

scholarly journals Cholinergic Regulation of the Posterior Medial Thalamic Nucleus

2006 ◽  
Vol 96 (5) ◽  
pp. 2265-2273 ◽  
Author(s):  
Radi Masri ◽  
Jason C. Trageser ◽  
Tatiana Bezdudnaya ◽  
Ying Li ◽  
Asaf Keller
Keyword(s):  
Brain Stem ◽  
Cholinergic System ◽  
Somatosensory System ◽  
Zona Incerta ◽  
State Dependent ◽  
Presynaptic Site ◽  
Behavioral States ◽  
Flow Of Information ◽  
The Brain

We previously showed that the GABAergic nucleus zona incerta (ZI) suppresses vibrissae-evoked responses in the posterior medial (POm) thalamus of the rodent somatosensory system. We proposed that this inhibitory incertothalamic pathway regulates POm responses during different behavioral states. Here we tested the hypothesis that this pathway is modulated by the ascending brain stem cholinergic system, which regulates sleep–wake cycles and states of vigilance. We demonstrate that cholinergic inputs facilitate POm responses to vibrissae stimulation. Activation of the cholinergic system by stimulation of brain stem cholinergic nuclei (laterodorsal tegmental and the pedunculopontine tegmental) or by tail pinch significantly increased the magnitude of POm responses to vibrissae stimulation. Microiontophoresis of the muscarinic receptor agonist carbachol enhanced POm responses to vibrissae stimulation. Application of carbachol to an in vitro slice preparation reduced the frequency but not the amplitude of miniature inhibitory postsynaptic currents, indicating a presynaptic site of action for carbachol. We conclude that the cholinergic system facilitates POm responses by suppressing GABAergic inputs from ZI. We propose the state-dependent gating hypothesis, which asserts that differing behavioral states, regulated by the brain stem cholinergic system, modulate the flow of information through POm.

scholarly journals Emergence of Time in Quantum Gravity: Is Time Necessarily Flowing?

KronoScope ◽  
2013 ◽  
Vol 13 (1) ◽  
pp. 67-84 ◽  
Author(s):  
Pierre Martinetti
Keyword(s):  
Quantum Mechanics ◽  
Quantum Gravity ◽  
Proper Time ◽  
Dimensional Space ◽  
Thermal Time ◽  
List Type ◽  
State Dependent ◽  
Dimensional Space Time ◽  
Flow Of Time ◽  
Time In Quantum Mechanics

Abstract We discuss the emergence of time in quantum gravity and ask whether time is always “something that flows.” We first recall that this is indeed the case in both relativity and quantum mechanics, although in very different manners: time flows geometrically in relativity (i.e., as a flow of proper time in the four dimensional space-time), time flows abstractly in quantum mechanics (i.e., as a flow in the space of observables of the system). We then ask the same question in quantum gravity in the light of the thermal time hypothesis of Connes and Rovelli. The latter proposes to answer the question of time in quantum gravity (or at least one of its many aspects) by postulating that time is a state-dependent notion. This means that one is able to make a notion of time as an abstract flow—that we call the thermal time—emerge from the knowledge of both: the algebra of observables of the physical system under investigation; a state of thermal equilibrium of this system. Formally, the thermal time is similar to the abstract flow of time in quantum mechanics, but we show in various examples that it may have a concrete implementation either as a geometrical flow or as a geometrical flow combined with a non-geometric action. This indicates that in quantum gravity, time may well still be “something that flows” at some abstract algebraic level, but this does not necessarily imply that time is always and only “something that flows” at the geometric level.

Representation of Sound Categories in Auditory Cortical Maps

2004 ◽  
Vol 47 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Frank H. Guenther ◽  
Alfonso Nieto-Castanon ◽  
Satrajit S. Ghosh ◽  
Jason A. Tourville
Keyword(s):  
Discrimination Training ◽  
Cortical Activation ◽  
Vowel Sound ◽  
Perceptual Distortion ◽  
Nonspeech Sounds ◽  
Acoustic Space ◽  
Sound Category ◽  
Cortical Representations ◽  
Training Discrimination ◽  
The Brain

Functional magnetic resonance imaging (fMRI) was used to investigate the representation of sound categories in human auditory cortex. Experiment 1 investigated the representation of prototypical (good) and nonprototypical (bad) examples of a vowel sound. Listening to prototypical examples of a vowel resulted in less auditory cortical activation than did listening to nonprototypical examples. Experiments 2 and 3 investigated the effects of categorization training and discrimination training with novel nonspeech sounds on auditory cortical representations. The 2 training tasks were shown to have opposite effects on the auditory cortical representation of sounds experienced during training: Discrimination training led to an increase in the amount of activation caused by the training stimuli, whereas categorization training led to decreased activation. These results indicate that the brain efficiently shifts neural resources away from regions of acoustic space where discrimination between sounds is not behaviorally important (e.g., near the center of a sound category) and toward regions where accurate discrimination is needed. The results also provide a straightforward neural account of learned aspects of perceptual distortion near sound categories: Sounds from the center of a category are more difficult to discriminate from each other than sounds near category boundaries because they are represented by fewer cells in the auditory cortical areas.

scholarly journals Cortical activation in alexithymia as a response to emotional stimuli

2008 ◽  
Vol 192 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Hasse Karlsson ◽  
Petri Näätänen ◽  
Hanna Stenman
Keyword(s):  
Emotion Processing ◽  
Three Dimensional ◽  
Brain Regions ◽  
Physical Symptoms ◽  
Cortical Activation ◽  
Anterior Cingulate ◽  
Control Group ◽  
Emotional Stimuli ◽  
Healthy Women ◽  
The Brain

BackgroundAlexithymia has been shown to be related to many psychiatric and somatic illnesses. Aberrant emotion processing in the brain may underlie several psychiatric disorders. However, little is known about the neurobiological underpinnings of alexithymia.AimsTo determine the way in which the brain processes emotion in alexithymia.MethodThe participants were 10 healthy women with alexithymia and 11 healthy women without this condition, recruited into the study on the basis of their scores on the 20-item Toronto Alexithymia Scale. Four films were projected on a video screen to induce each of three emotional conditions (neutral, amusement, sadness). The brain areas activated during emotional stimuli in the alexithymia group were compared with those activated in the non-alexithymia group. Scans of the distribution of [15O]H2O were acquired using a positron emission tomography (PET) scanner operated in three-dimensional mode.ResultsIn response to emotional stimuli participants with alexithymia activated more parts of their sensory and motor cortices and insula, especially on the left side, and less of their anterior cingulate, compared with the control group.ConclusionsWomen with alexithymia seem to over-activate their ‘bodily’ brain regions, implying a different mode of emotion processing. This may be related to their tendency to experience physical symptoms.

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