Spike Phase Shift Relative to Beta Oscillations Mediates Modality Selection

2020 ◽  
Vol 30 (10) ◽  
pp. 5431-5448
Author(s):  
Yanfang Zuo ◽  
Yanwang Huang ◽  
Dingcheng Wu ◽  
Qingxiu Wang ◽  
Zuoren Wang
Keyword(s):  
Phase Shift ◽  
Posterior Parietal Cortex ◽  
Visual Stimuli ◽  
Spike Timing ◽  
Male Rats ◽  
Top Down ◽  
Beta Oscillations ◽  
Neuronal Spike ◽  
Beta Power ◽  
The Brain

Abstract How does the brain selectively process signals from stimuli of different modalities? Coherent oscillations may function in coordinating communication between neuronal populations simultaneously involved in such cognitive behavior. Beta power (12–30 Hz) is implicated in top-down cognitive processes. Here we test the hypothesis that the brain increases encoding and behavioral influence of a target modality by shifting the relationship of neuronal spike phases relative to beta oscillations between primary sensory cortices and higher cortices. We simultaneously recorded neuronal spike and local field potentials in the posterior parietal cortex (PPC) and the primary auditory cortex (A1) when male rats made choices to either auditory or visual stimuli. Neuronal spikes exhibited modality-related phase locking to beta oscillations during stimulus sampling, and the phase shift between neuronal subpopulations demonstrated faster top-down signaling from PPC to A1 neurons when animals attended to auditory rather than visual stimuli. Importantly, complementary to spike timing, spike phase predicted rats’ attended-to target in single trials, which was related to the animals’ performance. Our findings support a candidate mechanism that cortices encode targets from different modalities by shifting neuronal spike phase. This work may extend our understanding of the importance of spike phase as a coding and readout mechanism.

scholarly journals Cortical beta oscillations reflect the contextual gating of visual action feedback

2020 ◽  
Author(s):  
Jakub Limanowski ◽  
Vladimir Litvak ◽  
Karl Friston
Keyword(s):  
Visual Information ◽  
Sensorimotor Integration ◽  
Beta Oscillations ◽  
Precision Control ◽  
Sensory Data ◽  
Causal Modelling ◽  
Beta Power ◽  
Current Context ◽  
The Brain ◽  
Real Hand

AbstractIn sensorimotor integration, the brain needs to decide how its predictions should accommodate novel evidence by ‘gating’ sensory data depending on the current context. Here, we examined the oscillatory correlates of this process using magnetoencephalography (MEG). We used virtual reality to decouple visual (virtual) and proprioceptive (real) hand postures during a task requiring matching either modality’s grasping movements to a target oscillation. Thus, we rendered visual information either task-relevant or a (to-be-ignored) distractor. Under visuo-proprioceptive incongruence, occipital beta power decreased relative to congruence when vision was task-relevant but increased when it had to be ignored. Dynamic causal modelling (DCM) revealed that this interaction was best explained by diametrical, task-dependent changes in visual gain. These results suggest a crucial role for beta oscillations in sensorimotor integration; particularly, in the contextual gating (i.e., gain or precision control) of visual vs proprioceptive action feedback, depending on concurrent behavioral demands.

scholarly journals Microstimulation of Posterior Parietal Cortex Biases the Selection of Eye Movement Goals During Search

2010 ◽  
Vol 104 (6) ◽  
pp. 3021-3028 ◽  
Author(s):  
Koorosh Mirpour ◽  
Wei Song Ong ◽  
James W. Bisley
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Visual Stimuli ◽  
Top Down ◽  
Lateral Intraparietal Area ◽  
Goal Selection ◽  
Priority Map ◽  
Posterior Parietal ◽  
Foraging Task ◽  
Selection Of

People can find objects in a visual scene fast and effortlessly. It is thought that this may be accomplished by creating a map of the outside world that incorporates bottom-up sensory and top-down cognitive inputs—a priority map. Eye movements are made toward the location represented by the highest activity on the priority map. We hypothesized that the lateral intraparietal area (LIP) of posterior parietal cortex acts as such a map. To test this, we performed low current microstimulation on animals trained to perform a foraging task and asked whether we could bias the animals to make a saccade to a particular stimulus, by creating an artificial peak of activity at the location representing that stimulus on the map. We found that microstimulation slightly biased the animals to make saccades to visual stimuli at the stimulated location, without actively generating saccades. The magnitude of this effect was small, but it appeared to be similar for all visual stimuli. We interpret these results to mean that microstimulation slightly biased saccade goal selection to the object represented at the stimulated location in LIP.

Chronic immobilization stress induces anxiety-related behaviors and affects brain essential minerals in male rats

2020 ◽  
pp. 1-8
Author(s):  
Zafer Sahin ◽  
Alpaslan Ozkurkculer ◽  
Omer Faruk Kalkan ◽  
Ahmet Ozkaya ◽  
Aynur Koc ◽  
...  
Keyword(s):  
Immobilization Stress ◽  
Central Area ◽  
Essential Elements ◽  
Male Rats ◽  
Control Group ◽  
Male Wistar Rats ◽  
Swimming Test ◽  
The Brain ◽  
Center Area ◽  
Chronic Immobilization Stress

Abstract. Alterations of essential elements in the brain are associated with the pathophysiology of many neuropsychiatric disorders. It is known that chronic/overwhelming stress may cause some anxiety and/or depression. We aimed to investigate the effects of two different chronic immobilization stress protocols on anxiety-related behaviors and brain minerals. Adult male Wistar rats were divided into 3 groups as follows ( n = 10/group): control, immobilization stress-1 (45 minutes daily for 7-day) and immobilization stress-2 (45 minutes twice a day for 7-day). Stress-related behaviors were evaluated by open field test and forced swimming test. In the immobilization stress-1 and immobilization stress-2 groups, percentage of time spent in the central area (6.38 ± 0.41% and 6.28 ± 1.03% respectively, p < 0.05) and rearing frequency (2.75 ± 0.41 and 3.85 ± 0.46, p < 0.01 and p < 0.05, respectively) were lower, latency to center area (49.11 ± 5.87 s and 44.92 ± 8.04 s, p < 0.01 and p < 0.01, respectively), were higher than the control group (8.65 ± 0.49%, 5.37 ± 0.44 and 15.3 ± 3.32 s, respectively). In the immobilization stress-1 group, zinc (12.65 ± 0.1 ppm, p < 0.001), magnesium (170.4 ± 1.7 ppm, p < 0.005) and phosphate (2.76 ± 0.1 ppm, p < 0.05) levels were lower than the control group (13.87 ± 0.16 ppm, 179.31 ± 1.87 ppm and 3.11 ± 0.06 ppm, respectively). In the immobilization stress-2 group, magnesium (171.56 ± 1.87 ppm, p < 0.05), phosphate (2.44 ± 0.07 ppm, p < 0.001) levels were lower, and manganese (373.68 ± 5.76 ppb, p < 0.001) and copper (2.79 ± 0.15 ppm, p < 0.05) levels were higher than the control group (179.31 ± 1.87 ppm, 3.11 ± 0.06 ppm, 327.25 ± 8.35 ppb and 2.45 ± 0.05 ppm, respectively). Our results indicated that 7-day chronic immobilization stress increased anxiety-related behaviors in both stress groups. Zinc, magnesium, phosphate, copper and manganese levels were affected in the brain.

MR venography of the brain with enhanced vessel contrast using image-domain high-pass filtering of the susceptibility phase shift

2011 ◽  
Vol 34 (5) ◽  
pp. 1218-1225 ◽  
Author(s):  
Zhaoyang Jin ◽  
Ling Xia ◽  
Min Lou ◽  
Minming Zhang ◽  
Yiping P. Du
Keyword(s):  
Phase Shift ◽  
Mr Venography ◽  
Image Domain ◽  
High Pass ◽  
The Brain

Gamma response of the brain: a multifunctional oscillation that represents bottom-up with top-down processing

2001 ◽  
Vol 39 (2-3) ◽  
pp. 137-150 ◽  
Author(s):  
S Karakaş ◽  
C Başar-Eroğlu ◽  
Ç Özesmi ◽  
H Kafadar ◽  
Ö.Ü Erzengin
Keyword(s):  
Top Down ◽  
Bottom Up ◽  
The Brain

Changes in the Cortex Neurons in Single and Fractional Gamma Radiation

2021 ◽  
Vol 66 (4) ◽  
pp. 18-24
Author(s):  
I. Ushakov ◽  
Vladimir Fyodorov
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Radiation Exposure ◽  
Comparative Assessment ◽  
Male Rats ◽  
Fractionated Irradiation ◽  
Radiation Induced ◽  
Post Radiation ◽  
Induced Changes ◽  
The Brain

Purpose: Comparative assessment of radiation-induced changes in neurons of the cerebral cortex after a single and fractionated exposure to ionizing radiation in doses of 0.1 – 1.0 Gy. Material and methods. The study was carried out in compliance with the rules of bioethics on 180 white outbred male rats at the age of 4 months. by the beginning of the experiment, exposed to a single or fractionated exposure to γ-quanta of 60Co in total doses of 0.1; 0.2; 0.5 and 1.0 Gy. Neuromorphological and histochemical methods were used to assess morphometric and tinctorial parameters of nerve cells, as well as changes in the content of protein and nucleic acids in neurons in the early and late periods of the post-radiation period. Using one-way analysis of variance, a comparative assessment of neuromorphological indicators under various modes of radiation exposure is given. Results: In the control and irradiated animals throughout their life, undulating changes in the indicators of the state of the neurons of the brain occur with a gradual decrease by the end of the experiment. Despite a number of features of the dynamics of neuromorphological parameters, these irradiation regimes do not cause functionally significant changes in the neurons of the cortex. However, in some periods of the post-radiation period, the changes under the studied irradiation regimes were multidirectional and did not always correspond to age control. Significant differences in the response of neurons to these modes of radiation exposure in the sensory and motor areas of the cerebral cortex have not been established. Conclusion: No functionally significant radiation-induced changes in neurons were found either with single or fractionated irradiation. At the same time, different modes of irradiation in general caused the same type of changes in neurons. However, in some periods of observation, changes in neuromorphological parameters under the studied irradiation regimes were not unidirectional and differed from age control, which indicates a possible risk of disturbances in the functioning of the nervous system against the background of other harmful and dangerous factors.

scholarly journals ANTINEURODEGENERATIVE ACTIVITY OF MICROALGAE DUNALIELLA SALINA IN RATS WITH ALZHEIMER’S DISEASE

2016 ◽  
Vol 10 (1) ◽  
pp. 134 ◽  
Author(s):  
Farouk Kamel Elbaz ◽  
Hanan F Aly ◽  
Wagdy Kb Khalil ◽  
Hoda F Booles ◽  
Gamila H Al
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurotrophic Factor ◽  
Dunaliella Salina ◽  
Brain Derived Neurotrophic Factor ◽  
Male Rats ◽  
Paraoxonase 1 ◽  
Pon1 Activity ◽  
The Brain ◽  
Antioxidant Effects

ABSTRACTObjective: The present study is aimed to investigate the promising action of Dunaliella salina extract as a natural protector against Alzheimer’sdisease (AD) and reported to possess a variety of activities, including antioxidant effects due to its ability to create large amount of carotenoids.Methods: D. salina is a type of halophile green microalgae was used in the present study. 50 male rats were used in this study, where aluminumchloride was orally administered to induce AD in a dose of 100 mg/kg, daily for 6 weeks. Al-intoxicated rats treated orally daily with D. salinaethanolic extract for 6 weeks in a dose of 150 mg/kg b.wt., whereas standard anti-Alzheimer drug donepezil tartrate was administered at the doseof 10 mg/kg b.wt./day for 6 consecutive weeks. The anti-Alzheimer properties of D. salina extract were achieved through measuring the calmodulin(CaM) level, paraoxonase 1 (PON1) activity, the antiapoptotic marker (Bcl2), brain-derived neurotrophic factor (BDNF), the generation of the DNAadducts (8-hydroxy-2-deoxyguanosine [8-OHdG]/2-deoxy guanosine [2-dG]), and alteration in the expression of amyloid precursor protein, β-siteAPP-cleaving enzyme 1 (BACE1), and β-site APP-cleaving enzyme 2 (BACE2) in AD rats.Results: The current results demonstrated that supplementation of AD rats with D. salina extract-enhanced CaM level, and increased PON1 activity,upregulated Bcl2 and BDNF, decreased the levels of DNA adducts (8-OHdG/2-dG), and suppressed the alterations of the expression levels of APP,BACE1, and BACE2-m RNAs as compared with those in AD rats.Conclusion: It could be concluded that the biological activity of D. salina extract might be regulated by 9-cis b-carotene protecting the brain cells fromthe oxidative stress in AD rats.Keywords: Dunaliella salina, Calmodulin, Paraoxonase 1, Bcl2, Brain-derived neurotrophic factor, Alzheimer’s disease, DNA adduct, Amyloid precursorprotein.

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