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1

Alteration of spontaneous spectral powers and coherences of local field potential in prenatal valproic acid mouse model of autism

100%
Cheaha D., Kumarnsit E.
Acta Neurobiologiae Experimentalis
|
2015
|
tom 75
|
nr 4
Previously, autism spectrum disorder (ASD) has been identified mainly by social communication deficits and behavioral symptoms. However, a link between behaviors and learning process in the brain of animal model of autism remained largely unexplored. Particularly, spontaneous neural signaling in learning-related brain areas has not been studied. This study investigated local field potential (LFP) of the hippocampus (HP), the olfactory bulb (OB) and the medial prefrontal cortex (mPFC) in mice prenatally exposed to valproic acid (VPA) on gestational day 13. Adult male Swiss albino mouse offspring implanted with intracranial electrodes were used. VPA-exposed mice exhibited ASD-associated behaviors. Hippocampal LFP analysis revealed that VPA group significantly increased low gamma activity (25–45 Hz) during awake immobility. Regression analyses confirmed positive correlations between locomotor speed and hippocampal theta oscillations in control but not VPA group. VPA group exhibited increases in delta (1–4 Hz) and beta (25–35 Hz) activities in OB during awake immobility and active exploring, respectively. Moreover, significantly increased and decreased coherences between HP and OB of VPA animals were seen within gamma (active exploration) and theta (awake immobility) ranges, respectively. In addition, significant increase in coherence between HP and mPFC was seen within delta range during active exploration. In addition to three ASD symptoms, VPA animals also exhibited differential patterns of olfacto-hippocampal LFP, altered locomotor speed-related hippocampal theta activities and distinct interplays between HP and learning-related brain areas. The altered olfacto-hippocampal and medial prefrontal cortex-hippocampal networks may underlie impairments in autism mouse model.
2

Nucleus accumbens local field potential power spectrums, phase - amplitude couplings and coherences following morphine treatment

81%
Reakkamnuan C., Cheaha D., Kumarnsit E.
Acta Neurobiologiae Experimentalis
|
2017
|
tom 77
|
nr 3
In the past decade, neural processing has been extensively studied in cognitive neuroscience. However, neural signaling in the nucleus accumbens (NAc) that might clarify reward process remained to be investigated. Male Swiss albino ICR mice implanted with intracranial electrodes into the NAc and the ventral tegmental area (VTA) were used for morphine administration and local field potential (LFP) recording. One‑way ANOVA revealed significant increases in low (30.3–44.9 Hz) and high (60.5–95.7 Hz) gamma powers in the NAc following morphine administration (5 and 15 mg/kg, i.p.). These gamma activities oscillated independently with different time‑course responses. Locomotor activity was also significantly increased by morphine administration. Regression analyses revealed that high gamma activity induced by morphine was positively correlated with distance travelled by animals. Low and high gamma powers were completely abolished by injection of naloxone, a non‑specific opiate antagonist. Analysis of phase‑amplitude coupling confirmed that slow oscillations at 1–4 Hz (delta) and 4–8 Hz (theta) for phase were found to significantly increase modulation index of broad (30.27–80.77 Hz) and narrow (59.48–70.34 Hz) frequency ranges for amplitude, respectively. Moreover, significant increases in coherence values between the NAc and the VTA during 30–40 min following morphine administration were seen for 22.46–44.90 Hz frequency range. Altogether, this study demonstrated changes of LFP oscillations in the NAc with low and high gamma activities, delta‑ and theta‑gamma couplings and interplay with VTA in response to morphine administration. These findings represent neural signaling in the mesolimbic dopamine pathway that might process reward function.
3

Local field potential power spectra and locomotor activity following treatment with pseudoephedrine in mice

61%
Sa-ih N., Reakkamnuan C., Samerphob N., Cheaha D., Niyomdecha S., Kumarnsit E.
Acta Neurobiologiae Experimentalis
|
2020
|
tom 80
|
nr 1
The efficacy of pseudoephedrine (PSE) as a nasal decongestant has been well‑demonstrated; however, PSE is strictly prescribed as a control substance due to its controversial psychostimulant effects. Although standard stimulatory drugs increase exploratory behavior and stimulate the dopamine system, the exact effects of PSE on locomotion and electrical activity in the striatum have not been determined. This study aimed to examine and compare the locomotor activities, local field potential (LFP) and sleep‑wake patterns produced by PSE and morphine, which is a standard drug used to promote psychomotor activity. Male Swiss albino mice were anesthetized and implanted with an intracranial electrode into the striatum. Animals were divided into four groups, which received either saline, PSE or morphine. Locomotor activity and LFP signals were continuously monitored following pseudoephedrine or morphine treatment. One‑way ANOVA revealed that locomotor count was significantly increased by morphine, but not PSE. Frequency analyses of LFP signals using fast Fourier transform also revealed significant increases in spectral powers of low‑ and high‑gamma waves following treatment with morphine, but not PSE. Sleep‑wake analysis also confirmed significant increases in waking and decreases in both non‑rapid eye movement and rapid eye movement sleep following morphine treatment. Sleep‑wakefulness did not appear to be disturbed by PSE treatment. These findings indicate that acute PSE administration, even at high doses, does not have psychostimulatory effects and may be relatively safe for the treatment of non‑chronic nasal congestion.
4

Dexamethasone induces alterations of slow wave oscillation, rapid eye movement sleep and high‑voltage spindle in rats

61%
Issuriya A., Kumarnsit E., Reakkamnuan C., Samerphob N., Sathirapanya P., Cheaha D.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr 3
Glucocorticoids arising from chronic stress and long‑term inflammatory treatment with corticosteroids are both associated with neuropathology and cognitive impairments. Many previous studies have focused on changes in brain morphology and deficits in learning behavior. However, effects of long‑term exposure to stress hormones on electrical brain signaling and sleep‑wake patterns have remained largely unexplored. This study aimed to monitor electroencephalographic (EEG) patterns induced by prolonged dexamethasone exposure. Adult male Wistar rats implanted with electrodes on the skull over the frontal and parietal cortices were intraperitoneally injected with either saline or dexamethasone (0.5 mg/kg) once daily for 21 consecutive days. Longitudinal EEG recording was performed on day 6, 11, 16 and 21. Fast Fourier transform was used for frequency power analysis. One‑way ANOVA revealed significant increases in parietal EEG power of slow frequencies (delta, theta and alpha) particularly, with the dominant theta activity seen as early as day 11 of dexamethasone treatment. Sleep‑wake analysis on day 21 confirmed a significant reduction of rapid‑eye movement (REM) sleep and increased slow frequency oscillations mainly in the parietal cortex during the awake period. The number of high‑voltage spindles (HVSs) (6‑10 Hz EEG oscillation) was significantly increased during awake and slow wave sleep (SWS) periods following dexamethasone treatment. These findings demonstrated that distinct frequency oscillations, sleep‑wakefulness and sleep spindles may be parameters of neuropathology produced by long‑term dexamethasone exposure. Early detection of these parameters might be predictive of neuropathology in long‑term corticosteroid users.
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