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PubMed1997

The effect of hypercapnia and hypercapnia associated with central cooling on breathing in unanesthetized fetal lambs.

In utero breathing activity is present periodically, but it must become continuous at birth. We investigated the effect of hypercapnia and of hypercapnia combined with central cooling on fetal breathing in seven chronically instrumented fetal lambs of 131-134-d gestation, using an extracorporeal membrane oxygenation (ECMO) system to control fetal blood gases and fetal temperature. During fetal hypercapnia (from a partial pressure of arterial CO2 (Paco2) 6.18 +/- 0.11 kPa to Paco2 7.39 +/- 0.15 kPa) frequency, amplitude, and incidence of fetal breathing movements during low voltage electrocortical activity (LV ECoG) increased significantly compared with isocapnic control on ECMO, but breathing remained absent during high voltage electrocortical activity (HV ECoG). During hypercapnia accompanied by central cooling (Paco2 7.90 +/- 0.13 kPa, temperature decreased by 2.1 degrees C) there were similar changes in fetal breathing movements during LV ECoG, but in four out of seven fetuses fetal breathing movements continued throughout HV ECoG. Hypercapnia accompanied by central cooling can thus override the inhibitory effects of HV ECoG on fetal breathing movements. This may be due to changes in sensitivity to CO2 produced by an increase in afferent input to the CNS.

Animals↗

PubMed1998

Urine production rate and renal blood flow in the near-term ovine fetus are not related to high and low voltage electrocortical activity.

Studies in both the human and ovine near-term fetus have identified the clustering of physiologic and behavioral parameters into states. In a recent study in the human fetus a considerable decrease was found in fetal urine production during non-rapid eye movement (non-REM) compared with REM sleep. Whether this decrease was caused by decreased renal blood flow or changes in urine concentration is not known. This prompted us to investigate the relation between fetal urine production rate and electrocortical activity in the near-term ovine fetus. We hypothesized that in the ovine fetus urine production and renal blood flow during REM [comparable to low voltage electrocortical activity (LV ECoG)] would be lower than during non-REM [(high voltage (HV) ECoG)]. In eight fetal sheep between 123 and 127 d of gestation (term 147 d), ECoG, renal blood flow, urine flow, and urine osmolality were measured continuously for 6 h on 2 consecutive days. Data were analyzed into HV ECoG and LV ECoG whereafter urine flow, urine osmolality, and renal blood flow data were averaged per state. We found no significant differences in urine flow, urine osmolality, or renal blood flow between the two behavioral states in the ovine fetus. Because these data are in sharp contrast to those found in the human fetus, we conclude that the observed dissimilarities in renal responses between the human and sheep fetus add to the already known differences in behavioral states between the two species.

Animals↗

PubMed1986

[Pharmacological studies on Y-8894. (III). Its effect on the abnormal electrocorticogram induced by destruction of the internal capsule].

The effect of Y-8894 on the abnormal electrocorticogram (ECoG) of alcuronium-immobilized rats, induced by destruction of the internal capsule with heat, was compared with that produced by imipramine, amantadine and Ca-hopantenate. ECoG power in the delta + theta (1-7 Hz), alpha (7.5-12.5 Hz) and beta (13-30 Hz) bands was used as an index. Delta + theta power increased following destruction of the internal capsule with heat. The increased delta + theta power (abnormal ECoG) lasted for 60 min following the injection of saline at 60 degrees C for 3 min. Y-8894 (0.1-1 mg/kg, i.v.) apparently improved the abnormal ECoG dose-dependently by significantly reducing the increased delta + theta power. Similar results were obtained with amantadine (10 mg/kg, i.v.), but its potency was weaker than that of Y-8894. Imipramine (1 mg/kg, i.v.) and Ca-hopantenate (30 mg/kg, i.v.), however, both failed to modify the abnormal ECoG. All drugs, except Ca-hopantenate, decreased the magnitudes of the alpha and beta bands. The above results suggest that Y-8894 may be effective in ameliorating cerebral dysfunction induced experimentally by the lesion of the internal capsule.

Amantadine↗

PubMed1996

Intraoperative electrocorticography in children with medically intractable epilepsy.

Intraoperative electrocorticography (ECoG) was performed to localize epileptic foci in 20 children undergoing temporal and extratemporal surgery for intractable epilepsy under modified neuroleptanalgesia. Nitrous oxide gas was discontinued at least 15 minutes before and during preresection ECoG recording, which lasted for 30 minutes. Seventeen patients showed epileptiform discharges on preresection ECoG. Hyperventilation loading, monitored by electroencephalography or ECoG in all patients, induced enhanced or induced epileptiform activities in 17 patients and provoked electroencephalographic seizures in 10 patients. All foci in non-eloquent areas were resected. Fifteen patients have been seizure-free with reduced medication, and two patients have achieved worthwhile improvement. Habitual seizures have remained in three patients. Two of these patients had foci in eloquent areas which could not be resected. Intraoperative ECoG can improve the outcome of surgery for intractable epilepsy by localizing epileptic foci for resection.

Adolescent↗

PubMed1988

Auditory brainstem responses and extratympanic electrocochleography. A threshold comparison in children.

Electrocochleography (ECoG) and auditory brainstem response (ABR) have been recorded simultaneously in 23 children referred for threshold evaluation. The ECoG electrode is an extratympanic silver ball (Life-Tech) whereas the ABR is recorded with Ag-AgCl surface electrodes. Of the 30 ears investigated according to this protocol, 11 had no response with either technique, and in a further 11 no difference was found between ECoG and ABR thresholds. In the remaining 8 ears, ABR threshold was lower in 6 and the ECoG in 2. We conclude that the extra time needed for cleansing the ear canal and inserting the electrode does not justify the use of ECoG in threshold evaluations, since the ABR alone has the necessary sensitivity.

Adolescent↗

PubMed1997

Antagonism of soman-induced convulsions by midazolam, diazepam and scopolamine.

The effects of midazolam (MDZ), diazepam (DZ) and scopolamine (SCP) therapies on soman-induced electrocorticogram (ECoG) and biceps femoris electromyogram (EMG) activities and brain lesions were assessed in male rats. Animals received pyridostigmine (26 micrograms/kg, im) 30 min before soman (87.1 micrograms/kg, im) followed by therapy consisting of atropine (1.5 mg/kg) admixed with 2-PAM (25 mg/kg, im) 1 min later; MDZ (0.5 mg/kg), DZ (1.77 mg/kg) or SCP (0.43 mg/kg) was administered im at 1 min after the onset of convulsions (CVs). Typically, within 5 min after soman the ECoG profile changed to a full-blown, spike-and-dome epileptiform (SDE) pattern followed by CVs and increased amplitude of EMG activity. Treatment with SCP restored ECoG and EMG profiles by 30 min. At 2 hr after exposure only 1 animal demonstrated a slight abnormality in ECoG activity which was normal at 24 hr. Similarly, DZ and MDZ restored EcoG and EMG profiles by 30 min; however, in contrast to SCP, 83% of the animals demonstrated reappearance of SDE 2 hrs after soman. SCP therapy also enabled rats to move about in their cages by 30 min post treatment. In contrast, DZ- and MDZ-treated rats remained incapacitated as late as 2 hr post-exposure. Animals were euthanized at 24 hr, and the extent of soman-induced brain lesions was determined by light microscopic analysis. When present, brain lesions were minimal in SCP-treated rats. The mean brain lesion scores across all experimental conditions ranked as follows: soman control > MDZ > DZ > or = SCP = saline control. These observations suggest that SCP may be highly effective in severe soman intoxication.

Animals↗

PubMed2000

Intraoperative hippocampal electrocorticography to predict the extent of hippocampal resection in temporal lobe epilepsy surgery.

OBJECT: Among the variety of surgical procedures that are performed for the treatment of medically refractory mesial temporal lobe epilepsy (TLE), no consensus exists as to how much of the hippocampus should be removed. Whether all patients require a maximal hippocampal resection has not yet been determined. METHODS: At the University of Washington, all TLE operations are performed in a tailored fashion, guided by electrocorticography (ECoG). The amount of hippocampal resection is determined intraoperatively by the extent of interictal epileptiform abnormalities on ECoG recorded from that structure, resulting in a hippocampal resection that is individualized for each patient. Using this approach, the authors prospectively observed 140 consecutive patients who underwent surgery for mesial TLE with pathological diagnoses of either mesial temporal sclerosis with neuronal loss (MTS group) or mild gliosis without neuronal loss (non-MTS group) to determine whether the extent of hippocampal resection correlates with outcome when a tailored approach is used. Additionally, the authors analyzed whether the presence of residual interictal epileptiform activity on ECoG following mesial temporal resection predicts poorer seizure control. With at least 18 months of clinical follow up, 67% of the 140 patients were seizure free or had only a single postoperative seizure. There was no correlation between the size of the hippocampal resection and seizure control in the group as a whole or when stratified by pathological subtype. Using an intraoperatively tailored strategy, individuals with a larger hippocampal resection (> 2.5 cm) were not more likely to have seizure-free outcomes than patients with smaller resections (p = 0.9). Additionally, both MTS and non-MTS patients, in whom postoperative ECoG detected residual epileptiform hippocampal (but not cortical or parahippocampal) interictal activity following surgical resection, had significantly worse seizure outcomes (p = 0.01 in the MTS group; p = 0.002 in the non-MTS group). CONCLUSIONS: Intraoperative hippocampal ECoG can predict how much hippocampus should be removed to maximize seizure-free outcome, allowing for sparing of possibly functionally important hippocampus.

Adolescent↗

PubMed2005

Analysis of prognostic factors and applicability of Kohne's prognostic groups in patients with metastatic colorectal cancer treated with first-line irinotecan or oxaliplatin-based chemotherapy.

BACKGROUND: The objective of this study was to analyze prognostic factors for survival and to assess the applicability of Kohne's classification in patients treated with irinotecan- or oxaliplatin-based first-line chemotherapy. PATIENTS AND METHODS: One hundred forty-two consecutive cases from a single center were retrospectively reviewed. Median patient age was 62 years. Sixty percent were men. Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0/1 in 88%. Primary tumor resection (PTR) was performed in 80.6% of patients who initially had stage IV disease. Chemotherapy consisted of fluoropyrimidines or raltitrexed plus irinotecan (50.5%), oxaliplatin (38.5%), or both (11%). Univariate and multivariate analyses for survival were performed using pretreatment patient characteristics. RESULTS: Median follow-up was 33.9 months and median overall survival was 15.9 months. Significantly unfavorable prognostic factors were PTR not being performed, disease involvement of >1 organ, liver metastases, undifferentiated histology, EGOG PS>1, increased serum carcinoembryonic antigen and cancer antigen 19.9 levels, hypoalbuminemia, leucocytosis, and elevated alkaline phosphatase and lactate dehydrogenase (LDH) levels. Only ECOG PS, PTR, increased LDH level, no hypoalbuminemia, and number of organs involved retained prognostic value in the multivariate analysis. The incidence and median survival for Kohne's prognostic groups were as follows: good (54.2%; 20 months), intermediate (26.8%; 15.7 months), and poor (19%; 6.8 months). For patients with stage IV disease at presentation, PTR was associated with a significantly longer survival, mainly in patients with an ECOG PS of 0/1. CONCLUSION: Eastern Cooperative Oncology Group PS, PTR, serum albumin, increased LDH levels, and organ involvement were the main prognostic indicators in our series. Kohne's prognostic groups, developed in the era of 5-fluorouracil treatment, also seem to be applicable to patients treated with combination chemotherapy. Primary tumor resection should always be considered, especially in patients with an ECOG PS of 0/1. However, the benefit of PTR and multiple-agent chemotherapy is questionable in patients with an ECOG PS of >1.

Aged↗

PubMed2000

Endoscopic laser ablation as palliative treatment of endobronchial, nonresectable, or recurrent lung cancer: assessment of its impact on quality of life.

Laser ablation (LA) is currently used in our institute as palliative treatment for endobronchial nonresectable or recurrent lung cancer. The objective of this study was to assess the impact of LA on the quality of life (QOL) in a large group of patients with endobronchial obstructions due to nonresectable or re-current lung cancer. Evaluation was based on Eastern Cooperative Oncology Group performance status (ECOG PS) for the "objective" assessment of QOL and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 version 1.0 (EORTC QLQ-C30(v1)) for the "subjective" assessment of QOL. From May 1994 to June 1997, 133 LAs were performed using neodymium: yttrium-aluminum garnet (Nd:YAG) laser at low power settings (< 30W) on 89 evaluable patients (Male/Female 78/11, mean age 63.5/62.8 years, range 42-82/47-73). The QOL was evaluated by ECOG PS and QLQ-C30(v1) at baseline (3 days before LA), t1 (7 days after LA), and t2 (1 month after LA). The objective tumor response was evaluated at t2. The objective tumor response to LA intervention was "excellent," ie, complete response (CR), in 33 (24.8%) patients and "fair," ie, partial response (PR), in 97 (72.9%) patients, with an overall response rate (ORR) of 97.7%. A highly significant decrease in high score (ECOG PS 3-4) was registered from baseline to t1 and from t1 to t2. However, at the same time a significant increase of low score (ECOG PS 0-2) was observed. The comparison of patient QOL assessment by QLQ-C30(v1) at different times during the study was also made; the functioning scales, the global QOL scale, and the symptom scales/items showed a highly significant improvement at t1 compared to baseline (P < 0.001), whereas only global QOL improved at t2 compared to t1. A comparison of baseline ECOG PS scale with QLQ-C30(v1) scale revealed a strong relationship between PS and the symptom "fatigue." Our study demonstrates that dramatic clinical improvement obtained by an effective though palliative treatment such as LA improves QOL based on both physician-rated (PS) and mostly self-rated (QLQ-C30(v1)) assessment.

Journal Article↗

PubMed1997

[Functional changes in the cochlea of guinea pigs in chronic renal failure--electrocochleography. Effect of noise exposure].

An animal model of chronic renal failure (CRF) was created by the 5/6 nephrectomy procedure in guinea pigs. Levels of serum Cr and BUN were abnormally elevated at 1,2 and 3 months after the procedure. ECoG (CAP, CM) was recorded through a silver ball electrode placed on the round window 1,2 and 3 months after surgery. EP was measured with a glass microelectrode from the scala media via the round window membrane. Only slight ECoG changes were seen 1 month after surgery. On the other hand, moderate or profound changes were observed 2 and 3 months after-surgery. No significant decrease in EP was found in the post-surgery animals which distinctly showed abnormal CAP, CM, although a limited number of animals were studied. The above results indicate that CRF is one of the etiological factors of cochlear dysfunction and the sensory hair cells appeared to be the site of the lesion. To study the interaction between noise exposure and CRF, 1 month post-surgery animals with only a little change in ECoG were exposed to a broad band noise. Changes in the ECoGs were followed up for 6 hours after the noise exposure. In contrast to the controls, animals with CRF did not recover from the reduced ECoG which occurred immediately after the noise exposure. This suggests synergistic interaction between noise and CRF.

Animals↗

PubMed1992

[Effects of inner ear immune responses on auditory function in guinea pigs].

Following direct challenge with KLH antigen primary or secondary (after systemic immunization) to the ES (endolymphatic sac) in guinea pigs, ECoG (electrocochleograms) were recorded from the round window induced by click and tone pips. The recordings were carried out on the 2nd, 7th and 21st days after local antigen challenge. There were no abnormal findings in the ECoG of the primary antigen challenged animals. On the other hand, prolongation of latencies, decrease in amplitudes of APs (compound action potentials) and increases in SP/AP ratios were observed in the 2nd day recordings of the secondary antigen challenged animals. However, all parameters of ECoG in the 7th day recordings were normal. Decreases in AP amplitudes were again found in the 21st day recordings. The ECoG findings with click and tone pip stimulation showed similar results. From these findings, in conjunction with morphological observations, it is speculated that these ECoG findings are caused by immuno-injury to the ES and cochlea, as well as the resultant endolymphatic hydrops which develops acutely and gradually subsides after secondary challenge.

Animals↗

PubMed1999

Role of electrocorticography at surgery for lesion-related frontal lobe epilepsy.

BACKGROUND: The prognostic significance of epileptiform activity (EA) recorded intraoperatively at electrocorticography (ECOG) in patients with lesion-related frontal lobe epilepsy (FLE) is unknown. METHODS: The results of ECOG performed in 22 patients with intractable FLE and a circumscribed frontal lobe structural lesion were compared with postoperative seizure control. Three patients underwent re-operation for a total of 25 cases, 23/25 with post-resection ECOG. Lesions were neoplasms (12), hamartomas (6) and arteriovenous malformations (4). RESULTS: Outcomes were 15/25 Class I, 5/25 Class III and 5/25 Class IV (Engel classification). Class I outcome was associated with pre-excision EA recorded from < or = 2 gyri (p < 0.05) and absence of EA, or EA limited to the resection border, at post-excision ECOG (p < 0.01). Complete lesion excision was highly correlated with Class I outcome (p < 0.001). The most significant correlations were seen when ECOG and lesionectomy variables were considered together: all 12 cases with complete lesionectomy and absent post-excision EA distant to the resection border had Class I outcome (p < 0.00015) and all 13 cases with complete lesionectomy and pre-excision EA recorded from < or = 2 gyri had Class I outcome (p < 0.00005). CONCLUSIONS: Postoperative seizure control in lesion-related FLE is assured in the setting of complete lesion resection with pre-excision EA recorded from < or 2 gyri and no post-excision EA distant to the resection border; complete lesion excision is of paramount importance.

Adolescent↗

PubMedDate not supplied

Treatment of metastatic renal cell carcinoma with high-dose bolus interleukin-2 in a non-intensive care unit: an analysis of 124 consecutively treated patients.

PURPOSE: In prior studies of high-dose interleukin-2 (IL-2) therapy in the treatment of metastatic renal cell carcinoma, the majority of patients were asymptomatic (65% of patients had Eastern Cooperative Oncology Group [ECOG] scores of 0 [no cancer-related symptoms]). These studies demonstrated that an ECOG score of 0 predicted an objective antitumor response to IL-2 (P = 0.03). The current study determined the response frequency to high-dose IL-2 therapy in a primarily symptomatic patient population (ECOG = 1 [presence of cancer-related symptoms] for 57.3% of patients). The IL-2 therapy was administered in a non-intensive care unit (non-ICU). PATIENTS AND METHODS: In this single-institution study of high-dose IL-2 therapy, 124 patients were consecutively enrolled and treated with the drug. Antitumor responses and safety were assessed by radiographic methods and the occurrence of grade 3 and 4 adverse events, respectively. RESULTS: The frequency of objective responses was 14.5% (18 of 124 patients). Seven patients (5.6%) and 11 patients (8.9%) experienced complete responses (CRs) and partial responses (PRs), respectively. Two of 7 patients (28.6%) with CR and 7 of 11 patients (63.6%) with PR had ECOG scores of 1. The median response duration is 18 months for all responders (CR plus PR). The median survival duration is 15 months for all patients. It was not possible to estimate the median survival duration for all responders because the majority of responding patients were alive at close of study. All patients with CR and 5 patients with PR were alive at close of study. The frequency of grade 3 and 4 adverse events was comparable to or less than published data and IL-2 was safely administered in a non-intensive care unit. CONCLUSION: The frequency of objective antitumor responses in patients with ECOG scores of 1 suggests that high-dose IL-2 therapy may have comparable effectiveness in symptomatic and asymptomatic patients. High-dose IL-2 can be administered in a non-ICU setting with acceptable toxicity and the chance of clinical benefit.

Adult↗

PubMedDate not supplied

[Prognostic value of electrocorticography in temporal lobe epilepsy: patterns of relationing mesial and neocortical activity].

INTRODUCTION: Electrocorticography (ECoG) monitoring in temporal lobe epilepsy (TLE) has been employed since the 40 s as a means to delineate surgical removal especially in lesional epilepsy, to reduce resection size and decrease cognitive sequelae (memory, naming). However in recent years, ECoG has been claimed to lack indications and prognostic value in cases of non lesional TLE. On the grounds of the pathophysiological relationship between mesial structures and neocortex (through propagation pathways) we have suggested a classification of ECoG activity patterns regarding the activities simultaneously recorded in mesial and neocortical grids. PATIENTS AND METHODS: Two experienced neurophysiologists (over 200 ECoG performed) have independently reviewed the recordings (including video EEG monitoring with foramen ovale electrodes) of 33 consecutive (28 non-lesional) TLE patients with the major criterion of a leading activity in mesial or neocortical areas, and related the results to the clinical course. RESULTS: As a result we identified five patterns: I. Pure mesial; II. Mesial with neocortial-related activity; III. Non-related mesial and neocortical activities; IV. Neocortical preponderance (although some mesial unrelated discharges may be seen), and V. Neocortical origin. In all 33, a tailored, ECpG-guided two-steps resection was performed. Surgical success significantly (c2 test) associated with patterns I, II and IV. Pattern V precluded a good outcome. CONCLUSIONS: ECoG reflects the state of pathological involvement of neocortex and mesial structures. An expertise approach, although brief in time (20-30 min), may either lead to preservation of relevant tissue (patterns I, II) and to establish a prognosis on the grounds of the initial epileptogenic activity.

Adolescent↗

PubMedDate not supplied

[An EEG study of different behavioral states of freely moving dolphins].

ECoG and EMG of neck and eye muscles of four free moving dolphins were recorded during sleep-wakefulness cycle through chronically implanted electrodes. Wakefulness is accompanied by desynchronized ECoG, and slow sleep by synchronized ECoG, including the sleep spindles and theta- and delta-waves. The standard EMG criteria do not allow the discrimination between fast sleep and wakefulness in dolphins. Behavioral observations alone do not inform about dolphin's sleep or wakefulness. The respiration of dolphins may be observed during bilateral ECoG synchronization in slow sleep without arousal. ECoG synchronization as well as desynchronization may be observed when the contralateral eye is open.

Animals↗

PubMed1991

Studies of interferons in the therapy of melanoma.

Melanoma does not respond meaningfully to systemic chemotherapy. No significant improvement in overall survival has been observed with any therapy in the setting of advanced disease, nor in the adjuvant setting. The most active single drugs achieve 14% to 22% response rates in larger phase II series, and drug combinations have not in general improved true response rates by 15% or more. Experience with recombinant interferon alpha-2 (rIFN alpha 2) administered by a variety of schedules and routes has demonstrated tumor response rates of 12% to 22% in advanced melanoma. Administered combined with chemotherapy, rIFN alpha 2 has improved response rates in some, but not all trials to date. On the basis of increased responsiveness noted to be inversely related to tumor size, IFN alpha has been explored over the past 7 years as an adjuvant to definitive surgery for melanoma. The North Central Cancer Treatment Group (NCCTG) and Eastern Cooperative Oncology Group (ECOG) have recently completed trials of 3 and 12 months' duration of maximal dosages of rIFN alpha 2 in subjects with high-risk resected deep primary or lymph node metastatic melanoma. These randomized controlled studies completed accrual in 1990. The ECOG trial EST 1684 has tested the effect of rIFN alpha 2b, given intravenously daily for 5 days per week for 4 weeks at 20 x 10(6) IU/m2/d, then subcutaneously three times a week at 10 x 10(6) IU/m2/d for 11 months. A series of three analyses is planned for the ECOG trial, and the first of these interim analyses was reported to the ECOG in June, 1990, revealing an encouraging divergence of survival curves that does not achieve statistical significance at this early time. A randomized controlled study of 3 months' duration of rIFN alpha 2a at 12 x 10(6) IU/m2/d intramuscularly three times a week performed by the NCCTG is also in too early a stage to allow definitive conclusions yet. The toxicity of IFN alpha administered at maximum tolerated doses has been significant in terms of constitutional symptoms and organ dysfunction. There have been two instances of fatal toxicity observed in the ECOG study (286 subjects). Consideration of lower, more tolerable dosage regimens has been derived from the desire to evaluate longer periods of IFN alpha 2 therapy, and long-term maintenance treatment with IFN alpha 2 in adjuvant melanoma therapy. In addition, immunologic studies suggest that dosages of 3 x 10(6) IU/m2/d may be more immunologically active in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1990

[A simplified polygraphic method for studying sleep in the rat].

Experiments were performed on 10 healthy Wistar rats with chronically implanted electrodes for the recording of electrocorticogram (ECoG), electro-oculogram (EOG), and electromyography (EMG). All the rats were prepared for the implantation of recording electrodes under 5% Ketamine (100 mg/kg i.p.) anesthesia. Four to six days after operation, the rat was put in an apparatus which was designed specifically sensitive to detect the movement of the animal without electrode on the body so that electroactogram (EAG) could be recorded readily. One group of experiment animal (n = 5), recorded ECoG, EAG, EOG and EMG simultaneously, was compared to another group (n = 5), recorded ECoG and EAG simultaneously. The results of experiments indicate that the ECoG, recorded from the the mesial frontal and occipital areas, have certain characteristics during different sleep phases, and the characteristics for classifying sleep phases by the two kinds of somnopolygram are similar. Therefore, simultaneous recording of the ECoG and EAG can be used to discriminate the sleep phases in the rat. In this way, the somnopolygraphic recording method for studying sleep in the rat would be simplified.

Animals↗

PubMed1990

Hypoxia and electrocortical activity in the fetal lamb: effects of brainstem transection and chemoreceptor denervation.

In order to investigate possible mechanisms for the effect of hypoxia on fetal electrocortical (ECoG) activity, the effects of 30 min of isocapnic hypoxia on ECoG were studied in three groups of unanaesthetized late-gestation fetal lambs in utero. One group was intact, in the second the brainstem was transected between the colliculi, and in the third the carotid sinus nerves and cervical vagosympathetic trunks were cut bilaterally to denervate the systemic arterial chemoreceptors. The incidence of high voltage (HV) ECoG activity was lower in brainstem-transected fetuses than in the other groups. All three groups showed an increased number of changes from low to high voltage and an increase in the incidence of HV activity at the onset of hypoxia, but the increases reached statistical significance only in the brainstem-transected group. It is concluded that the onset of hypoxia is often associated with an increase in HV ECoG activity, with the most consistent changes occurring after brainstem transection and similar but smaller increases in intact and denervated fetuses. Thus the response of fetal electrocortical activity to the onset of hypoxia does not depend on intact connections with the lower brainstem. However, the effect of hypoxia on fetal ECoG is minor and inconsistent and may be physiologically unimportant.

Animals↗