Averaged evoked potentials: event related potentials (ERPs) and their applications.

Endogenous potentials are evoked responses that occur independent of the stimulus evoking them. They are related to different aspects of information processing. Two types of event related potentials (ERPs) are recorded, the P300 wave and contingent negative variation (CNV). The P300 wave is the most frequently studied factor in various clinical diseases and also for neurological research. Different tasks, paradigms can be used of which the oddball paradigm, consisting of target and non-target stimuli and their variations is most popular. The effect on P300 of physiological factors like age, IQ, pregnancy, exercise and others along with the clinical application in various neurophysiological and psychiatric disorders are discussed. This review deals with various aspects of (ERPs), their methodology with a broad view of the scope and clinical horizon as regard their application in neurophysiological research.

Lipid profile of coronary risk subjects following yogic lifestyle intervention.

The effect of yogic lifestyle on the lipid status was studied in angina patients and normal subjects with risk factors of coronary artery disease. The parameters included the body weight, estimation of serum cholesterol, triglycerides, HDL, LDL and the cholesterol - HDL ratio. A baseline evaluation was done and then the angina patients and risk factors subjects were randomly assigned as control (n = 41) and intervention (yoga) group (n = 52). Lifestyle advice was given to both the groups. An integrated course of yoga training was given for four days followed by practice at home. Serial evaluation of both the groups was done at four, 10 and 14 weeks. Dyslipidemia was a constant feature in all cases. An inconsistent pattern of change was observed in the control group of angina (n = 18) and risk factor subjects (n = 23). The subjects practising yoga showed a regular decrease in all lipid parameters except HDL. The effect started from four weeks and lasted for 14 weeks. Thus, the effect of yogic lifestyle on some of the modifiable risk factors could probably explain the preventive and therapeutic beneficial effect observed in coronary artery disease.

Nociception, antinociceptive potency of morphine in streptozotocin induced diabetic rats.

There are controversial reports on the effect of diabetes on the pain threshold. We used male Wistar rats to see the effect of streptozotocin induced diabetes on the tail flick, vocalisation and vocalisation after discharge responses. These represent the spinal, lower brain stem and hypothalamic responses respectively. The effect of morphine in these parameters was studied for both the control and diabetic group. In diabetic rats, the pain threshold was increased. However, this increase was not significant. Morphine produced significant analgesia after thirty minutes for tail flick and vocalisation responses and after fifteen minutes for after discharge in the control group. The antinociceptive effect of morphine was delayed and reduced for all three pain threshold confirming the antagonistic action of glucose on opiate receptors.

Immobilisation stress induced analgesia in diabetic rats.

Stress is known to produce analgesia. The pain threshold is altered in diabetes. We studied the effect of 1 hr of immobilisation stress on pain threshold in male Wistar rats. The same effect was tested in streptozotocin induced diabetic rats. The pain threshold of tail flick, vocalisation and vocalisation after discharge increased in the control group after the stress procedure. Significant analgesia was also obtained in diabetic rats, for flick and after discharge pain threshold. However the vocalisation threshold was not altered, probably due to the antagonistic action of glucose on opiate receptor at the level of brain stem.