Effects of glutamate receptor agonists on the p13 auditory evoked potential and startle response in the rat.

The P13 potential is the rodent equivalent of the P50 potential, which is an evoked response recorded at the vertex (Vx) 50 ms following an auditory stimulus in humans. Both the P13 and P50 potentials are only present during waking and rapid eye movement (REM) sleep, and are considered to be measures of level of arousal. The source of the P13 and P50 potentials appears to be the pedunculopontine nucleus (PPN), a brainstem nucleus with indirect ascending projections to the cortex through the intralaminar thalamus, mediating arousal, and descending inhibitory projections to the caudal pontine reticular formation (CPRF), which mediates the auditory startle response (SR).

Modafinil increases arousal determined by P13 potential amplitude: an effect blocked by gap junction antagonists.

Study Objectives: We recorded the effects of administration of the stimulant modafinil on the amplitude of the sleep state-dependent auditory P13 evoked potential in freely moving rats, a measure of arousal thought to be generated by the cholinergic arm of the reticular activating system, specifically the pedunculopontine nucleus (PPN).

Design: Groups of rats were implanted for recording auditory evoked responses and the effects on P13 potential amplitude of intracranial injections into the PPN of neuroactive agents determined.

Measurements And Results: The effects of intracranial injections into the PPN of modafinil showed that P13 potential amplitude increased in a dose-dependent manner at doses of 100, 200, and 300 microM.

Long-term deficits of preterm birth: evidence for arousal and attentional disturbances.

Objective: Quantitative measures of pre-attentional, attentional and frontal lobe processes were compared to evaluate quantitative measures of these deficits in Ex-Preterm vs. Ex-Term adolescents.

Methods: We compared 43 Ex-Preterm with 26 Ex-Term adolescents using the P50 auditory potential, the Psychomotor Vigilance Task (PVT), a reaction time (RT) test, and Near Infrared Spectroscopy (NIRS).