Geomagnetic Reversal in Brunhes Normal Polarity Epoch

The magnetic stratigraphly of seven cores of deep-sea sediment established the existence of a short interval of reversed polarity in the upper part of the Brunches epoch of normal polarity. The reversed zone in the cores correlates well with paleontological boundaries and is named the Blake event. Its boundaries are estimated to be 108,000 and 114,000 years ago +/- 10 percent.

Gamete selection with an inbred tester

A common inbred tester was used to evaluate gametes selected from three complex hybrid populations using two different inbreds as elite lines. The results support STADLER'S contention that gamete selection is an efficient method for extracting superior gene combinations from hybrid populations. The inbred tester increases the resolving power of the method by eliminating extraneous genetic variability and by providing a homogeneous check population for comparative purposes.

Midbrain single units correlating with pupil response to light

The consensual response of the pupil in the cat was driven by means of a light flux impinging on the contralateral retina. Spike trains recorded extracellularly from single units in the midbrain show correlation with the concurrently recorded pupil area. The temporal dynamics found confirm two earlier studies of sinigle-unit responses and quantitative nerve stimulation. Both of these indicate that most of the 200-millisecond transport delay resides in the neuromuscular apparatus. Neurons whose activity correlated either with constriction with dilatation phases of Change in the pupil area were observed.