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Biomedical subjects

M H Frederickson

Publications and source records attributed to M H Frederickson.

8 recordsLinked to original sources
PubMed1982

In vitro recording of raphe unit activity: evidence for endogenous rhythms in presumed serotonergic neurons.

The spontaneous activity of single neurons in the nucleus raphe dorsalis was recorded in vitro in mouse brain slices. The neurons displayed the slow and regular discharge pattern characteristic of raphe neurons recorded in vivo. When magnesium ion was added to increase the medium concentration to 20-30 mM for the purpose of inhibiting all synaptic transmission, raphe neurons continued to display the same discharge pattern and rate. The data suggest that the steady rhythmic firing of nucleus raphe dorsalis neurons is generated by an intracellular pacemaker mechanism.

Animals↗
PubMed1979

Emergence of spontaneous alternation in the kitten.

Two studies are reported that describe the development of spontaneous alternation in the kitten. The first indicates that 3- and 4-week-old kittens do not alternate whereas animals 5 weeks and older do alternate. The second suggests that inability to discriminate maze arms is an unlikely explanation for the lack of alternation among the youngest animals. The approximate simultaneity between the onset of alternation (described here) and the maturation of the kitten hippocampus (described by others) is taken as support for the notion that hippocampal maturation may be related to the development of spontaneous alternation.

Aging↗
PubMed1979

Developmental changes in open-field behavior in the kitten.

Seventy-eight kittens from 3 to 7 weeks of age were studied in an open-field arena. Three major age-dependent changes were noted: (1) the number of floor squares entered was markedly higher for 5- and 6-week-olds than for younger animals, and slightly lower for 7-week-olds than for 5- and 6-week-olds; (2) the tendency to backtrack from 1 square to a just-vacated square decreased with age, the largest change occurring between 4 and 5 weeks of age; (3) the within-session decrement in locomotion was largest for 3-week-old kittens but was smallest for 4-week-olds and increased monotonically with age thereafter. The results suggest a possible role of hippocampal maturation.

Aging↗