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C J Frederickson

Publications and source records attributed to C J Frederickson.

10 recordsLinked to original sources
PubMed1992

Retrograde tracing of zinc-containing neurons by selenide ions: a survey of seven selenium compounds.

The autometallographic retrograde tracing of zinc-containing neurons by intracerebral injection of sodium selenite (Na2SeO3), introduced by Danscher in 1982, has recently been described in more detail. Intracerebral injections of both sodium selenide (Na2Se) and sodium selenite (Na2SeO3) have been successfully used; however, sodium selenite had a rather toxic effect on the injected tissue. In the present study, we tested seven different selenium compounds to find the most suitable compound for retrograde tracing of zinc-positive pathways. Among the tested compounds, sodium selenide (Na2Se) caused insignificant necrosis within the injection site and was easily transported retrogradely when handled anaerobically. Sodium selenide is therefore recommended as the compound of choice.

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↗
PubMed1978

Functional characteristics of cochlear nucleus in behaving cat examined by acoustic masking of electrical stimuli.

1. Cats were trained, using an operant procedure, to detect and respond to electrical stimulation delivered in the vicinity of the cochlear nucleus. The electrical stimuli were presented both in silence and in synchrony with repeated noise bursts to determine whether detection thresholds for the electrical stimuli were elevated by the acoustic masking noise. 2. For stimulation sites centered within auditory structures (cochlear nucleus or acoustic nerve root), the acoustic maskers caused a consistent elevation of the electrical detection thresholds. For stimulation sites that were in or bordered on nonacoustic neural structures (e.g., vestibular), the acoustic maskers caused little or no elevation of electrical detection thresholds. 3. The magnitude of the acoustic masking effect was monotonically related to the intensity of the acoustic masker across the range of intensities tested. 4. The magnitude of the masking effect was strongly dependent on the relative timing of the stimulus pulse and the masker noise burst. Maximum masking occurred when the pulse just followed the onset of the neural activity in cochlear nucleus evoked by the masker burst. Less masking occurred when the electrical pulse occurred at the middle or end of the masker burst, and still less when the pulse occurred just prior to the onset (backward masking) or just after the offset (forward masking) of the masker burst. 5. The magnitude of the masking effect also depended on the frequency of the acoustic masker. For tone bursts, masking was maximal for each electrode at a particular frequency and declined monotonically for masker frequencies above or below the optimal frequency. 6. It is concluded that the masking of an electrical stimulus by an acoustic stimulus depends on a direct interaction between the neural responses evoked by the two stimuli, and that similar central, neural interactions may contribute to acoustic masking of acoustic stimuli. It is also concluded that the technique of masking an electrical stimulus by an acoustical stimulus is a precise and useful tool for the study of sensory-neural organization in intact behaving animals.

Animals↗
PubMed1978

Effects of sleep deprivation on awakening thresholds and sensory evoked potentials in the rat.

The EEG desynchronization response to stimuli presented during slow-wave sleep was studied in 25 chronically implanted rats after 12 hr of sleep deprivation and during control periods of normal sleep. Compared to normal sleep, sleep after deprivation was accompanied by a significant decrease in the number of EEG desynchronization responses to auditory stimuli and by an additional disproportionate decrease in the number of sustained desynchronization responses. Thalamic auditory evoked potentials were not reduced in amplitude during postdeprivation sleep, thus the decrease in number of EEG desynchronization responses to the auditory stimuli was apparently not mediated by decreased responsiveness in the peripheral auditory system. On the other hand, postdeprivation sleep was not accompanied by any significant change in total number of EEG desynchronization responses to direct trigeminal nerve stimulation nor by any change in the duration of responses to trigeminal stimulation. The results suggest that recovery from sleep loss in accompanied not by a nonspecific increase in the threshold for arousal per se but instead by a selective increase in the threshold for arousal to certain classes of peripheral stimuli.

Acoustic Stimulation↗
PubMed1977

Masking of electrical by acoustic stimuli: behavioral evidence for tonotopic organization.

When pure-tone acoustic masking stimuli of various frequencies were presented simultaneously with electrical stimuli applied to cochlear nucleus, only those maskers within a limited frequency range interfered with the detection of the electrical stimuli. The form of the masking functions obtained suggest that the electrical stimulus directly activated only a small population of neurons which were functioning in a tonotopic fashion.

Acoustic Stimulation↗
PubMedDate not supplied

Movement-dependent and movement-independent changes in hippocampal RSA in cats.

EEG was recorded from the dorsal hippocampus of cats during walking in situations intended to elicit a minimum of orienting or attentional behavior. The situations included walking in an alley for food after prolonged overtraining, and ad lib walking in an observation chamber after 24 hours habituation. In virtually all (82-100%) cases of sustained walking RSA was present in the dorsal hippocampus; however, the amplitude of the RSA during walking was quite variable and in many cases quite small. The results suggest that in the cat motoric factors may influence the occurrence of RSA and non-motoric factors may influence the amplitude of RSA.

Animals↗
PubMedDate not supplied

Distribution of histochemically reactive zinc in the forebrain of the rat.

The major cytoarchitectonic regions of the rat brain that stain with the Timm-Danscher metal stain were tested with the fluorescent probe for zinc, 6-methoxy 8-para toluene sulfonamide quinoline (TSQ). Throughout most of the striatum, cerebral cortex and limbic system, the diffuse, even neuropil staining produced by the Timm-Danscher method was mirrored by comparable fluorescence in TSQ-stained sections. Blockade of the TSQ fluorescence by prior treatment with sulphide indicated that the Timm-Danscher and the TSQ procedures both labeled the same pool of endogenous metal, which is inferred to be the zinc that is in axonal boutons. It is concluded that the Timm-Danscher staining generally indicates zinc-containing axonal boutons. The distribution of the zinc-containing axonal boutons throughout the forebrain is described.

Aminoquinolines↗