H.G.J.M. Kuypers

Retrograde axonal transport of horseradish peroxidase from spinal cord to brain stem cell groups in the cat.

Abstract Horseradish peroxidase was injected in cervical, thoracic and lumbar segments o of the cats spinal cord through several transverse rows of narrowly spaced needle penetrations. In all these cases the enzyme was transported retrogradely to brain stem neurons in the bulbar medial reticular formation, the vestibular complex and the red nucleus. Moreover, the enzyme was also transported to an upper pontine cell group adjoining the rubrospinal tract, as well as to neurons in the locus coeruleus and subcoeruleus nuclei and the dorsal hypothalamus.

Two new fluorescent retrograde neuronal tracers which are transported over long distances

Two new fluorescent retrograde neuronal tracers are reported: Nuclear Yellow (Hoechst S 769121), which mainly labels the neuronal nucleus; and Fast Blue (diamidino compound 253/50), which mainly labels the neuronal cytoplasm. Both tracers appear to be transported effectively over long distances in rat and cat.

The Anatomy of Brain Stem Pathways to the Spinal Cord in Cat. A Labeled Amino Acid Tracing Study

Publisher Summary This chapter discusses the anatomy of brain stem pathways to the spinal cord in cat. In the series of experiments described in the chapter, [3H] leucine injections were made in the brain stem and the spinal distribution of the labeled descending brain stem pathways was studied autoradiographically. The pontine reticulospinal tract, as well as the vestibulospinal tracts, distribute to the ventromedial parts of the intermediate zone mainly ipsilaterally. Anterograde fiber degeneration findings obtained since the early decades of this century by means of several techniques consistently showed that the descending brain stem pathways to the spinal cord terminate mainly in the spinal intermediate zone—for example, in Rexeds laminae V–VIII. However, to facilitate the identification of the various descending pathways, the brain stem distribution of the cells of origin of these pathways in the cat has been reinvestigated by means of the horseradish peroxidase (HRP) technique by using the procedure of Mesulam.

Double retrograde neuronal labeling through divergent axon collaterals, using two fluorescent tracers with the same excitation wavelength which label different features of the cell.

SummaryRecent studies show that several fluorescent substances are transported retrogradely through axons to their parent cell bodies and label in different colors different features of the cell at the same 360 nm excitation wavelength. Thus, Bisbenzimide (Bb) and “Nuclear Yellow” (NY; Hoechst S 769121) produce green and golden-yellow retrograde labeling of the neuronal nucleus. “True Blue” (TB) and “Fast Blue” (FB) produce blue retrograde labeling of the neuronal cytoplasm. In the present study the possibility of retrograde double labeling of neurons by way of divergent axon collaterals using combinations of Bb or NY with TB or FB has been explored in rat and cat. The findings show that in these animals these tracer combinations are transported retrogradely through two axon collaterals to one and the same cell. Neurons which are retrogradely double-labeled with these tracer combinations display a blue fluorescent cytoplasm and a white or golden-yellow fluorescent nucleus at the same 360 nm excitation wavelength. Therefore, these tracer combinations can be successfully used to demonstrate the existence of divergent axon collaterals in the brain.

Diamidino yellow dihydrochloride (DY·2HCl); a new fluorescent retrograde neuronal tracer, which migrates only very slowly out of the cell

SummaryEarlier studies showed that Nuclear Yellow (NY), True Blue (TB) and Fast Blue (FB) are transported retrogradely through axons to their parent cell bodies. NY produces a yellow fluorescent labeling of the neuronal nucleus at 360 nm excitation wavelength, while TB and FB produce a blue fluorescence of the cytoplasm at this same wavelength. Therefore, NY may be combined with TB or FB in double-labeling experiments demonstrating the existence of axon collaterals. However, retrograde neuronal labeling with TB or FB requires a relatively long survival time, while NY requires a short survival time since NY migrates rapidly out of the retrogradely labeled neurons. This complicates double-labeling experiments since TB and FB must be injected first and NY later, a short time before the animal is sacrificed. We report a new yellow fluorescent tracer which labels mainly the nucleus and migrates much more slowly out of the retrogradely labeled neurons than NY. This new tracer can be used instead of NY in combination with TB or FB in double-labeling experiments and unlike NY can be injected at the same time as TB or FB. The new tracer is a diamidino compound (no. 28826) which is commerciallyDistributed by Dr. Illing KG, Warthweg 14-18, Postfach 1150, D-6114 Groß-Umstadt, FRG available. It will be referred to as Diamidino Yellow Dihydrochloride (DY·2HCl). According to the present study DY·2HCl is transported over long distances in rat and cat, and produces a yellow fluorescence of the neuronal nucleus at 360 nm excitation wavelength, resembling that obtained with NY. When combined with TB or FB, DY·2HCl is as effective as NY in double labeling of neurons by way of divergent axon collaterals.

Cortical afferents and efferents of monkey postarcuate area: an anatomical and electrophysiological study.

SummaryA study has been made of the corticocortical efferent and afferent connections of the posterior bank of the arcuate sulcus in the macaque monkey. The distribution of efferent projections to the primary motor cortex (MI) was studied by injecting three different fluorescent retrograde tracers into separate regions of MI. The resultant labeling showed a discrete and topographically organized projection: neurons lying below the inferior limb of the arcuate sulcus project into the MI face area, while neurons located in the posterior bank of the inferior limb of the arcuate sulcus and in the arcuate spur region project into the MI hand area. These findings were confirmed electrophysiologically by demonstrating that postarcuate neurons could only be activated antidromically by stimulation within restricted regions of MI. HRP injections within postarcuate cortex indicated that afferents to this region arise from a number of cortical areas. However, the largest numbers of labeled neurons were found in the posterior parietal cortex (area 7b; PF) and in the secondary somatosensory region (SII). Neurons in both 7b (PF) and SII could be antidromically activated by postarcuate stimulation. It was further shown that stimulation of area 7b (PF) gives rise to short-latency synaptic responses in postarcuate neurons, including some neurons with identified projections to MI. The results are discussed in relation to the possible function of the postarcuate region of the premotor cortex in the sensory guidance of movement.

Retrograde anoxal transport of fluorescent substances in the rat's forebrain

Abstract A search was made for fluorescent substances which are transported retrogradely through axons to their parent cell bodies, using as a model the axons from the parafascicular nucleus and the substantia nigra to the caudate-putamen in the rat. Evans Blue without albumin, as well as Primuline and DAPI were found to be transported retrogradely through these axons and each of these substances resulted in a characteristic fluorescent labeling of the parent cell body. Moreover, after double labelling of these neurons by means of Evans Blue either in combination with HRP or in combination with a DAPI-Primuline mixture, both labels could be demonstrated independently in the individual neurons.

The organization of the efferent projections of the substantia nigra in the rat. A retrograde fluorescent double labeling study.

The organization of three of the efferent projections of substantia nigra has been investigated in rat by means of combined injections of two fluorescent retrograde tracers: red fluorescent Evans Blue and blue fluorescent DAPI-primuline mixture. First the distributions of the retrogradely labeled neurons in substantia nigra after injections of each of the two tracers in the striatum, thalamus and superior colliculus were compared with the distributions of the retrogradely labeled nigral neurons after HRP injections in these same structures. The findings in these sets of experiments were the same. This indicates that the two fluorescent retrograde tracers are as effective as HRP in tracing the efferent fiber connections of the substantia nigra. Subsequently the retrograde labeling of the substantia nigra neurons was studied after combined injections of the two fluorescent retrograde tracers in two of the above structures, in different combinations. In these experiments both single labeled neurons fluorescing either red or blue, as well as double labeled neurons fluorescing both red and blue were found. Double labeled neurons were present only in pars reticulata and occurred only after injections of the two tracers in thalamus and superior colliculus respectively. From this it has been concluded that in rat the various efferent projections from the substantia nigra are mainly derived from different neurons, but that at least part of the neurons which distribute fibers to superior colliculus also distributes collaterals to the thalamus.

Retrograde transport of bisbenzimide and propidium iodide through axons to their parent cell bodies

Two fluorescent substances bisbenzimide (Bb), which fluoresces yellow-green and propidium iodide (PI), which fluoresces orange were found to be transported retrogradely through axons to their parent cell bodies in rat and cat. Bb gives a very strong and long lasting fluorescent retrograde neuronal labeling and is very effectively transported over long distances both in rat and cat. Bb and PI also label glial nuclei around retrogradely labeled neurons. Bb in addition labels glial nuclei along axons through which it is transported. Bb and PI can be transported retrogradely through two divergent collaterals to one and the same cell.

Behaviour of neurons in monkey peri-arcuate and precentral cortex before and during visually guided arm and hand movements

SummaryNeuron activity was recorded in monkey cerebral cortex during a visually guided reaching task. Cells located in the banks of the arcuate sulcus at its curvature changed their activity during the period in which the monkey saw a food reward in a certain position, but before it moved to retrieve the reward. A role of these neurons in visual guidance of arm and hand movements is postulated.