Corticopontine projection in the rat: The distribution of labelled cortical cells after large injections of horseradish peroxidase in the pontine nuclei

Legg, Charles; Mercier, Barbara; Glickstein, Mitchell

doi:10.1002/cne.902860403

Cited by 104 publications

(91 citation statements)

References 26 publications

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“…The ipsilateral cerebral cortex showed extensive retrograde labeling, as seen in previous anatomical studies (Legg et al 1989). Labeled neurons were mostly seen in layer 5 (Fig.…”

Section: Experiments 2: Matn Project To the Pontine Nucleisupporting

confidence: 78%

Medial auditory thalamic stimulation as a conditioned stimulus for eyeblink conditioning in rats

Campolattaro¹,

Halverson²,

Freeman³

2007

Learn. Mem.

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The neural pathways that convey conditioned stimulus (CS) information to the cerebellum during eyeblink conditioning have not been fully delineated. It is well established that pontine mossy fiber inputs to the cerebellum convey CS-related stimulation for different sensory modalities (e.g., auditory, visual, tactile). Less is known about the sources of sensory input to the pons that are important for eyeblink conditioning. The first experiment of the current study was designed to determine whether electrical stimulation of the medial auditory thalamic nuclei is a sufficient CS for establishing eyeblink conditioning in rats. The second experiment used anterograde and retrograde tract tracing techniques to assess neuroanatomical connections between the medial auditory thalamus and pontine nuclei. Stimulation of the medial auditory thalamus was a very effective CS for eyeblink conditioning in rats, and the medial auditory thalamus has direct ipsilateral projections to the pontine nuclei. The results suggest that the medial auditory thalamic nuclei and their projections to the pontine nuclei are components of the auditory CS pathway in eyeblink conditioning.A primary emphasis in neurobiological analyses of Pavlovian eyeblink conditioning has been on identifying the anatomical sites and cellular mechanisms of memory storage (Christian and Thompson 2003;Thompson 2005). Less emphasis has been placed on identifying the neural pathways that conduct stimulation from conditioned stimuli to the sites of memory induction and retention. The cerebellum is the anatomical site of memory storage in Pavlovian eyeblink (eyelid and nictitating membrane movement) conditioning (Christian and Thompson 2003;Thompson 2005;Ohyama et al. 2006). Cerebellar function may be influenced by processes occurring within its sensory input pathways, interactions among components of the input pathways, and sources of feedback to the input pathways (Clark et al. 1997;Bao et al. 2000;Medina et al. 2002). A full characterization of the sensory input pathways to the cerebellum necessary for motor learning is, therefore, critical for developing a comprehensive understanding of cerebellar function. Identification of sensory input pathways to the cerebellum is also critical for elucidating the mechanisms underlying the ontogeny of motor learning (Freeman et al. 2005).Several key components of the conditioned stimulus (CS) pathway in eyeblink conditioning have been identified using lesion, inactivation, unit recording, stimulation, and tract tracing techniques (Steinmetz et al. 1986(Steinmetz et al. , 1987(Steinmetz et al. , 1989Lewis et al. 1987;Knowlton and Thompson 1988;Steinmetz 1990;Steinmetz and Sengelaub 1992;Gould et al. 1993;Tracy et al. 1998;Hesslow et al. 1999;Bao et al. 2000;Freeman and Rabinak 2004;Freeman et al. 2005). The pontine mossy fiber projection to the cerebellum is necessary for eyeblink conditioning with CSs of different modalities and stimulation of the pontine nuclei or the middle cerebellar peduncle is sufficient for eyeblink condit...

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“…The ipsilateral cerebral cortex showed extensive retrograde labeling, as seen in previous anatomical studies (Legg et al 1989). Labeled neurons were mostly seen in layer 5 (Fig.…”

Section: Experiments 2: Matn Project To the Pontine Nucleisupporting

confidence: 78%

Medial auditory thalamic stimulation as a conditioned stimulus for eyeblink conditioning in rats

Campolattaro¹,

Halverson²,

Freeman³

2007

Learn. Mem.

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“…The ipsilateral contribution of cerebrocerebellar connections correlated nicely with the laterality of the CTb labeling in the pontine nuclei suggesting that this ipsilateral connection predominantly stems from the bilateral projection of the pontine nuclei to the cerebellar cortex (Serapide et al, 2002) rather than from a bilateral corticopontine projection (Legg et al, 1989;Leergaard et al, 2000b). Although the ipsilateral distribution of cortical RV labeling was similar to that observed contralaterally, local differences in density were observed; e.g., the density of the rostral M1/M2 patch was usually increased with respect to the ipsilateral main patch of labeling (Fig.…”

Section: Bilateral Labelingmentioning

confidence: 72%

Organization of Cerebral Projections to Identified Cerebellar Zones in the Posterior Cerebellum of the Rat

et al. 2012

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The cerebrocerebellar connection makes use of two of the largest fiber tracts in the mammalian brain, i.e., the cerebral and medial cerebellar peduncles. Neuroanatomical approaches aimed to elucidate the organization of this important connection have been hindered by its multisynaptic nature, the complex organization of its components, and the dependency of conventional tracers on precisely placed injections. To overcome these problems, we used rabies virus (

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“…However, the methods available at the time the study was done were relatively insensitive (13) and a comparison with more recent work (14) shows that only a subset of the entire population of corticopontine cells was identified. Wise and Jones (figure 6a in ref.…”

mentioning

confidence: 99%

Basal ganglia and cerebellum receive different somatosensory information in rats.

Mercier

Legg

Glickstein

1990

Proc. Natl. Acad. Sci. U.S.A.

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There are two great subcortical circuits that relay sensory information to motor structures in the mammalian brain. One pathway relays via the pontine nuclei and cerebellum, and the other relays by way of the basal ganglia.We studied the cells of origin of these two major pathways from the posteromedial barrel subfield ofrats, a distinct region ofthe somatosensory cortex that contains the sensory representation of the large whiskers. We itjected tracer substances into the caudate putamen or the pontine nuclei and charted the location of retrogradely filled cortical cells. In preliminary studies, we used double-labeling techniques to determine whether the cells of origin of these two pathways send axon collaterals to other subcortical targets. Lamina V of the rat posteromedial barrel subfield contains two distinct populations of subcortically projecting neurons, which are organized into distinct sublaminae. Corticopontine cells are located exclusively in sublamina Vb, the deeper of two sublaminae revealed by cytochrome oxidase staining. Corticostriate cells are located almost exclusively in the more superficial sublamina Va. Experiments using double-labeling fluorescent tracers demonstrate that about one-quarter of the corticopontine cells send a collateral branch to the superior colliculus. Other studies have shown that cells in Vb are activated at very short latency after vibrissal stimulation; hence, they would seem to be an appropriate relay for the rapid transmission of sensory information to the cerebellum for use in sensory guidance of movement.Sensory areas of the cerebral cortex are connected to motor areas by way of corticocortical circuits and two prominent subcortically directed pathways. One subcortical pathway goes to the basal ganglia, and the other goes to the cerebellum via the pontine nuclei (1-4). The efferent terminals from the basal ganglia and cerebellum remain largely distinct in the thalamus and their thalamic targets project to nonoverlapping regions of the motor cortex (5). Do the basal ganglia and the cerebellum receive inputs from the same or a different population of sensory cortical cells?The great majority of the cells in the sensory cortex that project to these two motor systems are located in lamina V of the cerebral cortex (2, 6-8). Lamina V may be divided into two sublaminae: a superficial sublamina Va and a deep sublamina Vb, which differ in a number of important respects. In mice, lamina Vb receives direct input from the somatosensory relay nucleus in the thalamus; Va does not (9). Stimulation of the appropriate whisker in rats activates cells in sublamina Vb at a latency that is as short as that for activating cells in lamina IV, the principal target of incoming thalamic fibers (10). In contrast, cells in Va respond at much longer latency to such stimulation. Cells in Va stain palely when tested for the presence of the metabolic enzymes cytochrome oxidase or succinic dehydrogenase (11). Cells in sublamina Vb stain far more densely, suggesting that they are capable ofh...

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Corticopontine projection in the rat: The distribution of labelled cortical cells after large injections of horseradish peroxidase in the pontine nuclei

Cited by 104 publications

References 26 publications

Medial auditory thalamic stimulation as a conditioned stimulus for eyeblink conditioning in rats

Medial auditory thalamic stimulation as a conditioned stimulus for eyeblink conditioning in rats

Organization of Cerebral Projections to Identified Cerebellar Zones in the Posterior Cerebellum of the Rat

Basal ganglia and cerebellum receive different somatosensory information in rats.

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