Medial cerebellar nuclear projections and activity patterns link cerebellar output to orofacial and respiratory behavior - PubMed Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Apr 2:7:56.
doi: 10.3389/fncir.2013.00056. eCollection 2013.

Medial cerebellar nuclear projections and activity patterns link cerebellar output to orofacial and respiratory behavior

Lianyi Lu  1 , Ying Cao, Kenichi Tokita, Detlef H Heck, John D Boughter Jr
Affiliations

Medial cerebellar nuclear projections and activity patterns link cerebellar output to orofacial and respiratory behavior

Lianyi Lu et al. Front Neural Circuits. .

Abstract

There is ample evidence that the cerebellum plays an important role in coordinating both respiratory and orofacial movements. However, the pathway by which the cerebellum engages brainstem substrates underlying these movements is not well understood. We used tract-tracing techniques in mice to show that neurons in the medial deep cerebellar nucleus (mDCN) project directly to these putative substrates. Injection of an anterograde tracer into the mDCN produced terminal labeling in the ventromedial medullary reticular formation, which was stronger on the contralateral side. Correspondingly, injection of retrograde tracers into these same areas resulted in robust neuronal cell labeling in the contralateral mDCN. Moreover, injection of two retrograde tracers at different rostral-caudal brainstem levels resulted in a subset of double-labeled cells, indicating that single mDCN neurons collateralize to multiple substrates. Using an awake and behaving recording preparation, we show that spiking activity in mDCN neurons is correlated with respiratory and orofacial behaviors, including whisking and fluid licking. Almost half of the recorded neurons showed activity correlated with more than one behavior, suggesting that these neurons may in fact modulate multiple brainstem substrates. Collectively, these results describe a potential pathway through which the cerebellum could modulate and coordinate respiratory and orofacial behaviors.

Keywords: brainstem; deep cerebellar nucleus; neuronal tract-tracers; orofacial; respiration.

PubMed Disclaimer

Figures

FIGURE 1
FIGURE 1
mDCN neurons project to the contralateral reticular formation, as revealed by anterograde tracing. (A) Tracer injection site in the mDCN (Med), approximately -6.3 from bregma. (B) Low power image of labeling in the rostral brainstem in both the ipsilateral and contralateral Gi and LPGi, approximately -6.0 from bregma. At higher power, punctate labeling indicates terminal fields in contralateral Gi (C); relatively fewer terminals are found on the ipsilateral side (D). The level for (E,F) is approximately -6.8 from bregma. (E) Low power image of labeling in the caudal brainstem, in the contralateral MdV and LRt, approximately -7.3 mm from bregma. (F) Labeling in the contralateral vestibular nucleus, approximately -7.0 from bregma. With the exception of (F), all images were prepared from a single mouse brain. Scale bars: (A,B,E,F) = 200 μ; (C,D) = 100 μ. Arrows point to examples of terminal/axonal labeling in lower power images.
FIGURE 2
FIGURE 2
Injection of the retrograde tracer Fluorogold into ventromedial brainstem labels neurons in the mDCN. (A–D) Following injection into Gi in the rostral medulla (A) neurons were sparsely labeled in the ipsilateral mDCN (B), whereas greater numbers of neurons were labeled in the contralateral mDCN (C). The rostral–caudal level for (B,C) is approximately -6.2 mm from bregma. (D) Higher magnification of retrogradely labeled neurons from (C). (E,F) Following injection into the Gi and LPGi at a more caudal level of the medulla (E), neurons are labeled in the contralateral mDCN, including MedDL (F); approximate level is -6.6 mm from bregma). (G) Quantification of labeled cells in DCN subnuclei from mice with tracer injections placed caudally (open bars) or rostrally (shaded bars; n = 6 per group) reveals no significant difference between the groups. For both groups, significantly more labeled cells were found on the contralateral side (p < 0.0001). Scale bars: (A–C,E,F) = 200 mm; (D) = 50 mm.
FIGURE 3
FIGURE 3
A subset of mDCN neurons collateralize to rostral and caudal locations in the brainstem. (A,B) Plots of injection sites of rostral (red) and caudal (green) fluorescent microspheres in brainstem. (C) Retrogradely labeled mDCN neurons appear green or red, respectively; a subset (yellow) is double-labeled. Labeling is confined to the cell body. (D) High power picture of labeling, showing that double-labeled cells (arrows) could be reliably discriminated from single-labeled cells. Approximate level is -6.4 mm from bregma. (E) Plots of cells in the mDCN at rostral to caudal levels in a single animal (left to right); a subset of cells at each level are double-labeled (blue circles). Red and green circles correspond to cells labeled by rostral and caudal injections, respectively. Approximate rostral–caudal levels are -6.2, -6.4, and -6.6 mm from bregma (left to right). Scale bars: (C) = 100 mm; (D) = 50 mm. Atlas sections from Paxinos and Franklin (2001).
FIGURE 4
FIGURE 4
Raw data example of DCN spike activity correlated with licking, whisking and respiratory behavior. (A) Raw data examples of single-unit DCN spike activity with licking, whisking and respiratory behavior. Under each trace are time markers marking the tongue-to-spout contact times for the licking trace, the time of whisker beam crossing for whisking trace, the end-of-expiration and inspiration times for the respiratory trace, and spike activity for the DCN spike train recording, respectively. (B) Histograms showing the inter-lick interval, inter-whisking interval, inter-expiration interval, and inter-spike interval distribution. (C) Histograms showing the cross-correlation between DCN spikes with licking, whisking, and expiration events.
FIGURE 5
FIGURE 5
Summary of behavior-spike cross-correlation results expressed as Z-scores of peak correlation values for breathing, whisking, and licking behavior (left, middle, and right column, respectively). Each symbol represents one mDCN unit’s Z-score for each behavior. Only Z-scores > 1 are shown. Spike activity of all 11 units was significantly correlated (Z-scores > 2, dashed horizontal line) with either breathing or whisking. Activity of five units was correlated with respiration alone, one unit’s activity was correlated with whisking alone, and the remaining five units had spike activity correlated with both breathing and whisking. One unit (red circle) had spike activity significantly correlated with all three behaviors. Box and whisker plots show median, 25th and 75th percentile (box) and 9th and 91st percentile (whiskers).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Alheid G. F., Jiao W., McCrimmon D. R. (2011). Caudal nuclei of the rat nucleus of the solitary tract differentially innervate respiratory compartments within the ventrolateral medulla. Neuroscience 190 207–227 - PMC - PubMed
    1. Andrezik J. A., Dormer K. J., Foreman R. D., Person R. J. (1984). Fastigial nucleus projections to the brain stem in beagles: pathways for autonomic regulation. Neuroscience 11 497–507 - PubMed
    1. Apps R., Ruigrok T. J. (2007). A fluorescence-based double retrograde tracer strategy for charting central neuronal connections. Nat. Protoc. 2 1862–1868 - PubMed
    1. Bagnall M. W., Zingg B., Sakatos A., Moghadam S. H., Zeilhofer H. U, du Lac S. (2009). Glycinergic projection neurons of the cerebellum. J. Neurosci. 29 10104–10110 - PMC - PubMed
    1. Bassal M., Bianchi A. L. (1982). Inspiratory onset or termination induced by electrical stimulation of the brain. Respir. Physiol. 50 23–40 - PubMed

Publication types

LinkOut - more resources