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Segregated fronto-cerebellar circuits revealed by intrinsic functional connectivity.

Krienen FM, Buckner RL - Cereb. Cortex (2009)

Bottom Line: The presence of circuits that involve prefrontal regions confirms that the cerebellum participates in networks important to cognition including a specific fronto-cerebellar circuit that interacts with the default network.Overall, the extent of the cerebellum associated with prefrontal cortex included a large portion of the posterior hemispheres consistent with a prominent role of the cerebellum in nonmotor functions.We conclude by providing a provisional map of the topography of the cerebellum based on functional correlations with the frontal cortex.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA. krienen@wjh.harvard.edu

ABSTRACT
Multiple, segregated fronto-cerebellar circuits have been characterized in nonhuman primates using transneuronal tracing techniques including those that target prefrontal areas. Here, we used functional connectivity MRI (fcMRI) in humans (n = 40) to identify 4 topographically distinct fronto-cerebellar circuits that target 1) motor cortex, 2) dorsolateral prefrontal cortex, 3) medial prefrontal cortex, and 4) anterior prefrontal cortex. All 4 circuits were replicated and dissociated in an independent data set (n = 40). Direct comparison of right- and left-seeded frontal regions revealed contralateral lateralization in the cerebellum for each of the segregated circuits. The presence of circuits that involve prefrontal regions confirms that the cerebellum participates in networks important to cognition including a specific fronto-cerebellar circuit that interacts with the default network. Overall, the extent of the cerebellum associated with prefrontal cortex included a large portion of the posterior hemispheres consistent with a prominent role of the cerebellum in nonmotor functions. We conclude by providing a provisional map of the topography of the cerebellum based on functional correlations with the frontal cortex.

Show MeSH
Raw correlation maps show some bilateral cerebellar connectivity from unilateral cortical seeds. Although subtraction of left and right seeds in a given cortical region highlights the contralateral organization of cerebellar connectivity (see Fig. 1), the raw left and right seeds show present, but weaker, ipsilateral connectivity with the cerebellum. This observation is consistent with the smaller percentage of cerebellar projections that cross back to the ipsilateral hemisphere (see text). Maps are at a threshold of z(r) > 0.1.
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fig5: Raw correlation maps show some bilateral cerebellar connectivity from unilateral cortical seeds. Although subtraction of left and right seeds in a given cortical region highlights the contralateral organization of cerebellar connectivity (see Fig. 1), the raw left and right seeds show present, but weaker, ipsilateral connectivity with the cerebellum. This observation is consistent with the smaller percentage of cerebellar projections that cross back to the ipsilateral hemisphere (see text). Maps are at a threshold of z(r) > 0.1.

Mentions: The specificity of the cerebellar effect is particularly prominent when the background correlations that are common between the left and right seeded maps are removed via the subtraction method. As shown in Figure 5, raw correlation maps of the cerebellum without subtraction reveal bilateral functional connectivity (peak correlation coordinates in Table 2); the contralateral cerebellum shows relatively stronger connectivity that becomes prominent when the right and left hemisphere seeded maps are directly contrasted (as in Fig. 1). These observations are consistent with the known contralateral, polysynaptic connections between cerebral cortex and the cerebellum (Schmahmann 1996; Middleton and Strick 2001; Kelly and Strick 2003). It should also be noted that in all of our analyses, we saw robust connectivity with the thalamus, which is the obligatory anatomical step in projections from the cerebellum to the cerebral cortex (see also Zhang et al. 2008). We could also detect correlations in the pons but not in all instances (Fig. 3).


Segregated fronto-cerebellar circuits revealed by intrinsic functional connectivity.

Krienen FM, Buckner RL - Cereb. Cortex (2009)

Raw correlation maps show some bilateral cerebellar connectivity from unilateral cortical seeds. Although subtraction of left and right seeds in a given cortical region highlights the contralateral organization of cerebellar connectivity (see Fig. 1), the raw left and right seeds show present, but weaker, ipsilateral connectivity with the cerebellum. This observation is consistent with the smaller percentage of cerebellar projections that cross back to the ipsilateral hemisphere (see text). Maps are at a threshold of z(r) > 0.1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742600&req=5

fig5: Raw correlation maps show some bilateral cerebellar connectivity from unilateral cortical seeds. Although subtraction of left and right seeds in a given cortical region highlights the contralateral organization of cerebellar connectivity (see Fig. 1), the raw left and right seeds show present, but weaker, ipsilateral connectivity with the cerebellum. This observation is consistent with the smaller percentage of cerebellar projections that cross back to the ipsilateral hemisphere (see text). Maps are at a threshold of z(r) > 0.1.
Mentions: The specificity of the cerebellar effect is particularly prominent when the background correlations that are common between the left and right seeded maps are removed via the subtraction method. As shown in Figure 5, raw correlation maps of the cerebellum without subtraction reveal bilateral functional connectivity (peak correlation coordinates in Table 2); the contralateral cerebellum shows relatively stronger connectivity that becomes prominent when the right and left hemisphere seeded maps are directly contrasted (as in Fig. 1). These observations are consistent with the known contralateral, polysynaptic connections between cerebral cortex and the cerebellum (Schmahmann 1996; Middleton and Strick 2001; Kelly and Strick 2003). It should also be noted that in all of our analyses, we saw robust connectivity with the thalamus, which is the obligatory anatomical step in projections from the cerebellum to the cerebral cortex (see also Zhang et al. 2008). We could also detect correlations in the pons but not in all instances (Fig. 3).

Bottom Line: The presence of circuits that involve prefrontal regions confirms that the cerebellum participates in networks important to cognition including a specific fronto-cerebellar circuit that interacts with the default network.Overall, the extent of the cerebellum associated with prefrontal cortex included a large portion of the posterior hemispheres consistent with a prominent role of the cerebellum in nonmotor functions.We conclude by providing a provisional map of the topography of the cerebellum based on functional correlations with the frontal cortex.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA. krienen@wjh.harvard.edu

ABSTRACT
Multiple, segregated fronto-cerebellar circuits have been characterized in nonhuman primates using transneuronal tracing techniques including those that target prefrontal areas. Here, we used functional connectivity MRI (fcMRI) in humans (n = 40) to identify 4 topographically distinct fronto-cerebellar circuits that target 1) motor cortex, 2) dorsolateral prefrontal cortex, 3) medial prefrontal cortex, and 4) anterior prefrontal cortex. All 4 circuits were replicated and dissociated in an independent data set (n = 40). Direct comparison of right- and left-seeded frontal regions revealed contralateral lateralization in the cerebellum for each of the segregated circuits. The presence of circuits that involve prefrontal regions confirms that the cerebellum participates in networks important to cognition including a specific fronto-cerebellar circuit that interacts with the default network. Overall, the extent of the cerebellum associated with prefrontal cortex included a large portion of the posterior hemispheres consistent with a prominent role of the cerebellum in nonmotor functions. We conclude by providing a provisional map of the topography of the cerebellum based on functional correlations with the frontal cortex.

Show MeSH