Purkinje Cells in Posterior Cerebellar Vermis Encode Motion in an Inertial Reference Frame

Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Neuron (Impact Factor: 15.05). 07/2007; 54(6):973-85. DOI: 10.1016/j.neuron.2007.06.003
Source: PubMed


The ability to orient and navigate through the terrestrial environment represents a computational challenge common to all vertebrates. It arises because motion sensors in the inner ear, the otolith organs, and the semicircular canals transduce self-motion in an egocentric reference frame. As a result, vestibular afferent information reaching the brain is inappropriate for coding our own motion and orientation relative to the outside world. Here we show that cerebellar cortical neuron activity in vermal lobules 9 and 10 reflects the critical computations of transforming head-centered vestibular afferent information into earth-referenced self-motion and spatial orientation signals. Unlike vestibular and deep cerebellar nuclei neurons, where a mixture of responses was observed, Purkinje cells represent a homogeneous population that encodes inertial motion. They carry the earth-horizontal component of a spatially transformed and temporally integrated rotation signal from the semicircular canals, which is critical for computing head attitude, thus isolating inertial linear accelerations during navigation.

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Available from: Pablo M Blazquez, Oct 03, 2015
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    • "Using transgenic L7PKCI mice, which selectively lack protein kinase C-dependent plasticity at parallel fiber-Purkinje cell synapses in the cerebellum, Rochefort et al. (2011) examined hippocampal place cells during navigation. Purkinje cells are thought to transform vestibular head-orientation information into Earth-reference spatial orientation and self-motion information (Yakusheva et al., 2007). Although the L7PKCI mice had significantly fewer place cells compared with wild-type littermates, place fields were largely unaffected during normal conditions when both idiothetic and landmark information were available . "
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    ABSTRACT: Navigation is a complex cognitive process that is vital for survival. The rodent hippocampus has long been implicated in spatial memory and navigation. Following the discovery of place cells, found in the hippocampus, a variety of other spatially tuned neural correlates of navigation have been found in a widely distributed network that is both anatomically and functionally interconnected with the hippocampus. Angular head velocity, head direction, and grid cells are among some of the additional spatial neural correlates. The importance of these different cells and how they function interdependently to subserve navigation is reviewed below. © 2015 Elsevier B.V. All rights reserved.
    Progress in brain research 06/2015; 219:83-102. DOI:10.1016/bs.pbr.2015.03.004 · 2.83 Impact Factor
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    • "In our mutant mice, Cre/loxP recombination was observed in the cerebellum (Figure 2A), and slight motor abnormalities were found in homozygous mice (see Results), suggesting the possibility that mutated GluN2A in the cerebellum may contribute to the mutant phenotype even in heterozygotes. The cerebellum is known to process self-motion signals [45,46], and a recent report showed that a transgenic mouse line with impaired protein kinase C-dependent plasticity at parallel fiber–Purkinje cell synapses has impaired hippocampal place field activity under specific circumstances, i.e., when animals rely on self-motion cues, or when there is conflict between visual cues and self-motion cues [47]. This report indicated a role for the cerebellum in processing self-motion signals for shaping hippocampal place field activity. "
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    ABSTRACT: Background Voltage-dependent block of the NMDA receptor by Mg2+ is thought to be central to the unique involvement of this receptor in higher brain functions. However, the in vivo role of the Mg2+ block in the mammalian brain has not yet been investigated, because brain-wide loss of the Mg2+ block causes perinatal lethality. In this study, we used a brain-region specific knock-in mouse expressing an NMDA receptor that is defective for the Mg2+ block in order to test its role in neural information processing. Results We devised a method to induce a single amino acid substitution (N595Q) in the GluN2A subunit of the NMDA receptor, specifically in the hippocampal dentate gyrus in mice. This mutation reduced the Mg2+ block at the medial perforant path–granule cell synapse and facilitated synaptic potentiation induced by high-frequency stimulation. The mutants had more stable hippocampal place fields in the CA1 than the controls did, and place representation showed lower sensitivity to visual differences. In addition, behavioral tests revealed that the mutants had a spatial working memory deficit. Conclusions These results suggest that the Mg2+ block in the dentate gyrus regulates hippocampal spatial information processing by attenuating activity-dependent synaptic potentiation in the dentate gyrus.
    Molecular Brain 06/2014; 7(1):44. DOI:10.1186/1756-6606-7-44 · 4.90 Impact Factor
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    • "be used to resolve head movements into changes in orientation and motion in the planes of the environment . Interestingly , controlling and referencing the velocity storage response to gravity is also related to the vestibular pathway that connects to the nodulus and uvula ( Solomon and Cohen , 1994 ; Wearne et al . , 1998 ; Cohen et al . , 2002 ; Yakusheva et al . , 2007 ; Laurens et al . , 2013 ) . As discussed above , these parts of the cau - dal cerebellum may provide a similar reference control for the ascending angular velocity signal in the NPH ( Carleton and Carpenter , 1983 ; Horowitz et al . , 2005 ) , and would reference the AHV signal sent to the HD circuit by aligning the head rotation with "
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    ABSTRACT: Head direction (HD) cells have been identified in a number of limbic system structures. These cells encode the animal's perceived directional heading in the horizontal plane and are dependent on an intact vestibular system. Previous studies have reported that the responses of vestibular neuron within the vestibular nuclei are markedly attenuated when an animal makes a volitional head turn compared to passive rotation. This finding presents a conundrum in that if vestibular responses are suppressed during an active head turn how is a vestibular signal propagated forward to drive and update the HD signal? This review identifies and discusses four possible mechanisms that could resolve this problem. These mechanisms are: 1) the ascending vestibular signal is generated by more than just vestibular-only neurons, 2) not all vestibular-only neurons contributing to the HD pathway have firing rates that are attenuated by active head turns, 3) the ascending pathway may be spared from the affects of the attenuation in that the HD system receives information from other vestibular brainstem sites that do not include vestibular-only cells, 4) the ascending signal is affected by the inhibited vestibular signal during an active head turn, but the HD circuit compensates and uses the altered signal to accurately update the current head direction. Future studies will be needed to decipher which of these possibilities is correct.
    Neuroscience 04/2014; 270. DOI:10.1016/j.neuroscience.2014.03.053 · 3.36 Impact Factor
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