Differences of the primate flocculus and ventral paraflocculus in the mossy and climbing fiber input organization

Nagao, Soichi; Kitamura, Taiko; Nakamura, Naoya; Hiramatsu, Takehito; Yamada, Jinzo

doi:10.1002/(sici)1096-9861(19970616)382:4<480::aid-cne5>3.0.co;2-z

Cited by 91 publications

(35 citation statements)

References 76 publications

(112 reference statements)

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“…Anatomical studies indicate the DLPN projects most heavily to the ventral paraflocculus (Glickstein et al 1994;Nagao 1990Nagao , 1997. Recent lesion studies indicate that the ventral paraflocculus contributes to both smooth pursuit and VOR adaptation (Rambold et al 2002).…”

Section: Discussionmentioning

confidence: 99%

“…The DLPN is known to receive visual cortical inputs from the extrastriate cortex (Distler et al 2002;Glickstein et al 1980Glickstein et al , 1994May and Andersen 1986), including areas middle temporal (MT) and medial superior temporal (MST), which are specialized for visual motion processing (Andersen et al 1990;Maunsell and Newsome 1987). In turn, the DLPN sends mossy fiber projections to the contralateral ventral paraflocculus and dorsal paraflocculus (Glickstein et al 1994;Nagao 1997) and vermal lobule VI and VII (Brodal 1979(Brodal , 1982Langer 1985). Single-unit recording (Kawano et al 1992;Mustari et al 1988;Suzuki and Keller 1984;Suzuki et al 1990;Thier et al 1988) and lesion studies (May et al 1988) demonstrate that DLPN neurons carry appropriate signals to play a role in the initiation and maintenance of smooth pursuit, optokinetic and ocular following eye movements.…”

Section: Introductionmentioning

confidence: 99%

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Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

Ono¹,

Das

Mustari

2003

Journal of Neurophysiology

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Ono, Seiji, V. E. Das, and M. J. Mustari. Role of the dorsolateral pontine nucleus in short-term adaptation of the horizontal vestibuloocular reflex. J Neurophysiol 89: 2879 -2885, 2003; 10.1152/jn.00602.2002. The dorsolateral pontine nucleus (DLPN) is a major component of the cortico-ponto-cerebellar pathway that carries signals essential for smooth pursuit. This pathway also carries visual signals that could play a role in visually guided motor learning in the vestibular ocular reflex (VOR). However, there have been no previous studies that tested this possibility directly. The aim of this study was to determine the potential role of the DLPN in short-term VOR gain adaptation produced by viewing a scene through lenses placed in front of both eyes. In control experiments, adaptation of VOR gain was achieved by sinusoidal rotation (0.2 Hz, 30°/s) for 2 h while the monkey viewed a stationary visual surround through either magnifying (ϫ2) or minifying (ϫ0.5) lenses. This led to increases (23-32%) or decreases (22-48%) of VOR gain as measured in complete darkness (VORd). We used injections of muscimol, a potent GABA A agonist (0.5 l; 2%), to reversibly inactivate the DLPN, unilaterally, in three monkeys. After DLPN inactivation, initial acceleration of ipsilateral smoothpursuit was reduced by 35-68%, and steady-state gain was reduced by 32-61%. Despite these significant deficits (P Ͻ 0.01) in ipsilesional smooth pursuit, the VOR during lens viewing was similar to that measured in preinjection control experiments. Similarly, after 2 h of adaptation, VORd gain was not significantly different (P Ͼ 0.61) from control adaptation values for either ipsi-or contralesional directions of head rotation. This was the case even though a stable ipsilesional smooth pursuit deficit persisted throughout the full adaptation period. Our results suggest that visual error signals for short-term adaptation of the VOR are derived from sources other than the DLPN perhaps including other basilar pontine nuclei and the accessory optic system.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

Ono¹,

Das

Mustari

2003

Journal of Neurophysiology

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“…Even though FTN response behavior during saccades and VOR suppression could vary greatly, their unique characteristics include a strong eye-velocity sensitivity with a small and often non-linear eye-position sensitivity. FPNs, on the other hand, have been described as cells with small eye-movement sensitivity and represent distinctly different and nonoverlapping populations from FTNs (Nagao et al 1997;Zhang et al 1993Zhang et al , 1995a. Neuroanatomical and electrophysiological studies have identified FTNs in the rostral medial and ventrolateral vestibular nuclei (Langer et al 1985a;Lisberger et al 1994;Nagao et al 1997;Sato et al 1988).…”

Section: Classes Of Vestibuloocular Neurons and Comparison Of Their Rmentioning

confidence: 99%

Eyes on Target: What Neurons Must do for the Vestibuloocular Reflex During Linear Motion

Angelaki

2004

Journal of Neurophysiology

121

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Angelaki, Dora E. Eyes on target: what neurons must do for the vestibuloocular reflex during linear motion. J Neurophysiol 92: 20 -35, 2004; 10.1152/jn.00047.2004. A gaze-stabilization reflex that has been conserved throughout evolution is the rotational vestibuloocular reflex (RVOR), which keeps images stable on the entire retina during head rotation. An ethological newer reflex, the translational or linear VOR (TVOR), provides fast foveal image stabilization during linear motion. Whereas the sensorimotor processing has been extensively studied in the RVOR, much less is currently known about the neural organization of the TVOR. Here we summarize the computational problems faced by the system and the potential solutions that might be used by brain stem and cerebellar neurons participating in the VORs. First and foremost, recent experimental and theoretical evidence has shown that, contrary to popular beliefs, the sensory signals driving the TVOR arise from both the otolith organs and the semicircular canals. Additional unresolved issues include a scaling by both eye position and vergence angle as well as the temporal transformation of linear acceleration signals into eye-position commands. Behavioral differences between the RVOR and TVOR, as well as distinct differences in neuroanatomical and neurophysiological properties, raise multiple functional questions and computational issues, only some of which are readily understood. In this review, we provide a summary of what is known about the functional properties and neural substrates for this oculomotor system and outline some specific hypotheses about how sensory information is centrally processed to create motor commands for the VORs. I N T R O D U C T I O NThe world is viewed from a constantly shifting platform, where visual mechanisms function optimally only if images on the retina remain stable. This is achieved primarily by the vestibuloocular reflexes (VORs), which provide fast compensation during both translational and rotational motions. Although the rotational VOR (RVOR) is phylogenetically older and highly conserved throughout evolution, the translational VOR (TVOR) represents a relatively recent evolutionary acquisition that appears to have evolved in parallel with foveal vision, vergence eye movements, and stereopsis (Miles 1993(Miles , 1998. Its amplitude and functional properties are only well described for humans and non-human primates (Angelaki and McHenry 1999; McHenry and Angelaki 2000;Paige 1989; Paige and Tomko 1991a,b;Ramat and Zee 2003;Schwarz and Miles 1991;Schwarz et al. 1989;Telford et al. 1997;Zhou et al. 2003). In contrast, an image-stabilization system appropriate to compensate for the visual consequences of translational motion remains rudimentary or absent in lateral-eyed species (Baarsma and Collewijn 1975; Dickman and Angelaki 1999;Hess and Dieringer 1990, 1991; Hess et al. 1984; Maruta et al. 2001). The functional goal of the TVOR is to decrease conjugate retinal slip and minimize binocular disparities during either self-motion...

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“…The cerebellar cortical circuit can be integrated into the VOR circuitry in a feedback arrangement, such as that shown in Figure 1C. Information about head movement arrives at the lateral vestibulocerebellum from the vestibular primary afferents and the vestibular nuclei (Langer et al 1985;Nagao et al 2002), by way of the mossy fiber/parallel fiber pathway (Miles et al 1980b). At the same time, the cerebellar Purkinje cell receives climbing fiber input from the inferior olivary nucleus that encodes visual information (Maekawa and Simpson 1973).…”

Section: The Vor Neural Networkmentioning

confidence: 99%

Learning in a Simple Motor System

Broussard¹,

Kassardjian²

2004

Learn. Mem.

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Motor learning is a very basic, essential form of learning that appears to share common mechanisms across different motor systems. We evaluate and compare a few conceptual models for learning in a relatively simple neural system, the vestibulo-ocular reflex (VOR) of vertebrates. We also compare the different animal models that have been used to study the VOR. In the VOR, a sensory signal from the semicircular canals is transformed into a motor signal that moves the eyes. The VOR can modify the transformation under the guidance of vision. The changes are persistent and share some characteristics with other types of associative learning. The cerebellar cortex is directly linked to the VOR reflex circuitry in a partnership that is present in all vertebrates, and which is necessary for motor learning. Early theories of Marr, Albus, and Ito, in which motor memories are stored solely in the cerebellar cortex, have not explained the bulk of the experimental data. Many studies appear to indicate a site of learning in the vestibular nuclei, and the most successful models have incorporated long-term memory storage in both the cerebellar cortex and the brainstem. Plausible cellular mechanisms for learning have been identified in both structures. We propose that short-term motor memory is initially stored in the cerebellar cortex, and that during consolidation of the motor memory the locus of storage shifts to include a brainstem site. We present experimental results that support our hypothesis.In many situations, inaccurate movements are worse than useless. If the movement is slow, errors can be corrected online by visual or other sensory feedback. However, rapid movements must be intrinsically accurate. This could be accomplished by hard-wiring an accurate movement, which has the obvious disadvantage that the movement cannot be readjusted for changes in downstream motor centers or (in the case of a reflex) for changes in sensory sensitivity. A better solution is to calibrate the movement by trial and error, that is, by motor learning. For our purposes, motor learning is defined as the process by which we acquire precise, coordinated movements, like those that are required in order to run, serve a tennis ball, and type accurately. Because accurate movements are necessary whenever predators must be avoided or prey captured, we can speculate that motor learning may have been one of the earliest types of associative learning to evolve. It has been demonstrated in the ventral nerve cord of insects (Horridge 1962) and is probably universal in freely-moving animals. Furthermore, because its substrate can be relatively simple and well understood, there is a real possibility of understanding motor learning both on the molecular level and on the level of brain circuitry.Motor learning is classified as procedural learning. Errors are monitored and used to guide adaptive changes without conscious awareness. Instead of learning a concept, the subject learns an accurate and appropriate motor response. Distinctions have also been made b...

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Differences of the primate flocculus and ventral paraflocculus in the mossy and climbing fiber input organization

Cited by 91 publications

References 76 publications

Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

Role of the Dorsolateral Pontine Nucleus in Short-Term Adaptation of the Horizontal Vestibuloocular Reflex

Eyes on Target: What Neurons Must do for the Vestibuloocular Reflex During Linear Motion

Learning in a Simple Motor System

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