The microscopic anatomy and physiology of the mammalian saccadic system

Moschovakis, Adonis; Scudder, C. A.; Highstein, Stephen M.

doi:10.1016/s0301-0082(96)00034-2

Cited by 327 publications

(245 citation statements)

References 602 publications

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“…Redgrave et al [96] make the incisive observation that the midbrain DA neurons respond to a visual event before the animal has had the opportunity to make a visual saccade, and therefore, before the animal has foveated the stimulus. The visual saccade has a latency of 180Á/ 200 or 80 Á/110 ms for express saccades [82]. Whatever the nature of the information that elicits VTA DA firing to a visual event, it appears to be relatively low-level (pre-attentive) information (although the DA response may be modulated by topÁ/down influences prior to the eliciting event).…”

Section: Da Neurons Respond To Salient Unexpected Eventsmentioning

confidence: 99%

Dopamine gating of glutamatergic sensorimotor and incentive motivational input signals to the striatum

Horvitz

2002

Behavioural Brain Research

187

148

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Section: Da Neurons Respond To Salient Unexpected Eventsmentioning

confidence: 99%

Dopamine gating of glutamatergic sensorimotor and incentive motivational input signals to the striatum

Horvitz

2002

Behavioural Brain Research

187

148

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“…To maintain the position of the eye after a saccade, extraocular motoneurons need a persistent activity called "eye position signal" (Cannon and Robinson, 1987;Delgado-García et al, 1989;Fukushima et al, 1992;Moschovakis et al, 1996;Moschovakis, 1997). Because PPRF excitatory burst neurons fire only slightly in advance and during part of the ongoing saccade, a repeated question has been how do neuronal circuits implicated in eye movements generate eye position signals.…”

Section: Role Of Ph Neurons In the Generation Of Eye Position Signalsmentioning

confidence: 99%

A Cholinergic Synaptically Triggered Event Participates in the Generation of Persistent Activity Necessary for Eye Fixation

Navarro‐López¹,

Alvarado²,

Márquez-Ruiz³

et al. 2004

J. Neurosci.

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An exciting topic regarding integrative properties of the nervous system is how transient motor commands or brief sensory stimuli are able to evoke persistent neuronal changes, mainly as a sustained, tonic action potential firing. A persisting firing seems to be necessary for postural maintenance after a previous movement. We have studied in vitro and in vivo the generation of the persistent neuronal activity responsible for eye fixation after spontaneous eye movements. Rat sagittal brainstem slices were used for the intracellular recording of prepositus hypoglossi (PH) neurons and their synaptic activation from nearby paramedian pontine reticular formation (PPRF) neurons. Single electrical pulses applied to the PPRF showed a monosynaptic glutamatergic projection on PH neurons, acting on AMPA-kainate receptors. Train stimulation of the PPRF area evoked a sustained depolarization of PH neurons exceeding (by hundreds of milliseconds) stimulus duration. Both duration and amplitude of this sustained depolarization were linearly related to train frequency. The trainevoked sustained depolarization was the result of interaction between glutamatergic excitatory burst neurons and cholinergic mesopontine reticular fibers projecting onto PH neurons, because it was prevented by slice superfusion with cholinergic antagonists and mimicked by cholinergic agonists. As expected, microinjections of cholinergic antagonists in the PH nucleus of alert behaving cats evoked a gaze-holding deficit consisting of a re-centering drift of the eye after each saccade. These findings suggest that a slow, cholinergic, synaptically triggered event participates in the generation of persistent activity characteristic of PH neurons carrying eye position signals.

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“…Early studies showed that stimulation of the RF resulted in motor responses (Magoun & Rhines 1946); electrical stimulation of specific mRF regions can elicit locomotion ( Kinjo et al 1990;Whelan 1996). Neurons within other regions of the mRF are critical for the maintenance of posture (Mori 1987), the control of feeding behaviours ( Lund et al 1998) and the generation of eye movements (Moschovakis et al 1996). In a comprehensive review, Siegel (1979) found that multiple competencies were attributed to the mRF because its neural activity correlated with a wide range of responses to stimuli and with naturally occurring behaviours.…”

Section: Introductionmentioning

confidence: 99%

Is there a brainstem substrate for action selection?

Humphries

Gurney

Prescott

2007

Phil. Trans. R. Soc. B

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The search for the neural substrate of vertebrate action selection has focused on structures in the forebrain and midbrain, and particularly on the group of sub-cortical nuclei known as the basal ganglia. Yet, the behavioural repertoire of decerebrate and neonatal animals suggests the existence of a relatively self-contained neural substrate for action selection in the brainstem. We propose that the medial reticular formation (mRF) is the substrate's main component and review evidence showing that the mRF's inputs, outputs and intrinsic organization are consistent with the requirements of an action-selection system. The internal architecture of the mRF is composed of interconnected neuron clusters. We present an anatomical model which suggests that the mRF's intrinsic circuitry constitutes a small-world network and extend this result to show that it may have evolved to reduce axonal wiring. Potential configurations of action representation within the internal circuitry of the mRF are then assessed by computational modelling. We present new results demonstrating that each cluster's output is most likely to represent activation of a component action; thus, coactivation of a set of these clusters would lead to the coordinated behavioural response observed in the animal. Finally, we consider the potential integration of the basal ganglia and mRF substrates for selection and suggest that they may collectively form a layered/hierarchical control system.

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The microscopic anatomy and physiology of the mammalian saccadic system

Cited by 327 publications

References 602 publications

Dopamine gating of glutamatergic sensorimotor and incentive motivational input signals to the striatum

Dopamine gating of glutamatergic sensorimotor and incentive motivational input signals to the striatum

A Cholinergic Synaptically Triggered Event Participates in the Generation of Persistent Activity Necessary for Eye Fixation

Is there a brainstem substrate for action selection?

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