Pulvinar Inactivation Disrupts Selection of Movement Plans

Wilke, Melanie; Turchi, Janita; Smith, Katy; Mishkin, Mortimer; Leopold, David A.

doi:10.1523/jneurosci.0953-10.2010

Cited by 149 publications

(189 citation statements)

References 63 publications

Supporting

Mentioning

172

Contrasting

Order By: Relevance

“…In addition, these and other oculomotor areas with direct projections to the SC could be activated antidromically. We speculate that structures activated through the ascending output are not likely to exert a role in producing SC stimulation-evoked saccades, because their inactivation does not produce deficits in mediating motoric control (Sommer and Wurtz 2002;Wilke et al 2010). Furthermore, the primary FEF output pathway involved in saccade generation is likely relayed through the SC (Hanes and Wurtz 2001), and the same could be true for other cortical regions.…”

Section: Interpretation Of Stimulation Resultsmentioning

confidence: 95%

Order of operations for decoding superior colliculus activity for saccade generation

Katnani

Gandhi²

2011

Journal of Neurophysiology

View full text Add to dashboard Cite

Katnani HA, Gandhi NJ. Order of operations for decoding superior colliculus activity for saccade generation. J Neurophysiol 106: 1250-1259, 2011. First published June 15, 2011 doi:10.1152/jn.00265.2011To help understand the order of events that occurs when generating saccades, we simulated and tested two commonly stated decoding models that are believed to occur in the oculomotor system: vector averaging (VA) and center-of-mass. To generate accurate saccades, each model incorporates two required criteria: 1) a decoding mechanism that deciphers a population response of the superior colliculus (SC) and 2) an exponential transformation that converts the saccade vector into visual coordinates. The order of these two criteria is used differently within each model, yet the significance of the sequence has not been quantified. To distinguish between each decoding sequence and hence, to determine the order of events necessary to generate accurate saccades, we simulated the two models. Distinguishable predictions were obtained when two simultaneous motor commands are processed by each model. Experimental tests of the models were performed by observing the distribution of endpoints of saccades evoked by weighted, simultaneous microstimulation of two SC sites. The data were consistent with the predictions of the VA model, in which exponential transformation precedes the decoding computation.sequence of decoding; dual microstimulation; vector averaging; vector summation; center-of-mass THE SUPERIOR COLLICULUS (SC) is a critical, subcortical hub that plays a major role in converting sensory information into a motor command for saccade generation (Gandhi and Katnani 2011;Sparks 1986). Visual information in the SC is organized topographically in a logarithmic manner. A disproportionately large amount of SC tissue is allocated for (para-) foveal space and small-amplitude saccades, whereas a compressed region is attributed for the visual periphery and large-amplitude saccades (Cynader and Berman 1972;Robinson 1972). With the presentation of a stimulus, a population of neurons becomes active at a locus that represents the vector between the stimuli and line of sight (Wurtz and Goldberg 1972). Under ordinary circumstances, a comparable population discharges a highfrequency premotor burst to produce a saccade of the appropriate displacement (Sparks et al. 1976). To make certain that the saccadic eye movement lands near the desired location, two critical operations must be performed. One, the population response must be decoded using standard decoding mechanisms such as averaging or summation. Two, the SC output must undergo an exponential transformation to convert the saccade vector into visual coordinates (Ottes et al. 1986), the inverse transformation used to map visual space into SC coordinates. Studies have implemented the order of these two operations in different fashions. To the best of our knowledge, no attempt has been made to distinguish the order of these operations.In one scheme, the exponential transformation is applie...

show abstract

Section: Interpretation Of Stimulation Resultsmentioning

confidence: 95%

Order of operations for decoding superior colliculus activity for saccade generation

Katnani

Gandhi²

2011

Journal of Neurophysiology

View full text Add to dashboard Cite

show abstract

“…For instance, the neglect-like symptoms observed in monkeys after pulvinar inactivation could be related either to attentional deficits or deficits in the decision process (e.g., devaluation of the contralesional hemifield; Wilke et al, 2010). To address this question, we need to explore whether the choice bias is effector specific.…”

Section: Introductionmentioning

confidence: 99%

Inactivation of Parietal Reach Region Affects Reaching But Not Saccade Choices in Internally Guided Decisions

et al. 2015

View full text Add to dashboard Cite

The posterior parietal cortex (PPC) has traditionally been considered important for awareness, spatial perception, and attention. However, recent findings provide evidence that the PPC also encodes information important for making decisions. These findings have initiated a running argument of whether the PPC is critically involved in decision making. To examine this issue, we reversibly inactivated the parietal reach region (PRR), the area of the PPC that is specialized for reaching movements, while two monkeys performed a memory-guided reaching or saccade task. The task included choices between two equally rewarded targets presented simultaneously in opposite visual fields. Free-choice trials were interleaved with instructed trials, in which a single cue presented in the peripheral visual field defined the reach and saccade target unequivocally. We found that PRR inactivation led to a strong reduction of contralesional choices, but only for reaches. On the other hand, saccade choices were not affected by PRR inactivation. Importantly, reaching and saccade movements to single instructed targets remained largely intact. These results cannot be explained as an effector-nonspecific deficit in spatial attention or awareness, since the temporary "lesion" had an impact only on reach choices. Hence, the PPR is a part of a network for reach decisions and not just reach planning.

show abstract

“…An important advantage of this approach is the ability to use each animal as its own control in a repeated-measures design. In monkeys, we (22)(23)(24)(25)(26) and others (27)(28)(29) have used this technique to probe functions of several brain regions, but it has yet to be applied to the hippocampus.…”

mentioning

confidence: 99%

Memory loss in a nonnavigational spatial task after hippocampal inactivation in monkeys

Forcelli

Palchik

Leath³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The hippocampus has a well-documented role for spatial navigation across species, but its role for spatial memory in nonnavigational tasks is uncertain. In particular, when monkeys are tested in tasks that do not require navigation, spatial memory seems unaffected by lesions of the hippocampus. However, the interpretation of these results is compromised by long-term compensatory adaptation occurring in the days and weeks after lesions. To test the hypothesis that hippocampus is necessary for nonnavigational spatial memory, we selected a technique that avoids long-term compensatory adaptation. We transiently disrupted hippocampal function acutely at the time of testing by microinfusion of the glutamate receptor antagonist kynurenate. Animals were tested on a self-ordered spatial memory task, the Hamilton Search Task. In the task, animals are presented with an array of eight boxes, each containing a food reinforcer; one box may be opened per trial, with trials separated by a delay. Only the spatial location of the boxes serves as a cue to solve the task. The optimal strategy is to open each box once without returning to previously visited locations. Transient inactivation of hippocampus reduced performance to chance levels in a delay-dependent manner. In contrast, no deficits were seen when boxes were marked with nonspatial cues (color). These results clearly document a role for hippocampus in nonnavigational spatial memory in macaques and demonstrate the efficacy of pharmacological inactivation of this structure in this species. Our data bring the role of the hippocampus in monkeys into alignment with the broader framework of hippocampal function.A lthough a role for the hippocampus in navigational spatial memory has been well documented in many species, including humans (1-4), rodents (5, 6), and monkeys (7-9), a role for hippocampus in nonnavigational spatial memory is less certain. Because nonhuman primates have a close neuroanatomical and behavioral homology to humans, they offer a unique opportunity to assess the neural substrates of spatial memory using nonnavigational tasks. However, studies using nonnavigational spatial tasks with nonhuman primates have found little or no effect of hippocampal lesions (10-15).The ability of hippocampal-lesioned monkeys to perform these tasks without impairment has been explained by the reliance on a strategy that is not dependent on hippocampus. Whereas the use of allocentric (world-centered) cues depends on the hippocampus, it is thought that the use of egocentric (body-centered) cues does not. Indeed, it has been suggested that the use of egocentric cues is supported by extrahippocampal substrates including striatum and parietal cortex (15)(16)(17)(18).Following a hippocampal lesion, subjects may learn to resolve a given task by developing a strategy distinct from that used in the presence of an intact hippocampus. Several factors may support this compensatory strategy, including (i) postlesion training or retraining and (ii) postlesion network reorganization (19-21). T...

show abstract

Pulvinar Inactivation Disrupts Selection of Movement Plans

Cited by 149 publications

References 63 publications

Order of operations for decoding superior colliculus activity for saccade generation

Order of operations for decoding superior colliculus activity for saccade generation

Inactivation of Parietal Reach Region Affects Reaching But Not Saccade Choices in Internally Guided Decisions

Memory loss in a nonnavigational spatial task after hippocampal inactivation in monkeys

Contact Info

Product

Resources

About