Pulvinar influences parietal delay activity and information transmission between dorsal and ventral visual cortex in macaques (original) (raw)
Related papers
The Pulvinar Regulates Information Transmission Between Cortical Areas Based on Attention Demands
Science, 2012
The Conductor in the Thalamus The pulvinar is the largest thalamic nucleus in the brain but its functions remain unclear. The pulvinar is ideally positioned to synchronize activity across the visual cortex. Saalmann et al. (p. 753 ) combined diffusion tensor imaging with multi-electrode recordings from three different brain areas in monkeys to probe thalamo-cortical interactions during visual attention. The pulvinar was found to play a vital role in attention by routing behaviorally relevant information across the visual cortex.
Pulvinar-Cortex Interactions in Vision and Attention
Neuron, 2016
The ventro-lateral pulvinar is reciprocally connected with the visual areas of the ventral stream important for object recognition. To understand the mechanisms of attentive stimulus processing in this pulvinar-cortex loop, we investigated the interactions between the pulvinar, area V4, and IT cortex in a spatial attention task. Sensory processing and the influence of attention in the pulvinar appeared to reflect its cortical inputs. However, pulvinar deactivation led to a reduction of attentional effects on firing rates and gamma synchrony in V4, a reduction of sensory-evoked responses and overall gamma coherence within V4, and severe behavioral deficits in the affected portion of the visual field. Conversely, pulvinar deactivation caused an increase in low frequency cortical oscillations, often associated with inattention or sleep. Thus, cortical interactions with the ventro-lateral pulvinar are necessary for normal attention and sensory processing, and for maintaining the cortex in an active state.
Engagement of pulvino-cortical feedforward and feedback pathways in cognitive computations
2018
Computational modeling of brain mechanisms of cognition has been largely focused on the cortex, but recent experiments have shown that higher-order nuclei of the thalamus, in particular the pulvinar, participate in major cognitive functions and are implicated in psychiatric disorders. Here we show that a pulvino-cortical circuit model, composed of two cortical areas and the pulvinar, captures a range of physiological and behavioral observations related to the macaque pulvinar. Effective connections between the two cortical areas are gated by the pulvinar, allowing the pulvinar to shift the operation regime of these areas during attentional processing and working memory, as well as to resolve decision-making conflict. Furthermore, cortico-pulvinar projections that engage the thalamic reticular nucleus enable the pulvinar to estimate decision-making confidence. Finally, feedforward and feedback pulvino-cortical pathways participate in frequency-dependent inter-areal interactions that ...
Journal of Neuroscience, 2007
Local field potentials from different visual cortical areas and subdivisions of the cat's lateral posterior-pulvinar complex of the thalamus (LP-P) were recorded during a behavioral task based on delayed spatial discrimination of visual or auditory stimuli. During visual but not auditory attentive tasks, we observed an increase of  activity (12-25 Hz) as calculated from signals recorded from the caudal part of the lateral zone of the LP-P (LPl-c) as well as from cortical areas 17 and 18 and the complex located at the middle suprasylvian sulcus (MSS). This  activity appeared only in the trials that ended with a successful response, proving its relationship to the mechanism of visual attention. In contrast, no enhanced  activity was observed in the rostral part of the lateral zone of the LP-P and in the pulvinar proper. Two subregions of LPl-c (ventromedial and dorsolateral) were distinguished by visually related, attentional  activity of low (12-18 Hz) and high (18-25 Hz) frequencies, respectively. At the same time, area 17 exhibited attentional activation in the whole  range, and an increase of power in low-frequency  was observed in the medial bank of MSS, whereas cortical area 18 and the lateral bank of the MSS were activated in the high  range. Phase-correlation analysis revealed that two distinct corticothalamic systems were synchronized by the  activity of different frequencies. One comprised of cortical area 17, ventromedial region of LPl-c, and medial MSS, the second involved area 18 and the dorsolateral LPl-c. Our observations suggest that LPl-c belongs to the wide corticothalamic attentional system, which is functionally segregated by distinct streams of  activity.
Neuroscience Letters, 2006
This fMRI study investigates the activation of the thalamic nuclei in a spatial focusing-of-attention task previously shown to activate the pulvinar with FDG-PET and assesses the connectivity of the thalamic nuclei with cortical areas. Normal right-handed subjects (eight men, eight women, average age = 32 years) viewed four types of stimuli positioned to the right or left of the central fixation point (left hemifield-large letter, left hemifield-small letter display with flanking letters; right hemifield-large letter, right hemifield-small letter display with flankers). BOLD responses to small letters surrounded by flankers were compared with responses to large isolated letters. To examine maximum functional regional connectivity, we modeled "subject" as a random effect and attained fixed effect parameter estimates and t-statistics for functional connectivity between each of the thalamic nuclei (pulvinar, medial dorsal, and anterior) as the seed region and each non-seed voxel. Greater BOLD activation for letters surrounded by flankers than for large letters was observed in the pulvinar as anticipated and was also marked in the medial dorsal nucleus (MDN), anterior and superior cingulate (BA24 and BA24), dorsolateral prefrontal cortex, and frontal operculum and insula. For the MDN, maximal functional connectivity was with the dorsolateral prefrontal cortex; correlations with left superior temporal, parietal, posterior frontal, and occipital regions were also observed. For the pulvinar, maximal functional connectivity was with parietal BA39; for anterior thalamus, with anterior cingulate.
The role of the pulvinar in distractor processing and visual search
Human Brain Mapping, 2013
The pulvinar nuclei of the thalamus are hypothesized to coordinate attentional selection in the visual cortex. Different models have, however, been proposed for the precise role of the pulvinar in attention. One proposal is that the pulvinar mediates shifts of spatial attention; a different proposal is that it serves the filtering of distractor information. At present, the relation between these possible operations and their relative importance in the pulvinar remains unresolved. We address this issue by contrasting these proposals in two fMRI experiments. We used a visual search paradigm that permitted us to dissociate neural activity reflecting shifts of attention from activity underlying distractor filtering. We find that distractor filtering, but not the operation of shifting attention, is associated with strong activity enhancements in dorsal and ventral regions of the pulvinar as well as in early visual cortex areas including the primary visual cortex. Our observations indicate that distractor filtering is the preponderant attentional operation subserved by the pulvinar, presumably mediated by a modulation of processing in visual areas where spatial resolution is sufficiently high to separate target from distractor input. Hum Brain Mapp 00:000-000,
Memory and attention interact. Information held in working memory (WM) can bias visual selection toward matching stimuli in a subsequent search display, while a search target that is different from the memory stimulus can interfere with its subsequent recognition. In recent fMRI studies, the pulvinar has been consistently shown to have an enhanced response when an item in WM matches a search target and a reduced response when the WM item matches a distracter in search. Here we used Granger causality analysis to help understand the role of the pulvinar in resolving competition between memory and selection processes. Across three experiments the results showed increased coupling between the pulvinar and the ipsilateral superior frontal gyrus, contralateral temporal–parietal junction (TPJ) and calcarine sulcus when a visual search distracter matched the item held in memory. This connection pattern suggests that the pulvinar suppresses visual responses to the target when a contralateral distracter contains information held in working memory. We propose that this suppression acts to protect the memory item from interference arising from information associated with the search target. Consistent with this proposal we showed that the strength of the thalamus-to-visual connection predicted performance on a subsequent memory test. The data therefore suggest that the thalamus modulates bottom up processing in sensory cortex to minimize interference to WM content.
2021
Causal perturbations suggest that the primate dorsal pulvinar (dPul) plays a crucial role in target selection and saccade planning, but its basic visuomotor neuronal properties are unclear. While some functional aspects of dPul and interconnected frontoparietal areas – e.g. ipsilesional choice bias after inactivation – are similar, it is unknown if dPul shares oculomotor properties of the cortical circuitry, in particular the delay and choice-related activity. We investigated such properties in macaque dPul during instructed and free-choice memory saccades. Most recorded units showed visual (16%), visuomotor (29%) or motor-related (35%) responses. Visual responses were mainly contralateral; motor-related responses were predominantly post-saccadic (64%) and showed weak contralateral bias. Pre-saccadic enhancement was infrequent (9-15%) – instead, activity was often suppressed during saccade planning (30%) and execution (19%). Surprisingly, only few units exhibited classical visuomoto...
Proceedings of the National Academy of Sciences, 2009
We examined the contributions of the human pulvinar to goal directed selection of visual targets in 3 patients with chronic, unilateral lesions involving topographic maps in the ventral pulvinar. Observers completed 2 psychophysical tasks in which they discriminated the orientation of a lateralized target grating in the presence of vertically-aligned distracters. In experiment 1, where distracter contrast was varied while target contrast remained constant, the patients' contralesional contrast thresholds for discriminating the orientation of grating stimuli were elevated only when the task required selection of a visual target in the face of competition from a salient distracter. Attentional selectivity was restored in the patients in experiment 2 where target contrast was varied while distracter contrast remained constant. These observations provide the first evidence that the human pulvinar plays a necessary role in modulating physical saliency in attentional selection, and supports a homology in global pulvinar structure between humans and monkey.
The functional logic of cortico-pulvinar connections
Philosophical Transactions of the Royal Society B: Biological Sciences, 2003
The pulvinar is an 'associative' thalamic nucleus, meaning that most of its input and output relationships are formed with the cerebral cortex. The function of this circuitry is little understood and its anatomy, though much investigated, is notably recondite. This is because pulvinar connection patterns disrespect the architectural subunits (anterior, medial, lateral and inferior pulvinar nuclei) that have been the traditional reference system. This article presents a simplified, global model of the organization of cortico-pulvinar connections so as to pursue their structure-function relationships.