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Neuroscience and Biobehavioral Reviews Jun 2021Perception in ambiguous environments relies on the combination of sensory information from various sources. Most associative and primary sensory cortical areas are... (Review)
Review
Perception in ambiguous environments relies on the combination of sensory information from various sources. Most associative and primary sensory cortical areas are involved in this multisensory active integration process. As a result, the entire cortex appears as heavily multisensory. In this review, we focus on the contribution of the pulvinar to multisensory integration. This subcortical thalamic nucleus plays a central role in visual detection and selection at a fast time scale, as well as in the regulation of visual processes, at a much slower time scale. However, the pulvinar is also densely connected to cortical areas involved in multisensory integration. In spite of this, little is known about its multisensory properties and its contribution to multisensory perception. Here, we review the anatomical and functional organization of multisensory input to the pulvinar. We describe how visual, auditory, somatosensory, pain, proprioceptive and olfactory projections are differentially organized across the main subdivisions of the pulvinar and we show that topography is central to the organization of this complex nucleus. We propose that the pulvinar combines multiple sources of sensory information to enhance fast responses to the environment, while also playing the role of a general regulation hub for adaptive and flexible cognition.
Topics: Animals; Cerebral Cortex; Primates; Pulvinar; Somatosensory Cortex
PubMed: 33662442
DOI: 10.1016/j.neubiorev.2021.02.043 -
NeuroImage Oct 2023Spatial attention is often described as a mental spotlight that enhances information processing at the attended location. Using fMRI, we investigated background...
Spatial attention is often described as a mental spotlight that enhances information processing at the attended location. Using fMRI, we investigated background connectivity between the pulvinar and V1 in relation to focused versus diffused attention allocation, in weak and strong crowding contexts. Our findings revealed that focused attention led to enhanced correlations between the pulvinar and V1. Notably, this modulation was initiated by the pulvinar, and the strength of the modulation was dependent on the saliency of the target. These findings suggest that the pulvinar initiates information reweighting to V1, which underlies attentional selection in cluttered scenes.
Topics: Humans; Pulvinar; Cognition; Diffusion
PubMed: 37619793
DOI: 10.1016/j.neuroimage.2023.120341 -
Journal of Anatomy Sep 2019The pulvinar is primarily referred to for its role in visual processing. However, the 'visual pulvinar' only encompasses the inferior and lateral regions of this complex... (Review)
Review
The pulvinar is primarily referred to for its role in visual processing. However, the 'visual pulvinar' only encompasses the inferior and lateral regions of this complex thalamic nucleus. The remaining medial portion (medial pulvinar, PM) establishes distinct cortical connectivity and has been associated with directed attention, executive functions and working memory. These functions are particularly impaired in neurodevelopmental disorders, including schizophrenia and attention deficit and hyperactivity disorder (ADHD), both of which have been associated with abnormal PM architecture and connectivity. With these disorders becoming more prevalent in modern societies, we review the literature to better understand how the PM can participate in the pathophysiology of cognitive disorders and how a better understanding of the development and function of this thalamic nucleus, which is most likely exclusive to the primate brain, can advance clinical research and treatments.
Topics: Animals; Biological Evolution; Humans; Neurodevelopmental Disorders; Pulvinar
PubMed: 30657169
DOI: 10.1111/joa.12932 -
Trends in Cognitive Sciences Feb 2016The pulvinar is the largest thalamic nucleus in primates and one of the most mysterious. Endeavors to understand its role in vision have focused on its abundant... (Review)
Review
The pulvinar is the largest thalamic nucleus in primates and one of the most mysterious. Endeavors to understand its role in vision have focused on its abundant connections with the visual cortex. While its connectivity mapping in the cortex displays a broad topographic organization, its projections are also marked by considerable convergence and divergence. As a result, the pulvinar is often regarded as a central forebrain hub. Moreover, new evidence suggests that its comparatively modest input from structures such as the retina and superior colliculus may critically shape the functional organization of the visual cortex, particularly during early development. Here we review recent studies that cast fresh light on how the many convergent pathways through the pulvinar contribute to visual cognition.
Topics: Animals; Cognition; Humans; Neuronal Plasticity; Pulvinar; Visual Pathways; Visual Perception
PubMed: 26553222
DOI: 10.1016/j.tics.2015.10.003 -
Neuron Jan 2019The functional role of the pulvinar, with its widespread cortical connectivity, has remained elusive. In this issue of Neuron, Jaramillo et al. (2019) provide a...
The functional role of the pulvinar, with its widespread cortical connectivity, has remained elusive. In this issue of Neuron, Jaramillo et al. (2019) provide a computational roadmap for how the pulvinar might influence various cognitive behaviors across multiple large-scale networks.
Topics: Cognition; Neurons; Pulvinar
PubMed: 30653933
DOI: 10.1016/j.neuron.2018.12.032 -
Consciousness and Cognition Nov 2015Following destruction or denervation of the primary visual cortex (V1) cortical blindness ensues. Affective blindsight refers to the uncanny ability of such patients to... (Review)
Review
Following destruction or denervation of the primary visual cortex (V1) cortical blindness ensues. Affective blindsight refers to the uncanny ability of such patients to respond correctly, or above chance level, to visual emotional expressions presented to their blind fields. Fifteen years after its original discovery, affective blindsight still fascinates neuroscientists and philosophers alike, as it offers a unique window on the vestigial properties of our visual system that, though present in the intact brain, tend to be unnoticed or even actively inhibited by conscious processes. Here we review available studies on affective blindsight with the intent to clarify its functional properties, neural bases and theoretical implications. Evidence converges on the role of subcortical structures of old evolutionary origin such as the superior colliculus, the pulvinar and the amygdala in mediating affective blindsight and nonconscious perception of emotions. We conclude that approaching consciousness, and its absence, from the vantage point of emotion processing may uncover important relations between the two phenomena, as consciousness may have evolved as an evolutionary specialization to interact with others and become aware of their social and emotional expressions.
Topics: Affect; Amygdala; Blindness, Cortical; Consciousness; Humans; Pulvinar; Social Perception; Superior Colliculi
PubMed: 26058355
DOI: 10.1016/j.concog.2015.05.007 -
Vision (Basel, Switzerland) Dec 2019Current evidence supports the view that the visual pulvinar of primates consists of at least five nuclei, with two large nuclei, lateral pulvinar ventrolateral (PLvl)... (Review)
Review
Current evidence supports the view that the visual pulvinar of primates consists of at least five nuclei, with two large nuclei, lateral pulvinar ventrolateral (PLvl) and central lateral nucleus of the inferior pulvinar (PIcl), contributing mainly to the ventral stream of cortical processing for perception, and three smaller nuclei, posterior nucleus of the inferior pulvinar (PIp), medial nucleus of the inferior pulvinar (PIm), and central medial nucleus of the inferior pulvinar (PIcm), projecting to dorsal stream visual areas for visually directed actions. In primates, both cortical streams are highly dependent on visual information distributed from primary visual cortex (V1). This area is so vital to vision that patients with V1 lesions are considered "cortically blind". When the V1 inputs to dorsal stream area middle temporal visual area (MT) are absent, other dorsal stream areas receive visual information relayed from the superior colliculus via PIp and PIcm, thereby preserving some dorsal stream functions, a phenomenon called "blind sight". Non-primate mammals do not have a dorsal stream area MT with V1 inputs, but superior colliculus inputs to temporal cortex can be more significant and more visual functions are preserved when V1 input is disrupted. The current review will discuss how the different visual streams, especially the dorsal stream, have changed during primate evolution and we propose which features are retained from the common ancestor of primates and their close relatives.
PubMed: 31905909
DOI: 10.3390/vision4010003 -
The Journal of Neuroscience : the... Feb 2023Distributed cortical regions show differential responses to visual objects belonging to different domains varying by animacy (e.g., animals vs tools), yet it remains...
Distributed cortical regions show differential responses to visual objects belonging to different domains varying by animacy (e.g., animals vs tools), yet it remains unclear whether this is an organization principle also applying to the subcortical structures. Combining multiple fMRI activation experiments (two main experiments and six validation datasets; 12 females and 9 males in the main Experiment 1; 10 females and 10 males in the main Experiment 2), resting-state functional connectivity, and task-based dynamic causal modeling analysis in human subjects, we found that visual processing of images of animals and tools elicited different patterns of response in the pulvinar, with robust left lateralization for tools, and distinct, bilateral (with rightward tendency) clusters for animals. Such domain-preferring activity distribution in the pulvinar was associated with the magnitude with which the voxels were intrinsically connected with the corresponding domain-preferring regions in the cortex. The pulvinar-to-right-amygdala path showed a one-way shortcut supporting the perception of animals, and the modulation connection from pulvinar to parietal showed an advantage to the perception of tools. These results incorporate the subcortical regions into the object processing network and highlight that domain organization appears to be an overarching principle across various processing stages in the brain. Viewing objects belonging to different domains elicited different cortical regions, but whether the domain organization applied to the subcortical structures (e.g., pulvinar) was unknown. Multiple fMRI activation experiments revealed that object pictures belonging to different domains elicited differential patterns of response in the pulvinar, with robust left lateralization for tool pictures, and distinct, bilateral (with rightward tendency) clusters for animals. Combining the resting-state functional connectivity and dynamic causal modeling analysis on task-based fMRI data, we found domain-preferring activity distribution in the pulvinar aligned with that in cortical regions. These results highlight the need for coherent visual theories that explain the mechanisms underlying the domain organization across various processing stages.
Topics: Male; Female; Animals; Humans; Pulvinar; Magnetic Resonance Imaging; Brain; Brain Mapping; Amygdala
PubMed: 36596697
DOI: 10.1523/JNEUROSCI.0613-22.2022 -
The Journal of Comparative Neurology Feb 2019This review provides a historical account of the discovery of secondary visual pathways (from retina to the superior colliculus to the dorsal thalamus and extrastriate... (Review)
Review
This review provides a historical account of the discovery of secondary visual pathways (from retina to the superior colliculus to the dorsal thalamus and extrastriate cortex), and Vivien Casagrande's pioneering studies of this system using the tree shrew as a model. Subsequent studies of visual pathways in the tree shrew are also reviewed, beginning with a description of the organization and central projections of the tree shrew retina. The organization and connectivity of second visual system components that include the retino-recipient superior colliculus, tecto-recipient pulvinar nucleus and its projections, and the tecto-recipient dorsal lateral geniculate nucleus and its projections are detailed. Potential functions of the second visual system are discussed in the context of this work and in the context of the behavioral studies that initially inspired the secondary visual system concept.
Topics: Animals; Pulvinar; Retina; Superior Colliculi; Tupaiidae; Visual Cortex; Visual Pathways
PubMed: 29446088
DOI: 10.1002/cne.24413