scholarly journals Engagement of pulvino-cortical feedforward and feedback pathways in cognitive computations

2018 ◽  
Author(s):  
Jorge Jaramillo ◽  
Jorge F. Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Decision Making ◽  
Working Memory ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Attentional Processing ◽  
Contextual Modulation ◽  
Cortical Areas ◽  
Behavioral Observations ◽  
Cortical Circuit ◽  
Feedback Pathways

AbstractComputational 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 modify the relative hierarchical positions of cortical areas. Overall, our model suggests that the pulvinar provides crucial contextual modulation to cortical computations associated with cognition.

scholarly journals Selective Loss and Selective Sparing of Neurons in the Thalamic Reticular Nucleus following Human Cardiac Arrest

1993 ◽  
Vol 13 (4) ◽  
pp. 558-567 ◽  
Author(s):  
Douglas T. Ross ◽  
David I. Graham
Keyword(s):  
Cardiac Arrest ◽  
Heart Surgery ◽  
Neuronal Damage ◽  
Open Heart Surgery ◽  
Thalamic Reticular Nucleus ◽  
Global Cerebral Ischemia ◽  
Reticular Nucleus ◽  
Thalamic Nuclei ◽  
Attentional Processing ◽  
Thalamic Relay Nuclei

Neurons in the portion of the human thalamic reticular nucleus (RT) associated with the prefrontal cortex and mediodorsal thalamic nuclei were found to be selectively vulnerable to ischemic neuronal damage following relatively short (≤5-min) duration cardiac arrest. In contrast, selective sparing of these RT neurons occurred in cases with longer (>10-min) duration of arrest that was sufficient to produce extensive ischemic neuronal damage throughout the cerebral cortex and thalamic relay nuclei. The selective degeneration of RT neurons appears to require the sustained activity of corticothalamic or thalamocortical projections to the RT following the ischemic insult. Loss of RT neurons associated with the frontal cortex and mediodorsal thalamus may be the biological basis of some types of persisting cognitive deficits in attentional processing experienced by patients following cardiac arrest, open heart surgery, or other forms of brief global cerebral ischemia.

First order connections of the visual sector of the thalamic reticular nucleus in marmoset monkeys (Callithrix jacchus)

2007 ◽  
Vol 24 (6) ◽  
pp. 857-874 ◽  
Author(s):  
THOMAS FITZGIBBON ◽  
BRETT A. SZMAJDA ◽  
PAUL R. MARTIN
Keyword(s):  
Visual Field ◽  
Callithrix Jacchus ◽  
Higher Order ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Lower Visual Field ◽  
First Order ◽  
Cortical Areas ◽  
Visual Areas

The thalamic reticular nucleus (TRN) supplies an important inhibitory input to the dorsal thalamus. Previous studies in non-primate mammals have suggested that the visual sector of the TRN has a lateral division, which has connections with first-order (primary) sensory thalamic and cortical areas, and a medial division, which has connections with higher-order (association) thalamic and cortical areas. However, the question whether the primate TRN is segregated in the same manner is controversial. Here, we investigated the connections of the TRN in a New World primate, the marmoset (Callithrix jacchus). The topography of labeled cells and terminals was analyzed following iontophoretic injections of tracers into the primary visual cortex (V1) or the dorsal lateral geniculate nucleus (LGNd). The results show that rostroventral TRN, adjacent to the LGNd, is primarily connected with primary visual areas, while the most caudal parts of the TRN are associated with higher order visual thalamic areas. A small region of the TRN near the caudal pole of the LGNd (foveal representation) contains connections where first (lateral TRN) and higher order visual areas (medial TRN) overlap. Reciprocal connections between LGNd and TRN are topographically organized, so that a series of rostrocaudal injections within the LGNd labeled cells and terminals in the TRN in a pattern shaped like rostrocaudal overlapping “fish scales.” We propose that the dorsal areas of the TRN, adjacent to the top of the LGNd, represent the lower visual field (connected with medial LGNd), and the more ventral parts of the TRN contain a map representing the upper visual field (connected with lateral LGNd).

Giant Spontaneous Depolarizing Potentials in the Developing Thalamic Reticular Nucleus

2007 ◽  
Vol 97 (3) ◽  
pp. 2364-2372 ◽  
Author(s):  
Susanne Pangratz-Fuehrer ◽  
Uwe Rudolph ◽  
John R. Huguenard
Keyword(s):  
Developmental Stage ◽  
Postnatal Development ◽  
Gaba Receptors ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Glutamate Antagonists ◽  
Early Postnatal Development ◽  
Functional Development ◽  
Α3 Subunit ◽  
Cortical Circuit

The thalamic reticular nucleus (nRt) provides a major source of inhibition in the thalamo-cortical circuit and is critically involved in the generation of spindle oscillations. Here we describe the properties of thalamic giant depolarizing potentials (tGDPs) that were observed in nRt during early development. tGDPs persisted in presence of ionotropic glutamate antagonists but were completely abolished by GABAAR antagonist SR 35591. tGDPs occurred primarily between p3 and p8 (in 30–50% of cells) and occasionally up until p15. tGDPs lasted 0.4–3 s with peak conductances of 2–13 nS and occurred at frequencies between 0.02 and 0.06 Hz. We used mice with a benzodiazepine-insensitive α3 subunit [α3(H126R)] to probe for the identity of the GABA receptors responsible for tGDP generation. Benzodiazepine enhancement of tGDP amplitude and duration persisted in nRt neurons in α3(H126R) mice, indicating that the GABAARs containing α3 are not critical for tGDP generation and suggesting that tGDPs are mediated by GABAARs containing the α5 subunit, which is transiently expressed in nRt neurons in early postnatal development. Furthermore we found that exogenous GABA application depolarized nRt neurons younger than p8, indicating elevated [Cl−]i at this developmental stage. Taken together, these data suggest that in immature nRt, long-lasting depolarizing responses mediated by GABA receptors could trigger Ca2+ entry and play a role in functional development of the spindle-generating circuitry.

Prefrontal Cortex

2017 ◽  
pp. 75-84
Author(s):  
Xiao-Jing Wang
Keyword(s):  
Decision Making ◽  
Working Memory ◽  
Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Synaptic Integration ◽  
Input Output ◽  
Cortical Areas ◽  
Inhibitory Circuit ◽  
Distinct Features ◽  
The Brain

The prefrontal cortex (PFC) circuits are characterized by several distinct features. First, the input–output connections of a PFC circuit with the rest of the brain are extraordinarily extensive. In the primates, pyramidal neurons in PFC are greatly more spinous than in the primary sensory areas, so they have a much larger capacity for synaptic integration. Second, PFC areas are endowed with strong intrinsic recurrent connections that are sufficient to generate reverberatory activity underlying working memory and decision-making. Third, excitation and inhibition are balanced dynamically. Unlike early sensory cortical areas, in the frontal areas of both monkey and mouse, the synaptic inhibitory circuit is predominated by GABAergic cell subclasses that are dedicated to controlling inputs to, rather than outputs from, pyramidal neurons, likely reflecting the functional demand of selectively gating input pathways into the PFC in accordance with the behavioral context and goals.

scholarly journals Thalamic reticular control of local sleep in mouse sensory cortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Laura MJ Fernandez ◽  
Gil Vantomme ◽  
Alejandro Osorio-Forero ◽  
Romain Cardis ◽  
Elidie Béard ◽  
...  
Keyword(s):  
Brain Activity ◽  
Sensory Cortex ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Dependent Manner ◽  
Rapid Eye Movement Sleep ◽  
Sleep Regulation ◽  
Cortical Areas ◽  
Low Threshold ◽  
Local Sleep

Sleep affects brain activity globally, but many cortical sleep waves are spatially confined. Local rhythms serve cortical area-specific sleep needs and functions; however, mechanisms controlling locality are unclear. We identify the thalamic reticular nucleus (TRN) as a source for local, sensory-cortex-specific non-rapid-eye-movement sleep (NREMS) in mouse. Neurons in optogenetically identified sensory TRN sectors showed stronger repetitive burst discharge compared to non-sensory TRN cells due to higher activity of the low-threshold Ca2+ channel CaV3.3. Major NREMS rhythms in sensory but not non-sensory cortical areas were regulated in a CaV3.3-dependent manner. In particular, NREMS in somatosensory cortex was enriched in fast spindles, but switched to delta wave-dominated sleep when CaV3.3 channels were genetically eliminated or somatosensory TRN cells chemogenetically hyperpolarized. Our data indicate a previously unrecognized heterogeneity in a powerful forebrain oscillator that contributes to sensory-cortex-specific and dually regulated NREMS, enabling local sleep regulation according to use- and experience-dependence.

scholarly journals Neural Mechanisms of Visual Motion Anomalies in Autism: A Two-Decade Update and Novel Aetiology

2021 ◽  
Vol 15 ◽  
Author(s):  
Samuel Spiteri ◽  
David Crewther
Keyword(s):  
Visual Motion ◽  
Central Area ◽  
Dorsal Stream ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Main Hypothesis ◽  
Attentional Processing ◽  
Synaptic Competition ◽  
Perceptual Anomalies ◽  
Primate Vision

The 21st century has seen dramatic changes in our understanding of the visual physio-perceptual anomalies of autism and also in the structure and development of the primate visual system. This review covers the past 20 years of research into motion perceptual/dorsal stream anomalies in autism, as well as new understanding of the development of primate vision. The convergence of this literature allows a novel developmental hypothesis to explain the physiological and perceptual differences of the broad autistic spectrum. Central to these observations is the development of motion areas MT+, the seat of the dorsal cortical stream, central area of pre-attentional processing as well as being an anchor of binocular vision for 3D action. Such development normally occurs via a transfer of thalamic drive from the inferior pulvinar → MT to the anatomically stronger but later-developing LGN → V1 → MT connection. We propose that autistic variation arises from a slowing in the normal developmental attenuation of the pulvinar → MT pathway. We suggest that this is caused by a hyperactive amygdala → thalamic reticular nucleus circuit increasing activity in the PIm → MT via response gain modulation of the pulvinar and hence altering synaptic competition in area MT. We explore the probable timing of transfer in dominance of human MT from pulvinar to LGN/V1 driving circuitry and discuss the implications of the main hypothesis.

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