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Neurobiology of Disease Apr 2023Neuromodulation (neurostimulation) is a relatively new and rapidly growing treatment for refractory epilepsy. Three varieties are approved in the US: vagus nerve... (Review)
Review
Neuromodulation (neurostimulation) is a relatively new and rapidly growing treatment for refractory epilepsy. Three varieties are approved in the US: vagus nerve stimulation (VNS), deep brain stimulation (DBS) and responsive neurostimulation (RNS). This article reviews thalamic DBS for epilepsy. Among many thalamic sub-nuclei, DBS for epilepsy has been targeted to the anterior nucleus (ANT), centromedian nucleus (CM), dorsomedial nucleus (DM) and pulvinar (PULV). Only ANT is FDA-approved, based upon a controlled clinical trial. Bilateral stimulation of ANT reduced seizures by 40.5% at three months in the controlled phase (p = .038) and 75% by 5 years in the uncontrolled phase. Side effects related to paresthesias, acute hemorrhage, infection, occasional increased seizures, and usually transient effects on mood and memory. Efficacy was best documented for focal onset seizures in temporal or frontal lobe. CM stimulation may be useful for generalized or multifocal seizures and PULV for posterior limbic seizures. Mechanisms of DBS for epilepsy are largely unknown, but animal work points to changes in receptors, channels, neurotransmitters, synapses, network connectivity and neurogenesis. Personalization of therapies, in terms of connectivity of the seizure onset zone to the thalamic sub- nucleus and individual characteristics of the seizures, might lead to improved efficacy. Many questions remain about DBS, including the best candidates for different types of neuromodulation, the best targets, the best stimulation parameters, how to minimize side effects and how to deliver current noninvasively. Despite the questions, neuromodulation provides useful new opportunities to treat people with refractory seizures not responding to medicines and not amenable to resective surgery.
Topics: Animals; Deep Brain Stimulation; Epilepsy; Thalamus; Seizures; Drug Resistant Epilepsy
PubMed: 36809846
DOI: 10.1016/j.nbd.2023.106045 -
Advances in Experimental Medicine and... 2020Fear is defined as a fundamental emotion promptly arising in the context of threat and when danger is perceived. Fear can be innate or learned. Examples of innate fear... (Review)
Review
Fear is defined as a fundamental emotion promptly arising in the context of threat and when danger is perceived. Fear can be innate or learned. Examples of innate fear include fears that are triggered by predators, pain, heights, rapidly approaching objects, and ancestral threats such as snakes and spiders. Animals and humans detect and respond more rapidly to threatening stimuli than to nonthreatening stimuli in the natural world. The threatening stimuli for most animals are predators, and most predators are themselves prey to other animals. Predatory avoidance is of crucial importance for survival of animals. Although humans are rarely affected by predators, we are constantly challenged by social threats such as a fearful or angry facial expression. This chapter will summarize the current knowledge on brain circuits processing innate fear responses to visual stimuli derived from studies conducted in mice and humans.
Topics: Anger; Animals; Brain; Facial Expression; Fear; Humans; Snakes; Spiders
PubMed: 32852735
DOI: 10.1007/978-981-15-7086-5_1 -
Advances in Anatomy, Embryology, and... 2018The pulvinar can be subdivided into well-delimitated regions based on chemoarchitectural, cytoarchitectural, myeloarchitectural, connectivity, and electrophysiological...
The pulvinar can be subdivided into well-delimitated regions based on chemoarchitectural, cytoarchitectural, myeloarchitectural, connectivity, and electrophysiological criteria. Subdivisions of the pulvinar based on its chemoarchitectural features are the most consistently preserved across species of New and Old World monkeys. It is reasonable to speculate that the occurrence and distribution of calcium-binding proteins in the pulvinar, such as calbindin and parvalbumin, have been preserved along evolution. Therefore, they have proven to be valuable tools capable of probing the basic pulvinar scaffold across primate species. Along this review, we will provide an overview of the available data regarding the various subdivisions of the pulvinar that have been proposed based on architectural criteria such as the distribution of molecular markers, neuronal morphology, and fiber layout.
PubMed: 29116442
DOI: 10.1007/978-3-319-70046-5_1 -
World Neurosurgery May 2020The thalamus is a deep cerebral structure that is crucial for proper neurological functioning as it transmits signals from nearly all pathways in the body. Insult to the... (Review)
Review
The thalamus is a deep cerebral structure that is crucial for proper neurological functioning as it transmits signals from nearly all pathways in the body. Insult to the thalamus can, therefore, result in complex syndromes involving sensation, cognition, executive function, fine motor control, emotion, and arousal, to name a few. Specific territories in the thalamus that are supplied by deep cerebral arteries have been shown to correlate with clinical symptoms. The aim of this review is to enhance our understanding of the arterial anatomy of the thalamus and the complications that can arise from lesions to it by considering the functions of known thalamic nuclei supplied by each vascular territory.
Topics: Anterior Thalamic Nuclei; Basilar Artery; Brain Infarction; Circle of Willis; Geniculate Bodies; Humans; Lateral Thalamic Nuclei; Mediodorsal Thalamic Nucleus; Posterior Cerebral Artery; Pulvinar; Thalamus; Ventral Thalamic Nuclei
PubMed: 32036065
DOI: 10.1016/j.wneu.2020.01.237 -
Current Neurology and Neuroscience... Nov 2021Subcortical structures have long been thought to play a role in language processing. Increasingly spirited debates on language studies, arising from as early as the... (Review)
Review
PURPOSE OF REVIEW
Subcortical structures have long been thought to play a role in language processing. Increasingly spirited debates on language studies, arising from as early as the nineteenth century, grew remarkably sophisticated as the years pass. In the context of non-thalamic aphasia, a few theoretical frameworks have been laid out. The disconnection hypothesis postulates that basal ganglia insults result in aphasia due to a rupture of connectivity between Broca and Wernicke's areas. A second viewpoint conjectures that the basal ganglia would more directly partake in language processing, and a third stream proclaims that aphasia would stem from cortical deafferentation. On the other hand, thalamic aphasia is more predominantly deemed as a resultant of diaschisis. This article reviews the above topics with recent findings on deep brain stimulation, neurophysiology, and aphasiology.
RECENT FINDINGS
The more recent approach conceptualizes non-thalamic aphasias as the offspring of unpredictable cortical hypoperfusion. Regarding the thalamus, there is mounting evidence now pointing to leading contributions of the pulvinar/lateral posterior nucleus and the anterior/ventral anterior thalamus to language disturbances. While the former appears to relate to lexical-semantic indiscrimination, the latter seems to bring about a severe breakdown in word selection and/or spontaneous top-down lexical-semantic operations. The characterization of subcortical aphasias and the role of the basal ganglia and thalamus in language processing continues to pose a challenge. Neuroimaging studies have pointed a path forward, and we believe that more recent methods such as tractography and connectivity studies will significantly expand our knowledge in this particular area of aphasiology.
Topics: Aphasia; Basal Ganglia; Diaschisis; Humans; Semantics; Thalamus
PubMed: 34817710
DOI: 10.1007/s11910-021-01156-5 -
Neuron Jan 2016While the function of the pulvinar remains one of the least explored among the thalamic nuclei despite occupying the most thalamic volume in primates, it has long been...
While the function of the pulvinar remains one of the least explored among the thalamic nuclei despite occupying the most thalamic volume in primates, it has long been suspected to play a crucial role in attentive stimulus processing. In this issue of Neuron, Zhou et al. (2016) use simultaneous pulvinar-visual cortex recordings and pulvinar inactivation to provide evidence that the pulvinar is essential for intact stimulus processing, maintenance of neuronal oscillatory dynamics, and mediating the effects of attention.
Topics: Animals; Attention; Male; Pulvinar; Vision, Ocular; Visual Cortex; Visual Pathways
PubMed: 26748085
DOI: 10.1016/j.neuron.2015.12.022 -
Current Opinion in Neurology Apr 2023Neurostimulation is a quickly growing treatment approach for epilepsy patients. We summarize recent approaches to provide a perspective on the future of neurostimulation. (Review)
Review
PURPOSE OF REVIEW
Neurostimulation is a quickly growing treatment approach for epilepsy patients. We summarize recent approaches to provide a perspective on the future of neurostimulation.
RECENT FINDINGS
Invasive stimulation for treatment of focal epilepsy includes vagus nerve stimulation, responsive neurostimulation of the cortex and deep brain stimulation of the anterior nucleus of the thalamus. A wide range of other targets have been considered, including centromedian, central lateral and pulvinar thalamic nuclei; medial septum, nucleus accumbens, subthalamic nucleus, cerebellum, fornicodorsocommissure and piriform cortex. Stimulation for generalized onset seizures and mixed epilepsies as well as increased efforts focusing on paediatric populations have emerged. Hardware with more permanently implanted lead options and sensing capabilities is emerging. A wider variety of programming approaches than typically used may improve patient outcomes. Finally, noninvasive brain stimulation with its favourable risk profile offers the potential to treat increasingly diverse epilepsy patients.
SUMMARY
Neurostimulation for the treatment of epilepsy is surprisingly varied. Flexibility and reversibility of neurostimulation allows for rapid innovation. There remains a continued need for excitability biomarkers to guide treatment and innovation. Neurostimulation, a part of bioelectronic medicine, offers distinctive benefits as well as unique challenges.
Topics: Child; Humans; Deep Brain Stimulation; Epilepsy; Seizures; Cerebral Cortex; Thalamus
PubMed: 36762660
DOI: 10.1097/WCO.0000000000001138 -
Neurobiology of Disease Feb 2020Sleep and circadian rhythms are among the most powerful but least understood contributors to cognitive performance and brain health. Here we capitalize on the circadian... (Randomized Controlled Trial)
Randomized Controlled Trial
A randomized, double-blind, placebo-controlled trial of blue wavelength light exposure on sleep and recovery of brain structure, function, and cognition following mild traumatic brain injury.
Sleep and circadian rhythms are among the most powerful but least understood contributors to cognitive performance and brain health. Here we capitalize on the circadian resetting effect of blue-wavelength light to phase shift the sleep patterns of adult patients (aged 18-48 years) recovering from mild traumatic brain injury (mTBI), with the aim of facilitating recovery of brain structure, connectivity, and cognitive performance. During a randomized, double-blind, placebo-controlled trial of 32 adults with a recent mTBI, we compared 6-weeks of daily 30-min pulses of blue light (peak λ = 469 nm) each morning versus amber placebo light (peak λ = 578 nm) on neurocognitive and neuroimaging outcomes, including gray matter volume (GMV), resting-state functional connectivity, directed connectivity using Granger causality, and white matter integrity using diffusion tensor imaging (DTI). Relative to placebo, morning blue light led to phase-advanced sleep timing, reduced daytime sleepiness, and improved executive functioning, and was associated with increased volume of the posterior thalamus (i.e., pulvinar), greater thalamo-cortical functional connectivity, and increased axonal integrity of these pathways. These findings provide insight into the contributions of the circadian and sleep systems in brain repair and lay the groundwork for interventions targeting the retinohypothalamic system to facilitate injury recovery.
Topics: Actigraphy; Adolescent; Adult; Brain; Brain Concussion; Brain Mapping; Cognition; Double-Blind Method; Female; Humans; Light; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Phototherapy; Sleep; Treatment Outcome; Young Adult
PubMed: 31751607
DOI: 10.1016/j.nbd.2019.104679 -
Annual Review of Psychology Jan 2020Spatial attention is comprised of neural mechanisms that boost sensory processing at a behaviorally relevant location while filtering out competing information. The... (Review)
Review
Spatial attention is comprised of neural mechanisms that boost sensory processing at a behaviorally relevant location while filtering out competing information. The present review examines functional specialization in the network of brain regions that directs such preferential processing. This attention network includes both cortical (e.g., frontal and parietal cortices) and subcortical (e.g., the superior colliculus and the pulvinar nucleus of the thalamus) structures. Here, we piece together existing evidence that these various nodes of the attention network have dissociable functional roles by synthesizing results from electrophysiology and neuroimaging studies. We describe functional specialization across several dimensions (e.g., at different processing stages and within different behavioral contexts), while focusing on spatial attention as a dynamic process that unfolds over time. Functional contributions from each node of the attention network can change on a moment-to-moment timescale, providing the necessary cognitive flexibility for sampling from highly dynamic environments.
Topics: Attention; Cerebral Cortex; Humans; Nerve Net; Pulvinar; Space Perception; Superior Colliculi
PubMed: 31514578
DOI: 10.1146/annurev-psych-010418-103429 -
The Journal of Physiology Jan 2023The thalamus and cortex are interconnected both functionally and anatomically and share a common developmental trajectory. Interactions between the mediodorsal thalamus... (Review)
Review
The thalamus and cortex are interconnected both functionally and anatomically and share a common developmental trajectory. Interactions between the mediodorsal thalamus (MD) and different parts of the prefrontal cortex are essential in cognitive processes, such as learning and adaptive decision-making. Cortico-thalamocortical interactions involving other dorsal thalamic nuclei, including the anterior thalamus and pulvinar, also influence these cognitive processes. Our work, and that of others, indicates a crucial influence of these interdependent cortico-thalamocortical neural networks that contributes actively to the processing of information within the cortex. Each of these thalamic nuclei also receives potent subcortical inputs that are likely to provide additional influences on their regulation of cortical activity. Here, we highlight our current neuroscientific research aimed at establishing when cortico-MD thalamocortical neural network communication is vital within the context of a rapid learning and memory discrimination task. We are collecting evidence of MD-prefrontal cortex neural network communication in awake, behaving male rhesus macaques. Given the prevailing evidence, further studies are needed to identify both broad and specific mechanisms that govern how the MD, anterior thalamus and pulvinar cortico-thalamocortical interactions support learning, memory and decision-making. Current evidence shows that the MD (and the anterior thalamus) are crucial for frontotemporal communication, and the pulvinar is crucial for frontoparietal communication. Such work is crucial to advance our understanding of the neuroanatomical and physiological bases of these brain functions in humans. In turn, this might offer avenues to develop effective treatment strategies to improve the cognitive deficits often observed in many debilitating neurological disorders and diseases and in neurodegeneration.
Topics: Animals; Male; Humans; Macaca mulatta; Learning; Thalamus; Prefrontal Cortex; Neural Pathways
PubMed: 35851953
DOI: 10.1113/JP282626