Current topics in behavioral neurosciences
-
Curr Top Behav Neurosci · Jul 2020
Functional Neuroanatomy of Salicylate- and Noise-Induced Tinnitus and Hyperacusis.
Tinnitus and hyperacusis are debilitating conditions often associated with aging or exposure to intense noise or ototoxic drugs. One of the most reliable methods of inducing tinnitus is with high doses of sodium salicylate, the active ingredient in aspirin. High doses of salicylate have been widely used to investigate the functional neuroanatomy of tinnitus and hyperacusis. ⋯ Functional connectivity of the BOLD signal revealed increased neural coupling between several auditory areas and non-auditory areas such as the amygdala, cerebellum, reticular formation, hippocampus, and caudate/putamen; these strengthened connections likely contribute to the multifaceted dimensions of tinnitus. Taken together, these results suggest that salicylate-induced tinnitus disrupts a complex neural network involving many auditory centers as well as brain regions involved with emotion, arousal, memory, and motor planning. These extra-auditory centers embellish the basic auditory percepts that results in tinnitus and which may also contribute to hyperacusis.
-
Curr Top Behav Neurosci · Jan 2018
ReviewDiscriminative Stimulus Properties of Phytocannabinoids, Endocannabinoids, and Synthetic Cannabinoids.
Psychoactive cannabinoids from the marijuana plant (phytocannabinoids), from the body (endocannabinoids), and from the research lab (synthetic cannabinoids) produce their discriminative stimulus effects by stimulation of CB1 receptors in the brain. Early discrimination work with phytocannabinoids confirmed that Δ9-tetrahydrocannabinol (Δ9-THC) is the primary psychoactive constituent of the marijuana plant, with more recent work focusing on characterization of the contribution of the major endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), to Δ9-THC-like internal states. ⋯ In the absence of a reliable model of cannabinoid self-administration (specifically, Δ9-THC self-administration), cannabinoid discrimination represents the most validated and pharmacologically selective animal model of an abuse-related property of cannabinoids - i.e., marijuana's subjective effects. The influx of recent papers in which cannabinoid discrimination is highlighted attests to its continued relevance as a valuable method for scientific study of cannabinoid use and abuse.
-
Curr Top Behav Neurosci · Jan 2017
Over-the-Counter Codeine-from Therapeutic Use to Dependence, and the Grey Areas in Between.
Codeine is a widely used analgesic, that is available for sale in pharmacies over the counter (OTC) in a number of countries including the UK, South Africa, Ireland, France and Australia. In these countries with OTC codeine sales there has been emerging concerns about misuse of and dependence on codeine containing combination analgesics, with increasing numbers of people presenting for help with codeine dependence at primary care and addiction treatment services. This has led to many countries reviewing availability of codeine in OTC available preparations, and considering possible measures to reduce harms from misuse of OTC codeine containing combination analgesics.
-
Multiple system atrophy (MSA) is a predominantly sporadic, adult-onset, fatal neurodegenerative disease of unknown etiology. MSA is characterized by autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal signs in any combination. MSA belongs to a group of neurodegenerative disorders termed α-synucleinopathies, which also include Parkinson's disease and dementia with Lewy bodies. ⋯ On one hand, neurotoxin-based models have been produced to reproduce neuronal loss in substantia nigra pars compacta and striatum. On the other hand, transgenic mouse models with overexpression of α-synuclein in oligodendroglia have been used to reproduce GCIs-related pathology. This chapter gives an overview of the atypical Parkinson's syndrome MSA and summarizes the currently available MSA animal models and their relevance for pre-clinical testing of disease-modifying therapies.
-
The connectivity of neuronal systems is their most fundamental characteristic. Here, we focus on recent developments in understanding structural and functional connectivity at the macroscale, which is accessible with current imaging technology. Structural connectivity is examined via diffusion weighted imaging methods, of which diffusion tensor imaging is the most frequently used. ⋯ Functional connectivity has been studied through task-based functional magnetic resonance imaging, and increasingly through studies on task-free functional imaging, also known as resting state functional imaging. The study of intrinsic functional connectivity beginning during fetal life reveals the developmental organization of intrinsic connectivity networks such as the default mode network, the dorsal attention network, the frontal-parietal executive control network, as well as primary cortical networks. As methods of examining both structural and functional connectivity mature, they increasingly inform our understanding of the development of connectivity in service of the long-term goal of delineating the substrates of much of developmental psychopathology.