Behavioural brain research
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Optogenetic techniques have given researchers unprecedented access to the function of discrete neural circuit elements and have been instrumental in the identification of novel brain pathways that become dysregulated in neuropsychiatric diseases. For example, stress is integrally linked to the manifestation and pathophysiology of neuropsychiatric illness, including anxiety, addiction and depression. ⋯ Using optogenetic tools, we are now able to selectively isolate distinct neural circuits that contribute to these disorders and perturb these circuits in vivo, which in turn may lead to the normalization of maladaptive behavior. This review will focus on current optogenetic strategies to identify, manipulate, and record from discrete neural circuit elements in vivo as well as highlight recent optogenetic studies that have been utilized to parcel out BNST function.
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The cerebellum consists of the cerebellar cortex and the cerebellar nuclei. Although the basic neuronal circuitry of the cerebellar cortex is uniform everywhere, anatomical data demonstrate that the input and output relationships of the cortex are spatially segregated between different cortical areas, which suggests that there are functional distinctions between these different areas. Perturbation of cerebellar cortical functions in a spatially restricted fashion is thus essential for investigating the distinctions among different cortical areas. ⋯ Although this type of approach has for many years been technically difficult, recent advances in optogenetics now enable selective activation or inhibition of Purkinje cell activities, with high temporal resolution. Here we discuss the effectiveness of using Purkinje cell-specific optogenetic approaches to elucidate the functions of local cerebellar cortex regions. We also discuss what improvements to current methods are necessary for future investigations of cerebellar functions to provide further advances.
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Recent breakthroughs in optogenetic technologies to alter neuronal firing and function with light, combined with cell type-specific transgenic animal lines, has led to important insights into the function of distinct neuronal cell subtypes and afferent connections in the heterogeneously complex striatum. A vital part of the basal ganglia, the striatum is heavily implicated in both motor control and motivation-based behavior; as well as in neurological disorders and psychiatric diseases including Parkinson's Disease, Huntington's Disease, drug addiction, depression, and schizophrenia. ⋯ These studies confirmed the classical hypothesis of movement control and reward seeking behavior through direct versus indirect pathway MSNs; illuminated a selective role for TANs in cocaine reward; dissected the roles of glutamatergic and dopaminergic inputs to striatum in reward; and highlighted a role for striatal signaling molecules including an adrenergic G-protein coupled receptor in reward and the rho-GTPase Rac1 in cocaine reward and cocaine induced structural plasticity. This review focuses on how the evolving optogenetic toolbox provides insight into the distinct behavioral roles of striatal cell subpopulations and striatal afferents, which has clinically relevant implications into neurological disorders and psychiatric disease.