Neuroscience
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The neural pathways of the auditory system underlie our ability to detect sounds and to transform amplitude and frequency information into rich and meaningful perception. While it shares some organizational features with other sensory systems, the auditory system has some unique functions that impose special demands on precision in circuit assembly. In particular, the cochlear epithelium creates a frequency map rather than a space map, and specialized pathways extract information on interaural time and intensity differences to permit sound source localization. ⋯ These proteins provide graded cues used in establishing tonotopically ordered connections between auditory areas, as well as discrete cues that enable axons to form connections with appropriate postsynaptic partners within a target area. Throughout the auditory system, Eph proteins help to establish patterning in neural pathways during early development. This early targeting, which is further refined with neuronal activity, establishes the precision needed for auditory perception.
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Temporal lobe epilepsy (TLE) is the most common form of focal epilepsies in adults. It is often initiated by an insult or brain injury which triggers a series of alterations which ultimately lead to seizures (epilepsy). ⋯ BBB changes have been observed in brain tissue of people with epilepsy as well as in experimental models at the structural, cellular and molecular level that could explain its role in the development and progression of epilepsy (epileptogenesis) as well as the development of drug resistance. Here, we will discuss the role of the BBB in TLE and drug resistance and summarize potential new therapies that may restore normal BBB function in order to put a brake on epileptogenesis and/or to improve drug treatment.
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Birdsong offers a unique model system to understand how a developing brain - once given a set of purely acoustic targets - teaches itself the vocal-tract gestures necessary to imitate those sounds. Like human infants, to juvenile male zebra finches (Taeniopygia guttata) falls the burden of initiating the vocal-motor learning of adult sounds. ⋯ Distinct forebrain pathways for structured (theme) and unstructured (variation) singing not only raise new questions about mechanisms of sensory-motor integration, but also provide a fascinating new research opportunity. A cortical locus for a motor memory of the learned song is now firmly established, meaning that anatomical, physiological, and computational approaches are poised to reveal the neural mechanisms used by the brain to compose the songs of birds.
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In this review we summarize findings published over the past 10 years focusing on the neural correlates of perceptual decision-making. Importantly, this review highlights only studies that employ a model-based approach, i.e., they use quantitative cognitive models in combination with neuroscientific data. The model-based approach allows capturing latent decision-making processes such as strategic adjustments of response thresholds and relate these to interindividual differences or single-trial blood-oxygenated level dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) responses. ⋯ More concretely, we show that evidence accumulation is associated with a fronto-parietal network which is partly overlapping with choice bias in perceptual decision making. The setting of decision thresholds is associated with fronto-basal ganglia networks which are also found for choice bias. In sum, we argue that the model-based approach holds great promises to understand the neural correlates of latent cognitive processes.
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Chronic exposure to alcohol produces changes in the prefrontal cortex that are thought to contribute to the development and maintenance of alcoholism. A large body of literature suggests that stress hormones play a critical role in this process. Here we review the bi-directional relationship between alcohol and stress hormones, and discuss how alcohol acutely stimulates the release of glucocorticoids and induces enduring modifications to neuroendocrine stress circuits during the transition from non-dependent drinking to alcohol dependence. We propose a pathway by which alcohol and stress hormones elicit neuroadaptive changes in prefrontal circuitry that could contribute functionally to a dampened neuroendocrine state and the increased propensity to relapse-a spiraling trajectory that could eventually lead to dependence.