Androgens are an important output of the hypothalamic-pituitary-gonadal (HPG) axis that controls reproduction in all vertebrates. In male teleosts two androgens, testosterone and 11-ketotestosterone, control sexual differentiation and development in juveniles and reproductive behavior in adults. Androgenic signals provide feedback at many levels of the HPG axis, including the hypothalamic neurons that synthesize and release gonadotropin-releasing hormone 1 (GnRH1), but the precise cellular site of androgen action in the brain is not known. Here we describe two androgen receptor subtypes, ARα and ARβ, in the cichlid Astatotilapia burtoni and show that these subtypes are differentially located throughout the adult brain in nuclei known to function in the control of reproduction. ARα was expressed in the ventral part of the ventral telencephalon, the preoptic area (POA) of the hypothalamus and the ventral hypothalamus, whereas ARβ was more widely expressed in the dorsal and ventral telencephalon, the POA, and the ventral and dorsal hypothalamus. We provide the first evidence in any vertebrate that the GnRH1-releasing neurons, which serve as the central control point of the HPG axis, express both subtypes of AR. Using quantitative real-time PCR, we show that A. burtoni AR subtypes have different expression levels in adult tissue, with ARα showing significantly higher expression than ARβ in the pituitary, and ARβ expressed at a higher level than ARα in the anterior and middle brain. These data provide important insight into the role of androgens in regulating the vertebrate reproductive axis. Keywordsin situ hybridization; gonadotropin-releasing hormone; androgen receptor subtypes; teleost Androgens are one endocrine output of the hypothalamic-pituitary-gonadal (HPG) axis that controls reproduction in all vertebrates. In male fish, the major androgens testosterone and 11-ketotestosterone (11-KT) are important for regulating sexual differentiation and functional development at all levels of the HPG axis (Borg, 1994). For example, exogenous androgens accelerate gonadal differentiation, spermatogenesis, and maturation of the hypothalamic and pituitary cells that synthesize and release the signaling peptides to mediate reproductive function (Amano et al., 1994;Goos et al., 1986;Miura et al., 1991a;Montero et al., 1995;Piferrer et al., 1993;Schreibman et al., 1986). If administered early enough in development in some teleost species, sex steroids can induce complete gonadal sex inversion in either direction (Hunter and Donaldson, 1983). In addition androgens also influence the adult HPG axis, mediating important social and reproductive behaviors, including courtship, territoriality, and aggression (Borg, 1994;Breton and Sambroni, 1996;Trudeau et al., 1991).Many physiological actions of androgens are mediated by the androgen receptor (AR) family. As with other steroid hormone receptors, ARs are ligand-dependent transcription factors, containing a highly conserved DNA-binding domain (DBD) and a moderately well cons...

A human driver requires a period of motor adaptation to resume normal steering after taking control of an automated vehicle.

No abstract

Improvements in vehicle safety require understanding of the neural systems that support the complex, dynamic task of real-world driving. We used functional near infrared spectroscopy (fNIRS) and pupilometry to quantify cortical and physiological responses during a realistic, simulated driving task in which vehicle dynamics were manipulated. Our results elucidate compensatory changes in driver behavior in response to changes in vehicle handling. We also describe associated neural and physiological responses under different levels of mental workload. The increased cortical activation we observed during the late phase of the experiment may indicate motor learning in prefrontal-parietal networks. Finally, relationships among cortical activation, steering control, and individual personality traits suggest that individual brain states and traits may be useful in predicting a driver's response to changes in vehicle dynamics. Results such as these will be useful for informing the design of automated safety systems that facilitate safe and supportive driver-car communication.

Visuomotor ability is quite crucial for everyday functioning, particularly in driving and sports. While there is accumulating evidence regarding neural correlates of visuomotor transformation, less is known about the brain regions that accommodate visuomotor mapping under different cognitive demands. We concurrently measured cortical activity and pupillary response, using functional near infrared spectroscopy (fNIRS) and eye-tracking glasses, to examine the neural systems linked to pupil dilation under varying cognitive demands. Twenty-three healthy adults performed two sessions of a navigation task, in which the cognitive load was manipulated by either reversing the visuomotor mapping or increasing the speed of the moving object. We identified a region in the right superior parietal lobule that responded to both types of visuomotor load and its activity was associated with larger pupillary response and better performance in the task. Our multimodal analyses suggest that activity in this region arises from the need for increased attentional effort and alertness for visuomotor control and is an ideal candidate for objective measurement of visuomotor cognitive load. Our data extend previous findings connecting changes in pupil diameter to neural activity under varying cognitive demand and have important implications for examining brain-behavior associations in real-world tasks such as driving and sports.