Hyperactivity and Learning Deficits in Transgenic Mice Bearing a Human Mutant Thyroid Hormone β1 Receptor Gene

Resistance to thyroid hormone (RTH) is a human syndrome mapped to the thyroid receptor β (TRβ) gene on chromosome 3, representing a mutation of the ligandbinding domain of the TRβ gene. The syndrome is characterized by reduced tissue responsiveness to thyroid hormone and elevated serum levels of thyroid hormones. A common behavioral phenotype associated with RTH is attention deficit hyperactivity disorder (ADHD). To test the hypothesis that RTH produces attention deficits and/or hyperactivity, transgenic mice expressing a mutant TRβ gene were generated. The present experiment tested RTH transgenic mice from the PV kindred on behavioral tasks relevant to the primary features of ADHD: hyperactivity, sustained attention (vigilance), learning, and impulsivity. Male transgenic mice showed elevated locomotor activity in an open field compared to male wild-type littermate controls. Both male and female transgenic mice exhibited impaired learning of an autoshaping task, compared to wild-type controls. On a vigilance task in an operant chamber, there were no differences between transgenics and controls on the proportion of hits, response latency, or duration of stimulus tolerated. On an operant go/no-go task measuring sustained attention and impulsivity, there were no differences between controls and transgenics. These results indicate that transgenic mice bearing a mutant human TRβ gene demonstrate several behavioral characteristics of ADHD and may serve a valuable heuristic role in elucidating possible candidate genes in converging pathways for other causes of ADHD.     

The misperception of angles: Estimating the vertex of converging line segments

Estimates of the point of intersection of converging line segments depended upon the angle between lines and the orientation of the display. Main conclusion: The tilt of a line is perceptually altered to appear more nearly parallel to the more closely aligned axis, either horizontal or vertical, of an O’s visual field.     

Contour displacements and tracking errors: Probing ’twixt Poggendorff parallels

Explanations of the Poggendorff effect were tested by varying the separation between outer parallels and by adding interior parallels. Error decreased with the addition of interior parallels, which can be explained by repulsion of parallels. A strong linear trend existed for judgmental error in millimeters plotted against separation between outer parallels. The nonzero intercept of a best-fit line and the slight nonlinearity of the data suggest a hypothesis of contour repulsion between parallels at moderate separations coupled with mistracking of the transversal across the region between parallels. Since the Poggendorff effect was independent of viewing distance, perceptual errors cannot be explained by purely peripheral mechanisms. A true intersection between transversal and parallel was the most critical feature of a display. Inverting a display increased the mean error.     

Comparing the effects of low-level and high-level worker need-satisfaction: A synthesis of the self-determination and Maslow need theories

According to Maslow’s (Psychol Rev 50:370–396, 1943) hierarchical theory of needs, people do not become sensitized to “higher” level needs until they have satisfied their “lower” level needs (a moderator hypothesis); until then, they are unprepared to benefit from higher-level satisfactions. But according to the self-determination theory (SDT) model, high-level psychological needs, when met, are non-contingently beneficial (a main effect-only hypothesis). In two large-N studies of Russian energy companies, we measured low-level need-satisfaction in terms of felt security and felt financial satisfaction, and measured high-level need satisfaction in terms of SDT’s basic needs of autonomy, competence, and relatedness. In both studies, both the lower level and higher level need-satisfaction sets had strong main effects upon many positive work outcomes, including intrinsic motivation, organizational commitment, and SWB. In Study 2, Maslow’s “prepared to benefit” hypothesis was supported, in that satisfaction of high-level needs had slightly larger effects on outcomes when combined with satisfaction of low-level needs. However this was not found in Study 1. Potentials for integrating the SDT and Maslow need theories are discussed.