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111.
Ambiguity has long been used as a probe into visual processing. Here, we describe a new dynamic ambiguous figure-the chimeric point-light walker--which we hope will prove to be a useful tool for exploring biological motion. We begin by describing the construction of the stimulus and discussing the compelling finding that, when presented in a mask, observers consistently fail to notice anything odd about the walker, reporting instead that they are watching an unambiguous figure moving either to the left or right. Some observers report that the initial percept fluctuates, moving first to the left, then to the right, or vice versa; others always perceive a constant direction. All observers, when briefly shown the unmasked ambiguous figure, have no difficulty in perceiving the novel motion pattern once the mask is returned. These two findings--the initial report of unambiguous motion and the subsequent 'primed' perception of the ambiguity--are both consistent with an important role for top-down processing in biological motion. We conclude by suggesting several domains within the realm of biological-motion processing where this simple stimulus may prove to be useful.  相似文献   
112.
    
Sex differences in the neurobiological mechanisms involved in fear conditioning and extinction have been suggested to contribute to differential vulnerability for the development of posttraumatic stress disorder (PTSD) in women compared with men. Reproductive hormones, such as estradiol, have been shown to facilitate fear conditioning and extinction learning and may explain some of these differences. However, the effect of commonly used hormonal contraceptives on the neurobiological mechanisms of fear conditioning and extinction is poorly understood. A laboratory study was conducted in trauma-exposed men and women with and without full or partial PTSD to examine effects of sex and use of hormonal birth control on fear conditioning, fear extinction learning, and extinction retention. Participants underwent fear conditioning with stimuli that were paired (CS+) or unpaired (CS−) with shock. Extinction learning occurred 72 h later, and extinction retention was tested 1 wk after extinction. Women on hormonal contraceptives (HCs) demonstrated enhanced acquisition of fear conditioning and enhanced extinction of fear as compared with women off hormonal birth control and men. While clinical implications have yet to be determined, these results suggest that hormonal contraceptives may facilitate learning during both fear acquisition and extinction. Understanding the impact of sex and hormones on fear conditioning and extinction processes may lead to new insights into the pathophysiology of PTSD and result in advancements in treatment that may vary by sex.

It is widely recognized that posttraumatic stress disorder (PTSD) is a common consequence of trauma exposure, and women are at particularly high risk, with some but not all studies finding that women develop PTSD at twice the rate of men, despite greater trauma exposure in men (Breslau et al. 1998; Tanielian et al. 2008). Although some have suggested that greater exposure to interpersonal violence may contribute to higher rates of PTSD in women, other evidence implicates sex differences in the neurobiological mechanisms that are involved in fear conditioning and extinction. Enhanced fear conditioning and diminished extinction of conditioned fear have been associated with higher levels of endogenous estrogen in women, as well as the development and maintenance of PTSD in both sexes (Orr et al. 2000; Milad et al. 2009b; Glover et al. 2012). Furthermore, as one of the most empirically supported treatments for PTSD is prolonged exposure therapy, which is largely based on fear extinction principles and the success of extinction learning (Rothbaum and Davis 2003), a clear understanding of the individual factors impacting fear conditioning and extinction is critical.Although some of the studies examining sex differences in fear conditioning are inconsistent (Guimaraes et al. 1991; Zorawski et al. 2005; Milad et al. 2006), an increasing body of evidence from rodent and human studies supports the existence of sex differences in fear extinction learning and recall (Maren et al. 1994; Pryce et al. 1999; Milad et al. 2009a; Merz et al. 2013). One possible explanation for the lack of consistent findings in the fear conditioning literature may be related to potential floor effects associated with subclinical impairment of nonclinical samples, as most laboratory studies examining sex differences were conducted in healthy humans. Another explanation that is gaining substantial support is the impact of hormones that differ between the sexes, among individuals, and even within individuals across time (Quirk and Mueller 2008; Lebron-Milad and Milad 2012; Arevalo et al. 2015; Hwang et al. 2015; Herrera et al. 2017; Maeng et al. 2017; Antov and Stockhorst 2018).The available literature indicates that estradiol, the primary estrogen in women during the childbearing years, is also present at overall lower concentrations in males and plays a large role in the fear conditioning and extinction differences observed between men and women (Gupta et al. 2001; Jasnow et al. 2006; Chang et al. 2009; Milad et al. 2009a, 2010; Zeidan et al. 2011; Maddox et al. 2018; Matsumoto et al. 2018; Carvalho et al. 2021). In both sexes, estradiol plays a variety of important functions in the brain, including the regulation of oxidative stress, inflammation, and gene expression, as well as in cognitive functions such as learning and memory (Hammoud et al. 2020). Estrogen receptors are found throughout brain regions that are important for fear conditioning and extinction processes (e.g., the amygdala, ventromedial prefrontal cortex, and hippocampus), likely via enhancements to learning and memory (Milad et al. 2008; Quirk and Mueller 2008; Lebron-Milad and Milad 2012). In women, as peripheral levels of estradiol vary over the course of the menstrual cycle, so do levels of estradiol in the brain (Arevalo et al. 2015). Estradiol has been shown to enhance memory consolidation across stages of fear conditioning, extinction, and retention (Lebron-Milad and Milad 2012). Most relevant to learning in PTSD, women with high levels of estradiol demonstrate enhanced memory formation in the presence of stress exposure (Herrera et al. 2017; Antov and Stockhorst 2018). In animal and human models, higher estradiol levels appear to facilitate acquisition of fear conditioning and extinction (Maeng et al. 2017). For example, women with high endogenous estradiol levels have enhanced responses in fear circuitry during fear conditioning, extinction, and recall as compared with men (Hwang et al. 2015). When phase of menstrual cycle has been taken into account, differences have been observed in conditioned fear responses and severity of PTSD symptoms. Specifically, when women are in the midluteal phase of the menstrual cycle (higher endogenous estradiol), they demonstrate a stronger positive relationship between SCR during fear conditioning and PTSD symptoms than women in the early follicular phase of menstruation (lower endogenous estradiol) (Carpenter et al. 2022). In the complimentary literature on the startle response, low-estradiol women demonstrated reduced discrimination between CS+ and CS− during fear conditioning and reduced inhibition of fear-potentiated startle during extinction and extinction recall, indicating less successful learning than their high-estradiol counterparts (Glover et al. 2012, 2013; Armbruster et al. 2018). This literature suggests that higher levels of estradiol relate to enhanced acquisition of associations between an unconditioned stimulus (UCS) and a conditioned stimulus (CS) during fear conditioning and enhanced extinction of this association during the extinction phase due to greater memory consolidation.A variety of factors can account for hormone differences in women, including menstrual phase, age, and use of hormonal birth control. Approximately 11%–20% of women aged 20–39 yr use oral contraceptives (OCs) (Daniels and Abma 2020). Commonly used OCs directly affect estradiol levels and hormonal fluctuation associated with the menstrual cycle. However, hormonal contraceptives (HCs) have received little attention in the fear conditioning literature. At the time of writing, we were unable to locate studies examining the impact of other HCs on fear conditioning circuitry, although these forms of birth control are increasingly popular among women, and evidence suggests that a variety of HCs has impacts on brain structure, function, and cognitive processes (Brønnick et al. 2020). Literature suggests that estradiol levels in women on HCs are typically low, similar to those of women in the early follicular phase of menstruation (Brynhildsen 2014). Although Hwang et al. (2015) did not demonstrate an effect of HCs on fear conditioning, many HCs contain ethinyl estradiol, which is synthetic estrogen that binds to estrogen receptors at high levels. Further research is needed to determine whether synthetic estrogen present in HCs impacts fear conditioning and fear extinction and contributes to associated sex differences, particularly in a highly sensitized population such as those with PTSD. In the current study, differences in fear conditioning, extinction, and retention were examined in women on hormonal birth control and in the early follicular phase of the menstrual cycle as compared with men to determine whether the synthetic hormones present in HCs confer any enhancement to these processes over and above women off of birth control with theoretically low levels of endogenous estradiol.Fear conditioning is measured by assessing the differential SCR to a conditioned stimulus (CS+) paired with an unconditioned stimulus (shock; UCS) and a stimulus unpaired with a shock (CS−). Greater acquisition of fear conditioning is evidenced by greater SCR response to the CS+ when compared with the CS−. Fear extinction refers to repeated exposure to the CS in the absence of the US, which results in diminishing reactivity to previously conditioned stimuli due to an inhibitory neural link that is formed (Myers and Davis 2007). Extinction is therefore operationalized by reduced discrimination of responding to the CS+ and CS− over time, and its retention is evidenced by a maintenance of low differential SCR in response to presentation of CS+ and CS− cues at follow-up.In previous work, our group examined sex differences in skin conductance responses to a fear conditioning paradigm in men and women with PTSD (Inslicht et al. 2013). In that sample, women were premenopausal and underwent conditioning during the follicular phase of the menstrual cycle. We found that women had greater differential fear acquisition compared with men. Other work has indicated that the effects of endogenous gonadal hormones on fear extinction are moderated by PTSD diagnosis, such that women with PTSD demonstrated impaired fear extinction during the midluteal phase of menstruation but not during the early follicular phase (Pineles et al. 2016b). The current study examines the effect of sex, HC use, and PTSD severity on fear conditioning, fear extinction, and extinction retention in medically healthy trauma-exposed premenopausal women on or off HCs and age-matched men across a range of PTSD symptom severity. We used a validated laboratory conditioning paradigm (Inslicht et al. 2021) that occurred over several days in which fear acquisition was separated from extinction by 72 h to avoid influencing consolidation of fear conditioning, and extinction retention was evaluated 1 wk after the fear extinction session to provide a test of durability of extinction over time.Given evidence for impaired fear extinction in PTSD, we hypothesized that participants high in PTSD (men and women combined) would have decreased fear extinction learning and extinction retention compared with those with low PTSD symptom scores. As estradiol appears to enhance learning during stress in women, we predicted that women on HCs would demonstrate higher differential SCR during acquisition and lower differential SCR during extinction and extinction retention than naturally cycling women in the early follicular phase of menstruation and men. Finally, we predicted a PTSD × sex interaction effect for extinction learning and retention; women on HCs with high levels of current PTSD would have enhanced acquisition but decreased extinction learning and retention compared with women with low levels of current PTSD and men.  相似文献   
113.
Reductions in everyday problem solving (EPS) are often reported in older age, although the underlying mechanisms remain unclear. The authors examined the role of 2 variables predicted to mediate (neuropsychological abilities and health status) or moderate (health status) the relationship between age and EPS performance. Toward these ends, they compared EPS and neuropsychological performance in 50 functionally independent adults with chronic kidney disease (CKD) and 64 control participants matched on age and education. Both older age and CKD were associated with worse performance on measures of EPS and memory/executive abilities. Neuropsychological abilities were positively associated with EPS performance. In both the full sample and control participants only, memory/executive functioning mediated the association between presence of chronic illness and EPS. Furthermore, memory/executive functioning partially mediated the link between age and EPS. Findings indicate that relations among age, health status, and EPS are not straightforward. Although performance on neuropsychological measures appeared to underlie EPS declines in chronic illness, increasing age remained independently associated with reduced EPS. The authors discuss implications for models of adult developmental changes in everyday cognition.  相似文献   
114.
There has been a recent growth in philosophy of psychiatry that draws heavily (although not exclusively) on analytic philosophy with the aim of a better understanding of psychiatry through an analysis of some of its fundamental concepts. This 'new philosophy of psychiatry' is an addition to both analytic philosophy and to the broader interpretation of mental health care. Nevertheless, it is already a flourishing philosophical field. One indication of this is the new Oxford University Press series International Perspectives in Philosophy and Psychiatry seven volumes of which (by Bolton and Hill; Bracken and Thomas; Fulford, Morris, Sadler, and Stanghellini; Hughes, Louw, and Sabat; Pickering; Sadler; and Stanghellini) are examined in this critical review.  相似文献   
115.
Thornton C 《Cognitive Science》2009,33(8):1383-1412
Early agreement within cognitive science on the topic of representation has now given way to a combination of positions. Some question the significance of representation in cognition. Others continue to argue in favor, but the case has not been demonstrated in any formal way. The present paper sets out a framework in which the value of representation use can be mathematically measured, albeit in a broadly sensory context rather than a specifically cognitive one. Key to the approach is the use of Bayesian networks for modeling the distal dimension of sensory processes. More relevant to cognitive science is the theoretical result obtained, which is that a certain type of representational architecture is necessary for achievement of sensory efficiency. While exhibiting few of the characteristics of traditional, symbolic encoding, this architecture corresponds quite closely to the forms of embedded representation now being explored in some embedded/embodied approaches. It becomes meaningful to view that type of representation use as a form of information recovery. A formal basis then exists for viewing representation not so much as the substrate of reasoning and thought, but rather as a general medium for efficient, interpretive processing.  相似文献   
116.
117.
This article contributes to current conversations concerning the role pastoral care and theology can play in the renewal of public life.  相似文献   
118.
119.
Traditional approaches to comparing the utility of two tests have not systematically considered the effects of different levels of selectivity that are feasible and appropriate in various selection situations. For example, employers who hope to avoid adverse impact often find they can be more selective with some tests than with others. We conducted two studies to compare the utilities of two tests that differ in costs, validity, and feasible levels of selectivity which can be employed. First, an analytical solution was conducted starting with a standard formula for utility. This analysis showed that for both fixed and variable hiring costs, a higher-cost, lower-validity procedure can have higher utility than a lower-cost, higher-validity procedure when the selection ratios permissible using the two procedures are sufficiently (yet realistically) different. Second, using a computer simulation method, several combinations of the critical variables were varied systematically to detect the limits of this effect in a finite set of specific selection situations. The results showed that the existence of more severe levels of adverse impact greatly reduced the utility of a written test with relatively high validity and low cost in comparison with an assessment center with lower validity and higher cost. Both studies showed that the consideration of selectivity can yield surprising conclusions about the comparative utility of two tests. Even if one test has lower validity and higher cost than a second test, the first may yield higher utility if it allows the organization to exercise stricter levels of selectivity.  相似文献   
120.
An investigation into the QEEG parameters of effective cognitive functioning of visual memory for six Korean figures was conducted employing 69 normal subjects. Subjects studied the figures for 1 minute, engaged in an immediate 30-second quiet recall period, which was then followed by the subjects drawing the figures. A delayed recall of 45 minutes later followed the same methodology. The recall performances were correlated with the QEEG variables. For the input stage, total memory was determined predominantly by specific patterns of left frontal (F7, F3, Fpl) projections (phase and coherence activity) and left central/posterior (T3, C3, P3) phase (Alpha and Betal( 13–32 Hz)) projections. Success during immediate silent recall was determined by left frontal (F7, Fpl, F3) projections and left central/posterior (T3, T5, Ol, P3) projections in the Beta frequencies. Long term-delayed recall was determined by Ol coherence Alpha projection activity and Symmetry of Beta2 (32–64 Hz) at F8. Degree of activation variables (from visual attention and eyes closed) showed different patterns of successful activations.  相似文献   
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