Second-order olfactory-mediated fear-potentiated startle

Recently, we reported that discrete (4-sec) olfactory cues paired with footshock serve as effective conditioned stimuli (CSs) for potentiating the acoustic startle response in rats using the fear-potentiated startle paradigm. Because odors are such salient cues for the rat, and because of the robust olfactory conditioning observed previously, the current studies investigated second-order fear conditioning using olfactory and visual cues. In Experiments 1 and 2, we used a small number of first-order and second-order training trials on separate days to investigate second-order fear-potentiated startle. Significant potentiated startle was observed in animals receiving Paired/Paired training in both studies, but surprisingly, control animals in the Unpaired/Paired group (Exp. 1) also showed significant potentiated startle to a light S2 at testing. These findings are addressed in the Discussion. Overall, the results of both experiments suggest that olfactory cues serve as efficient S1 and S2 stimuli in second-order fear-potentiated startle paradigms when only a small number of first and second-order training trials are presented.     

Glutamate receptor antagonist infusions into the basolateral and medial amygdala reveal differential contributions to olfactory vs. context fear conditioning and expression

The basolateral amygdala's involvement in fear acquisition and expression to visual and auditory stimuli is well known. The involvement of the basolateral and other amygdala areas in fear acquisition and expression to stimuli of other modalities is less certain. We evaluated the contribution of the basolateral and medial amygdala to olfactory and to context fear and fear conditioning by infusing into these areas the NMDA receptor antagonist AP5, the AMPA/kainate receptor antagonist NBQX, or vehicle prior to either odor-shock pairings or fear-potentiated startle testing. Pre-training AP5 infusions into the basolateral amygdala disrupted fear conditioning to the odor but not the context conditioned stimulus (CS). Pre-test NBQX infusions disrupted fear-potentiated startle to the odor but not context CS. Neither compound blocked fear conditioning when infused into the medial amygdala prior to training, but pre-test NBQX infusions did block fear-potentiated startle. The results confirm and extend recent findings suggesting a role for the basolateral amygdala in olfactory fear and fear conditioning, reveal an unexpected dissociation of the basolateral amygdala's involvement in discrete cue versus context fear and fear conditioning, and implicate for the first time the medial amygdala in fear-potentiated startle.     

Differential effects of estrogen on hippocampal- and striatal-dependent learning

Estrogen's role in learning and memory may be to predispose animals to use specific cognitive strategies (Korol & Kolo, 2002). Specifically, estrogen may facilitate hippocampal-dependent learning, while at the same time attenuate striatal-dependent learning. As a stringent test of this hypothesis, place or response learning on an eight-arm radial maze was compared between ovariectomized (OVX) female Long-Evans rats and rats with chronic estrogen replacement (OVX+E; 5mg 17-beta estradiol 60-day release tablet). Reference and working memory errors were monitored separately for both place and response learning tasks. OVX+E rats learned the place task significantly faster than the response task, and faster than OVX rats. OVX rats required fewer days to reach criterion on the response task than OVX+E rats. Estrogen selectively enhanced reference memory performance, but only during place learning. The specific pattern of estrogen effects on learning suggests that future studies include verification of cognitive strategies used by animals.     

Reasons and psychological causes

The causal theory of reasons holds that acting for a reason entails that the agents action was caused by his or her beliefs and desires. While Donald Davidson (1963) and others effectively silenced the first objections to the theory, a new round has emerged. The most important recent attack is presented by Jonathan Dancy in Practical Reality (2000) and subsequent work. This paper will defend the causal theory against Dancy and others, including Schueler (1995), Stoutland (1999, 2001), and Ginet (2002).Dancy observes that our reasons are neither psychological states nor causes, and that our reasons can be both motivating and normative. I argue that these observations are fully compatible with the causal theory. According to the reductive version I develop for both cognitive and optative reasons, what it is for an action to be done for a reason is for certain beliefs and desires to cause the action in a particular way. Our reasons for action are the objects of some of those beliefs and desires. The causal process has two stages. This theory explains not only Dancys observations, but also many other facts about reasons that alternative theories leave unexplained. I argue against Schueler and others that the non-appetitive desires entailed by acting for reasons are no less distinct and independent causal factors than the beliefs entailed. I go on to rebut arguments that the relation between psychological states and actions cannot be causal because it is non-empirical, rational, normative, or non-deterministic, and that explanations in terms of psychological causes are incompatible with explanations in terms of reasons.I make no claim here about the precise adequacy of the theoretical definitions I present. My goal is to show that a systematic theory along these lines is the most promising and fruitful approach to understanding an important aspect of human nature.     

The Practice of the Everyday in the Literature of Nursing

If intense pain is "world-destroying," as Elaine Scarry has argued, one of the ways nurses respond to that loss is by re-enacting the commonplace-both in practice and in writing-through daily, accumulating acts of care. Such care poses a critique of medicine's emphasis on the exceptional moment and stresses forms of physical tending that are quotidian rather than heroic, ongoing rather than permanent or conclusive. I develop this view of care through the writings of nurses like Walt Whitman, Louisa May Alcott, Cortney Davis and Joyce Renwick.     

Lexical information drives perceptual learning of distorted speech: evidence from the comprehension of noise-vocoded sentences

Speech comprehension is resistant to acoustic distortion in the input, reflecting listeners' ability to adjust perceptual processes to match the speech input. For noise-vocoded sentences, a manipulation that removes spectral detail from speech, listeners' reporting improved from near 0% to 70% correct over 30 sentences (Experiment 1). Learning was enhanced if listeners heard distorted sentences while they knew the identity of the undistorted target (Experiments 2 and 3). Learning was absent when listeners were trained with nonword sentences (Experiments 4 and 5), although the meaning of the training sentences did not affect learning (Experiment 5). Perceptual learning of noise-vocoded speech depends on higher level information, consistent with top-down, lexically driven learning. Similar processes may facilitate comprehension of speech in an unfamiliar accent or following cochlear implantation.     

A statewide survey of audiologists regarding auditory processing disorders

This study surveyed all licensed Arkansas audiologists (N = 127) regarding auditory processing disorders in children and adults, with 16 items covering demographic information, knowledge, identification and diagnosis, service provision, and referral. Analysis indicated 40% and 35% of the 62 respondents were "very" or "somewhat comfortable" with diagnosing auditory processing disorders in adults and children, respectively. In the current work setting, 58% did not provide auditory processing testing, 44% had never performed such testing, and 40% did not answer a question related to referral sources. The lack of consistent testing or referral probably leaves community persons with auditory processing disorders at risk for being overlooked or misdiagnosed.