The co-consciousness hypothesis

Phenomenology and the Cognitive Sciences - Self-knowledge seems to be radically different from the knowledge of other people. However, rather than focusing on the gap between self and others, we...     

Successful generalized parent training and failed schedule thinning of response blocking for automatically maintained object mouthing

Mouthing of inedible objects maintained by automatic reinforcement can be particularly difficult to treat, given that the functional reinforcer is not socially mediated, and therefore it is difficult or impossible to withhold reinforcement. In the current investigation, response blocking was used to reduce automatically maintained object mouthing. Treatment effects were generalized to the natural environment. An attempt at schedule thinning was not successful; however, the participant's parents were trained to implement the treatment successfully in their home. Copyright © 2002 John Wiley & Sons, Ltd.     

Cognitive Mechanisms Underlying Recovered-Memory Experiences of Childhood Sexual Abuse

ABSTRACT— People sometimes report recovering long-forgotten memories of childhood sexual abuse. The memory mechanisms that lead to such reports are not well understood, and the authenticity of recovered memories has often been challenged. We identified two subgroups of people reporting recovered memories of childhood sexual abuse. These subgroups differed dramatically in their cognitive profiles: People who recovered memories of abuse through suggestive therapy exhibited a heightened susceptibility to the construction of false memories, but showed no tendency to underestimate their prior remembering. Conversely, people who recovered memories of abuse spontaneously showed a heightened proneness to forget prior incidences of remembering, but exhibited no increased susceptibility to false memories. This double dissociation points to mechanisms that underlie recovered-memory experiences and indicates that recovered memories may at times be fictitious and may at other times be authentic.     

Individual differences in using geometric and featural cues to maintain spatial orientation: Cue quantity and cue ambiguity are more important than cue type

Two experiments explored the role of environmental cues in maintaining spatial orientation (sense of selflocation and direction) during locomotion. Of particular interest was the importance of geometric cues (provided by environmental surfaces) and featural cues (nongeometric properties provided by striped walls) in maintaining spatial orientation. Participants performed a spatial updating task within virtual environments containing geometric or featural cues that were ambiguous or unambiguous indicators of self-location and direction. Cue type (geometric or featural) did not affect performance, but the number and ambiguity of environmental cues did. Gender differences, interpreted as a proxy for individual differences in spatial ability and/or experience, highlight the interaction between cue quantity and ambiguity. When environmental cues were ambiguous, men stayed oriented with either one or two cues, whereas women stayed oriented only with two. When environmental cues were unambiguous, women stayed oriented with one cue.     

Impairments in fear conditioning in mice lacking the nNOS gene

The fear conditioning paradigm is used to investigate the roles of various genes, neurotransmitters, and substrates in the formation of fear learning related to contextual and auditory cues. In the brain, nitric oxide (NO) produced by neuronal nitric oxide synthase (nNOS) functions as a retrograde neuronal messenger that facilitates synaptic plasticity, including the late phase of long-term potentiation (LTP) and formation of long-term memory (LTM). Evidence has implicated NO signaling in synaptic plasticity and LTM formation following fear conditioning, yet little is known about the role of the nNOS gene in fear learning. Using knockout (KO) mice with targeted mutation of the nNOS gene and their wild-type (WT) counterparts, the role of NO signaling in fear conditioning was investigated. Plasma levels of the stress hormone corticosterone were measured to determine the relationship between physiological and behavioral response to fear conditioning. Contextual fear learning was severely impaired in male and female nNOS KO mice compared with WT counterparts; cued fear learning was slightly impaired in nNOS KO mice. Sex-dependent differences in both contextual and cued fear learning were not observed in either genotype. Deficits in contextual fear learning in nNOS KO mice were partially overcome by multiple trainings. A relationship between increase in plasma corticosterone levels following footshock administration and the magnitude of contextual, but not cued freezing was also observed. Results suggest that the nNOS gene contributes more to optimal contextual fear learning than to cued fear learning, and therefore, inhibition of the nNOS enzyme may ameliorate context-dependent fear response.Anxiety disorders, such as post-traumatic stress disorder (PTSD), constitute the most prevalent mental illnesses in the United States, costing nearly one-third of the country''s total health bill (Greenberg et al. 1999). The treatment of these disorders requires overcoming complications such as reluctance to seek mental health treatment and an extremely high comorbidity rate with other affective disorders, reaching 80% (Brady 1997; Solomon and Davidson 1997). Emerging evidence suggests that dysfunctions underlying acquired anxiety and PTSD include an abnormal reaction to stress, which is mediated by specific neurochemical and neuroanatomical substrates (Yehuda and McFarlane 1995; Adamec 1997). Pharmacotherapies that target neuronal signaling molecules, such as nitric oxide (NO), may play a role in the treatment of these disorders.In the brain, N-methyl-d-aspartate receptor (NMDAR) activation and calcium influx into the cell activates the neuronal nitric oxide synthase (nNOS) enzyme to produce NO, which has the role of retrograde messenger (Snyder 1992). NO is involved in memory formation and synaptic plastic events such as late-phase long-term potentiation (LTP) (Lu et al. 1999; Arancio et al. 2001; Puzzo et al. 2006). Behavioral evidence in invertebrates (Lewin and Walters 1999; Muller 2000; Kemenes et al. 2002; Matsumoto et al. 2006) and vertebrates (Medina and Izquierdo 1995; Rickard et al. 1998; Ota et al. 2008) suggest that NO has a major role in consolidation of long-term memory (LTM). Recently, studies have shown that site-specific pharmacological blockade of NO signaling in rats impairs contextual (Resstel et al. 2008) and cued (Schafe et al. 2005) fear learning. However, the role of the nNOS gene in fear conditioning has not been investigated.In the present study, fear conditioning was investigated in homozygous nNOS knockout (KO) and wild-type (WT) mice. In the fear-conditioning paradigm, the association of a footshock (unconditioned stimulus; US), with a specific context and a neutral stimulus (auditory cue) results in learned fear. Re-exposure to the conditioning context and to the previously neutral auditory cue (conditioned stimulus; CS) elicits a freezing response in the absence of the aversive US. Thus, the fear-conditioning paradigm includes both contextual and cued fear learning components, which can be measured in separate tests. Fear conditioning recruits both the amygdala (emotional cue learning) and the hippocampus (spatial/contextual learning) (Phillips and LeDoux 1992; Goosens and Maren 2004; Mei et al. 2005). The involvement of these brain regions in fear learning and anxiety has been confirmed by animal and human imaging studies (LeDoux 1998; Rauch et al. 2006).We report that nNOS KO mice showed a severe deficiency in contextual fear learning and a less marked deficit in cued fear learning compared with WT mice after a single fear-conditioning session. This deficiency was partially improved by multiple (four) fear-conditioning sessions. In addition, we observed that plasma levels of corticosterone, the primary stress hormone in rodents, are related to contextual fear learning ability.     

Primed picture naming within and across languages: An ERP investigation

In two experiments, while event-related potentials (ERPs) were recorded, participants named picture targets that were preceded by masked word primes that corresponded either to the name of the picture target or to an unrelated picture name. Experiment 1 showed significant priming effects in the ERP waveforms, free from articulator artifact, starting as early as 200 msec post target onset. Possible loci of these priming effects were proposed within the framework of generic interactive activation models of word recognition and picture naming. These were grouped into three main components: object-specific structural representations, amodal semantic representations, and word-specific phonological and articulatory representations. Experiment 2 provided an initial test of the possible role of each of these components by comparing within-language repetition priming with priming from translation equivalents in bilingual participants. The early and widespread effects of noncognate translation primes in L1 on picture naming in L2 point to object-specific and amodal semantic representations as the principal loci of priming effects obtained with masked word primes and picture targets.