Neurosteroids in the Hippocampus: Neuronal Plasticity and Memory

The hippocampus, which is critically involved in learning and memory processes, is known to be a target for the neuromodulatory actions of steroid hormones produced by the adrenal glands and gonads. Much of the work of B.S. McEwen and collaborators has focused on the role of glucocorticosteroids and estrogen in modulating hippocampal plasticity and functions. In addition to hormones derived from the endocrine glands, cells in the hippocampus may be exposed to locally synthesized neurosteroids, including pregnenolone, dehydroepiandrosterone and their sulfated esters as well as progesterone and its reduced metabolites. In contrast to hormones derived from the circulation, neurosteroids have paracrine and/or autocrine activities. In the hippocampus, they have been shown to have trophic effects on neurons and glial cells and to modulate the activity of a variety of neurotransmitter receptors and ion channels, including type A gamma-aminobutyric acid, N-methyl-D-aspartate and sigma receptors and N- and L-type Ca2+ channels. There is accumulating evidence that some neurosteroids, in particular pregnenolone sulfate, have strong influences on learning and memory processes, most likely by regulating neurotransmission in the hippocampus. However, the hippocampus is not the only target for the mnesic effects of neurosteroids. Associated brain regions, the basal nuclei of the forebrain and the amygdaloid complex, are also involved. Some neurosteroids may thus be beneficial for treating age- or disease-related cognitive impairments.     

Does understanding relational terminology mediate effects of intervention on compare word problems?

The purpose of this study was to assess whether understanding relational terminology (i.e., more, less, and fewer) mediates the effects of intervention on compare word problems. Second-grade classrooms (N=31) were randomly assigned to one of three conditions: researcher-designed word-problem intervention, researcher-designed calculation intervention, or business-as-usual (teacher-designed) control. Students in word-problem intervention classrooms received instruction on the compare problem type, which included a focus on understanding relational terminology within compare word problems. Analyses, which accounted for variance associated with classroom clustering, indicated that (a) compared with the calculation intervention and business-as-usual conditions, word-problem intervention significantly increased performance on all three subtypes of compare problems and on understanding relational terminology, and (b) the intervention effect was fully mediated by students' understanding of relational terminology for one subtype of compare problems and partially mediated by students' understanding of relational terminology for the other two subtypes.     

Sleep disturbance and emotion dysregulation as transdiagnostic processes in a comorbid sample

Sleep disturbance and emotion dysregulation have been identified as etiologic and maintaining factors for a range of psychopathology and separate literatures support their relationships to anxiety, depression, PTSD, and alcohol dependence (AD) symptom severity. Previous studies have examined these relationships in isolation, failing to account for the high rates of comorbidity among disorders. It is not yet known whether these processes uniquely predict symptom severity in each of these domains. Participants were 220 patients in residential substance abuse treatment, who had experienced a potentially traumatic event and exceeded screening cutoffs for probable PTSD and problematic alcohol use. Controlling for emotion dysregulation and the interrelationships among the outcome variables, insomnia was uniquely associated with anxiety (B = .27, p < .001), depression (B = .25, p < .001), PTSD (B = .22, p < .001), and AD (B = .17, p = .01) symptom severity. Similarly, controlling for insomnia, emotion dysregulation was uniquely associated with anxiety (B = .40, p < .001), depression (B = .47, p < .001), PTSD (B = .38, p < .001), and AD (B = .26, p < .001) symptom severity. Insomnia and emotion dysregulation appear to be transdiagnostic processes uniquely associated with symptom severity across a number of different domains and might be important treatment targets for individuals with PTSD and AD.     

Evaluation of the immediate and subsequent effects of response interruption and redirection on vocal stereotypy

We evaluated 2 3-component multiple-schedule sequences-a response interruption and redirection (RIRD) treatment sequence and a no-interaction control sequence-using a multielement design. With this design, we were able to evaluate the immediate and subsequent effects of RIRD on 2 participants' vocal stereotypy. For both participants, RIRD produced an immediate decrease in vocal stereotypy and did not result in a subsequent increase.     

Do we have to be Realists about Colour in order to be able to attribute Colour Perceptions to Other Persons?

One of the main targets of Barry Stroud’s criticism in his recent book ‚The Quest for Reality. Subjectivism and the Metaphysics of Colour’ are eliminativist theories of colour which he regards as a version of the metaphysical project of the unmasking of colours (Stroud, 2000). According to this view, no physical objects have any of the colours we see them or believe them to have. However, although this error theory describes all our colour perceptions as illusory, and all our colour beliefs as false, it cannot deny that we actually perceive colours and that we do believe that physical objects are coloured. Therefore, it has to account for these psychological facts without relying on any assumptions about the colours of things. Thus, the central question for the unmasking project is whether it is possible to acknowledge someone’s perceiving a certain colour or having beliefs about the colours of things without holding that anything anywhere has any colour at all. Contrary to Stroud, this paper defends the view that we can acknowledge that people believe in colours without having ourselves to accept their existence.     

Electromyographic evidence for response conflict in the exclude recognition task

How do memory retrieval processes lead to overt responses in strategic recognition tasks (responding “old” to one class of familiar stimulus and “new” to another)? Many current theories of memory retrieval ignore the response requirements in such memory tasks, instead modeling them using memory processes (e.g., familiarity and recollection) alone (see Yonelinas, 2002). We argue that strategic recognition involves conflict in response processing similar to canonical conflict tasks (e.g., the Stroop task). The parallel task set (PTS) model (Seymour, 2001) accounts for performance in strategic recognition tasks (e.g., the exclude recognition task) by suggesting that motor response conflict occurs when one responds “new” to familiar stimuli. We tested this prediction using surface electromyography, a measure incontrovertibly related to motor execution. Overall, results are consistent with the PTS model’s assumption that recognition, motor, and control processes interact in strategic retrieval tasks. The implications of these data for models of memory retrieval and response conflict are discussed.