Bilingual language processing after a lesion in the left thalamic and temporal regions. A case report with early childhood onset.

This case study concerns an 18-year-old bilingual girl who suffered a radiation lesion in the left (dominant) thalamic and temporal region when she was 4 years old. Language and memory assessment revealed deficits in auditory short-term memory, auditory word comprehension, nonword repetition, syntactic processing, word fluency, and confrontation naming tasks. Both languages (English and Dutch) were found to be affected in a similar manner, despite the fact that one language (English) was acquired before and the other (Dutch) after the period of lesion onset. Most of the deficits appear to be related to verbal (short-term) memory dysfunction. Several hypotheses of subcortical involvement in memory processes are discussed with reference to existing theories in this area.     

Discriminative properties of morphine that modulate associations between tastes and lithium chloride

Wistar rats learned to withhold consumption of a target solution when morphine preceded presentation of the target solution and lithium chloride (LiCl) and to consume the same target solution when saline preceded the presentation of the solution. After this serial feature discrimination training, morphine did not block the formation of a Pavlovian association between saccharin and LiCl but did suppress consumption of familiar tap water. After Pavlovian conditioning, morphine blocked the formation of an association between saccharin and LiCl but did not suppress consumption of a familiar tap water solution. The roles of morphine and saline can be interchanged. It appears that the morphine discriminative stimulus is calling up a representation of neither the conditioned stimulus nor the unconditional stimulus alone, but rather a modified representation of some aspect of their association.     

Time courses in visual-information processing: Some theoretical considerations

Summary In the literature two different views with regard to the time course of activation of recognition units —hypothetical entities that represent identity information —are proposed. Both views are derived from a restricted set of phenomena in visual perception. The first view gets its intuitions from phenomena such as those summarized by Bloch's law; these phenomena show integration or summation of activation over time. This grow-and-grow view assumes that recognition units accumulate activation gradually over times The second view finds its inspiration in phenomena such as Mach-bands and simultaneous contrast; these phenomena show inhibition or steady-state suppression over time. This grow-and-shrink view assumes that the activation levels increase fast initially and then start to decrease.The perception literature strongly suggests that it may be light intensity that determines whether mainly integration (and phenomena such as Bloch's law) or inhibition (and phenomena such as Mach-bands) is obtained. So it is also likely that both information-processing views apply only to a limited range of intensity conditions; the grow-and-grow view to conditions of low-flight intensities, and the grow-and-shrink view to conditions of intermediate-and high-light intensities.It is argued that, to arrive at a complete view, a visual phenomenon that applies to the complete range of light intensities should be taken as a background for generating hypotheses about time courses in visual-information processing. The Broca-Sulzer effect is such a phenomenon. Starting from this phenomenon a simple, synthesizing, information-processing model is derived that is compatible with both the grow-and-grow view and the grow-andshrink view. It is shown that, besides the relevant temporal properties, this model also produces the appropriate spatial properties.     

Indeterminacy of the isomorphism heuristic

Summary We are less prone today than in Köhler's time to believe in a unified science. The Gestalt program could therefore safely abandon the psychophysical isomorphism heuristic if it wished to. Indeterminacy of the heuristic might be a reason for doing so. The determination of the components involved in the isomorphism of the visual field as well as the electrocortical events would have to occur simultaneously. In the Gestalt program, however, components are determined by their position in the whole. They can therefore not be compared in different contexts, so no independent test of a candidate heuristic is possible.     

Time courses in visual-information processing: Some empirical evidence for inhibition

Summary In the literature two different views on the time course of activation of recognition units — hypothetical units that represent identity information — are proposed. The first view assumes that the recognition units accumulate activation gradually over time. The second assumes that the activation levels increase fast initially and then start to decrease. Hagenzieker and Van der Heijden (1990) have proposed a more general information-processing model, which is compatible with both views. In this model a treshold determines what type of time course will be obtained. For below-threshold-activation values a gradual accumulation of activation will be found; for above-threshold values activation levels will first increase and then, because of inhibition, decrease. This model served as a starting-point for the present paper. Elaboration of this model led to two testable hypotheses with regard to identification performance. The first prediction is that evidence for inhibition should be observed only under relatively bright luminance conditions. The second is that, given inhibition, the amount of the effect of this inhibition should increase over time. A partial-report bar-probe task was used to test the predictions. The experiment involved two luminance conditions and the information was sampled at two different moments in time. To control for possible localization artefacts a digit-naming task was also used. Evidence for inhibition was found in both luminance conditions. In accordance with the model the amount of the effect of inhibition increased over time.     

Transformation of Perception of Trauma by Child Survivors of the Holocaust in Group Therapy

Intensive work with child survivors of the Holocaust has made us aware of the clinical importance of understanding the ways children perceive their traumas and the conclusions they draw about how they must live their lives. When these perceptions are transformed congruently with the child's development, the survivors can cope quite well. In this paper we refer to now middle-aged survivors who are still guided by their child perceptions. We will describe how we have used conjoint group psychotherapy to facilitate processes of transformation even at this late stage. The model we provide for trauma work with Holocaust survivors whose traumatization occurred decades ago may well provide tools to reduce future suffering of children who are victims of massive traumatization today.     

Are there nontrivial constraints on colour categorization?

In this target article the following hypotheses are discussed: (1) Colour is autonomous: a perceptuolinguistic and behavioural universal. (2) It is completely described by three independent attributes: hue, brightness, and saturation: (3) Phenomenologically and psychophysically there are four unique hues: red, green, blue, and yellow; (4) The unique hues are underpinned by two opponent psychophysical and/or neuronal channels: red/green, blue/yellow. The relevant literature is reviewed. We conclude: (i) Psychophysics and neurophysiology fail to set nontrivial constraints on colour categorization. (ii) Linguistic evidence provides no grounds for the universality of basic colour categories. (iii) Neither the opponent hues red/green, blue/yellow nor hue, brightness, and saturation are intrinsic to a universal concept of colour. (iv) Colour is not autonomous.     

Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.