The activity of the hypothalamo-neurohypophysial system in response to acute stressor exposure: neuroendocrine and electrophysiological observations

The present mini review focuses on stress-induced alterations of the electrical and secretory activity of vasopressin (AVP) and oxytocin (OXT) neurones originating within the supraoptic nucleus (SON) and constituting the hypothalamo-neurohypophysial system (HNS) in the male rat. Previously, it was thought that SON neurones are predominantly activated by osmotic and reproductive stimuli. However, recent findings also suggest a selective activation of AVP and/or OXT neurones in response to specific stressors. Inhibitory amino acids seem to participate at the level of the SON in the control of HNS activity during stress. Taurine, probably of glial origin, selectively inhibits the secretory activity of AVP neurones. In contrast, GABA, probably of neuronal origin, interferes with the release of OXT both from axon terminals into blood and from somata/dendrites into the extracellular fluid of the SON. Depending upon whether a defined stressor triggers taurine and/or GABA release within the SON the secretion of AVP and/or OXT from HNS neurones will be inhibited. These observations shed new light on the neurone-neurone and glial-neurone interactions that ensure an appropriate neuroendocrine stress response.     

A comparison of the MCMI-III personality disorder and modifier indices with the MMPI-2 clinical and validity scales

In this study, we examined the relationship of the MCMI-III (Millon, Davis, & Millon, 1997; Millon, Millon, & Davis, 1994) modifier indices and personality disorder scales to the validity and basic clinical scales of the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). The MCMI-III modifier indices highly correlated with all of the MMPI-2 validity scales except for the F(p) scale. Similarly, the MCMI-III personality disorder scales strongly covaried with the MMPI-2 validity and clinical scales except for the F(p) and 5 (Mf) scales. A factor analysis with Promax rotation revealed substantial relationships between the MMPI-2 and MCMI-III. However, the MMPI-2 F(p) scale did not tend to correlate with MMPI-2 or MCMI-III scales, indicating that F(p) scale variance was largely independent of other scales. The results suggest that clinicians should consider the interrelationship between personality characteristics and dissimulation.     

Middle East and north Africa regional conference of psychology, dubai, United arab emirates

The first Middle East and North Africa Regional Conference of Psychology (MENA RCP) was held in Dubai. United Arab Emirates, December 13–18, 2003, under the auspices of the International Union of Psychological Science (IUPsyS), the International Association of Applied Psychology (IAAP), and the International Association for Cross–Cultural Psychology (IACCP). It was organized by a local Conference Committee and by the Yemen Psychological Association (YPA), in collaboration with the Egyptian Association for Psychological Studies (EAPS). High attendance, with participation from 35 countries, including 17 from the neighbouring Middle East and North Africa region, was a major achievement of the conference. Conference participants, many of them leaders of their national psychology associations, who also attended the concomitant National Capacity Building Workshop organized by the IUPsyS, signed an official Declaration to create a Regional Council of Arab Psychological Associations during the coming year and to follow this first MENA Conference with a second conference to be held in Amman. Jordan, in 2005.     

Seeing double: the role of meaning in alphanumeric-colour synaesthesia

When PD, an alphanumeric-colour synaesthete, is shown black digits or letters, each grapheme elicits a highly specific colour, called a "photism" (e.g., a 2 induces green, a Z induces brown). Previous experiments showed that photisms interfere with video-colour naming when the photism colour and the video colour are incongruent. Here we used coloured ambiguous graphemes that could be interpreted as either digits or letters depending on context (e.g., an ambiguous grapheme was interpreted as a 2 if presented within a block of digit trials, but as a Z if presented within a block of letter trials). Ambiguous graphemes were presented in video colours that were either congruent or incongruent with PD's photisms. Crucially, what was a congruent trial in one context was an incongruent trial in the other context. PD's pattern of response times indicated that identical graphemes could induce differently coloured photisms depending on their interpretation. This suggests that the meaning of graphemes ultimately determines their synaesthetic colour.     

Backward inhibition as a means of sequential task-set control: evidence for reduction of task competition

Endogenously initiated transitions between tasks are associated with inhibition of the attentional set for the task preceding the transition, as demonstrated by slowed reactions to a task most recently switched away from (U. Mayr & S. W. Keele, 2000). Using an altered methodological approach, the authors found that this backward inhibition counteracts perseverative tendencies when switching to a new task in that it selectively reduces interference exerted by the preceding task set. The reduction of interference was dependent on endogenous preparation for the new task and did not occur for unpredictable task switches or for task switches that were precued without information about the identity of the new task.     

Synaesthetic photisms guide attention

We evaluated whether synaesthetic colour experiences (i.e., photisms) guide or attract attention. An alphanumeric-colour synaesthete, J, and seven non-synaesthetes searched for target digits presented against backgrounds that were either congruent or incongruent with the colours of J's photisms for the target digits. For J, the slope of the search function for detecting the target digits on incongruent trials was shallower than the slope of the search function for detecting the target digits on congruent trials. In contrast, for the seven non-synaesthetes, the slopes of the search functions for detecting the target digits on congruent and incongruent trials were equivalent. These findings suggest that synaesthetic colour experiences influence the efficiency of visual search by guiding or attracting attention.     

Now you feel it, now you don't: frontal brain electrical asymmetry and individual differences in emotion regulation

Recent theoretical accounts of emotion regulation assign an important role in this process to the prefrontal cortex, yet there is little relevant data available to support this hypothesis. The current study assessed the relation between individual differences in asymmetric prefrontal activation and an objective measure of uninstructed emotion regulation. Forty-seven participants 57 to 60 years old viewed emotionally arousing and neutral visual stimuli while eyeblink startle data were collected. Startle probes were also presented after picture presentation to capture the persistence or attenuation of affect following the offset of an emotional stimulus. Subjects with greater relative left-sided anterior activation in scalp-recorded brain electrical signals displayed attenuated startle magnitude after the offset of negative stimuli. This relation between resting frontal activation and recovery following an aversive event supports the idea of a frontally mediated mechanism involved in one form of automatic emotion regulation.     

The anatomy of auditory word processing: individual variability

This study used functional magnetic resonance imaging (fMRI) to investigate the neural substrate underlying the processing of single words, comparing activation patterns across subjects and within individuals. In a word repetition task, subjects repeated single words aloud with instructions not to move their jaws. In a control condition involving reverse speech, subjects heard a digitally reversed speech token and said aloud the word "crime." The averaged fMRI results showed activation in the left posterior temporal and inferior frontal regions and in the supplementary motor area, similar to previous PET studies. However, the individual subject data revealed variability in the location of the temporal and frontal activation. Although these results support previous imaging studies, demonstrating an averaged localization of auditory word processing in the posterior superior temporal gyrus (STG), they are more consistent with traditional neuropsychological data, which suggest both a typical posterior STG localization and substantial individual variability. By using careful head restraint and movement analysis and correction methods, the present study further demonstrates the feasibility of using overt articulation in fMRI experiments.     

Incidental learning of real-world regularities

The large literature on incidental learning relies almost exclusively on laboratory experiments. Whenever researchers have attempted to demonstrate incidental learning of real-world regularities, they have typically failed to show learning. For example, it is well established that people do not learn regularities in everyday objects, such as the left-right orientation of faces on coins, despite a very large exposure to them. In this report, we examine this apparent contradiction. We argue that most studies exploring real-life incidental learning use tests that are not as sensitive to low-confidence information as those traditionally used in laboratory tasks. Using more sensitive measures, we show that it is possible to learn regularities from British and Japanese cultural life as a direct result of exposure to these regularities. Further, confidence measures suggest that although the information may be acquired incidentally, it can be expressed with and without concomitant awareness of that knowledge.     

Asymmetric dependencies in perceiving identity and emotion: experiments with morphed faces.

We investigated whether an asymmetric relationship between the perception of identity and emotional expressions in faces (Schweinberger & Soukup, 1998) may be related to differences in the relative processing speed of identity and expression information. Stimulus faces were morphed across identity within a given emotional expression, or were morphed across emotion within a given identity. In Experiment 1, consistent classifications of these images were demonstrated across a wide range of morphing, with only a relatively narrow category boundary. At the same time, classification reaction times (RTs) reflected the increased perceptual difficulty of the morphed images. In Experiment 2, we investigated the effects of variations in the irrelevant dimension on judgments of faces with respect to a relevant dimension, using a Garner-type speeded classification task. RTs for expression classifications were strongly influenced by irrelevant identity information. In contrast, RTs for identity classifications were unaffected by irrelevant expression information, and this held even for stimuli in which identity was more difficult and slower to discriminate than expression. This suggests that differences in processing speed cannot account for the asymmetric relationship between identity and emotion perception. Theoretical accounts proposing independence of identity and emotion perception are discussed in the light of these findings.