A new standardized set of ecological pictures for experimental and clinical research on visual object processing

A new set of 174 pictures in black-and-white, coloured and spatially filtered versions, taken from photographs of real objects belonging to different semantic categories, was realised for experimental and clinical research on visual object processing. Two samples, one of English speakers and one of Italian speakers, were tested in order to provide the normative data for each picture, in both black-and-white and coloured versions, in relation to familiarity, visual complexity and name agreement.     

Shared and distinct neurophysiological components of the digits forward and backward tasks as revealed by functional neuroimaging

The digits forward (DF) and backward (DB) tasks are widely used neuropsychological measures believed to tap overlapping systems of phonological processing and working memory. Studies of focal brain lesions have partially elucidated the brain regions essential for these tasks; however relatively little information exists on the underlying functional neuroanatomy in the intact brain. We therefore examined the shared and separate neural systems of these tasks in two positron emission tomography (PET) experiments. In Experiment 1, eight healthy participants performed verbal DF, DB, and a sensorimotor control task during measurement of regional cerebral blood flow (rCBF). DF and DB each activated frontal, parietal, and cerebellar regions as well as prominently activating medial occipital cortex. To eliminate possible visuospatial confounds, Experiment 2 replicated the first experiment in six additional healthy participants who were blindfolded during the study. No differences in activation were found between the two experimental groups. Combined data from both experiments demonstrate that DF and DB rely upon a largely overlapping functional neural system associated with working memory, most notably right dorsolateral prefrontal cortex (DLPFC) and bilateral inferior parietal lobule (IPL) as well as the anterior cingulate, a region associated with attentional effort. The degree of activation increased linearly with increasing task difficulty in DF. DB additionally recruited bilateral DLPFC, left IPL, and Broca's area. Medial occipital cortex (including higher and lower visual processing areas) was robustly activated in both DF and DB and could not be attributed to visual processing per se, suggesting a possible visual imagery strategy for these aural-verbal tasks.     

Understanding 'not': neuropsychological dissociations between hand and head markers of negation in BSL

Simple negation in natural languages represents a complex interrelationship of syntax, prosody, semantics and pragmatics, and may be realised in various ways: lexically, morphologically and prosodically. In almost all spoken languages, the first two of these are the primary realisations of syntactic negation. In contrast, in many signed languages negation can occur without lexical or morphological marking. Thus, in British Sign Language (BSL), negation is obligatorily expressed using face-head actions alone (facial negation) with the option of articulating a manual form alongside the required face-head actions (lexical negation). What are the processes underlying facial negation? Here, we explore this question neuropsychologically. If facial negation reflects lexico-syntactic processing in BSL, it may be relatively spared in people with unilateral right hemisphere (RH) lesions, as has been suggested for other 'grammatical facial actions' [Language and Speech 42 (1999) 307; Emmorey, K. (2002). Language, cognition and the brain: Insights from sign language research. Mahwah, NJ: Erlbaum (Lawrence)]. Three BSL users with RH lesions were specifically impaired in perceiving facial compared with manual (lexical and morphological) negation. This dissociation was absent in three users of BSL with left hemisphere lesions and different degrees of language disorder, who also showed relative sparing of negation comprehension. We conclude that, in contrast to some analyses [Applied Psycholinguistics 18 (1997) 411; Emmorey, K. (2002). Language, cognition and the brain: Insights from sign language research. Mahwah, NJ: Erlbaum (Lawrence); Archives of Neurology 36 (1979) 837], non-manual negation in sign may not be a direct surface realisation of syntax [Language and Speech 42 (1999) 143; Language and Speech 42 (1999) 127]. Difficulties with facial negation in the RH-lesion group were associated with specific impairments in processing facial images, including facial expressions. However, they did not reflect generalised 'face-blindness', since the reading of (English) speech patterns from faces was spared in this group. We propose that some aspects of the linguistic analysis of sign language are achieved by prosodic analysis systems (analysis of face and head gestures), which are lateralised to the minor hemisphere.     

Expression of aminopeptidase B in the developing and adult rat retina

Aminopeptidase B (Ap-B), a ubiquitous enzyme, catalyses the amino-terminal cleavage of basic residues of peptide or protein substrates, indicating a role in precursor processing. The physiological function of Ap-B still remains an open question, even though its activity suggests that it could be involved in inflammatory processes and proliferation of tumor cells. This study was conducted to determine the expression of Ap-B in the developing and adult retina as a path to envisage physiological roles of Ap-B. RT-PCR and in situ hybridization were used to detect expression of Ap-B mRNA and activity tests, Western blotting and immunofluorescence microscopy were performed to identify and localize the enzyme in the rat retina. These biochemical and morphological methods show that Ap-B is expressed in the retina from embryo to adult. Expression level is restricted to specific layers (pigmented epithelium, outer and inner plexiform layers and ganglion cell layer) and is developmentally regulated. Moreover, a preliminary analysis indicates that Ap-B, the glucose transporter GLUT3 and choline acetyltransferase (ChAT) share a similar expression pattern in retina. Altogether, Ap-B appears predominantly expressed in neuronal cells lying in retinal layers containing neuritic extensions and synaptic junctions. Such expression is up-regulated during ontogenesis allowing to hypothesized that Ap-B participates in processes accompanying retinal neuronal cell differentiation.     

Pretreatment neurophysiological and clinical characteristics of placebo responders in treatment trials for major depression

Rationale High placebo response rates are a confound in treatment trials for major depressive disorder (MDD). A method for prospective identification of placebo responders could enhance the efficiency of clinical trials.Objective The objective was to identify the neurophysiological, symptomatic, and cognitive characteristics of subjects who were likely to respond to placebo in clinical trials for MDD.Methods Fifty-one subjects with MDD were treated in clinical trials with either fluoxetine (n=24) or venlafaxine (n=27) versus placebo. All subjects underwent pretreatment assessment with quantitative electroencephalographic (QEEG) power and cordance, as well as symptom ratings and neuropsychological testing. After a 1-week single-blind placebo lead-in, subjects were randomized to double-blind placebo controlled treatment with a medication or placebo. At the end of 8 weeks, the blind was broken and treatment response assessed. Response was defined by a final Hamilton Depression Rating Scale score of 10.Results Of the medication-treated and placebo-treated subjects, 52% (13/25) and 38% (10/26) responded. Placebo responders had lower pretreatment frontocentral cordance in the theta frequency band than all other subjects (P<0.006) and medication responders in particular (P<0.004). Placebo responders also had faster cognitive processing time, as assessed by neuropsychological testing, and lower reporting of late insomnia (P<0.03). Exploratory examination of a multiple variable model for predicting placebo response was conducted using logistic regression, in which these three pretreatment measures accurately identified 97.6% of eventual placebo responders.Conclusions These findings suggest that combined clinical, neurophysiological, and cognitive assessments of prospective subjects for clinical trials may be useful for identifying MDD subjects who are likely to show robust response to placebo. Prospective validation of these results in a larger, independent sample of subjects is necessary to establish the reliability and usefulness of this method for prospective identification of placebo responders.From the Laboratory of Behavioral Pharmacology, UCLA Neuropsychiatric Institute, and the Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA.     

Visual awareness of low-contrast stimuli is reflected in event-related brain potentials

Visual awareness was studied in 11 subjects by using coherent and scrambled objects as stimuli. The stimuli were presented near the subjective perceptual threshold. Explicitly recognized stimuli elicited a specific negative ERP deflection peaking at 460 ms. Our reaction time experiment suggests that this visual awareness negativity (VAN) is similar to that found previously at a shorter latency. We propose that VAN might reflect the exact moment of becoming aware of the task-relevant stimulus properties and provide an online marker of the temporal dynamics of visual awareness.     

Comparison of three computer methods of sperm head analysis

OBJECTIVE: Analysis of sperm heads using three different computer morphometrical tools and experimental conditions to find a more reliable and secure strategy among them. DESIGN: Controlled experiments on sperm morphology analysis from volunteers. SETTING: Laboratory of microscopy and imaging processing. PATIENT(S): Ten human semen samples donated by different zoospermic men. INTERVENTION(S): Semen samples were collected by masturbation after > or =72 hours of abstinence. MAIN OUTCOME MEASURE(S): Spermatozoon head morphology was compared by the use of different video-microscopy systems, three computer programs, and various staining conditions and manipulation by different operators. Nonbiological material in the form of latex beads was also used. RESULT(S): The data obtained suggest that the semiautomatic computer program is the most reliable and secure method for performing sperm analysis, besides the fact that it is a fast process compared with manual methods. CONCLUSION(S): Computer systems of sperm analysis should incorporate a step of interactive object identification to work properly, allowing the operator to confirm or correct possible computer misidentification. The latex beads were used to confirm the capability of all three computer programs to correctly evaluate nonbiological material.     

Intermittent human immunodeficiency type 1 virus (HIV-1) shedding in semen and efficiency of sperm processing despite high seminal HIV-1 RNA levels

To study seminal excretion of human immunodeficiency virus type 1 (HIV-1) during 4 years of follow-up in an HIV-1-infected patient, the relationship between high viral excretion and inflammatory status of semen, and the efficiency of sperm processing methods in obtaining spermatozoa with undetectable RNA and proviral DNA levels.Case report.University hospital and research group on human fertility.One HIV-1-infected patient.Paired blood and semen samples were obtained during 4 years of follow-up.CD4 cell count; blood and seminal plasma viral load; and HIV-1 RNA and proviral DNA in different cell fractions obtained during sperm processing, as measured by the density gradient method and the swim-up method; sperm parameters; and polymorphonuclear granulocyte count.Shedding of HIV-1 in semen was intermittent. The highest seminal viral loads were associated with a markedly increased polymorphonuclear granulocyte count, which reflects inflammation of the genital tract. Spermatozoa with undetectable levels of HIV-1 RNA or DNA were obtained regardless of the viral load in semen.In an HIV-1-infected man with intermittent seminal viral excretion, sperm processing was effective in obtaining spermatozoa without detectable HIV-1 genomes.     

Potential limitations in using minor histocompatibility antigen-specific cytotoxic T cells for targeting solid tumor cells

We have shown previously that KIAA0223, a gene encoding a minor histocompatibility antigen, HA-1, whose expression was believed to be restricted to the hematopoietic cells, is aberrantly expressed in some solid tumor cell lines. However, its significance in tumor immunity needs to be determined. Cytotoxic activity of HA-1(H)-specific cytotoxic T lymphocytes (CTLs) was assessed against solid tumor cell lines expressing KIAA0223 using (51)Cr release assays. Five of seven cell lines were lysed when HLA-A*0201 was adequately expressed. One of the two CTL-resistant cell lines became susceptible after treatment with IFN-gamma and TNF-alpha, while the other was lysed only after pulsing with HA-1(H) peptide. In most cell lines tested, HA-1(H) peptide was properly generated and presented for recognition by the CTL. However, impaired antigen processing and presentation observed in this study may result in escape from CTL recognition in vivo, as well as in vitro, as observed in this study.     

Biological, psychological and social processes in the conduct disorders

BACKGROUND: This paper reviews recent evidence on the causes and maintenance of aggressive and disruptive behaviours in childhood and adolescence. It considers the relative merits of several different ways of conceptualising such problems, in relation to the contribution of biological, psychological and social factors. METHOD: It focuses on conduct problems appearing in young childhood, which greatly increase the likelihood of persistent antisocial behaviours in adolescence and adult life in association with wider interpersonal and social role impairments. It considers the contribution of individual factors, including impaired verbal skills, deficits in executive functions, and an imbalance between behavioural activation and inhibition systems. These are viewed in interaction with commonly associated environmental disadvantages such as hostile or intrusive parenting. The roles of attributional biases, unrealistic self-evaluations, and insecure attachment are considered in relation to affect regulation, and effective social action. The contributions of the wider social environments of peers, neighbourhood and socio-economic conditions are evaluated. CONCLUSIONS: The paper concludes that, although considerable progress has been made over the past ten years, there is a need to further refine our conceptualisation of the behaviours to be explained, to develop a coherent theory of the causal and maintaining processes, and to carry out prospective studies with adequate numbers of high risk children.