A quadratic model captures the human V1 response to variations in chromatic direction and contrast

An important goal for vision science is to develop quantitative models of the representation of visual signals at post-receptoral sites. To this end, we develop the quadratic color model (QCM) and examine its ability to account for the BOLD fMRI response in human V1 to spatially-uniform, temporal chromatic modulations that systematically vary in chromatic direction and contrast. We find that the QCM explains the same, cross-validated variance as a conventional general linear model, with far fewer free parameters. The QCM generalizes to allow prediction of V1 responses to a large range of modulations. We replicate the results for each subject and find good agreement across both replications and subjects. We find that within the LM cone contrast plane, V1 is most sensitive to L-M contrast modulations and least sensitive to L+M contrast modulations. Within V1, we observe little to no change in chromatic sensitivity as a function of eccentricity.

Sulcal Depth in the Medial Ventral Temporal Cortex Predicts the Location of a Place-Selective Region in Macaques, Children, and Adults

The evolution and development of anatomical-functional relationships in the cerebral cortex is of major interest in neuroscience. Here, we leveraged the fact that a functional region selective for visual scenes is located within a sulcus in the medial ventral temporal cortex (VTC) in both humans and macaques to examine the relationship between sulcal depth and place selectivity in the medial VTC across species and age groups. To do so, we acquired anatomical and functional magnetic resonance imaging scans in 9 macaques, 26 human children, and 28 human adults. Our results revealed a strong structural-functional coupling between sulcal depth and place selectivity across age groups and species in which selectivity was strongest near the deepest sulcal point (the sulcal pit). Interestingly, this coupling between sulcal depth and place selectivity strengthens from childhood to adulthood in humans. Morphological analyses suggest that the stabilization of sulcal-functional coupling in adulthood may be due to sulcal deepening and areal expansion with age as well as developmental differences in cortical curvature at the pial, but not the white matter surfaces. Our results implicate sulcal features as functional landmarks in high-level visual cortex and highlight that sulcal-functional relationships in the medial VTC are preserved between macaques and humans despite differences in cortical folding.

A cross-validated cytoarchitectonic atlas of the human ventral visual stream

The human ventral visual stream consists of several areas that are considered processing stages essential for perception and recognition. A fundamental microanatomical feature differentiating areas is cytoarchitecture, which refers to the distribution, size, and density of cells across cortical layers. Because cytoarchitectonic structure is measured in 20-micron-thick histological slices of postmortem tissue, it is difficult to assess (a) how anatomically consistent these areas are across brains and (b) how they relate to brain parcellations obtained with prevalent neuroimaging methods, acquired at the millimeter and centimeter scale. Therefore, the goal of this study was to (a) generate a cross-validated cytoarchitectonic atlas of the human ventral visual stream on a whole brain template that is commonly used in neuroimaging studies and (b) to compare this atlas to a recently published retinotopic parcellation of visual cortex (Wang et al., 2014). To achieve this goal, we generated an atlas of eight cytoarchitectonic areas: four areas in the occipital lobe (hOc1-hOc4v) and four in the fusiform gyrus (FG1-FG4), then we tested how the different alignment techniques affect the accuracy of the resulting atlas. Results show that both cortex-based alignment (CBA) and nonlinear volumetric alignment (NVA) generate an atlas with better cross-validation performance than affine volumetric alignment (AVA). Additionally, CBA outperformed NVA in 6/8 of the cytoarchitectonic areas. Finally, the comparison of the cytoarchitectonic atlas to a retinotopic atlas shows a clear correspondence between cytoarchitectonic and retinotopic areas in the ventral visual stream. The successful performance of CBA suggests a coupling between cytoarchitectonic areas and macroanatomical landmarks in the human ventral visual stream, and furthermore, that this coupling can be utilized for generating an accurate group atlas. In addition, the coupling between cytoarchitecture and retinotopy highlights the potential use of this atlas in understanding how anatomical features contribute to brain function. We make this cytoarchitectonic atlas freely available in both BrainVoyager and FreeSurfer formats (http://vpnl.stanford.edu/vcAtlas). The availability of this atlas will enable future studies to link cytoarchitectonic organization to other parcellations of the human ventral visual stream with potential to advance the understanding of this pathway in typical and atypical populations.

Microstructural proliferation in human cortex is coupled with the development of face processing

How does cortical tissue change as brain function and behavior improve from childhood to adulthood? By combining quantitative and functional magnetic resonance imaging in children and adults, we find differential development of high-level visual areas that are involved in face and place recognition. Development of face-selective regions, but not place-selective regions, is dominated by microstructural proliferation. This tissue development is correlated with specific increases in functional selectivity to faces, as well as improvements in face recognition, and ultimately leads to differentiated tissue properties between face- and place-selective regions in adulthood, which we validate with postmortem cytoarchitectonic measurements. These data suggest a new model by which emergent brain function and behavior result from cortical tissue proliferation rather than from pruning exclusively.

Occipital White Matter Tracts in Human and Macaque

We compare several major white-matter tracts in human and macaque occipital lobe using diffusion magnetic resonance imaging. The comparison suggests similarities but also significant differences in the tracts. There are several apparently homologous tracts in the 2 species, including the vertical occipital fasciculus (VOF), optic radiation, forceps major, and inferior longitudinal fasciculus (ILF). There is one large human tract, the inferior fronto-occipital fasciculus, with no corresponding fasciculus in macaque. We could identify the macaque VOF (mVOF), which has been little studied. Its position is consistent with classical invasive anatomical studies by Wernicke. VOF homology is supported by similarity of the endpoints in V3A and ventral V4 across species. The mVOF fibers intertwine with the dorsal segment of the ILF, but the human VOF appears to be lateral to the ILF. These similarities and differences between the occipital lobe tracts will be useful in establishing which circuitry in the macaque can serve as an accurate model for human visual cortex.

Defining the most probable location of the parahippocampal place area using cortex-based alignment and cross-validation

The parahippocampal place area (PPA) is a widely studied high-level visual region in the human brain involved in place and scene processing. The goal of the present study was to identify the most probable location of place-selective voxels in medial ventral temporal cortex. To achieve this goal, we first used cortex-based alignment (CBA) to create a probabilistic place-selective region of interest (ROI) from one group of 12 participants. We then tested how well this ROI could predict place selectivity in each hemisphere within a new group of 12 participants. Our results reveal that a probabilistic ROI (pROI) generated from one group of 12 participants accurately predicts the location and functional selectivity in individual brains from a new group of 12 participants, despite between subject variability in the exact location of place-selective voxels relative to the folding of parahippocampal cortex. Additionally, the prediction accuracy of our pROI is significantly higher than that achieved by volume-based Talairach alignment. Comparing the location of the pROI of the PPA relative to published data from over 500 participants, including data from the Human Connectome Project, shows a striking convergence of the predicted location of the PPA and the cortical location of voxels exhibiting the highest place selectivity across studies using various methods and stimuli. Specifically, the most predictive anatomical location of voxels exhibiting the highest place selectivity in medial ventral temporal cortex is the junction of the collateral and anterior lingual sulci. Methodologically, we make this pROI freely available (vpnl.stanford.edu/PlaceSelectivity), which provides a means to accurately identify a functional region from anatomical MRI data when fMRI data are not available (for example, in patient populations). Theoretically, we consider different anatomical and functional factors that may contribute to the consistent anatomical location of place selectivity relative to the folding of high-level visual cortex.

Microstructural proliferation in human cortex is coupled with the development of face processing

How does cortical tissue change as brain function and behavior improve from childhood to adulthood? By combining quantitative and functional magnetic resonance imaging in children and adults, we find differential development of high-level visual areas that are involved in face and place recognition. Development of face-selective regions, but not place-selective regions, is dominated by microstructural proliferation. This tissue development is correlated with specific increases in functional selectivity to faces, as well as improvements in face recognition, and ultimately leads to differentiated tissue properties between face- and place-selective regions in adulthood, which we validate with postmortem cytoarchitectonic measurements. These data suggest a new model by which emergent brain function and behavior result from cortical tissue proliferation rather than from pruning exclusively.

The Cytoarchitecture of Domain-specific Regions in Human High-level Visual Cortex

A fundamental hypothesis in neuroscience proposes that underlying cellular architecture (cytoarchitecture) contributes to the functionality of a brain area. However, this hypothesis has not been tested in human ventral temporal cortex (VTC) that contains domain-specific regions causally involved in perception. To fill this gap in knowledge, we used cortex-based alignment to register functional regions from living participants to cytoarchitectonic areas in ex vivo brains. This novel approach reveals 3 findings. First, there is a consistent relationship between domain-specific regions and cytoarchitectonic areas: each functional region is largely restricted to 1 cytoarchitectonic area. Second, extracting cytoarchitectonic profiles from face- and place-selective regions after back-projecting each region to 20-μm thick histological sections indicates that cytoarchitectonic properties distinguish these regions from each other. Third, some cytoarchitectonic areas contain more than 1 domain-specific region. For example, face-, body-, and character-selective regions are located within the same cytoarchitectonic area. We summarize these findings with a parsimonious hypothesis incorporating how cellular properties may contribute to functional specialization in human VTC. Specifically, we link computational principles to correlated axes of functional and cytoarchitectonic segregation in human VTC, in which parallel processing across domains occurs along a lateral-medial axis while transformations of information within domain occur along an anterior-posterior axis.

Factors affecting children's adolescents', and young adults' perceptions of parental discipline

A total of 663 second graders, sixth graders, high school students, and college undergraduates were shown three videotapes depicting a mother's or father's reaction to a daughter or son who had treated peers unkindly. Although the participants generally favored induction over power assertion and love withdrawal, their perceptions of the particular discipline techniques were found to be influenced by their gender and age, as well as the genders of the child-transgressor and parent-disciplinarian. In addition, the evaluation of a given discipline technique (and, among the older participants, the reported intention of using this technique with their own son or daughter in the future) was found to be related to participants' reports of the extent to which their own parents had used the same technique.

Correlates of reminiscence activity among elderly individuals

The purpose of this study was to examine several psychological characteristics and life experiences that may be related to aspects of reminiscence activity among elderly individuals. Seventy elderly individuals completed a reminiscence questionnaire assessing 1) the extent to which reminiscence is motivated by a desire to enhance self understanding, 2) reminiscence affect, and 3) the preferred social modality of reminiscence. The respondents also completed questionnaires assessing existential vacuum, extraversion, and the recent experience of various life events. Existential vacuum was positively associated with a tendency to engage in reminiscence in an effort to enhance self understanding as well as a negative bias in reminiscence affect. Extra-version was found to be positively related to a preference for interpersonal reminiscence. Specific life experiences (e.g., death of a spouse, retirement) were also related to reminiscence activity. The present results provide support for the notion that aspects of reminiscence activity are associated with individual differences in specific psychological and situational variables.

Very-low-dose streptozotocin induces diabetes in insulin promoter-mB7-1 transgenic mice

Transgenic mice that express mouse B7-1 (mB7-1, recently designated CD80) on their pancreatic beta-cells maintain normal islet architecture, have normal pancreatic insulin content, and only rarely spontaneously develop insulitis and diabetes. Nevertheless, these mice display an extreme sensitivity to streptozotocin (STZ)-induced diabetes. Female mice were administered two STZ doses intraperitoneally, 20 and 40 mg/kg body wt, each for five consecutive days. Nontransgenic but otherwise syngeneic mice responded to the STZ with a moderate diminution in pancreatic insulin content but not with persistent glycosuria. In striking contrast, STZ administered to transgenic mice resulted in a severe diminution of pancreatic insulin content and in diabetes. Notably, the lower STZ dose resulted in diabetes only after a prolonged (26- to 100-day) latency. STZ-induced diabetes appears to be T-cell dependent, since treatment with T-cell-depleting (and in particular CD8+ subset-depleting) antibodies ameliorated the response. Anti-mB7-1 monoclonal antibody administration also prevented STZ-induced diabetes. Thus, unmasked mB7-1 is a required component in the pathway resulting in beta-cell killing. Immunohistological analysis revealed that early after STZ administration, both mB7-1 transgenic and nontransgenic mice developed insulitis. While this insulitis resolved in the nontransgenic mice, the islet-infiltrating CD4+ and CD8+ T-cells in the transgenic mice were associated with complete beta-cell destruction. These data suggest that STZ-induced diabetes in mB7-1 transgenic mice is an immune-mediated process with distinct potential advantages over existing insulin-dependent diabetes models.

Dissecting the centromere of the human Y chromosome with cloned telomeric DNA

We have used telomeric DNA to break the human Y chromosome within the centromeric array of alphoid satellite DNA and have created two derivative chromosomes; one consists of the short arm and 140 kb of alphoid DNA, the other consists of the long arm and 480 kb of alphoid DNA. Both segregate accurately at mitosis. It is known that there is no large scale sequence duplication around the alphoid DNA and so the simplest interpretation of our results is that the sequence responsible for accurate segregation is the alphoid DNA itself. Although the long arm acrocentric derivative segregates accurately it lags with respect to the other chromosomes in about 10% of anaphase cells and thus additional sequences may be required for orderly segregation. The short arm acrocentric chromosome is probably no larger than 12 Mb in size and thus our results also demonstrate that chromosomes of this size are capable of accurate segregation.

Telomere directed fragmentation of mammalian chromosomes

Cloned human telomeric DNA can integrate into mammalian chromosomes and seed the formation of new telomeres. This process occurs efficiently in three established human cell lines and in a mouse embryonic stem cell line. The newly seeded telomeres appear to be healed by telomerase. The seeding of new telomeres by cloned telomeric DNA is either undetectable or very inefficient in non-tumourigenic mouse or human somatic cell lines. The cytogenetic consequences of the seeding of new telomeres include large chromosome truncations but most of the telomere seeding events occur close to the pre-existing ends of natural chromosomes.

Targeted breakage of a human chromosome mediated by cloned human telomeric DNA

Novel approaches to the structural and functional analysis of mammalian chromosomes would be possible if the gross structure of the chromosomes in living cells could be engineered. Controlled modifications can be engineered by conventional targeting techniques based on homologous recombination. Large but uncontrolled modifications can be made by the integration of cloned human telomeric DNA. We describe here the combined use of gene targeting and telomere-mediated chromosome breakage to generate a defined truncation of a human chromosome. Telomeric DNA was targeted to the 6-16 gene on the short arm of chromosome 1 in a human cell line. Molecular and cytogenetic analyses showed that, of eight targeted clones that were isolated, one clone had the predicted truncation of chromosome 1.

Factors affecting reactions to a rape victim

We examined the influence of the sex of the subject reacting to the rape victim, the type of rape (stranger vs. acquaintance), the location of the rape (inside vs. outside the victim's home), and the victim's attribution concerning the cause of the rape, on undergraduates' reactions to a rape victim. American undergraduates (264 women, 230 men) read a Rape Crisis Center Intake Form, watched a videotape of a rape victim (an actress) describing her psychological and behavioral reactions to the rape, and completed three questionnaires assessing their reactions to the victim. Women were more supportive of the rape victim than were men, and the stranger rape evoked more chance and characterological attributions than did the acquaintance rape. A rape outside the home evoked more chance attributions than did an "inside" rape. The rape victim was rated as having been more traumatized by the experience if she made any causal attribution than if she made no attribution at all.

The relation of distressful childhood experiences and empathy in college undergraduates

We assessed the relation between the empathic responsiveness of young adults and the relative frequency and intensity of distressful events they experienced as children. Undergraduate subjects (N = 111; 56 men and 55 women) were led to believe that they were participating in two separate studies. In the first study, students completed the Distress Experiences in Childhood questionnaire, a filler task, and a slightly abbreviated version of the Mehrabian and Epstein (1972) empathy measure. In the second study, students watched an emotion-laden videotape of a patient (actually an actress) in a therapy session and subsequently completed an emotional-response questionnaire adapted from Batson, O'Quin, Fultz, Vanderplas, and Isen (1983). Students who rated their distressful childhood experiences as highly distressing scored higher on both measures of empathy than did students who rated their experiences as relatively less distressing. In contrast, the number of distressful childhood experiences reported was generally unrelated to empathy scores.

T lymphocyte subset abnormalities and HLA antigens in scleroderma (systemic sclerosis)

Studies of T lymphocyte subsets were carried out in a group of 50 scleroderma patients, of whom 46 were also HLA phenotyped. The total lymphocyte count was depressed in 22 patients, and CD4 (helper cells) numbers were normal. CD8 (suppressor-cytotoxic) cells were reduced in 27 patients, and the CD4/CD8 number ratio increased above normal in three additional patients, resulting in 30 patients being classified as CD8-deficient. In the 46 patients HLA phenotyped, DRw8 was significantly increased in the entire patient group, but when the patients were subdivided into CD8-deficient (n = 29) and CD8-normal (n = 17), the increase in DRw8 was confined to the CD8-deficient patients. B18 was also increased in patients with limited sclerosis, while DR4 and DRw53 were significantly decreased and DR5 significantly increased in patients with more extensive skin sclerosis. These findings suggest that scleroderma is a heterogeneous condition and that this heterogeneity is reflected in different HLA profiles in patients subtyped according to their clinical profile and subpopulations of T cells.

Influence of the reason for the other's affect on preschoolers' empathic response

Forty-six preschoolers were individually presented four slide-sequence stories in which the main character performed acts that resulted in the character displaying happiness (in two stories) or sadness (in two stories). Within each happy and sad story pair, one story portrayed the main character as having an "acceptable" reason for his or her affect (e.g., the character was happy after finding a friend to play with) and one story portrayed the character as having an "unacceptable" reason for his or her affect (e.g., the character was happy after transgressing against another child). Affective and evaluative responses to the main characters in the four stories were assessed. The preschoolers generally empathized more with (and evaluated more favorably) a story character whose affect was associated with the performance of an acceptable rather than an unacceptable act.

Changes in lymphocyte status and responsiveness in pregnancy detected by a fluorescent cell probe

Lymphocyte reactivity assessed by a fluorescent lipophilic probe test of responsiveness to concanavalin A (con A) was shown to differ from normal in early pregnancy. The difference was most marked in multiparas. Abnormal reactivity was detected in the earliest pregnancy examined (5 weeks' gestation) and up to about the 20th week; after 20 weeks, reactivity was normal in all of the multiparas and most of the nulliparas studied. However, in pregnancy induced hypertension (PIH), a disorder of late pregnancy, the same responsiveness as in early pregnancy was found. When unstimulated lymphocytes were examined, abnormal reactivity associated with increased fluorescence was observed in early pregnancy and in PIH, compared with normal late pregnancy, reflecting alteration in lymphocyte membrane phospholipids. It is postulated that pregnancy is associated with sequential change in immunity, disturbance of which may result in immunologically-determined obstetric morbidity.

Lymphocyte subclasses in pregnancy induced hypertension

Peripheral blood lymphocyte subclasses were studied by flow cytofluorimetry and monoclonal antibodies in 21 women with Pregnancy Induced Hypertension (PIH), 20 healthy women in their third trimester of pregnancy and in 20 nulliparous, nonpregnant women. The cells were stained with the monoclonal antibodies OKT3, OKT4 and OKT8 to define total T cells, T helper cells (Th) and T suppressor-cytotoxic cells (Ts/c) respectively. B lymphocytes were defined by their surface immunoglobulin. Absolute numbers of total T cells and Ts/c cells were significantly decreased (p less than 0.05) in patients with PIH compared to either control group. The proportion of B lymphocytes was significantly (p less than 0.01) increased and absolute numbers were marginally increased. These findings reflect an immune disturbance which may be of prime importance in the pathogenesis of this disease.

Altered blood lymphocyte subclasses in patients with ulcerative colitis

Peripheral blood lymphocytes were studied by flow cytofluorimetry and monoclonal antibody techniques in 107 patients with ulcerative colitis and in 20 healthy controls of similar ages. Total T, T helper (TH), and T cytotoxic/suppressor (TC/S) lymphocytes were defined by the monoclonal antibodies OKT3, OKT4 and OKT8, respectively, while B lymphocytes were defined by surface immunoglobulin. Patients had a significantly (P less than 0.05) lower proportion of TC/S lymphocytes than the controls, and patients with quiescent disease had a reduced proportion of B lymphocytes compared to controls and those with active disease. Patients with marked mucosal dysplasia had a significantly (P less than 0.025) lower proportion of TH lymphocytes and a higher (P less than 0.01) proportion of B lymphocytes than those without dysplasia. There were no significant associations between lymphocyte levels and any other clinicopathological features assessed.

T helper lymphocyte depression in early human pregnancy

Peripheral blood lymphocyte subclasses were determined in 60 women with normal pregnancies, 20 from each trimester, and in 20 controls using automated flow cytofluorimetry. The cells were stained with the monoclonal antibodies OKT3, OKT4 and OKT8 to stain total T cells, T helper and T suppressor-cytotoxic lymphocytes, respectively. A polyvalent rabbit anti-human Ig serum was used to stain B lymphocytes. Absolute numbers of T lymphocytes were significantly reduced in both the first and second trimesters. This was due to a significant decrease in T helper lymphocytes and a smaller, statistically not significant, reduction in the number of T suppressor lymphocytes. There was no significant change in lymphocyte subclasses during the third trimester. Total lymphocyte numbers were normal throughout pregnancy.