Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

Measurement of the inclusive electron neutrino charged current cross section on carbon with the T2K near detector

The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1  GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³⁸ cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³⁸ cm²/nucleon and the GENIE prediction is 1.08×10⁻³⁸ cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.

Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

Search for a light pseudoscalar particle in the decay K_{L};{0}-->pi;{0}pi;{0}X

We performed a search for a light pseudoscalar particle X in the decay K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma with the E391a detector at KEK. Such a particle with a mass of 214.3 MeV/c;{2} was suggested by the HyperCP experiment. We found no evidence for X and set an upper limit on the product branching ratio for K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma of 2.4x10;{-7} at the 90% confidence level. Upper limits on the branching ratios in the mass region of X from 194.3 to 219.3 MeV/c;{2} are also presented.

Search for the Decay K L0-->pi0nu nu[over]

We performed a search for the K L0-->pi0nu nu[over] decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be 6.7 x 10(-8) at the 90% confidence level.

Simple fluctuation of Ca2+ elicits the complex circadian dynamics of cyclic AMP and cyclic GMP in Paramecium

The circadian dynamics of cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5′-monophosphate (cGMP) were simulated in Paramecium multimicronucleatum. The mathematical functions determined closely mimic the Ca2+ dependence of adenylate cyclase (AC) and guanylate cyclase (GC) activities as documented in P. tetraurelia. Patterns of cAMP concentration ([cAMP]), cGMP concentration ([cGMP]), and the ratio [cGMP]/[cAMP] were calculated with respect to Ca2+ concentrations ([Ca2+]) fluctuating sinusoidally with a period of 24 hours at three different levels: low, medium, and high. The functions displayed varying patterns of [cAMP] characteristic for [Ca2+] fluctuating at each level, while patterns of [cGMP] and [cGMP]/[cAMP] almost paralleled [Ca2+] fluctuations. Similar patterns were observed for actual [cAMP] and [cGMP] measured during the light/dark cycle in P. multimicronucleatum, grown in axenic media additionally containing [Ca2+] at 25 (low), 100 (medium), or 400 (high) microM, respectively. The coincidence between simulated and measured fluctuations of [cAMP] and [cGMP] suggests that the circadian fluctuations of intracellular [Ca2+] primarily stimulate activities of AC and GC via their different degrees of Ca2+ dependence, which are ultimately responsible for the circadian spatiotemporal organization of various physiological functions in Paramecium.

Neuronal activity in monkey visual areas V1, V2, V4 and TEO during fixation task

We analyzed 577 neurons recorded from visual areas V1, V2, V4, and the inferotemporal area (TEO) of macaque monkeys, which performed a visual fixation task and a spot-off-on (blink) test during the fixation period. Among these neurons, 35% were defined as task-related cells, because they gave responses at the task-start, fixation, or task-end periods but were unresponsive to the spot blink, which was physically identical to these stimuli. Blink-responsive cells accounted for 29% and task-unresponsive cells for 30% of the neurons. The task-related response was large and frequent in V4 (34%) and TEO (41%), but small and less frequent in V1 (31%) and V2 (27%). Other observations further demonstrated nonsensory activities in these areas: In some cells, response to the fixation spot was inhibitory, whereas light stimulation on the fovea was excitatory; some V1 and V2 cells had color-irrelevant responses, and some cells responded to the spot-off only when the monkey regarded it as a task-end cue.

[In vitro study on the effect of sex steroid and growth factor on growth and laminin, collagen IV, and tissue plasminogen activator production of normal endometrial cells and endometrial cancer cells in culture]

The mechanism of the invasion and proliferation of endometrial cancer is closely related to interactions between the endometrial glands and stroma. In this study, we examined the biological role of sex steroids (estradiol; E2, progesterone; P) and growth factors (epidermal growth factor; EGF, transforming growth factor-beta; TGF-beta) on cell growth and laminin, collagen IV and tissue plasminogen activator (t-PA) production of normal endometrial cells and endometrial cancer cells in culture. Normal endometrial gland cells and stromal cells, and endometrial cancer cell lines (Ishikawa, OMC-2) were used. E2, P, EGF and TGF-beta were added to the culture in physiological concentrations. The growth of normal endometrial gland cells was promoted by E2 and EGF, whereas that of Ishikawa cells and OMC-2 cells was promoted by EGF. E2 enhanced the effects of EGF in normal endometrial gland cells. The growth of normal endometrial stromal cells was not affected by them. OMC-2 was inhibited by anti-EGF receptor antibody. On the other hand, the production of laminin and collagen IV of these cultured cells was inhibited by EGF and promoted by TGF-beta, whereas that of t-PA was promoted by EGF and inhibited by TGF-beta. These results suggest that the growth of normal endometrial gland cells with estrogen receptor (ER) is controlled by both E2 and EGF, whereas that of endometrial cancer cells is affected only by EGF, and those cells without ER depend particularly on the autocrine growth mechanism of EGF.(ABSTRACT TRUNCATED AT 250 WORDS)

[Study on the management of dysplasia of the uterine cervix]

In this study, we investigated problems on the management of dysplasia on the basis of our clinical data obtained in the past ten years. In addition, we also examined the biological significance of protooncogene expression and human papilloma virus (HPV) infection in the initiation and promotion of dysplasia. Among 540 cases of dysplasia we have managed, 48.8% of the cases of mild, moderate and severe dysplasia which we followed up for more than 6 months regressed, and 24.1% of the cases progressed. The cure rate for laser therapy based on the follow up for 6 to 96 months was significantly high (97.9%) in 342 cases treated by the cone method, and low (89.5%) in 38 cases treated by the vaporization method. Preoperative histological findings confirmed 60.5% of postoperative findings, and several early cervical carcinomas were found in preoperative cases of dysplasia by laser conization. Among 28 cases (8.2%) of incomplete excision, 24 cases (85.7%) regressed spontaneously. On the other hand, the positive rate of immunostaining of epidermal growth factor receptor (EGF-R) and c-myc oncogene product (c-myc protein) increased from mild or moderate to severe dysplasia, and the positive rate for EGF-R was significantly high (80.0%) in the progressive group. The positive rate for HPV genome was quite low (16.0%) in dysplasia. Among them, EGF-R was most associated with the prognosis of dysplasia. These results suggest that laser conization should be performed for many cases of dysplasia because of the preoperative possibility of the existence of early cancer, and EGF-R is also useful in determining the necessity for therapy for dysplasia.

[In vitro studies on the expression of c-myc oncogene product in gynecological cultured cancer cells]

In this study, immunocytochemical and biochemical detection of c-myc protein in gynecological cultured cancer cells were performed together with gene expression of the cells. OMC-1 (cervical squamous carcinoma cell line), OMC-2 (endometrial adenocarcinoma cell line), OMC-3 (ovarian mucinous adenocarcinoma cell line) and OMC-4 (cervical adenocarcinoma cell line) were used. Immunocytochemically, c-myc protein was detected in both nuclei and cytoplasms of cultured cells when they were fixed in 95% ethanol, 10% formalin and 4% paraformaldehyde (PFA) including 10mM NaCl. However, it was detected in the nuclei of almost all of the cells in nuclei of the cells when they were fixed in 4% PFA including 1,000mM NaCl. Western blotting against a nuclear fraction of the cells demonstrated 66Kd protein in OMC-1 and 62Kd protein in OMC-2,3,4, respectively. They were completely absorbed by c-myc synthetic peptide. However, there was no reaction against the cytoplasmic fraction of the cells. Slot blot hybridization against the DNA of the cells demonstrated 15 times and 5 times c-myc gene amplification in OMC-2 and OMC-4, respectively. These results suggest that OMC-1,2,3,4 can be used as positive controls for the immunocyto- and histochemical detection of c-myc protein in clinical materials. However, it must be noted that the redistribution of c-myc nuclear protein into the cytoplasm may occur in the fixation process.

Neuronal activity in visual, auditory and polysensory areas in the monkey temporal cortex during visual fixation task

The activity of 252 neurons in the inferotemporal visual area TEO, the superior temporal auditory area (AA), and the superior temporal polysensory area (STP) during the performance of a visual spot-fixation task and two variations, blink and tone tests, was examined in two behaving monkeys. A considerable number of not only TEO cells (45%) but also AA (29%) and STP (34%) cells were activated during the spot-fixation task, but unresponsive to the blanking of the spot during the fixation stage in the blink test. In addition, it was found that the activity of a third of the TEO, AA and STP cells which fired during the task-start stage in the spot-fixation task was modulated by cross-interaction between spot and tone simultaneously presented in the tone test: among these, the spot-induced activity of all TEO cells was enhanced by the tone, whereas the spot-induced activity of all AA and STP cells was suppressed by the tone. These findings are discussed in relation to the process of attending selectively to a fixation-spot.

A role of amygdala in visual perception and cognition in macaque monkeys (Macaca fuscata and Macaca mulatta)

To elucidate the role of the amygdala in visual perception and cognition, the effects of ablations of the amygdala and inferotemporal cortex on several visual tasks were compared with each other, and also the distribution patterns of the projections between them were investigated. The findings indicate that the inferotemporal cortex plays a critical role in visual perception, cognition and memory, whereas the amygdala is involved fundamentally in controlling emotional and motivational behavior. However, the amygdala is concerned with vision in the following ways: It receives neutral visual information highly processed in the visual cortex, invests the information with emotional and motivational significance through interactions with the cortical and subcortical systems of emotion and motivation, and then it returns the information coded to the visual areas to be re-processed; to be consciously perceived in area TEO, and to be meaningfully cognized, recognized and memorized in areas TE and TEG. Therefore, two channel model regarding the mechanism of visual information processing in the inferotemporal cortex is proposed: A first channel is concerned with processing neutral information, while the second one, with processing meaning information coded emotionally and motivationally in the amygdala. In addition, the present studies demonstrate that area TEG, which is cytoarchitecturally a transitional area between areas TE and TG and whose functional significance has remained unclear, is involved significantly in visual cognition rather than visual perception.

Two-stage model of visual pattern discrimination learning in macaque monkeys (Macaca mulatta and Macaca fuscata)

To investigate the nature underlying the process of pattern discrimination learning, a series of seven experiments on seven working assumptions were undertaken. The main findings are as follows. The pattern discrimination learning consists of two time-dependent stages: The initial or first learning stage is the period of performance at chance, and the succeeding or second stage is the period of performance from just above the chance to a criterion level. The duration of the first stage is dependent on the degrees of cue-response separations, whereas that of the second stage is independent of. During the first stage, monkeys do not attend to the discriminative cue even at small cue-response separations, whereas during the second stage, they achieve pattern discrimination, or pattern perception and cognition, regardless of cue-response separations. After having learned the first pattern task with a cue-response separation, they learned new pattern tasks by means of the second stage, showing marked saving of the duration of the first stage. The findings in the present studies indicate that the first stage of learning is predominantly involved in the process of attending to the discriminative cues remote from the response site (a selective attention to the cue), whereas the second stage is concerned with the process of perception and cognition of the discriminative cue.

[Bone marrow suppression in gynecological patients with malignant tumor treated with combination chemotherapy cyclophosphamide, pirarubicin and cisplatin]

We treated 14 patients with cyclophosphamide, adriamycin and cisplatin (CAP), and 16 patients with cyclophosphamide, Pirarubicin and cisplatin (CTP). Hematological changes in the peripheral blood were compared in the two groups to determine whether there was any difference in bone marrow suppression. 1) The lowest leukocyte counts were similar in the two groups. The leukocyte count reached its nadir at 11.6 +/- 2.1 days in the CTP group and at 15.1 +/- 2.8 days in the CAP group, a significant difference (p less than 0.01). 2) The leukocyte count recovered rapidly in the CTP group and was significantly higher (p less than 0.01) at 3 to 4 weeks than in the CAP group, and it returned to the pretreatment level in the CTP group in the fourth week. 3) The platelet count reached its lowest level in the second week in both groups. In the CTP group, it was significantly higher (p less than 0.01) than in the CAP group. 4) Reticulocyte count reached its lowest level in the first week in both groups, and then started increasing. 5) In the CTP group, a course of treatment was 28.0 +/- 2.3 days and it was 29.5 +/- 2.3 days in the CAP group. In 28% of the CPA group, it took 30 days or more for the leukocyte count to return to normal after one course, while none of the CTP group did the leukocyte count remain low for 30 days. These results show that CTP causes more rapid bone marrow suppression (particularly leukocytopenia) than CAP, does but that a recovery is more rapid with CTP. These CTP may be a better form of treatment than CAP.

[A study of the expression of class II antigen on uterine cervical cancer cells and cell lines]

An immunohistochemical method with monoclonal antibody to DR antigen was used to study class II antigens and HLA-DR antigen in 20 patients with uterine cervical cancer. Eight patients had various amounts of DR antigen. Regional infiltrating lymphocytes were also examined with anti-Leu 1, Leu 2a, Leu 3a, and Leu 10. Among the many infiltrating T cells, Leu 3a-positive cells were relatively predominant surrounding the cancer nests which contained DR antigen. Cervical cancer cell lines OMC-1 and OMC-4 both demonstrated DR antigen. Interferon (IFN)-gamma treatment enhanced the expression of DR antigen in OMC-1 and OMC-4. The DR antigen in OMC-1 and OMC-4 were capable of stimulating allogenic lymphocytes in mixed lymphocyte reaction (MLR), and their stimulatory activity was significantly enhanced by IFN-gamma treatment. These results demonstrated the expression of class II antigen, especially DR, on some cervical cancer cells and cell lines and showed that the DR antigen in uterine cancer cell lines can stimulate MLR.

Polysensory properties of neurons in the anterior bank of the caudal superior temporal sulcus of the macaque monkey

1. We examined the sensory properties of cells in the anterior bank of the caudal part of the superior temporal sulcus (caudal STS) in anesthetized, paralyzed monkeys to visual, auditory, and somesthetic stimuli. 2. In the anterior bank of the caudal STS, there were three regions distinguishable from each other and also from the middle temporal area (MT) in the floor of the STS and area Tpt in the superior temporal gyrus. The three regions were located approximately in the respective inner, middle, and outer thirds of the anterior bank of the caudal STS. These three regions are referred to, from the inner to the outer, as the medial superior temporal region (MST), the mostly unresponsive region, and the caudal STS polysensory region (cSTP), respectively. 3. The extent of MST and its response properties agreed with previous studies. Cells in MST responded exclusively to visual stimuli, had large visual receptive fields (RFs), and nearly all (91%) showed directional selectivity. 4. In the mostly unresponsive region, three quarters of cells were unresponsive to any stimulus used in this study. A quarter of the cells responded to only visual stimuli and most did not show directional selectivity for moving stimuli. Several directionally selective cells responded to movements of three-dimensional objects, but not of projected stimuli. 5. The response properties of cells in the superficial cortex of the caudal superior temporal gyrus, a part of area Tpt, external to cSTP were different from those of cells in the three regions in the anterior bank of the STS. Cells in Tpt were exclusively auditory, and had much larger auditory RFs (mean = 271 degrees) than those of acoustically-driven cSTP cells (mean = 138 degrees). 6. The cSTP contained unimodal visual, auditory, and somesthetic cells as well as multimodal cells of two or all three modalities. The sensory properties of cSTP cells were as follows. 1) Out of 200 cells recorded, 102 (51%) cells were unimodal (59 visual, 33 auditory, and 10 somesthetic), 36 (18%) cells were bimodal (21 visual+auditory, 7 visual+somesthetic, and 8 auditory+somesthetic), and four (2%) cells were trimodal. Visual and auditory responses were more frequent than somesthetic responses: the ratio of the population of cells driven by visual: auditory: somesthetic stimuli was 3:2:1. 2) Visual RFs were large (mean diameter, 59 degrees), but two-thirds were limited to the contralateral visual hemifield. About half the cells showed directional selectivity for moving visual stimuli. None showed selectivity for particular visual shapes.(ABSTRACT TRUNCATED AT 400 WORDS)

[EGF receptor and effects of EGF on growth and tumor marker secretion in uterine cervical cancer cells]

Effects of EGF on proliferation and tumor marker secretion of cervical cancer cells are reported together with the characteristics of EGF receptors on the cells. TA-4 producing cell line (OMC-1) originating from cervical squamous cell carcinoma and CA-125 producing cell line (OMC-4) originating from cervical adenocarcinoma, were used. Scatchard plot of EGF binding to OMC-1 indicated a single class of binding sites with a dissociation constant (Kd) of 360pM, whereas that of OMC-4 was curvilinear suggesting two classes of binding sites with a Kd of 170pM and 510pM. The theoretical maximum number of binding sites of OMC-1 and OMC-4 was 2.4 X 10(4) and 1.6 X 10(5), respectively. Effects of EGF on growth were studied by monitoring cell number and the incorporation of 3H-thymidine into the DNA of the cells. OMC-1 was stimulated by EGF at low concentrations (0.01-0.1nM) and inhibited at higher concentrations. OMC-4 was not stimulated by EGF. The TA-4 secretion of OMC-1 was slightly stimulated by EGF at low concentrations (0.01-1nM) and significantly stimulated at high concentration (10nM). The CA-125 secretion of OMC-4 was not stimulated by EGF. These results suggest that there are some differences between cervical squamous cell carcinoma and adenocarcinoma in the mechanisms of regulation of proliferation and tumor marker secretion by EGF.

[Immunohistochemical studies on epidermal growth factor receptor in experimental squamous cell carcinoma of the uterine cervix of mice]

The tissue localization of epidermal growth factor receptor (EGF-R) in experimental squamous cell carcinoma of the mouse uterine cervix was examined immunohistochemically. Carcinoma was induced by the insertion of a 20-methylcholanthrene (MC)-impregnated thread into the cervical canal of the mouse. Tissue sections (of normal columnar epithelium, proliferation, atypical proliferation, early invasive carcinoma, invasive carcinoma and metastatic carcinoma) were stained by the avidin/biotin immunoperoxidase technique using anti-EGF-R monoclonal antibody. Normal columnar epithelium was negative for EGF-R, whereas proliferation was partly positive. The lesions of atypical proliferation and early invasive carcinoma had a positive staining for EGF-R. The staining for EGF-R declined in the lesion of invasive carcinoma. Metastatic carcinoma was not stained for EGF-R. These results suggest that EGF-R may play an important role in the early stage of carcinogenesis of the mouse uterine cervix induced by 20-MC.

Direct projections from the ventral TE area of the inferotemporal cortex to hippocampal field CA1 in the monkey

Anterogradely labeled terminals were found densely in field CA1, but not in any other field, of the hippocampal formation following injections of horseradish peroxidase into the ventral TE area of the inferotemporal cortex, whereas no label was seen in any field of the hippocampal formation following injections into the dorsal TE area. The labeled terminals were distributed mainly in a medial part of the stratum moleculare of field CA1 throughout its rostrocaudal extent. The present finding provides the first demonstration of direct projections from the inferotemporal cortex to the hippocampal formation.

A direct projection from hippocampal field CA1 to ventral area TE of inferotemporal cortex in the monkey

Retrogradely labeled cells were found in field CA1 of the hippocampal formation in monkeys following injections of horseradish peroxidase in ventral area TE of inferotemporal cortex. No hippocampal label was found following injections in dorsal area TE and area TEO. The findings provide the first demonstration of a direct projection from hippocampal field CA1 to area TE.

Amygdalar connections with middle and inferior temporal gyri of the monkey

The origins and terminations of the amygdalar connections with middle (ITm) and inferior temporal (ITi) gyri of inferotemporal cortex (area TE) were studied in Japanese monkeys by the horseradish peroxidase method. The ITm gyrus received a major projection from the lateral basal nucleus and a minor one from the accessory basal nucleus of the amygdala, whereas it sent a major projection to the lateral nucleus and a minor one to the lateral basal nucleus. The ITi gyrus had only minor amygdalar projections from the medial basal nucleus and to the medial basal and lateral nuclei.

Amygdalofugal and amygdalopetal connections with modality-specific visual cortical areas in macaques (Macaca fuscata, M. mulatta, and M. fascicularis)

The origins and terminations of the amygdaloid connections with the modality-specific visual cortical areas TEa (anterior TE area), TEp (posterior TE area), TEO, V4, V2, MST (medial superior temporal visual area), MT (middle temporal visual area), and V1 were studied in macaques. These were compared with the amygdaloid connections of a vision-related polysensory area TG by making cortical injections of horseradish peroxidase (HRP) and incubating the sections with tetramethylbenzidine (TMB) as the chromogen. Both areas TEa and TEp receive a major projection from the lateral basal nucleus and a minor one from the accessory basal nucleus of the amygdaloid complex, whereas these areas send a major projection to the lateral nucleus and a minor one to the lateral basal nucleus. Areas TEO, V4, V2, MST, MT, and V1 receive projections only from the lateral basal nucleus; none of them project to any amygdaloid nucleus. Thus, the amygdalofugal projections are more widespread and more complex than the amygdalopetal projections. These findings indicate that the connections between the amygdaloid nuclei and the visual areas are generally nonreciprocal and underlie the importance of a feedback mechanism from the amygdala to the visual cortical areas in visual information processing. There appears to be a caudorostral (occipitotemporal) gradient in the distribution and density of the amygdaloid projections, which become progressively more widespread and heavier among the progressively more rostral visual areas (from area V1 to area TEa). The amygdaloid connections with area TG are distinctly different from the connections with the visual areas. Area TG is reciprocally connected mainly with the periamygdaloid cortex, and with the lateral, accessory basal, and medial basal nuclei of the amygdala as well.

Inferotemporal neurons of the monkey responsive to auditory signal

Responsiveness of single inferotemporal (IT) neurons to a tone as a start or warning signal in each test trial was investigated in monkeys performing visual discrimination of 4 patterns. It was found that the same IT neurons were responsive to both auditory signal and visual discriminanda with different response characteristics from each other. The activity of IT neurons for the auditory signal in the visual discrimination paradigm reflects an engagement process in attention to the visual discriminanda.

Effect of small cue-response separation on pattern discrimination in macaques (Macaca fuscata and M. mulatta)

In order to elucidate the nature of the effect of small cue-response separations on pattern discriminations by monkeys, three studies were performed. When training on a pattern discrimination with a cue-response separation was discontinued during performance at the chance level, there was no saving on the rate of learning a second task (with identical cues but a different cue-response separation) relative to the performance of naive control animals. By contrast, when training was discontinued at a performance level a little better than chance, there was significant saving on learning a second task. After learning the second task, a third task with new pattern cues was learned, with marked saving on the duration of performance at the chance level. The results indicate that during the initial stage of performance at the chance level, monkeys do not attend to cues if there is even a small separation between the cue and the response site.

Acquisition of discrimination learning of patterns identical in configuration in macaques (Macaca mulatta and M. fuscata)

The acquisition of discrimination of five pairs of pattern cues in a Wisconsin General Testing Apparatus by 223 naive macaque monkeys was compared. The pairs of discriminanda were identical in configuration but varied slightly in either the size of the cue or the size of the background plaque; thus, the degree of separation of the cue from the fringe of the plaque, the response site, was slightly different for each pair of discriminanda. These small differences in cue-response separation had marked effects on the rate of acquisition of the discriminations. Even an increment of separation as small as 0.5 cm resulted in a remarkable retardation of the acquisition. This retardation was due entirely to prolonged performance at the chance level, and not to a slow rate of improvement from the chance to a criterion level. The finding indicates that the difficulty in the acquisition learning on pattern tasks depends largely on the difficulty of attending to the pattern cues at small cue-response separations.

Analysis of local and wide-field movements in the superior temporal visual areas of the macaque monkey

The middle temporal (MT) and medial superior temporal (MST) areas of the macaque cortex have many cells that respond to straight movements in the frontoparallel plane with directional selectivity (D cells). We examined their responses to movements of a bar, of a wide dot pattern, and to combined movements of the two in anesthetized and immobilized animals. D cells in MT showed a wide variety in the strength of the inhibitory field surrounding the excitatory center field. Responses of SI+-type cells to a bar moving across the excitatory field were suppressed when a wide dot pattern moved over the surround field in the same direction and at the same speed as the bar. Inhibition was selective to the direction and speed of the surround movement, and the effective area for inhibition occupied a wide area, which expanded in all radial directions. Responses of SI- -type cells to a center bar movement were changed little by a conjoint movement over the surround field. Consequently, SI- -type cells responded to wide-field movement as well as to stimuli confined within the excitatory field. Although D cells in MST commonly had large excitatory fields, a proportion of them (Figure type) responded to bar movement much more strongly than to wide-field movement. Their responses to a bar movement were suppressed direction-selectively by a conjoint movement of a wide dot-pattern background. The effective area for inhibition coexisted with the excitatory field in these cells. MST cells of the Nonselective type responded comparably well to the two stimuli, and those of the Field type responded much more strongly to wide-field movement than to bar movement. It is thus suggested that MT cells of the SI+ type and MST cells of the Figure type can detect a difference between movements of an object and its wide background, whereas MST cells of the Field type can detect a conjoint movement of a wide field, neglecting the movements of a single object.

Integration of direction signals of image motion in the superior temporal sulcus of the macaque monkey

Using anesthetized and paralyzed monkeys, we have studied the visual response properties of neurons in the cortical area surrounding the middle temporal area (MT) in the superior temporal sulcus (STS). Systematic electrode penetrations revealed that there is a functionally distinct region where three classes of directionally selective cells with large receptive fields cluster. This region is anteriorly adjoined to the dorsal two-thirds of MT, has a width of 4-5 mm mediolaterally, and therefore may correspond to the dorsal part of the medial superior temporal area (MST), which was previously defined as a MT-recipient zone. One class of cells responded to a straight movement of patterns in the frontoparallel plane with directional selectivity (D cells: 217/422, 51.4%). The second class of cells selectively responded to an expanding or contracting size change of patterns (S cells: 66/422, 15.7%). These cells responded neither to a change in width of a slit of any orientation or any length, nor to a change in brightness. The third class of cells responded only to a rotation of patterns in one direction (R cells: 58/422, 13.7%). A majority of these cells (41/58) responded to the clockwise or counterclockwise rotation of patterns in the frontoparallel plane (Rf cells), while the rest responded to a rotation of patterns in depth (Rd cells). We will suggest that these cells acquire the ability to discover whole events of visual motion--i.e., unidirectional straight movement, size change (radial movement), and rotation--by integrating elemental motion information extracted by MT cells. The receptive fields of D, S, and Rf cells can be constructed by converging signals of MT cells, the preferred directions of which are arranged in parallel (D cells), radially (S cells), and circularly (Rf cells). The receptive fields of Rd cells can be constructed, in turn, by the convergence of signals of S cells.

Laminar origin of direct projection from cortex area V1 to V4 in the rhesus monkey

Direct projection from cortex area V1 to V4 in the rhesus monkey was demonstrated by means of retrograde axonal transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). This projection originated at the layers 2 and 3 of the only representation area of central visual field (0-6 degrees) in V1 and terminated at the central representation of V4, whereas there was no projection between the extracentral representations of V1 and V4. Correlation of the present finding with the previous findings suggests that this projection is predominantly involved in the system of color information processing.

Neuropsychological basis of pattern vision in macaque monkeys

The central mechanisms of underlying pattern vision in macaques (rhesus and Japanese monkeys) were investigated behaviorally and electrophysiologically. A series of studies indicated that there are two major processes underlying pattern vision. One of two processes is the process of attending selectively to pattern cues at background, with which inferior parietal cortex is concerned predominantly. The other is the process of pattern perception and cognition, in which inferotemporal cortex is involved closely.

Further evidence on elevated discrimination limens for reduced patterns in monkeys with inferotemporal lesions

An attempt was made to elucidate the nature and neural basis of the elevated discrimination limen for visual stimuli of reduced sizes that had been discovered earlier in monkeys with inferotemporal lesions. Although anterior inferotemporal damage was found to have only negligible effect, both total inferotemporal and posterior inferotemporal lesions yielded markedly elevated limens for reduced pattern stimuli but not for reduced colour stimuli. The impaired animals could be trained to discriminate reduced patterns that were below their original discrimination limen, but this required many more trials than were needed for postoperative relearning of the initial pair; normal animals, by contrast, showed perfect transfer from the standard to the smallest pair. The findings suggest that the increased threshold for reduced patterns in monkeys with inferotemporal lesion is attributable not to a visual acuity disorder but to an impairment of pattern perception resulting mainly from damage to posterior inferotemporal cortex.

Direct projection from the dorsal lateral geniculate nucleus to the prestriate cortex in macaque monkeys

The enzyme horseradish peroxidase (HRP) was separately injected into striate, prestriate, inferotemporal, and parietal cortices in 19 macaque monkeys, and the lateral geniculate nucleus (LGN) was examined for retrograde transport. Labeled LGN cells were identified only in the animals, with HRP injections into the striate and prestriate cortex. Following injections into either of these regions, labeled cells were found in both parvocellular and magnocellular regions of the ipsilateral LGN only, in keeping with the topographic relation of HRP injection sites in the cortex to labeled areas in the LGN. It was also found that (1) labeled LGN cells were less numerous in both laminar and interlaminar zones following HRP injection into the prestriate cortex, whereas following HRP injection into the striate cortex labeled cells were found almost exclusively in the laminae, and localized to a wedge-shaped region; (2) following HRP injection into the prestriate cortex, the mean sizes of the labeled parvocellular and magnocellular cells, estimated in projected diameter, were almost the same, these means being significantly larger than the mean size of labeled parvocellular cells and much smaller than that of labeled magnocellular cells following HRP injection into the striate cortex; (3) the shapes of the labeled LGN cells following HRP injection into the prestriate cortex were ovoid, fusiform, or triangular (or multipolar), whereas those following HRP injection into the striate cortex were uniformly ovoid or round. The above findings following HRP injections into the prestriate cortex in normal monkeys were confirmed by HRP injections into the prestriate cortex of monkeys whose striate cortex had been removed several months prior to the injection; labeled cells were found in confines of areas of retrograde degeneration in the LGN and their labeling pattern was the same as that in intact animals. It was concluded that in macaque monkeys, just as in the cat, a geniculoprestriate projection system exists; it was suggested that there are two parallel system of visual information processing from the LGN to the prestriate cortex, a direct one and in indirect one through the striate cortex.

The locus of the posterior subdivision of the inferotemporal visual learning area in the monkey

In an attempt to define the posterior subdivision of the inferotemporal visual learning area more precisely than before, pattern discrimination retention, serial object discrimination learning and concurrent object discrimination learning were tested in 16 monkeys with lesions in one of four different cytoarchitectural areas; TEO, OA, OB and OC, and in five unoperated monkeys. Marked impairment was found only in pattern discrimination retention and only in the monkeys with lesions of area TEO. It was concluded that the posterior limit of the inferotemporal visual learning area is at the ascending limb of the inferior occipital sulcus, and that the posterior subdivision thus comprises the single anatomical area TEO and does not extend into areas OA and OB.

Responsiveness of inferotemporal single units to visual pattern stimuli in monkeys performing discrimination

Four monkeys were trained to choose two rewarded stimuli from four two-dimensional patterns presented successively, and the responsiveness of single units to these patterns was investigated. Eighty-three of 214 units (39%) recorded from the dorsolateral portion of the inferotemporal cortex were responsive; nearly half responded to all four patterns, irrespective of pattern shape and of whether the stimuli were rewarded or not. A few units were responsive to only one of the patterns, regardless of size, color, or luminance, and unresponsiveness to components of the response-eliciting patterns was indicated in some of these units. The activity of most units response to two or three patterns was dependent on pattern shapes rather than the learnt meaning of the patterns.

Elevation of visual pattern discrimination limen in monkeys with total removal of inferotemporal cortex

Attempts were made to test the validity of the general view that inferotemporal lesions in monkeys do not result in a visual acuity disorder. It was found in the first experiment that monkeys with total removal of the inferotemporal visual area (TIT monkeys) showed a significant elevation of the discrimination limen for visual patterns of reduced sizes even when compared to monkeys with removal of lateral striate cortex (LS monkeys); yet in a food-morsel (raisin) detection test the TIT monkeys performed as well as normal monkeys, although the LS monkeys showed significant deficits. A second experiment was conducted, in which the same subjects were tested with the same patterns as in the first experiment but with the stimulus background changed from the square used earlier to an enlarged disc. While both normal and LS monkeys performed this task easily, the TIT monkeys could not learn the discrimination within the training limit of 1,200 trials. The results suggest that such a marked elevation of the discrimination limen in the TIT monkeys as found in the first experiment is not attributable to a visual acuity disorder, but is explained as due to an impairment of the pattern perception mechanism.