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Objective: To assess the outcomes of low-risk differentiated thyroid cancer (DTC) with tumour size 1 to 4 cm post-thyroidectomy in patients who never received radioactive iodine (RAI) ablation and to compare the outcomes with those who received RAI therapy., Study Design: Observational study. Place and Duration of the Study: Department of Nuclear Medicine, Karachi Institute of Radiotherapy and Nuclear Medicine (KIRAN) Hospital, Karachi, Pakistan, from January 2016 to December 2020., Methodology: A total of 130 consecutive patients of low-risk DTC of both genders aged between 18-75 years were identified who underwent thyroidectomy. Patients were classified as either being treated or not treated with RAI, based on RAI data post-thyroidectomy. Patients were followed up for two to five years depending on their date of diagnosis from 2016 to 2020, using thyroglobulin (Tg), anti-thyroglobulin (anti-Tg), and thyrotropin (TSH) levels and ultrasound neck. Association between patients who received RAI and who did not receive RAI was determined and a p-value <0.05 was considered as statistical significance., Results: Patients had mean age of 34.5 ± 10.4 years with majority of females (75.4%). Majority of the patients (94.6%) had total thyroidectomy with no neck dissection (83.1%). RAI therapy was conducted among 70.8% participants, of which, 56.9% participants received a dose of 100 mci. Most of the patients had positive outcomes as there was no recurrence among 96.2% participants. There was a significant difference in RAI therapy with total thyroidectomy as compared to subtotal, RAI dose, tumour stage, neck dissection, and lymph node involvement (p ≤0.001)., Conclusion: After complete tumour resection, a highly selected group of patients with low-risk local disease have shown low rate of recurrence when managed without RAI. Interestingly, the disease recurrence was also only seen in patients who received RAI therapy in comparison to those who did not receive RAI therapy., Key Words: Outcomes, Differentiated thyroid cancer, Radioactive iodine, Ablation therapy, Post-surgery.

Carp oedema virus (CEV) has distinct molecularly identified genogroups of viral mutations, denoted as I, IIa, and IIb. Failure to propagate CEV in vitro limits studies towards understanding its interactions with host cells. Here, virus isolates belonging to genogroup I collected during natural outbreaks in the Czech Republic were employed for routine CEV cultivation in monolayers of carp-derived primary cells, common carp brain (CCB) cells, and epithelioma papulosum cyprinid (EPC) cells. Induction of cytopathic effects (CPEs) was observed and recorded in affected cells. Cell survival rate was evaluated under serial dilutions of the CEV inoculum. Virus cell entry was quantified and visualized by qPCR and transmission electron microscopy, respectively. Study findings indicate primary gills epithelia likely present the most suitable matrix for CEV growth in vitro. Cells of the head kidney and spleen facilitate virus entry with microscopically confirmed CPEs and the presence of cytoplasmic pleomorphic virus particles. Cells of the trunk kidney and gonads are unlikely to permit virus cell entry and CPEs development. Although CEV cultivation in cell lines was inconclusive, EPC cells were CEV permissible. Monolayers of carp-derived primary cells show promise for CEV cultivation that could enable elaborate study of mechanisms underlying cellular binding and responses., (© 2024 The Authors. Journal of Fish Diseases published by John Wiley & Sons Ltd.)

In recent years, the global prevalence of obesity and its associated metabolic disorders has reached alarming levels, presenting a significant challenge to public health worldwide. Visfatin, also known as pre-B cell colony-enhancing factor (PBEF) or nicotinamide phosphoribosyltransferase (NAMPT), is an adipokine that has been implicated in various physiological processes, including glucose homeostasis, lipid metabolism, and inflammation. The main objective of this proposed study is to find out the association between visfatin genetic variants and metabolic syndrome. The sample size of the study consisted of 300 blood samples (150 control and 150 cases). This study found that the genotypic frequency of visfatin SNPs, including rs2302559 (OD: 18.222; 95% CI 10.228-32.466; p-value < 0.001) and rs1215113036 (OD: 129.40; 95% CI 44.576-375.693; p-value < 0.001) were significantly associated with metabolic syndrome. Moreover, the frequency of the mutant alleles of both visfatin SNPs was found to be higher in patients with metabolic syndrome as compared to controls. Results of the current study indicate that people with any genetic variation of Visfatin, such as rs2302559 and rs1215113036, are more likely to develop metabolic syndrome. Visfatin genetic variants are linked to an increased risk of metabolic syndrome, implying it's role in disease pathophysiology., (© 2023. The Author(s).)

Objective: The aim of our study was to assess the association of eating habits with the dietary patterns of people with diabetes., Methods: This cross-sectional study was conducted at National Institute of Diabetes and Endocrinology (NIDE), Dow University Hospital in Karachi, Pakistan. A total 301 patients aged >18 with type 2 diabetes came to Outpatient department were recruited. Structured questionnaire was used to assess general characteristics, Anthropometric measurements, biochemical markers, and dietary intake., Results: A total of 301 patients with type 2 diabetes mellitus were included in this study. The average age of patients was 51.6 (SD ± 11.1) years which ranged from 21 to 80 years whereas the average BMI was 27.2 kg / m 2 (SD ± 5.6). Overall, 42% of patients were found to often have less than 1 serving of fruit, and 45% had less than 3 servings of vegetables daily. Of all, 77 (26%) patients often distributed carbohydrates all over the day. Results revealed that HbA1c was higher in those patients who took more than 3 roti (approximately each roti weight 60-80 g) ( P -value < .001) and full plate rice approximately 300 to 355 g cooked weight in a whole day ( P -value < .001) as compared to those patients whose intake of roti was 3 or less than 3 and rice was a half plate. Moreover, out of 301 patients, 102 were found physically active (52% females and 48% males), while 199 were not active. Pain in legs and lack of motivation were common barrier to physical activity., Conclusion: Our study revealed that patients' fruits and vegetable intake was not optimum, diet was not balanced and the quantity of starchy carbohydrates was not controlled which may affect their HBA1C levels. Proper counseling and awareness about the importance of a balanced diet and portion control in diabetes are needed., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Carp edema virus disease (CEVD), also known as koi sleepy disease (KSD), represents a serious threat to the carp industry. The expression of immune-related genes to CEV infections could lead to the selection of crucial biomarkers of the development of the disease. The expression of a total of eleven immune-related genes encoding cytokines (IL-1 β , IL-10, IL-6a, and TNF- α 2), antiviral response (Mx2), cellular receptors (CD4, CD8b1, and GzmA ), immunoglobulin (IgM), and genes encoding-mucins was monitored in gills of four differently KSD-susceptible strains of carp (Amur wild carp, Amur Sasan, AS; Ropsha scaly carp, Rop; Prerov scaly carp, PS; and koi) on days 6 and 11 post-infection. Carp strains were infected through two cohabitation infection trials with CEV genogroups I or IIa. The results showed that during the infection with both CEV genogroups, KSD-susceptible koi induced an innate immune response with significant up-regulation ( p  < 0.05) of IL-1 β , IL-10, IL-6a, and TNF- α 2 genes on both 6 and 11 days post-infection (dpi) compared to the fish sampled on day 0. Compared to koi, AS and Rop strains showed up-regulation of IL-6a and TNF- α 2 but no other cytokine genes. During the infection with CEV genogroup IIa, Mx2 was significantly up-regulated in all strains and peaked on 6 dpi in AS, PS, and Rop. In koi, it remained high until 11 dpi. With genogroup I infection, Mx2 was up-expressed in koi on 6 dpi and in PS on both 6 and 11 dpi. No significant differences were noticed in selected mucin genes expression measured in gills of any carp strains exposed to both CEV genogroups. During both CEV genogroups infections, the expression levels of most of the genes for T cell response, including CD4, CD8b1, and GzmA were down-regulated in AS and koi at all time points compared to day 0 control. The expression data for the above experimental trials suggest that both CEV genogroups infections in common carp strains lead to activation of the same expression pattern regardless of the fish's susceptibility towards the virus. The expression of the same genes in AS and koi responding to CEV genogroup IIa infection in mucosal tissues such as gill, gut, and skin showed the significant up-regulation of all the cytokine genes in gill and gut tissues from koi carp at 5 dpi. Significant down-regulation of CD4 and GzmA levels were only detected in koi gill on 5 dpi but not in other tissues. AS carp displayed significant up-expression of Mx2 gene in all mucosal tissues on 5 dpi, whereas in koi, it was up-regulated in gill and gut only. In both carp strains, gill harbored a higher virus load on 5 dpi compared to the other tissues. The results showed that resistance to CEV could not be linked with the selected immune responses measured. The up-regulation of mRNA expression of most of the selected immune-related genes in koi gill and gut suggests that CEV induces a more systemic mucosal immune response not restricted to the target tissue of gills., Competing Interests: The authors declare there are no competing interests., (©2023 Baloch et al.)

In the present study, we describe a natural outbreak of carp edema virus disease (CEVD) in koi carp, concentrating on clinical manifestation, gross and microscopic pathology, immunological parameters, viral diagnostics, and phylogenetic analysis. Examination of white blood cell parameters showed increased monocyte and decreased lymphocyte counts in CEV-affected fish compared to healthy control fish. Regarding immune system functioning, the present work shows, for the first time, enhanced phagocytic activity in CEV-affected fish. Respiratory burst of phagocytes was strongly increased in diseased fish, the increase being attributed to an increased phagocyte count rather than enhancement of their metabolic activity. The present work also newly shows histopathological changes in the pancreatic tissue of diseased koi.

Background: For the treatment of hypothyroidism, patients are usually placed on lifelong levothyroxine replacement therapy. Achieving clinical and biochemical euthyroid status is sometimes difficult because of several factors, including poor compliance or poor absorption of levothyroxine in the gut mucosa., Case Presentation: We present the case of a 45-year-old South Asian female with hypothyroidism on lifelong levothyroxine replacement. However, on her multiple follow-up visits over the past 2 years, it was noted that her thyrotropin level was never controlled and was not in range. A thorough history was unyielding in terms of compliance regarding levothyroxine medication and use of over-the-counter pills or mineral supplements that may interfere with the absorption of levothyroxine. Hence, we performed levothyroxine absorption test to rule out any malabsorption as well as document pseudo-malabsorption favoring drug nonadherence. Levothyroxine absorption test resulted in more than 56% absorption of levothyroxine; therefore, the patient was put on weekly directly observed treatment strategy resulting in normalization of thyrotropin levels on successive follow-ups., Conclusion: Directly observed treatment to replace levothyroxine once a week can be used as an alternative by health care professionals in patients in whom compliance to daily levothyroxine is the hidden cause of persistently raised thyrotropin. This strategy can reduce undue health burden on the patient and improve adherence to self-medication under confident supervision of the treating physician., (© 2023. The Author(s).)

Comparative genomics and computational biology offer powerful research tools for studying evolutionary mechanisms of organisms, and the identification and characterization of conserved/distant genes and gene families. The plant CNGC gene family encodes evolutionary conserved ion channel proteins involved in important signaling pathways and biological functions. The fundamental ideas and standard procedures for genome-wide identification and evolutionary analysis of plant cyclic nucleotide-gated ion channels employing various software, tools, and online servers have been discussed. In particular, this developed method focused on practical procedures involving the comparative analysis of paralogs and orthologs of CNGC genes in different plant species at different levels including phylogenetic analysis, nomenclature and classification, gene structure, molecular protein evolution, and duplication events as mechanisms of gene family expansion and synteny., (© The Author(s) 2022. Published by Oxford University Press.)

Objective: To assess the nourishment level of married women of reproductive age in a two rural setting., Methods: The cross-sectional study was based on secondary data of the Impact Assessment Survey 2019, which was conducted by the People's Primary Health Care Initiative from January to May, 2019, in Dadu and Jacobabad districts of the province of Sindh, Pakistan. Nutritional status of married women of reproductive age was analysed using mid-upper arm circumference; <23cm being indicative of under-nourishment, and <21cm of severe under-nourishment. Predicting factors were identified using multivariate logistic regression. Data was analysed using STATA 15., Results: Of 10,388 subjects, 5,138(49.5%) were from Dadu and 5,250(50.5%) from Jacobabad. The overall mean age was 32.9±8.1 with 4,739(45.6%) aged 25-35 years. Overall, 2,336(22.5%) subjects were undernourished and 609(5.9%) were severely undernourished. Age, education, socio-economic status and parity were significant predictors of the nourishment status (p<0.05), while location and health facility type were significant predictors of severe undernourishment (p<0.05), but were not related to undernourishment (p>0.05)., Conclusions: Overall nutrition status of the married women of reproductive age in the two rural districts of Sindh was less than satisfactory.

CNGCs are ligand-gated calcium signaling channels, which participate in important biological processes in eukaryotes. However, the CNGC gene family is not well-investigated in Brassica rapa L. (i.e., field mustard) that is economically important and evolutionary model crop. In this study, we systematically identified 29 member genes in BrCNGC gene family, and studied their physico-chemical properties. The BrCNGC family was classified into four major and two sub phylogenetic groups. These genes were randomly localized on nine chromosomes, and dispersed into three sub-genomes of B. rapa L. Both whole-genome triplication and gene duplication (i.e., segmental/tandem) events participated in the expansion of the BrCNGC family. Using in-silico bioinformatics approaches, we determined the gene structures, conserved motif compositions, protein interaction networks, and revealed that most BrCNGCs can be regulated by phosphorylation and microRNAs of diverse functionality. The differential expression patterns of BrCNGC genes in different plant tissues, and in response to different biotic, abiotic and hormonal stress types, suggest their strong role in plant growth, development and stress tolerance. Notably, BrCNGC-9, 27, 18 and 11 exhibited highest responses in terms of fold-changes against club-root pathogen Plasmodiophora brassicae, Pseudomonas syringae pv. maculicola, methyl-jasmonate, and trace elements. These results provide foundation for the selection of candidate BrCNGC genes for future breeding of field mustard., (© 2021. The Author(s).)

Introduction: Very little is known and predictable on how long the COVID-19 pandemic will last, even though dramatic preventive measures to flatten the curve and stop its transmission have been taken worldwide periodically since its start. These preventive measures coupled with people's fear of COVID-19, significantly altered people's health-seeking behavior and healthcare accessibility. This study aims to measure the impact of the COVID-19 pandemic on the utilization of reproductive, maternal, newborn, and child health (RMNCH) care services at primary health care (PHC) facilities in Pakistan.  Methods: A retrospective study was conducted in 22 districts using data from 1169 primary health care facilities. The District Health Information System (DHIS) was used to retrieve district-wise services utilization data from January to April 2020 i.e. January to February 2020 (pre-COVID-19) and March to April 2020 (during COVID-19). The monthly difference (in percentage change) for selected RMNCH services indicators was calculated using the expected number of clients (January to February average) versus the actual number of clients for March and April 2020., Results:  We observed a decrease of 12.5% for March and 33% for April 2020 in the total number of clients who availed of primary health care services in Sindh as compared to the pre-COVID-19 monthly average. A decrease in first antenatal care visits (15.6% and 16.3%), delivery coverage (12.8% and 17.9%) and family planning client visits (31.6% and 36.3%) were observed for March and April 2020 respectively. The pentavalent vaccine results revealed a decrease of 19.3% and 63.1%, while a decrease of 17.3% and 54.3% were observed for children receiving the first dose of measles vaccine in March and April, respectively.  Conclusions: Our findings show that the number of clients who avail of routine care or RMNCH services at the primary health care level considerably declined during the initial phase of the first wave of the COVID-19 outbreak in Sindh, Pakistan. These results highlight a rising threat to poor RMNCH and outcomes., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2021, Baloch et al.)

Background: Treating periodontitis through non-surgical periodontal therapy (NSPT) may improve glycemic control in type-2 Diabetes Mellitus (T2DM) patients. However, the evidence to maintain this improvement beyond four months is insufficient. Hence, this trial was conducted to assess clinical efficacy of NSPT on glycemic control in T2DM patients., Methods: This three-arm randomized controlled trial recruited 150 known T2DM participants (35-65 years), suffering from moderate to severe periodontitis, having HbA1c level ≥ 6.5% at baseline. Participants were followed up at 3 and 6 months. Intervention for test group-1 included scaling and root planing (SRP) with metronidazole (MET) and oral hygiene instructions (OHI). Test group-2 was intervened with SRP + OHI and control group with OHI only. Stata v. 14 was used to observe inter and intragroup mean changes in glycemic [glycated hemoglobin (HbA1c), fasting blood glucose (FBG)] and periodontal variables [bleeding on probing (BOP), periodontal pocket depth (PPD), clinical attachment loss (CAL)] using ANOVA and RMANOVA. Proportion of change in outcome variable (HbA1c) was assessed between treatment groups using chi-square test. Change was considered significant at p-value ≤ 0.05., Results: A significant reduction was observed in BOP, PPD, CAL, HbA1c and FBG over time [p < 0.05]. Significant reductions were observed in same variables in both test groups in comparison to control arm [p < 0.05]. No change between the two test groups was observed [p > 0.05]., Conclusion: Scaling and root planing improves glycemic control of T2DM patients independently of the use of MET. Therefore, SRP after every 6 months may be suggested and included as a part of overall diabetes management for patients suffering from T2DM. Clinical trial registration NCT 03,343,366 [Date of Registration: 17/11/2017].

Objective: To assess a relationship and predict changes in glycaemic control due to chronic periodontitis in type-2 diabetic patients., Methods: Chronic periodontitis (CP) of a cross-section of 118 patients (age ?32 years) was determined using bleeding on probing (BOP), periodontal pocket depth (PPD) and clinical attachment loss (CAL). Their HbA1c, fasting blood glucose (FBG), fasting serum insulin (FSI) and homeostasis assessment model of insulin resistance (HOMA-IR) levels were also tested. Stata 11.0 was used to assess correlation between periodontal and glycaemic measures. Univariate analysis followed by multiple regression analysis through stepwise forward selection process was used to explore significant variables that may predict change in HbA1c. Multi-collinearity and heteroskedasticity were assessed at p-value > 0.05., Results: Results of participants (n=95) showed significantly positive correlations (r) between HbA1c and BOP [r = 0.34, p-value = 0.002], PPD [r = 0.36, p-value = 0.003] and CAL [r=0.42, p-value = 0.002]. However, FBG and HOMA-IR were not found correlated with any of the periodontal measures; except CAL with FBG [r=0.27, p-value=0.02]. In addition to healthy controlled diet, cultural background, education and FBG, CAL was found significant [coef. = 0.746, p-value = 0.001, CI = 0.339, 1.153] to predict change in HbA1c in the final model [R2 = 0.549, p-value < 0.001] with no multicollinearity [mean VIF =1.30] and heteroskedasticity [chi 2 =0.02, p-value= 0.878] in fi n al model., Conclusions: Increased CAL is estimated to increase HbA1c level by 0.75% in T2DM patients after controlling other factors. It is suggested that periodontal prophylactic management may be planned with an aim to reduce HbA1c., Clinical Trial Registration No: NCT03343366.

Plant respiratory burst oxidase homolog (Rboh) gene family encodes the key enzymatic subunits of reactive oxygen species (ROS) production pathways, and play crucial role in plant signaling, development and stress responses. In present work, twenty genes were identified in Nicotiana tabacum Rboh family (NtabRboh) and classified into four phylogenetic groups (I-IV). Fourteen NtabRboh genes were positioned on ten chromosomes (i.e., Ch1, 2, 4, 7-11, 14 and 21), and six scaffolds. Synteny and evolutionary analysis showed that most of the NtabRboh genes have evolved from the genomes of the ancestor species (N. tomentosiformis and N. sylvestris), which afterwards expanded through duplication events. The promoter regions of the NtabRboh genes contained numerous cis-acting regulatory elements for hormones, plant growth, and different biotic and abiotic factors. The NtabRbohF gene transcript comprised target sites for wounding and stress responsive microRNAs: nta-miR166a-d, g and h. The transcript abundance of NtabRboh genes in different tissues reflected their important for plant growth and organ development in tobacco. RT-qPCR-assays demonstrated that the expression of NtabRboh genes are regulated by viral and bacterial pathogens, drought, cold and cadmium stress. The expression levels NtabRbohA, B and C were significantly up-regulated in "black shank and tobacco mosaic virus-inoculated susceptible and transgenic tobacco cultivars, showing that these genes play important roles in disease resistance., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The aim of this study is to describe the characteristics and outcome of thyroid storm patients presenting at two tertiary care centres of Karachi, i.e. at Dow University of Health Sciences; and Liaquat National Hospital, Karachi, from December 2018 to May 2019. All patients between 18-70 years of age, who were admitted with thyroid storm and fulfilled the Burch- Wartofsky criteria, were inducted. Demographics including age, gender, clinical presentations, systemic symptoms, clinical examination of the thyroid and laboratory findings were reviewed from the file records to identify factors associated with mortality using the available data. Overall, five (62.5%) out of eight patients were female. The mean age was 43 ±1.67 years. Infections were the most common comorbid condition followed by cardiovascular and gastrointestinal diseases. The in-hospital mortality rate was 87.5% (n=07).

The pathophysiology of type 2 diabetes (T2DM) is associated with perturbation of innate immune response. Several studies indicated alteration of pro-inflammatory and anti-inflammatory cytokines, chemokines and other mediators of innate immune response in T2DM. This study was designed to perform quantitative PCR-based expression profiling of genes involved in inflammation (i.e. CASP1, CASP5, CCL5, CXC11, CCR5, NF-Κb, IL-4, PPARG and PGC1α ) in peripheral blood leukocytes of T2DM patients. The T2DM patients are often prescribed with metformin and insulin while metformin has also been reported to possess anti-inflammatory activity. To address the question whether metformin exerts any effect on inflammatory mediators in bloodstream, human subjects in this study were divided into four groups on the basis of medication they were taking during last 6 month. These groups included NT-T2DM (T2DM patients not taking medication, n = 34), Met-T2DM (T2DM patients taking metformin, n = 33), INS-T2DM (T2DM patients taking insulin, n = 15) and NGT (normoglycemic subjects, n = 34) groups. Differential expression of gene transcripts at a cutoff of fourfold was considered significant. In the NT-T2DM group, transcripts of inflammation-related genes (i.e. CASP1, CASP5, CCL5, CCR5 and NF-kB) were up-regulated while transcripts of PPARG and PGC1α genes were down-regulated compared to NGT group. On the other hand, down-regulation of CASP1, CASP5, CCL5, CCR5 and NF-kB transcripts was evident in Met-T2DM and INS-T2DM groups when compared to the NT-T2DM group. The Met-T2DM group and INS-T2DM group showed a significant difference in the transcript level of CASP1 and CCL5 which are more down-regulated in the Met-T2DM group compared to INS-T2DM group. These findings indicated that (a) in T2DM, expression of inflammation-related genes is up-regulated and (b) anti-inflammatory activity of metformin appears to be independent of its anti-hyperglycemic activity.

Objectives: To determine the frequency of diseases contributing to End Stage Renal Failure (ESRF) and to determine the frequency of seropositivity for hepatitis B and hepatitis C in our patients., Methods: This is an observational study of two years duration from January 2012 till December 2013, done at Dow university of Health Sciences. Sample size is 189 by convenient method. Data collection is retrospective. Inclusion criteria includes all patients ever hemodialysed at DIMC with age 14 or above. Exclusion criteria is age below 14. Data maintained and analyzed on SPSS version 16. All categorical data in percentages and numeric data is given in frequencies and mean with Standard deviation., Result: Total number of patients included in study were 189, Males were 94/189 (49.7%), females were 95/189 (50.3%), Male to female ratio was 0.98: 1.0. Mean age was 51.88+15.2, range was14-86 years. Patients started on Hemodialysis were found to have hypertension in 40.2%, both diabetes and hypertension was present in 42.8%, diabetes alone in 3.1% of patients as likely etiology of renal failure. Seropositivity for HBV was found 4/189(2.1%) and HCV in 31/189(16.4%) at initiation of Hemodialysis., Conclusion: Hypertension alone is an important disease found in patients with renal failure as likely cause followed by diabetes. Hepatitis C positivity at start of hemodialysis is 16%.

A neural model of motion perception simulates psychophysical data concerning first-order and second-order motion stimuli, including the reversal of perceived motion direction with distance from the stimulus (gamma display), and data about directional judgments as a function of relative spatial phase or spatial and temporal frequency. Many other second-order motion percepts that have ascribed to a second non-Fourier processing stream can also be explained in the model by interactions between ON and OFF cells within a single, neurobiologically interpreted magnocellular processing stream. Yet other percepts may be traced to interactions between form and motion processing streams, rather than to processing within multiple motion processing streams. The model hereby explains why monkeys with lesions of the parvocellular layers, but not of the magnocellular layers, of the lateral geniculate nucleus (LGN) are capable of detecting the correct direction of second-order motion, why most cells in area MT are sensitive to both first-order and second-order motion, and why after 2-amino-4-phosphonobutyrate injection selectively blocks retinal ON bipolar cells, cortical cells are sensitive only to the motion of a moving bright bar's trailing edge. Magnocellular LGN cells show relatively transient responses, whereas parvocellular LGN cells show relatively sustained responses. Correspondingly, the model bases its directional estimates on the outputs of model ON and OFF transient cells that are organized in opponent circuits wherein antagonistic rebounds occur in response to stimulus offset. Center-surround interactions convert these ON and OFF outputs into responses of lightening and darkening cells that are sensitive both to direct inputs and to rebound responses in their receptive field centers and surrounds. The total pattern of activity increments and decrements is used by subsequent processing stages (spatially short-range filters, competitive interactions, spatially long-range filters, and directional grouping cells) to determine the perceived direction of motion.

The percepts known variously as the line motion illusion, motion induction, and transformational apparent motion have attracted a great deal of experimental interest, since they sensitively probe interactions between preattentive and attentive vision processes. The present article develops a neural model that qualitatively explains essentially all the data reported thus far, and quantitatively simulates key illustrative percepts. The model suggests how these data arise from neural mechanisms of preattentive boundary and surface formation, long-range apparent motion, formotion interactions, and spatial attention. The boundary and surface formation processes model aspects of the interblob V1-->interstripe V2-->V4 and blob V1-->thin stripe V2-->V4 cortical processing streams, respectively. The long-range apparent motion process models aspects of the V1-->MT-->MST processing stream. An interstream V2-->MT form-motion interaction is proposed to allow the motion processing stream to track transient properties of emergent boundaries and filled-in surface colors from the form processing stream. It does so by generating motion waves using the long-range apparent motion process. This interstream interaction controls the formation of form-motion percepts, which are herein called formotion percepts. Other transients directly cause motion waves within the motion processing stream. All the data are attributed to properties of such motion waves. It is also suggested how bottom-up motion mechanisms can engage top-down attention as part of the motion capture process that solves the aperture problem. This interaction is proposed to occur between areas MT and MST. The model hereby explains how attention can be engaged even in percepts whose explanation can be derived from preattentive mechanisms.