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In JoVE (5)
- تشريح الدماغ البشري غير الرئيسيات في الفضاء التجسيمي
- الخدمات المصرفية للدماغ : جعل معظم العينات بحوث الخاص
- عبارة في الدماغ : تشريح العين الرئيسيات
- معرفة ما يهم : التجسيم غير متحيز في الدماغ البشري غير الرئيسيات
- Immunostaining دفعي للكشف عن البروتين واسعة النطاق في الدماغ القرد الجامعة
Other Publications (8)
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Articles by Shahin Zangenehpour in JoVE
JoVE General
تشريح الدماغ البشري غير الرئيسيات في الفضاء التجسيمي
1Department of Physiology, University of Montreal, 2School of Optometry, University of Montreal, 3Département de chimie-biologie , Université du Québes à Trois-Rivières
الرئيسيات غير البشرية هي الأنواع الهامة متعدية لفهمنا لمعالجة العادي من الدماغ. يمكن للمنظمة التشريحية للدماغ الرئيسيات توفير معلومات هامة في الظروف العادية والمرضية لدى البشر.
JoVE General
الخدمات المصرفية للدماغ : جعل معظم العينات بحوث الخاص
1Department of Physiology, University of Montreal, 2School of Optometry, University of Montreal
الدماغ المصرفي وأخذ العينات من المواد البيولوجية المنهجي يوفر الأساس لالتجسيم غير منحازة ويزيد من إمكانية الحصول على بيانات من كل عينة.
JoVE General
عبارة في الدماغ : تشريح العين الرئيسيات
1Department of Physiology, University of Montreal, 2School of Optometry, University of Montreal, 3Departement de chimie-biologie, Universite du Quebec a Trois-Rivieres
الرئيسيات غير البشرية هي الأنواع الهامة متعدية لفهمنا للتنمية ، والشيخوخة. يجوز للمنظمة التشريحي للشبكية الرئيسيات توفير معلومات هامة في الظروف العادية والمرضية لدى البشر.
JoVE General
معرفة ما يهم : التجسيم غير متحيز في الدماغ البشري غير الرئيسيات
1Department of Physiology, University of Montreal, 2Ecole d’optometrie, University of Montreal, 3Stereology Resource Center
يمكن للمنظمة التشريحية للدماغ الرئيسيات توفير معلومات هامة في الظروف العادية والمرضية لدى البشر. التجسيم هو أسلوب غير متحيز لبدقة وكفاءة تقدير عدد الخلايا العصبية الكلي (أو غيرها من نوع من الخلايا) في الفضاء مرجعية محددة
JoVE General
Immunostaining دفعي للكشف عن البروتين واسعة النطاق في الدماغ القرد الجامعة
1Cognitive Neuroscience Unit, Montreal Neurological Institute, 2Ècole d’Optomètrie, Universitè de Montrèal, 3Department of Psychology, McGill University
على نطاق واسع مناعي للبروتينات المستهدفة في جميع أنحاء الدماغ الرئيسيات كله هو ممكن من خلال استخدام نسيج الرواية أساليب التضمين وsectioning جنبا إلى جنب مع استخدام أجهزة مبتكرة لتلوين مجموعة من المقاطع التعويم الحر متعددة في وقت معين.
Other articles by Shahin Zangenehpour on PubMed
Differential Induction and Decay Curves of C-fos and Zif268 Revealed Through Dual Activity Maps
The use of inducible transcription factors for mapping neural activity is now a common procedure. We have previously developed a double-labelling technique that allows visualization of activated neurons after two different stimulation sequences. The technique exploits the differential time course of mRNA versus protein expression of transcription factors. However, the precise details of the differential time course remained unknown. Here, we provide a complete up- and downregulation profile for both the c-fos and zif268 genes, as determined through combined in situ hybridization and immunocytochemical detection of the mRNA and protein products in primary visual cortex. The data presented here can be used in the design of future studies employing double-label mapping of neural activation following a compound stimulus.
Differential Impact of the FMR1 Gene on Visual Processing in Fragile X Syndrome
Fragile X syndrome (FXS) is the most common form of heritable mental retardation, affecting approximately 1 in 4000 males. The syndrome arises from expansion of a trinucleotide repeat in the 5'-untranslated region of the fragile X mental retardation 1 (FMR1) gene, leading to methylation of the promoter sequence and lack of the fragile X mental retardation protein (FMRP). Affected individuals display a unique neurobehavioural phenotype that includes striking visual-motor deficits. Here we provide neurobiological and behavioural evidence that supports the hypothesis that these visual-motor deficits are attributable to a magnocellular (M) visual pathway impairment. Immunohistochemical staining of a lateral geniculate nucleus (LGN) of a normal human male revealed high FMRP basal expression selectively within the M layers, suggesting an increased susceptibility of these neurons to the lack of FMRP as occurs in FXS. Similar staining of monkey LGNs for quantification purposes revealed that the difference is not an artefact of cell size differences between M and parvocellular (P) neurons. Further, Nissl staining of the LGNs of a male FXS patient revealed alaminar nuclei comprised of a homogenous population of small sized neurons, providing anatomical and morphological support for the idea that an M pathway pathology exists in FXS. Consistent with these neurobiological data, we have found that male patients with FXS have reduced sensitivity for psychophysical stimuli that probe the M pathway but not for those that probe the P pathway, a complementary visual stream that performs a separate set of early visual operations. Finally, male patients with FXS performed poorly on a global motion task but not on a form perception task, suggesting that the M pathway thalamic deficit may have a selective impact on cortical visual functioning in the parietal lobe, which is known to be a major recipient of M pathway afferents via the primary visual cortex. Together, these findings provide the first evidence that the loss of a single gene product, FMRP, in humans leads to abnormal neuroanatomical morphology of the LGN and a concomitant selective visual deficit of the M pathway.
Cellular-resolution Activity Mapping of the Brain Using Immediate-early Gene Expression
Immediate-Early Genes are a class of genes that are rapidly up-regulated following neural stimulation. Due to their quality as potential activity markers in the CNS, they have been used extensively in functional mapping studies. At least three genes have been popularly used, including zif268 (Egr1, NGFI, Krox-24, or ZENK), c-fos and recently, Arc. A number of techniques have been developed in applying IEG labelling for the development of functional maps, thus overcoming some of the earlier limitations of this approach. Current developments highlight the future prospects of cellular-resolution functional activity mapping of the brain.
Patchy Organization and Asymmetric Distribution of the Neural Correlates of Face Processing in Monkey Inferotemporal Cortex
It is believed that a face-specific system exists within the primate ventral visual pathway that is separate from a domain-general nonface object coding system. In addition, it is believed that hemispheric asymmetry, which was long held to be a distinct feature of the human brain, can be found in the brains of other primates as well. We show here for the first time by way of a functional imaging technique that face- and object-selective neurons form spatially distinct clusters at the cellular level in monkey inferotemporal cortex. We have used a novel functional mapping technique that simultaneously generates two separate activity profiles by exploiting the differential time course of zif268 mRNA and protein expression.
Heterochrony and Cross-species Intersensory Matching by Infant Vervet Monkeys
Understanding the evolutionary origins of a phenotype requires understanding the relationship between ontogenetic and phylogenetic processes. Human infants have been shown to undergo a process of perceptual narrowing during their first year of life, whereby their intersensory ability to match the faces and voices of another species declines as they get older. We investigated the evolutionary origins of this behavioral phenotype by examining whether or not this developmental process occurs in non-human primates as well.
Whole-brain Expression Analysis of FMRP in Adult Monkey and Its Relationship to Cognitive Deficits in Fragile X Syndrome
Fragile X syndrome (FXS) is one of the most prevalent forms of heritable mental retardation and developmental delay in males. The syndrome is caused by the silencing of a single gene (fragile X mental retardation-1; FMR1) and the lack of expression of its protein product (fragile X mental retardation-1 protein; FMRP). Recent work has linked the high expression levels of FMRP in the magnocellular layers of lateral geniculate nucleus (M-LGN) of the visual system to a specific reduction of perceptual function known to be mediated by that neural structure. This finding has given rise to the intriguing notion that FMRP expression level may be used as an index of susceptibility of specific brain regions to the observed perceptual and cognitive deficits in FXS. We undertook a comprehensive expression profiling study of FMRP in the monkey to obtain further insight into the link between FMPR expression and the behavioural impact of its loss in FXS. We report here the first 3D whole-brain map of FMRP expression in the Old-World monkey and show that certain brain structures display high FMRP levels, such as the cerebellum, striatum, and temporal lobe structures. This finding provides support for the notion that FMRP expression loss is linked to behavioural and cognitive impairment associated with these structures. We argue that whole-brain FMRP expression mapping may be used to formulate and test new hypotheses about other forms of impairments in FXS that were not specifically examined in this study.
Crossmodal Recruitment of Primary Visual Cortex Following Brief Exposure to Bimodal Audiovisual Stimuli
Several lines of evidence suggest that exposure to only one component of typically audiovisual events can lead to crossmodal cortical activation. These effects are likely explained by long-term associations formed between the auditory and visual components of such events. It is not certain whether such crossmodal recruitment can occur in the absence of explicit conditioning, semantic factors, or long-term association; nor is it clear whether primary sensory cortices can be recruited in such paradigms. In the present study we tested the hypothesis that crossmodal cortical recruitment would occur even after a brief exposure to bimodal stimuli without semantic association. We used positron emission tomography, and an apparatus allowing presentation of spatially and temporally congruous audiovisual stimuli (noise bursts and light flashes). When presented with only the auditory or visual components of the bimodal stimuli, naïve subjects showed only modality-specific cortical activation, as expected. However, subjects who had previously been exposed to the audiovisual stimuli showed increased cerebral blood flow in the primary visual cortex when presented with sounds alone. Functional connectivity analysis suggested that the auditory cortex was the source of visual cortex activity. This crossmodal activation appears to be the result of implicit associations of the two stimuli, likely driven by their spatiotemporal characteristics; it was observed after a relatively short period of exposure (approximately 45 min), and lasted for a relatively long period after the initial exposure (approximately 1 day). The findings indicate that auditory and visual cortices interact with one another to a larger degree than typically assumed.
Partial Recovery of Hemiparesis Following Hemispherectomy in Infant Monkeys
Hemiparesis, unilateral weakness or partial paralysis, is a common outcome following hemispherectomy in humans. We use the non-human primate as an invaluable translational model for our understanding of developmental plasticity in response to hemispherectomy. Three infant vervet monkeys (Chlorocebus sabeus) underwent hemispherectomy at a median age of 9 weeks and two additional monkeys at 48 months. Gross motor assessment was conducted in a large open field that contained a horizontal bar spanning the width of the cage. Subjects were assessed yearly following surgery in infantile lesions for a period of 3 years. Adult-lesioned subjects were assessed 40 months following surgery. Shortly after surgery both infant and adult-lesioned subjects were unable to move the contralateral side of their body, but all subjects were able to walk within 6 months following surgery. At each time point the lower limb gait was normal in infant-lesioned subjects with no apparent limp or dragging, however the upper limb demonstrated significant impairment. Horizontal bar crossing was significantly impaired during the first 24 months following surgery. Adult-lesioned subjects also displayed upper limb movement impairments similar to infant-lesioned subjects. In addition the adult-lesioned subjects displayed a noticeable lower limb limp, which was not observed in the infant-lesioned group. Both groups at each time point showed a propensity for ipsiversive turning. The upper limb gait impairment and horizontal bar crossing of lesioned subjects are reminiscent of hemiparesis seen in hemisperectomized humans with the young-lesioned subjects showing a greater propensity for recovery.
