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Journal of the International Neuropsychological Society : JINS (1)
Nature neuroscience (1)
PLoS ONE (1)
Plant Methods (1)
Dapretto, Mirella (2)
Iacoboni, Marco (2)
Alexis, Naudin (1)
BOOKHEIMER, SUSAN Y. (1)
Bookheimer, Susan Y (1)
Bookheimer, Susan Y. (1)
DAPRETTO, MIRELLA (1)
Davies, Mari S (1)
Davies, Mari S. (1)
Dickstein, Rebecca (1)
Kadel, Khem (1)
Kryvoruchko, Igor (1)
Pfeifer, Jennifer H (1)
SCOTT, ASHLEY (1)
SIGMAN, MARIAN (1)
Scott, Ashley (1)
Scott, Ashley A (1)
Scott, Ashley A. (1)
Sigman, Marian (1)
Sinharoy, Senjuti (1)
Taylor, Mark (1)
Uddin, Lucina Q. (1)
Udvardi, Michael (1)
Veerappan, Vijaykumar (1)
WANG, A. TING (1)
Zaidel, Eran (1)
Year of Publication
Keel petal incision: a simple and efficient method for genetic crossing in Medicago truncatula
Genetic crossing is an essential tool in both forward and reverse genetic approaches to understand the biological functions of genes. For Medicago truncatula (barrel medic) various crossing techniques have been used which differ in the methods used to dissect the female parent’s unopened flower bud to remove immature anthers for prevention of self-pollination. Previously described methods including front, side or back incision methods may damage the flower bud, impeding successful fertilization and/or seed development because they may allow pollen to dislodge and floral organs to desiccate after crossing, all of which diminish the success rates of crossing.
We report the keel petal incision method for genetic crossing in M. truncatula ecotype R108 and demonstrate successful crosses with two other M. truncatula ecotypes, A17 and A20. In the method presented here, an incision is made along the central line of the keel petal from the bottom 1/3rd of the female parent’s flower bud to its distal end. This allows easy removal of anthers from the flower bud and access for cross-pollination. After pollination, the stigma and the deposited pollen from the male donor are covered by the keel petal, wing petals and standard petal, forming a natural pouch. The pouch prevents dislodging of deposited pollen from the stigma and protects the internal floral organs from drying out, without using cling-film or water-containing chambers to maintain a humid environment. The keel petal incision method showed an approximate 80% success rate in the M. truncatula R108 ecotype and also in other ecotypes including Jemalong A17 and A20.
Our keel petal incision protocol shows marked improvement over existing methods with respect to the ease of crossing and the percentage of successful crosses. Developed for the M. truncatula R108 ecotype, the protocol has been demonstrated with A17 and A20 ecotypes and is expected to work with other ecotypes. Investigators of varying experience have achieved genetic crosses in M. truncatula using this method.
Legume; Genetic crossing; Barrel medic; Medicago truncatula; Artificial hybridization; Keel petal
Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders
Davies, Mari S
Pfeifer, Jennifer H
Bookheimer, Susan Y
To examine mirror neuron abnormalities in autism, high-functioning children with autism and matched controls underwent fMRI while imitating and observing emotional expressions. Although both groups performed the tasks equally well, children with autism showed no mirror neuron activity in the inferior frontal gyrus (pars opercularis). Notably, activity in this area was inversely related to symptom severity in the social domain, suggesting that a dysfunctional ‘mirror neuron system’ may underlie the social deficits observed in autism.
Frontal contributions to face processing differences in autism: Evidence from fMRI of inverted face processing
BOOKHEIMER, SUSAN Y.
WANG, A. TING
Journal of the International Neuropsychological Society : JINS
Functional neuroimaging studies of face processing deficits in autism have typically focused on visual processing regions, such as the fusiform face area (FFA), which have shown reduced activity in autism spectrum disorders (ASD), though inconsistently. We recently reported reduced activity in the inferior frontal region in ASD, implicating impaired mirror-neuron systems during face processing. In the present study, we used fMRI during a face processing task in which subjects had to match faces presented in the upright versus inverted position. Typically developing (TD) children showed a classic behavioral inversion effect, increased reaction time for inverted faces, while this effect was significantly reduced in ASD subjects. The fMRI data showed similar responses in the fusiform face area for ASD and TD children, with both groups demonstrating increased activation for inverted faces. However, the groups did differ in several brain regions implicated in social cognition, particularly prefrontal cortex and amygdala. These data suggest that the behavioral differences in processing upright versus inverted faces for TD children are related not to visual information processing but to the social significance of the stimuli. Our results are consistent with other recent studies implicating frontal and limbic dysfunction during face processing in autism.
Functional MRI; Autism; Asperger’s; Face processing; Face inversion; Development
Neural Basis of Self and Other Representation in Autism: An fMRI Study of Self-Face Recognition
Uddin, Lucina Q.
Davies, Mari S.
Bookheimer, Susan Y.
Autism is a developmental disorder characterized by decreased interest and engagement in social interactions and by enhanced self-focus. While previous theoretical approaches to understanding autism have emphasized social impairments and altered interpersonal interactions, there is a recent shift towards understanding the nature of the representation of the self in individuals with autism spectrum disorders (ASD). Still, the neural mechanisms subserving self-representations in ASD are relatively unexplored.
We used event-related fMRI to investigate brain responsiveness to images of the subjects' own face and to faces of others. Children with ASD and typically developing (TD) children viewed randomly presented digital morphs between their own face and a gender-matched other face, and made “self/other” judgments. Both groups of children activated a right premotor/prefrontal system when identifying images containing a greater percentage of the self face. However, while TD children showed activation of this system during both self- and other-processing, children with ASD only recruited this system while viewing images containing mostly their own face.
This functional dissociation between the representation of self versus others points to a potential neural substrate for the characteristic self-focus and decreased social understanding exhibited by these individuals, and suggests that individuals with ASD lack the shared neural representations for self and others that TD children and adults possess and may use to understand others.
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