About webmatr0n

This author has not yet filled in any details.
So far webmatr0n has created 57 blog entries.

Neuroscience: Sex Hormones at Work in the Neocortex

Sex hormones have easy access to the brain and their receptors are expressed by cortical neurons. Until recently, little was known about what impact, if any, they have on cortical processing. New data reveal that estradiol potently alters inhibitory neurotransmission in the neocortex.

Kristen Delevich, David Piekarski, Linda Wilbrecht, Neuroscience: Sex Hormones at Work in the Neocortex,
29(4) Current Biology R122–R125 (2019) https://doi.org/10.1016/j.cub.2019.01.013, http://www.sciencedirect.com/science/article/pii/S0960982219300156

Neuroscience: Sex Hormones at Work in the Neocortex2019-02-22T15:49:13+00:00

Adolescence and “Late Blooming” Synapses of the Prefrontal Cortex

The maturation of the prefrontal cortex (PFC) during adolescence is thought to be important for cognitive and affective development and mental health risk. Whereas many summaries of adolescent development have focused on dendritic spine pruning and gray matter thinning in the PFC during adolescence, we highlight recent rodent data from our laboratory and others to call attention to continued synapse formation and plasticity in the adolescent period in specific cell types and circuits. In particular, we highlight changes in inhibitory neurotransmission onto intratelencephalic (IT-type) projecting cortical neurons and late expansion of connectivity between the amygdala and PFC and the ventral tegmental area and PFC. Continued work on these “late blooming” synapses in specific cell types and circuits, and their interrelationships, will illuminate new opportunities for understanding and shaping the biology of adolescent development. We also address which aspects of adolescent PFC development are dependent on pubertal processes.

Kristen Delevich, A. Wren Thomas, and Linda E. Wilbrecht, Adolescence and “Late Blooming” Synapses of the Prefrontal Cortex [local pdf], Cold Spring Harb Symp Quant Biol (2019)

Adolescence and “Late Blooming” Synapses of the Prefrontal Cortex2019-02-01T12:32:47+00:00

Mice engineered to mimic a common Val66Met polymorphism in the BDNF gene show greater sensitivity to reversal in environmental contingencies

A common human polymorphism in the gene that encodes brain derived neurotrophic factor (BDNF), Val66Met, is considered a marker of vulnerability for mental health issues and has been associated with cognitive impairment. An alternate framework has been proposed in which “risk alleles” are reinterpreted as “plasticity alleles” that confer vulnerability in adverse environments and positive effects in neutral or positive environments (Belsky et al., 2009). These frameworks produce divergent predictions for tests of learning and cognitive flexibility. Here, we examined multiple aspects of learning and cognitive flexibility in a relatively new BDNF Val66Met mouse model (BDNF Val68Met, Warnault et al., 2016), including multiple choice discrimination and reversal, go/no-go learning and reversal, and appetitive extinction learning. We found that mice homozygous for the Met allele show more efficient reversal learning in two different paradigms, but learn at rates comparable to Val homozygotes on the multiple choice discrimination task, a go/no-go task, and in appetitive extinction. Our results dissociate reversal performance from go/no-go learning and appetitive extinction and support the plasticity allele framework that suggests BDNF Met carriers are potentially more sensitive to changes in the environment.

Angela Vandenberg, Wan Chen Lin, Lung-Hao Tai, Dorit Ron, Linda Wilbrecht, Mice engineered to mimic a common Val66Met polymorphism in the BDNF gene show greater sensitivity to reversal in environmental contingencies, 34 Developmental Cognitive Neuroscience 34–41 (2018)

Mice engineered to mimic a common Val66Met polymorphism in the BDNF gene show greater sensitivity to reversal in environmental contingencies2019-02-02T21:38:12+00:00

Imaging Striatal Dopamine Release Using a Non-Genetically Encoded Near-Infrared Fluorescent Catecholamine Nanosensor

Neuromodulation plays a critical role in brain function in both health and disease. New optical tools, and their validation in biological tissues, are needed that can image neuromodulation with high spatial and temporal resolution, which will add an important new dimension of information to neuroscience research. Here, we demonstrate the use of a catecholamine nanosensor with fluorescent emission in the 1000-1300 nm near-infrared window to measure dopamine transmission in ex vivo brain slices. These near-infrared catecholamine nanosensors (nIRCats) represent a broader class of nanosensors that can be synthesized from non-covalent conjugation of single wall carbon nanotubes (SWNT) with single strand oligonucleotides. We show that nIRCats can be used to detect catecholamine efflux in brain tissue driven by both electrical stimulation or optogenetic stimulation. Spatial analysis of electrically-evoked signals revealed dynamic regions of interest approximately 2 microns in size in which transients scaled with simulation intensity. Optogenetic stimulation of dopaminergic terminals produced similar transients, whereas optogenetic stimulation of glutamatergic terminals showed no effect on nIRCat signal. Bath application of nomifensine prolonged nIRCat fluorescence signal, consistent with reuptake blockade of dopamine. We further show that the chemically synthetic molecular recognition elements of nIRCats permit measurement of dopamine dynamics in the presence of dopamine receptor agonists and antagonists. These nIRCat nanosensors may be advantageous for future use because i) they do not require virus delivery, gene delivery, or protein expression, ii) their near-infrared fluorescence facilitates imaging in optically scattering brain tissue and is compatible for use in conjunction with other optical neuroscience tool sets, iii) the broad availability of unique near-infrared colors have the potential for simultaneous detection of multiple neurochemical signals, and iv) they are compatible with pharmacology. Together, these data suggest nIRCats and other nanosensors of this class can serve as versatile new optical tools to report dynamics of extracellular neuromodulation in the brain.

Abraham G Beyene, Kristen Delevich, Jackson Travis Del Bonis ODonnell, David J Piekarski, Wan Chen Lin, A Wren Thomas, Sarah J Yang, Polina Kosillo, Darwin Yang, Linda Wilbrecht, Markita P Landry, Imaging Striatal Dopamine Release Using a Non-Genetically Encoded Near-Infrared Fluorescent Catecholamine Nanosensor, biorxiv preprint (2018)

Imaging Striatal Dopamine Release Using a Non-Genetically Encoded Near-Infrared Fluorescent Catecholamine Nanosensor2019-02-02T22:06:38+00:00

Your Twelve-Year-Old’s Brain Chapter in Think Tank

Professor Wilbrecht’s essay, Your Twelve-Year-Old Isn’t Just Sprouting New Hair but Is Also Forming (and Being Formed by) New Neural Connections, appears in Think Tank: Forty Neuroscientists Explore the Biological Roots of Human Experience (David J. Linden, ed. 2018).

Your Twelve-Year-Old’s Brain Chapter in Think Tank2019-02-01T12:33:18+00:00

Hoshal & Okada Awards

Undergraduate awards: Ben Hoshal won an MCB poster award and Nana Okada won a Psychology poster award. Congratulations to Ben and Nana!

Hoshal & Okada Awards2018-04-24T10:57:44+00:00

Importance of investing in adolescence from a developmental science perspective

This review summarizes the case for investing in adolescence as a period of rapid growth, learning, adaptation, and formational neurobiological development. Adolescence is a dynamic maturational period during which young lives can pivot rapidly—in both negative and positive directions. Scientific progress in understanding adolescent development provides actionable insights into windows of opportunity during which policies can have a positive impact on developmental trajectories relating to health, education, and social and economic success. Given current global changes and challenges that affect adolescents, there is a compelling need to leverage these advances in developmental science to inform strategic investments in adolescent health.

Ronald E. Dahl, Nicholas B. Allen, Linda Wilbrecht & Ahna Ballonoff Suleiman, Importance of investing in adolescence from a developmental science perspective, Nature (v 554) pp. 441–450 (Feb. 2018), doi:10.1038/nature25770

Importance of investing in adolescence from a developmental science perspective2019-02-02T22:07:32+00:00