Book notes Neuroengineering

I learned a good amount from reading this collection of articles but it would have been better if the book were collected into a coherent whole instead of being so fragmented. Here are summaries of random parts of the book: Passing electrical current through tissues can stimulate neurons to produce action potentials. In vitro neuron [...]

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Book notes Creativity in Science

Dean Keith Simonton’s recent book is a tour de force, explaining the impact of publications and the number of publications produced by a given scientist as a function of that scientist’s attributes. If you are looking to produce your creative output, why bother with non-emprical, qualitative advice when you don’t have to? Read this book [...]

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Probabilistic spiking

Whether or not you accept the Bayesian framework of the brain wholesale there are good reasons to expect that most of its microscale processes are probabilistic. An interesting article by Kasabov proposes a spiking neural network model to account for this while maintaining biological consistency. I can’t explain the math easily, but here are a [...]

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Circuit substrates of ADHD drugs

Easton et al has used small animal pharmacological (ph) MRI on rats after administering a number of different ADHD drugs (methylphenidate, atomoxetine, guanfacine, and d-amphetamine) to determine their effects on various brain regions. Previous studies have performed immunohistochemical studies in the rat on the levels of dopamine and noradrenaline transporter (DAT and NET, respectively). The [...]

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Beta amyloid precursor promotes synaptogenesis

Amyloid precursor protein (APP) is heavily implicated in the progression of Alzheimer’s disease. When proteolytically processed they yield 40 and 42 amino acid amyloid peptides which form the beta amyloid plaques one often hears about.  APP/APLP2double knock-out mice have reduced protein expression at the neuromuscular synapse and have generally defective synapses. Wang et al have [...]

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Plasticity controlled via the extracellular matrix

Chondroitin sulphate proteoglycans (CSPG) are chondroitin sulfate polysaccharides that attach to the hydroxyl groups of serine residues on proteins. The negative charges on the chondroitin sulfate are important for regulating the brain’s perineuronal nets, mostly prominently via the inhibition of the sprouting and growth of axons. One region where it has been shown to regulate [...]

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Prefrontal cortex hemoglobin concentration in individuals with autism, unaffected siblings, and controls

Interesting article by Kawakubo et al correlating the level of hemoglobin in the prefrontal cortex during a letter fluency task using near infrared spectroscopy. Via twin studies autism is already believed to have a genetic aspect but this kind of dose-dependent effect is illuminating nonetheless. Here’s the meaty image, and note that the fluency task [...]

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No uniformity of cortical microstructure

The sensory cortex contains many columns of vertically arranged neurons that span the width of the cortex, share connectivity, and, importantly, respond to a single peripheral receptive field. This arrangement suggests homogeneity. But that assumption fails upon closer analysis, since cell type, synapse organization, and gene expression differ widely between and within species. Casanova et [...]

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