Major forms of pre-synaptic endocytosis

Above is a model of a generic synapse, showing the (upper) pre-synaptic nerve terminal and the (lower) post-synaptic neuron. The pre-synaptic neuron is constantly releasing vesicles that contain neurotransmitters (NT) into the synapse that diffuse to the post-synaptic neuron, and when a pre-synaptic nerve terminal receives an action potential, the rate of this release is [...]

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Binding potential variability connects to psychological variability

Interesting, ostensibly simple study: Buckholtz et al used PET (which is > fMRI, IMCO) on volunteers given amphetamine using a radio-labeled D2-like ligand, fallypride.  They found a significant inverse correlation (r = -0.42 and -0.35 for the left and right striatum) between average D2-like receptor binding potential (i.e. the density of “available” receptors) and striatal [...]

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Dopamine receptor binding potential in the thalamus and creativity

The link between creativity and baseline dopamine receptor availability in key brain regions is fascinating, especially when you attempt to consider how alleles pushing individuals along the schizophrenia spectrum might be adaptive. Manzano et al (here) measured the binding potential of D2 receptors* with PET in the striatum, thalamus, and frontal cortex in healthy individuals [...]

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Effects of protein inhibition on young and mature synaptic vesicle function

Inhibiting translation in hippocampal neurons for short periods of time (2 hours) has differential presynaptic effects based on the cell’s developmental time frame. In young neurons it inhibits induction of LTP and leads to reductions in the pool of available vesicles for exocytosis, which is exacerbated by synaptic activity. In mature neurons, the effects are [...]

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Active zones and postsynaptic clusters at the neuromuscular junction

The synaptic active zone is the site of vesicle docking and NT release. Here is a photo of a synaptic active zone from U Texas’s transmission electron microscopy department: These can look differently depending on the species and type of neuron. Generally they are recognizable by a high linear electron density in the EM image [...]

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Stimulating Kolmer–Agduhr cells elicits swimming in zebrafish

Wyart et al expressed the light-gated ion channel LiGluR as well as the UAS promoter in some zebrafish and crossed these with zebrafish containing the GAL4 transcription factor in various classes of ventral spinal neurons. When the progeny was photo-stimulated in the caudal spinal cord, 94% displayed tail oscillations. The effects were localized down to [...]

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Predicting the effects of psychostimulants with D2 receptors

In 1999 Volkow et al injected carbon-11 radioisotoped raclopride into 23 males, an antagonist on dopamine family 2 (D2) receptors. After the radiotracer had seeped through the blood brain barrier, the researchers scanned them using PET to find time activity curves and thus quantify the amount of D2 receptors. On a later date they gave [...]

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Maze learning in C. elegans

Qin and Wheeler (2006) show that C. elegans can learn to travel through a T maze, and that their latency to reach the bacterial reward diminishes as the trial number increases. These nematodes only have 302 neurons, so any example of them learning associatively always fascinates me. They also have data showing that cat-2 dopamine [...]

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Network activity in hippocampal interneurons is regulated by GABA receptors

In the mammalian hippocampus, parvalbulim (a calcium binding albumin protein) expressing interneurons can be classified into a number of groups. Basket, axo-axonic, and oriens–lacunosum-moleculare (O-LM) are the main three groups, and they each innervate different regions of pyramidal cells in CA1. These are also each GABA-releasing interneurons, which is the main inhibitory neurotransmitter in the [...]

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AVPR1A genetic polymorphisms affect pair bonding in humans

Most mammals do not form long-term pair bonding relationships, but two notable exceptions are prarie voles and humans. The explanation behind these relationships is that the animals have co-opted maternal love for the feelings they have towards their partner. This would explain the male fascination with breasts, which have been decoupled from sex but where [...]

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