In a study published in Cell, a research team led by Zhu Shujia from the Center for Excellence in Brain Science and Intelligence Technology of the Chinese Academy of Sciences (CAS), along with Li Yang from the Shanghai Institute of Materia Medica of CAS, has dissected the assembly and architecture of endogenous N-methyl-ᴅ-aspartate receptors (eNMDARs) in the adult mammalian cerebral cortex and hippocampus.

Learning and memory are fundamental brain functions that underlie human cognition and perception of the world, which rely on development-and activity-dependent synaptic plasticity. NMDA receptors, members of the excitatory ionotropic glutamate receptor family, are essential to these processes.

They regulate the strength of synaptic connections, playing a critical role in advanced brain functions. In higher brain structures involved in cognition, such as the cerebral cortex and hippocampus, they are especially vital for cognitive function.

The axon initial segment (AIS) is where nerve signals begin, and its adaptability is key to brain function. Scientists have found that the AIS changes in response to activity levels, helping neurons maintain balance. By using advanced imaging techniques, they have observed these changes live for the first time, deepening our understanding of brain plasticity.

This old talk by Daniel Dennett touches on a lot of topics we’ve discussed recently. Dennett explains why it’s wrong to regard phenomenal consciousness (the “what it’s likeness” or “raw experience” version) as separate from access consciousness (the cognitive access of information for decision making, memory, report, etc).

Note that Dennett doesn’t deny the existence of phenomenal consciousness here, just the idea that it’s something separate and apart from access. He even passes up opportunities to dismiss qualia, although he does provide a reduction of them.

This video is about 66 minutes long. Unfortunately the video and sound quality aren’t great, and the camera operation is annoying, but the talk is worth powering through.

Attention schema theory has some plausibility.

Lately I’ve been reading up on global workspace theory (GWT). In a survey published last year, among general consciousness enthusiasts, integrated information theory (IIT) was the most popular theory, followed closely by GWT. However, among active consciousness researchers, GWT was seen as the most promising by far (although no theory garnered a majority). Since seeing those results, I’ve been curious about why.

One reason might be that GWT has been around a long time, having first been proposed by Bernard Baars in 1988, with periodic updates all recently republished in his new book. It’s received a lot of development and has spawned numerous variants. Daniel Dennett’s multiple drafts model is one. But perhaps the one with the most current support is Stanislas Dehaene’s global neuronal workspace, which I read and wrote about earlier this year.

All of the variants posit that for an item to make it into consciousness, it has to enter a global workspace in the brain. This is most commonly described using a theater metaphor.