Brain Algorithms

I will praise thee; for I am fearfully and wonderfully made:

Psalm 139:14

"The human brain keeps surprising scientists with its unfathomable complexity as well as its nifty algorithms.

The cerebellum, or “little brain” located next to the brain stem, has gotten short shrift for years compared to its superior, the cerebral cortex with all those folds of gray matter. Scientists at SDSU are finding out it is more complex than expected. It now is seen as a highly versatile portion of the brain with complexity of its surface giving the cerebral cortex a run for its money.

It’s essentially a flat sheet with the thickness of a crepe, crinkled into hundreds of folds to make it fit into a compact volume about one-eighth the volume of the cerebral cortex. For this reason, the surface area of the cerebellum was thought to be considerably smaller than that of the cerebral cortex.

An SDSU neuroimaging expert discovered the tightly packed folds actually contain a surface area equal to 80% of the cerebral cortex’s surface area.

The scientists in the article are calling the cerebellum “quite the jack of all trades” because of its “versatile role, contributing to our five senses as well as pain, movements, thought, and emotion.”

Many readers may be unfamiliar with the “thalamic reticular nucleus” or TRN. It is “believed to act as a gatekeeper for sensory information flowing to the cortex,” this article says. Problems with

this region seem to be associated with autism and other attention disorders.
When sensory input from the eyes, ears, or other sensory organs arrives in our brains, it goes first to the thalamus, which then relays it to the cortex for higher-level processing. 

Impairments of these thalamo-cortical circuits can lead to attention deficits, hypersensitivity to noise and other stimuli, and sleep problems.

When functioning correctly, the TRN serves its users well by “blocking out distracting sensory input.” 

Without that filter, we could easily be overwhelmed with sensations coming too fast to process.

Scientists are finding that the brain constructs physical maps (like paths through a city) and virtual maps (like social networks) in much the same manner. 

Participants given network puzzles to solve were found to build them piecemeal, whether they were physical or virtual networks. Solving the networks called on secondary players in the brain: Without being prompted, based only on pairwise comparisons, the volunteers organized the information into a two-dimensional grid in their brains. This two-dimensional map was present across three brain regions called the hippocampus, entorhinal cortex and ventromedial prefrontal cortex/medial orbitofrontal cortex.

We tend to fit new data around a template with a few landmarks, and build up a “map” that can integrate new data into the template. 

It’s an intelligent way to design, the team found: That allows us to quickly adapt to a new situation based on past experience. 

This may help to explain humans’ remarkable flexibility in generalizing experiences from one task to another, a key challenge in artificial intelligence research.
“We know a lot about how the neural codes for representing physical space,” Boorman said. “It looks like the human brain uses the same codes to organize abstract, nonspatial information as well.”

CEH

Your Film Editor

I will praise thee; for I am fearfully and wonderfully made: Psalm 139:14

"The brain’s hippocampi may be the film editors of our lives, slicing our continuous experiences into discrete cuts that can be stored away as memories. 

That’s the idea raised by a new study that analyzed brain scan data from people watching films such as Forrest Gump.

Radvansky says “The mind is built to deal with complex events.”
While undergoing a functional MRI, 15 people watched Forrest Gump, and 253 people watched Alfred Hitchcock’s television drama Bang! You’re Dead. A separate group of 16 observers watched each of the productions and pressed buttons to indicate when they thought one event ended and another began.

With the data in hand, cognitive neuroscientists Aya Ben-Yakov and Rik Henson, both of the University of Cambridge, aligned participants’ brain activity with the transition points marked by the 16 observers. A brain structure called the hippocampus, known to be important for memory and navigation, seemed particularly active at these junctures, the team reports in the Journal of Neuroscience. When the researchers looked at hippocampus behavior over the entire shows, the brain structure was most active when the observers had indicated a shift from one event to another.
That response “was actually quite striking,” Ben-Yakov says. “I wasn’t expecting it to be this strong and this clear.”

These transitions didn’t always involve jumps to new places or times in the story. One such boundary came near the beginning of Forrest Gump as Forrest sits quietly on a bench. Suddenly, he blurts out his famous greeting: “Hello. My name’s Forrest. Forrest Gump.” The hippocampus may have helped slice that continuous bench scene into two events: before talking and after talking. Such divisions may help package information into discrete pieces that can then be stored as memories, the researchers suspect." 

ScienceNews