Fast alternating brainwaves: How do our brains make decisions in a bunch of options?

When faced with a decision, the brain makes a trade-off between options in a fast-moving brain wave cycle.in daily life, all people often face conscious and unconscious choices.this includes not only what to eat, what to wear, or how to spend the weekend, but also which hand should be used to hold the pen and whether to change the sitting posture.in order to make even trivial decisions, our brains sift through a bunch of "if's" and weigh various hypotheses.even those choices that seem to be made automatically - like avoiding a speeding car - the brain can infer from past experience very quickly, make predictions and guide your behavior.in a recent paper published in the journal Cell, a team of researchers in California studied the brains of rats that were about to make a decision, to see how their neurons made quick decisions about existing competitive options.the mechanisms described in this study may not only be the basis of decision-making, but also the ability of animals to imagine more abstract possibilities, similar to imagination.the team studied cell activity in the hippocampus of rats.the hippocampus is a hippocampal region of the brain, which is considered to play an important role in navigation, memory storage and retrieval.the researchers paid extra attention to a type of neuron called "location cell".these neurons are also known as "GPS of the brain" because when animals move through space, they map their location in the brain.in the middle of the maze, some of the location cells of the rat signal before (and during) their left turn, while others signal before (and during) the right turn.a logical guess is that when rats approach the turning point, the two groups of location cells sometimes signal at the same time, because in this area of the maze, the joint activity of the location cells reflects the current position of the rats.however, this phenomenon has never occurred.on the contrary, the cells in the two groups emit electrical signals in turn.when animals move in the environment, location cells can signal very quickly in a specific order.this activity is equivalent to scanning from behind to in front of the animal.studies have shown that this forward scan also contains information about the target or reward location.in the mouse brain, these neural activity patterns are called "theta cycle" and repeat about 8 times per second, which represents the constantly updated virtual trajectory of the mouse.however, when an animal is about to act, neural activity associated with theta cycle will recur between different possible future pathways.it's not just a prediction of what's going to happen, but it can be seen as a high-speed trial and error of many possibilities.alternative scenarios in the brain waves, the researchers trained rats to alternate different routes in a W-shaped maze, while recording the activity of location cells in their brains with electrodes.at the beginning of the experiment, rats would run to the middle of the maze and turn left or right.the researchers noticed that when the rats had to decide to turn left or right, some strange behaviors appeared in their location cells.in the middle of the maze, some of the location cells of the rat signal before (and during) their left turn, while others signal before (and during) the right turn.a logical guess is that when rats approach the turning point, the two groups of location cells sometimes signal at the same time, because in this area of the maze, the joint activity of the location cells reflects the current position of the rats.however, this phenomenon has never occurred.on the contrary, the cells in the two groups emit electrical signals in turn.this is like that before a rat decides which way to go, its hippocampus decides the position change it is about to face by alternately processing the "left" and "right" options, and always keeps the difference between the two.the brain is trying to distinguish these signals, but the question is, why? In previous studies, neuroscientists have revealed that when animals walk through mazes, their location cells also exhibit a similar phenomenon of scanning back and forth for possible future positions.however, these changes seem to be related to more cautious behavior, and scientists have not studied whether "left" or "right" performance is random or more regular.in contrast, the changes identified by the ucla-san Francisco research team are precisely consistent with each theta cycle.in one theta cycle, the hippocampus generates a left turn selection signal, and then switches to the right turn selection in the next theta cycle. during the whole experiment, these scenes are not always perfectly alternated, sometimes the same scene lasts for several cycles, but the structure of the signal is undeniable. these 125 millisecond sequences seem to separate the brain's different assumptions about the future into a coherent overall framework. one of the most surprising is its regularity. it's amazing. It's a one-to-one relationship: one cycle to the left, one cycle to the right, then left again, and then to the right. this highly structured arrangement enables each "if" scenario to be tested in a balanced and orderly manner, making it possible to make favorable decisions. when the researchers looked more closely at the neural activity of the theta cycle, they found that the first part of each cycle corresponded to the current position of the rat, while the second part showed the choice of "left" or "right". the whole pattern looks a bit like "current position - possibility to the left - current position - possibility to the right", and then repeats. keep all possible options, and some other interesting patterns are also reflected in the research data. for example, the researchers found that theta cycle not only repeatedly shifted between left and right possibilities faced by rats, but sometimes individual cycles also included the possibility of changing routes. this finding is puzzling because at that time, this change did not seem to be an option for rats to consider. this fact goes against the idea that the hippocampus can only predict what happens next to animals. this suggests that this circulatory structure may be a common way of connecting various things that the hippocampus can encode. this situation looks like a clear expression of thinking, "what happens if I go another way, is it worth going back?" Therefore, theta period seems to have a more general use when it comes to coding hypothetical scenarios. each theta cycle "contains specific content", which may be "left turn" or "right turn", but in a broader sense, it can be a specific memory, or a specific event has occurred, which is encoded in the 125 millisecond period provided by theta oscillation. the researchers said that theta period may be a basic unit of calculation, which the hippocampus uses to test these abstract choices. in most cases, the content of theta cycle may be based on experience, enabling animals to respond quickly and flexibly to changing environments, such as escaping from predators. but studies have also shown that theta cycle does not necessarily help us in any direct or very obvious way in the future, but may play a role in broader creative, productive or imaginative processes. this possibility improves the location of the hippocampus from a brain region that assists decision-making through memory related functions to a learning structure that can generate and extract information from imagined future scenarios and simulate options for other brain regions to evaluate and take action. theta cycle seems to be a clear entry point to help clarify how the hippocampus works. the transient theta cycle may also play an important role in understanding other cognitive processes or neurological conditions. in general, studies of neural processes uniformly observe cell activity during experiments, but frank and his colleagues have shown that it is important to parse information when it is "packaged" on a faster time scale. researchers are currently studying the mechanisms that lead to theta cycle alternation patterns and how this activity affects other parts of the brain in the decision-making process. they also conducted Maze experiments involving more than two alternative scenarios. although the brain rhythms of rodents are different from those of humans, the researchers hope their findings can be applied to other species, including humans.