Clever Corvids: a degree of abstract thought (Introduction)

by David Turell , Thursday, September 22, 2016, 20:26 (2772 days ago) @ dhw

Brain studies of the birds show they can mimic human brain function in different regions because the birds do not have neo-cortex: - http://nautil.us/issue/40/learning/why-neuroscientists-need-to-study-the-crow - "Corvids, such as crows, ravens, and magpies, are among the most intelligent birds on the planet—the list of their cognitive achievements goes on and on—yet neuroscientists have not scrutinized their brains for one simple reason: They don't have a neocortex. The obsession with the neocortex in neuroscience research is not unwarranted; what's unwarranted is the notion that the neocortex alone is responsible for sophisticated cognition. Because birds lack this structure—the most recently evolved portion of the mammalian brain, crucial to human intelligence—neuroscientists have largely and unfortunately neglected the neural basis of corvid intelligence. - "This makes them miss an opportunity for an important insight. Having diverged from mammals more than 300 million years ago, avian brains have had plenty of time to develop along remarkably different lines (instead of a cortex with its six layers of neatly arranged neurons, birds evolved groups of neurons densely packed into clusters called nuclei). So, any computational similarities between corvid and primate brains—which are so different neurally—would indicate the development of common solutions to shared evolutionary problems, like creating and storing memories, or learning from experience. If neuroscientists want to know how brains produce intelligence, looking solely at the neocortex won't cut it; they must study how corvid brains achieve the same clever behaviors that we see in ourselves and other mammals. - *** - "Examining the activity of over 300 neurons in two birds, Nieder's team found that the crow's NCL activity matched that of a primate's prefrontal cortex: Both of the species' neurons activated the most during the presentation of the rule cue, while activating much less in response to the images themselves. Some neurons responded specifically to the match cue (blue circle or glissando) and others to the non-match (red circle or noise); importantly, the neurons from each species activated in the same fashion regardless of the cue's sensory modality (auditory or visual). Nieder's results imply that both crows and primates evolved to use the same computation, albeit through radically different machinery, to solve the problem of representing abstract information—in this case, auditory or visual rules to a game. - *** - "Regardless of the dots' size and position, their quantity got encoded: Specific NCL neurons reacted to specific numbers, and activity in the NCL reflected the crows' behavior. The birds made more mistakes, for example, when comparing neighboring numbers, especially when the numbers were large (for instance, four versus five). This could potentially be explained by the pattern of neural activity Nieder saw in the NCL: Neurons that reacted strongly to higher numbers were also more likely to be activated by neighboring numbers than those that reacted to small numbers. Perhaps most intriguingly, the same behavioral and neural results were previously found in the primate PFC. That suggests that radically different brains may also have the same neural basis for the difficulty they each have in distinguishing large quantities. - "If, as Nieder told me, “the codes in the avian NCL and the mammalian PFC are the same, it suggests that there is one best neuronal solution to a common functional problem”—be it counting or abstract reasoning. What's fascinating is that these common computations come from such different machinery. One explanation for this evolutionary convergence could be that—beyond some basic requirements in processing—the manner in which neurons are connected does not make much difference: Perhaps different wiring in the NCL and PFC still somehow leads to the same neural dynamics." - Comment: This is an example of evolutionary convergence in brain function. Crows and humans are very far apart in mental ability, but these findings are a fascinatingview of how evolution progresses.