wench brains might not be quite as useless as their runty size suggests , and may even contain social structure that enable them to perform complex cognitive undertaking unremarkably associated with mammalian brains . This being the face , the authors of a new study in the journalTrends in Cognitive Scienceargue that sure high - degree mental capacity may not depend on brain size or structure , but on types of connectivity .
In mammalian head , an arena have sex as theprefrontal cortex(PFC ) controls executive purpose such as working retention , reasoning , and the power to empathize with others . Covering most of the prosencephalon , the PFC is arranged in six layers – known as laminae – each of which hold back a different type of neuronal cell and a finicky pattern of connectivity .
The comportment of this particular structure has therefore been identified as an essential precursor to the advanced cognitive abilities possessed only by mammal .
However , legion studies over the past few decade have argue that some birds may in fact have genial aptitudes on equation with sure mintage of high priest . In one such discipline , an African gray parrot namedAlexlearned to label items and used communicating skills to solve a range of cognitive tasks . Other experiments have let on thatravensemploy clever tactic to try and deceive others when competing for food , whilemagpiesand jackdraws appear to recognize themselves in a mirror , indicating a grade of ego - knowingness .
In illumination of such evidence , the source of the new work suggest that bird brains must hold an equivalent to the PFC , which coordinate executive function yet occupies a much smaller intensity than the mammalian cortex . Reviewing the lit on avian neuroanatomy compiled over several decades , they attempt to explicate how “ birds with humble , non - cortical brains of 5 to 20 grams can show selfsame capabilities to apes with large cortices and brain weight of between 275 and 500 g . ”
African grey parrot are notable for their communication skills . FrameAngel / Shutterstock
They begin with the work ofHarvey Karten , who show in the sixties that , even though avian and mammalian brains differ in structure , they really bear many of the same types of neurons and normal of connectivity . Future studies then showed that the neuron of an avian brainiac region call in thenidopallium caudolaterale(NCL ) connect with one another in a remarkably like way to the neuron of the mammalian PFC .
For example , the NCL has been shown to be pack withdopamine - free fibers , which delay the transmission system of signal so as to store data during work memory tasks , in on the nose the same way as the neurons in the PFCs of monkeys do .
Further studies have indicated that injury to the NCL badly disrupt birds ’ “ conclusion making , rule trailing , encoding of immanent values , and the association of result to actions . ”
As such , the researchers take that the NCL is the avian equivalent of the PFC . Remarkably , however , these two structures are only dissimilar in both their locating within the brain and in form . For case , the NCL does not turn back laminae , seemingly discredit the opinion that the layered structure of the PFC is necessary for the development of advanced cognitive capacities . alternatively , the type of connectivity between neurons may be a more reliable generator of mental aptitude .
Furthermore , because the evolutionary business of birds and mammals diverged some 300 million years ago , the research worker propose that they likely did not both inherit this connectivity from a common ancestor , but evolved to possess it independently of one another .
As such , they claim that “ the NCL and PFC perchance represent a spectacular case of evolutionary convergence , ” which refers to the process by which unrelated species build up the same evolutionary trait .
