#doupe

Soupe de semoule d’ogre 

Ce jour  là je suis revenue de l’épicerie non seulement avec mes emplettes mais aussi avec une recette et une invitation. Après m’avoir venter les bienfaits de la sémoule je ne peux que  vouloir gouter ainsi elle me donna la recette et je testais le même jour en attendant le jour de l’invitation pour avoir le vrai goût du belboula à la Marocaine .Je vous assure que depuis que j’ai gouter je suis…

Brainard MS, & Doupe AJ (2000). Interruption of a basal ganglia-forebrain circuit prevents plasticity of learned vocalizations. Nature, 404 (6779), 762-6 PMID: 10783889

We were devastated by the news that Dr. Allison Doupe, a much-loved neuroscientist at UCSF, passed away late last year, following a long battle with cancer, a struggle that she refused to let mitigate the exuberance and overflowing passion with which she carried out her research. A symposium in Allison’s honor is being held tomorrow as an opportunity to reflect upon her intellectual and personal life.

Allison was a scientific heroine of the highest order, and she published some maddeningly excellent papes. Her lab made fundamental contributions to our understanding of auditory processing, reinforcement learning, and the effects of social context on neural coding. She was also a vocal advocate for neuroethology and the study of non-traditional model organisms in systems neuroscience. Finally, Allison was an incredibly generous and vivid person.

Allison’s lab studied song learning in birds. Like humans, songbirds learn how to sing from older and wiser adults. During a critical period early in life, each bird memorizes the song of an adult tutor. It then goes off alone and practices, until its own song closely matches the template provided by the tutor.  Birds that are not tutored during their impressionable early days are forever stunted in their ability to produce a stable and satisfyingly melodious warble in their later years. This humbling fact illustrates the importance of the so-called critical period: the brief developmental window in which an animal acquires a skill that persists throughout adulthood. For humans, the critical period of childhood is not only a time in which we develop our motor capacities, but also a moment of heightened attentiveness, during which we learn the templates that guide our behavior as adults. A large part of Allison’s work was devoted to studying the brain circuits that underlie the fascinating processes of song template acquisition and vocal refinement.

During her post-doc with Mark Konishi, Allison was the first to record from neurons in the anterior forebrain pathway (AFP), a region of the bird brain analogous to the mammalian basal ganglia. The AFP is highly interconnected with the motor areas that control song production, and it plays an important but complex role in song learning. By the late 1990’s, several key observations had been made about the role of the AFP in song acquisition. First, lesioning the AFP of a young bird prevents song learning entirely. Second, inactivating the AFP of an adult bird does not disrupt singing of an already learned song. Third, as the bird develops and learns the template song, neurons in the AFP become more responsive to a bird’s own song or that of the tutor, and less responsive to the songs of other birds. 

These clues led Allison and her post-doc (and future husband) Michael Brainard, to hypothesize that the AFP monitors song production and fine-tunes motor output to more closely match the template song. To test this idea, Michael and Allison took advantage of the fact that deafening an adult bird leads to deterioration in song quality. They reasoned that, if the AFP is responsible for refining song production, then it might be the source of song deterioration in deaf birds. Indeed, when they lesioned the AFP in deaf birds, they found that the song no longer degraded. This remarkable result showed that the basal ganglia circuits of the AFP are critical for continual refinement of the bird’s song.

Over the last decade, Allison and her colleagues have continued to expose how the AFP contributes to the learning and maintenance of bird song.  This work has deepened our conception of learning itself, and how young critters of all sorts ascend from the moronic plains of un-coordination to the lofty heights of fine motor control.  One typifying leap in this direction was the discovery that juvenile experimentation is required for song learning, and that this is accomplished in the bird brain by the intrinsic injection of variability from the AFP into the song production pathway.  Work from the Doupe & Brainard labs have provided a fascinating window into how the AFP contributes to song variability, and, in doing so, revealed fundamental insights into how basal ganglia circuits contribute to motor skill learning.