Rmacfarl
Thu, Jun-22-06, 06:17
Further to the thread on capacity for literature comes this:
http://www.sciencedaily.com/releases/2006/06/060616092642.htm
Where The Brain Organizes Actions Researchers have discovered
that Broca's area in the brain -- best known as the region
that evolved to manage speech production -- is a major
"executive" center in the brain for organizing hierarchies of
behaviors. Such planning ability, from cooking a meal to
organizing a space mission, is considered one of the hallmarks
of human intelligence.
The researchers found that Broca's area -- which lies on the
left side of the brain about in the temple region -- and its
counterpart on the right side activate when people are asked
to organize plans of action. They said their finding of the
general executive function of Broca's area could explain its
key role in language production.
Importantly, the researchers found that this executive
function of these cortical regions was distinct from the
organization of temporal sequences of actions.
The researchers, Etienne Koechlin and Thomas Jubault of
Universit=E9 Pierre et Marie Curie and Ecole Normale
Sup=E9rieure, described their experiments in the June 15,
2006, issue of Neuron.
In their experiments, the researchers asked volunteers to
execute a sequence of button presses when they saw colored
squares or letters on a screen. Koechlin and Jubault designed
their experiment so that they could precisely distinguish
hierarchical planning of tasks from the temporal organization
of tasks. The subjects were asked to perform both simple
sequences of button presses in response to a stimulus, "simple
action chunks," and "superordinate action chunks." Simple
action chucks were single motor acts that required sequential
action. Superordinate action chunks included "a sequence of
categorization tasks, like sorting a deck of playing cards
first by color, then by suit, then by rank."
While they performed the tasks, the subjects were scanned
using functional magnetic resonance imaging. This scanning
technique involves using harmless magnetic fields and radio
waves to measure blood flow in brain regions, which reflects
brain activity.
Koechlin and Jubault found that Broca's area and its
right-brain counterpart were clearly responsible for
hierarchical processing.
"Our results provide evidence that Broca's area and its right
homolog implement a specialized executive system controlling
the selection and nesting of action segments comprising the
hierarchical structure of behavioral plans, regardless of
their temporal structure," wrote the researchers. "This
finding suggests a basic segregation between prefrontal
executive systems involved in the hierarchical and temporal
organization of goal-directed behaviors, highlighting the
specific contribution of Broca's area and its right homolog to
executive control.
"Interestingly, Broca's area is mostly known to be critically
involved in human language, especially in processing
hierarchical structures of human language and in organizing
linguistic segments that compose speech," they wrote. They
concluded that "our results support the view that Broca's area
implements an executive function specialized for processing
hierarchical structures in multiple domains of human
cognition. We speculate that the modular executive system of
hierarchical control we describe possibly captures key
functional components that may explain the critical
contribution of Broca's area to human language."
The researchers include Etienne Koechlin and Thomas Jubault of
INSERM at Universit=E9 Pierre et Marie Curie and Ecole Normale
Sup=E9rieure in Paris, France.
The work was supported by the French Ministry of Research
(ACI no. 22-2002-350) and the European Young Investigator
Award to E.K.
http://www.sciencedaily.com/releases/2006/06/060616092642.htm
Where The Brain Organizes Actions Researchers have discovered
that Broca's area in the brain -- best known as the region
that evolved to manage speech production -- is a major
"executive" center in the brain for organizing hierarchies of
behaviors. Such planning ability, from cooking a meal to
organizing a space mission, is considered one of the hallmarks
of human intelligence.
The researchers found that Broca's area -- which lies on the
left side of the brain about in the temple region -- and its
counterpart on the right side activate when people are asked
to organize plans of action. They said their finding of the
general executive function of Broca's area could explain its
key role in language production.
Importantly, the researchers found that this executive
function of these cortical regions was distinct from the
organization of temporal sequences of actions.
The researchers, Etienne Koechlin and Thomas Jubault of
Universit=E9 Pierre et Marie Curie and Ecole Normale
Sup=E9rieure, described their experiments in the June 15,
2006, issue of Neuron.
In their experiments, the researchers asked volunteers to
execute a sequence of button presses when they saw colored
squares or letters on a screen. Koechlin and Jubault designed
their experiment so that they could precisely distinguish
hierarchical planning of tasks from the temporal organization
of tasks. The subjects were asked to perform both simple
sequences of button presses in response to a stimulus, "simple
action chunks," and "superordinate action chunks." Simple
action chucks were single motor acts that required sequential
action. Superordinate action chunks included "a sequence of
categorization tasks, like sorting a deck of playing cards
first by color, then by suit, then by rank."
While they performed the tasks, the subjects were scanned
using functional magnetic resonance imaging. This scanning
technique involves using harmless magnetic fields and radio
waves to measure blood flow in brain regions, which reflects
brain activity.
Koechlin and Jubault found that Broca's area and its
right-brain counterpart were clearly responsible for
hierarchical processing.
"Our results provide evidence that Broca's area and its right
homolog implement a specialized executive system controlling
the selection and nesting of action segments comprising the
hierarchical structure of behavioral plans, regardless of
their temporal structure," wrote the researchers. "This
finding suggests a basic segregation between prefrontal
executive systems involved in the hierarchical and temporal
organization of goal-directed behaviors, highlighting the
specific contribution of Broca's area and its right homolog to
executive control.
"Interestingly, Broca's area is mostly known to be critically
involved in human language, especially in processing
hierarchical structures of human language and in organizing
linguistic segments that compose speech," they wrote. They
concluded that "our results support the view that Broca's area
implements an executive function specialized for processing
hierarchical structures in multiple domains of human
cognition. We speculate that the modular executive system of
hierarchical control we describe possibly captures key
functional components that may explain the critical
contribution of Broca's area to human language."
The researchers include Etienne Koechlin and Thomas Jubault of
INSERM at Universit=E9 Pierre et Marie Curie and Ecole Normale
Sup=E9rieure in Paris, France.
The work was supported by the French Ministry of Research
(ACI no. 22-2002-350) and the European Young Investigator
Award to E.K.