brain science in brooklyn

A Common Neural Currency for Desirability/Preference

An organism’s ability to function effectively in its environment depends on three abilities: (1) the ability to acquire information about the environment and about the organism itself; (2) the ability to manipulate elements of its environment or its own body; and (3) the ability to select among actions, based on available information and criteria that promote the organisms survival and fecundity. In animals, a significant portion of the nervous system’s activities are concerned with this last component, a process usually referred to as “decision making”. The flexibility in behavior conferred by an adaptable decision making system allows individuals to pursue common goals (homeostasis, nutrition, reproduction, etc.) across a wide range of environmental contingencies.

As a decision making agent, the nervous system has a difficult job, since it receives noisy signals from primary sensory organs about an uncertain and ever-changing environment. Information from many different sensory modalities (along with information from memory) must be integrated in order to select a
single action (or sequence) out of a wide range of alternatives. Likewise, the outcomes of the motor output commands it chooses to implement are subject to variability, depending on the state of the environment or the animal’s body (movements are less precise when muscles are fatigued, for example).

Comparison among various pieces of knowledge contributed by sensory systems and various predictions contributed by memory and motor imagery systems demands that all relevant information about the state of the animal with respect to its environment and potential future outcomes of actions be projected
onto some common scale of value or desirability. This allows the best states to be identified and pursued, and the worst states to be identified and avoided.

The form of this projection from multi-dimensional “polysensory and memory” space to approximately scalar “desirability” space and the possible mechanisms by which it is implemented in the brain remain an area of vigorous speculation and research. The search for the nature of the neural currency with which alternatives are compared forms the basis for the study of value-based decision making and neuroeconomics.

NIRS isosurfaces: Isosurfaces around oxyhemoglobin concentration levels in the brain at one instant in time.NIRS isosurfaces: Isosurfaces around oxyhemoglobin concentration levels in the brain at one instant in time.



Transfer Entropy - a measure of directed information transfer (in the Shannon Information sense), and behavior, specifically on rat sensorimotor loops.



"The geometric mean of the mass of a proton and the mass of the sun is 50kg, within a factor of two of the mass of a person." From a talk by Sir Martin Reese. At the intersection of the very large and very small, complexity ensues.

$ M_{sun} = 1.9889\times10^{30}\:kg $
$ M_{proton}=1.6726\times10^{-27}\:kg $
$ \sqrt{M_{sun}M_{proton}}=126.89\:kg \sim M_{person} $



"Equipped with his five senses, man explores the universe around him and calls the adventure Science." - Edwin Hubble (1889 - 1953)



Kings County at NightKings County at Night


Check out this other photo from the rooftops of Brooklyn.