Evidence accumulation in changing environments: The price of optimality
To make decisions in a constantly changing world, organisms must account for environmental volatility and discount old information when making decisions based on such accumulated evidence. We introduce Bayesian inference models of decision making, and derive an ideal observer model for inferring the present state of the environment along with the environment's rate of change. Such models can be derived when the evidence stream is persistent and noisy (e.g., random dot displays) or when evidence is pulsatile (e.g., clicks provided to the ears).
Regulation of cortical dynamics by internal models
Theoretical considerations and psychophysical studies of sensorimotor integration describe the dynamic regulation of behavior in terms of three computational building blocks: a controller (i.e., inverse model), a predictor (i.e., forward model) and a state estimator (i.e , Bayesian estimator). However, due to the complexity and concurrent engagement of these computations during natural movements, direct evidence that the nervous system establishes inverse and forward models remains elusive.
Pacemaking and Bursting in Midbrain Dopamine Neurons
Midbrain dopamine neurons are implicated in many disorders of dopamin signaling, including addiction, schizophrenia and Parkinson’s disease.In vivo, they exhibit two primary activity patterns, tonic (singlespike) firing and phasic bursting The spontaneous tonic firing ofthese neurons plays a fundamental role in dopaminergic signaling by setting the basal level of dopaminergic tone in the striatum andsetting the gain for phasic reward signaling.
The Neural Marketplace
The brain consists of billions of neurons, which together form the world’s most powerful information processing machine. The fundamental principles that allow these cells to organize into computing networks are unknown. This talk will describe a hypothesis for neuronal self-organization, in which competition for retroaxonal factors causes neurons to form functional networks, through processes akin to those of a free-market economy. Classically, neurons communicate by anterograde conduction of action potentials.