The mystery surrounding how plant neurotoxins came to possess reinforcing properties is termed the paradox of drug reward. Here we propose a resolution to this paradox whereby dopamine - which has traditionally been viewed as a signal of reward - initially signaled aversion and encouraged escape. We suggest that after being consumed, plant neurotoxins such as nicotine activated an aversive dopa...

Episodic memory encodes the unique contexts of events so that people can remember the details of an experience when cued by only a subset of event features (Tulving, 1972). In humans, the hippocampus is crucial for this kind of memory (Scoville and Milner, 1957; Vargha-Khadem et al., 1997). The present study tested whether the hippocampus was required for nonspatial, context-dependent memory re...

Reinforcement learning (RL) research typically develops algorithms for helping an RL agent best achieve its goals—however they came to be defined—while ignoring the relationship of those goals to the goals of the agent designer. We extend agent design to include the meta-optimization problem of selecting internal agent goals (rewards) which optimize the designer’s goals. Our claim is that well-...

Learning agents, whether natural or artificial, must update their internal parameters in order to improve their behavior over time. In reinforcement learning, this plasticity is influenced by an environmental signal, termed a reward, that directs the changes in appropriate directions. We apply a recently introduced policy learning algorithm from machine learning to networks of spiking neurons a...

to determine the level of anxiety and depression in hospitalized patients in surgical and internal departments. a cross sectional study on 359 hospitalized patients who were recruited from internal and surgical wards of khatam alanbia hospital. hospital anxiety and depression scale was used to collect information. borderline cases of anxiety and depression were 26.7% and 24.8%. probable cases o...

In analogy to animal research, where behavioral and internal neural dynamics are simultaneously analysed, this paper suggests a method for emergent behaviors arising in interaction with the underlying neural mechanism. This way an attempt to go beyond the indeterministic nature of the emergent behaviors of robots is made. The neural dynamics is represented as an interaction of memories of exper...