Humans can look beyond immediate positive and negative experiences, and can additionally encode behavioural traits. Both learning from reward and learning from traits involve processing in the ventral striatum. Learning about traits allows another person to be valued in contexts other than the immediate one, and this can be important in social decision-taking.
Archive for the ‘Neuroscience and emotions’ Category
A sub-population of the striatal direct-pathway neurons, known for being connected to voluntary movement, can be the basis of opiate-reward driven activities. The brain’s opioid system is basic to the reward value of stimuli and consequent behaviours. Opioid receptors bind to the brain’s opioid peptides such as enkephalin, β-endorphin, or dynorphin. μ-opioid receptors act to suppress the neuronal activity of neurons that otherwise…
The brain is viewed as having two systems for making decisions. The first approach is to value actions according to the rewards they have generated in the past. A second or model-based approach uses more flexible evaluation of new or changing options, or works on generalisation from known
This study shows that human decision-makers adapt their level of persistence in waiting for rewards to the environment in which the decision is being made. Neural signalling in the ventromedial prefrontal, an area involved with evaluation, could evolve differently for identical time delays, if there is a difference in the environment. The neural valuation system is here seen as including the ventromedial prefrontal (VMPFC), the ventral striatum (VS) and the posterior cingulate cortex
The choices of other people are argued to increase the value of such choices for individuals. The related neural processing is encoded in the ventromedial prefrontal cortex, and the signals are predictive of conformity with other people’s preferences.
This paper can be taken as suggesting that a sense of agency is part of the reward system, encouraging repetition or non-repetition of particular actions or behaviours.
The ventromedial prefrontal cortex is the brain region most associated with ratings of the relative value of stimuli. Subjects are seen as assigning subjective values to the potential outcomes of possible actions leading to valuable results.
A source of despair in consciousness studies is the way in which popular science writers continue to plough ahead making pronouncements that are flatly contradicted by the neuroscientific data of recent years. In particular, consciousness students might be forgiven for screaming every time Libet’s veteran 1980s experiment is trundled out. Halligan and Oakley writing in a recent issue of ‘New Scientist’ go down this predictable route. The brain prepares for actions such as reaching out prior to awareness of the intention to reach.
The paper focuses mainly on the lateral orbitofrontal. Orbitofrontal damage can lead to difficulties in switching from behaviours that were previously advantageous, but have ceased to be so. However, the ability to make an initial discrimination, as opposed to altering an existing one, is usually unaffected. Nevertheless, changes in response are not seen as a core function of the orbitofrontal, and damage to the orbitofrontal is seen to effect a range of other tasks.
A recent study by Aaron Schurger of the Swiss Federal Institute of Technology suggests that for conscious perception to occur brain activity has to be stabilised for some hundreds of milliseconds. In Schurger’s study, subjects saw a red-on-green line drawing in one eye, but a green-on-red drawing in the other eye.