Biomedical subjects

Brandon M Wagar

Publications and source records attributed to Brandon M Wagar.

3 recordsLinked to original sources

PubMed2005

Past experience influences object representation in working memory.

The nature of object representation in working memory is vital to establishing the capacity of working memory, which in turn shapes the limits of visual cognition and awareness. Although current theories discuss whether representations in working memory are feature-based or object-based, no theory has considered the role of past experience. However, work with humans and non-human primates suggests that once participants learn which features are important for category membership, these diagnostic features become more salient than non-diagnostic features in long-term memory and object recognition. Critically, the brain areas involved in this diagnosticity effect are also recruited during working memory tasks. We report two experiments testing whether a diagnosticity effect exists in working memory; and whether it is present when visual information is encoded into working memory, or if it is the result of maintenance within working memory. Results showed a diagnosticity effect which was present at encoding. Maintenance did not influence the nature of object representation in working memory. These findings show that the meaning we glean from our past experience has a profound influence on the nature of object representation in working memory.

Adult↗

PubMed2004

Spiking Phineas Gage: a neurocomputational theory of cognitive-affective integration in decision making.

The authors present a neurological theory of how cognitive information and emotional information are integrated in the nucleus accumbens during effective decision making. They describe how the nucleus accumbens acts as a gateway to integrate cognitive information from the ventromedial prefrontal cortex and the hippocampus with emotional information from the amygdala. The authors have modeled this integration by a network of spiking artificial neurons organized into separate areas and used this computational model to simulate 2 kinds of cognitive-affective integration. The model simulates successful performance by people with normal cognitive-affective integration. The model also simulates the historical case of Phineas Gage as well as subsequent patients whose ability to make decisions became impeded by damage to the ventromedial prefrontal cortex.

Affect↗

PubMed2003

Using computational neuroscience to investigate the neural correlates of cognitive-affective integration during covert decision making.

We presented a proposed neural level mechanism for the integration of cognitive and affective information during covert decision making. The central idea is that the ventromedial prefrontal cortex establishes predicted outcomes of responses through its connections with the amygdala, and that this information is passed through the context-moderated gateway in the nucleus accumbens in order to promote behaviours that are most beneficial to the long term survival of the organism. We then implemented the proposed mechanism in a network of spiking neurons, and tested one of its central claims. Results showed that the model was capable of producing behaviour similar to that observed in normal humans, as well as that exhibited during VMPFC damage.

Affect↗