Transcript Slide 1
A Computational Model of Emotional Influences on Visual Working Memory Related Neural Activity Nikos Fragopanagos ABSTRACT - We analyze the interaction between John Taylor Schematic outline of the model Model emotion and cognition in terms of a simulation of Based on CODAM model in which attention is created by ‘attention movement control signal’ generated by IMC. the inhibitory interaction observed between the cortex and the dorso-lateral 3 dedicated nodes per module, representing pleasant, neutral and unpleasant stimuli. prefrontal cortex while subjects are processing pictures of various levels of emotional valence. The Input module: node has activation of 1 when corresponding stimulus is presented in paradigm, 0 otherwise. Table of weights the cognitive character, and in addition amygdala Omitted connections are either 1 or nonexistent. Order of differential weights is U-N-P. activation is used as a further bias of attention. Good agreement with observations is obtained. Other single nodes consist of graded neurons with a sigmoid response function and no internal structure. 0 - 2.5 s Implicated brain sites: • PFC • Inferior temporal cortex • VAC • Parietal cortex 2.5 - 14 s 14 s These areas are also often associated with attentional processing. EC cognitive robot project (JT) EC Network of Excellence (NK) Memory task: Subject is required to remember stimulus Memory task: Assessment if probe is equal to remembered cue fMRI results detection DLPFC Conclusions With the current model, we have suggested an account of WM as an emergent property of recurrent interactions between the DLPFC and sensory areas, influenced by emotional stimuli via the amygdala and OFC. This account agrees with fMRI data as presented by Perlstein et al (2002). Analogous neural sites memory GOALS Similarly, in the Perlstein paradigm there is an inverse relationship between DLPFC and OFC activation, indicating a mutual inhibition between these two structures UK (NF) Presentation of unpleasant, neutral or pleasant stimulus Detection task: Comparison of two pictures within probe Emotional Influences on WM MFC IMC / Corollary Discharge Parietal areas Obj Map / Sensory WM VAC BOLD Blood Oxygen Level Dependent CODAM bla Corollary Discharge of Attention Movement DLPFC Dorsolateral prefrontal cortex IMC Inverse Model Controller OFC Orbitofrontal cortex PFC Prefrontal cortex VAC Visual Association Cortex WM Working Memory Outstanding Questions No agreement with some aspects of behavioral data. Is DLPFC accurate site of stimulus – probe matching? Attentional model applied to WM: is distraction caused by attentional mechanism? Handout References Dolcos, F. and McCarthy, G. (2006) "Brain systems mediating cognitive interference by emotional distraction," Journal of Neuroscience 26(7) 2072-2079 OFC This research was supported by Abbreviations Perlstein, Elbert & Stenger (2002) Separable brain structure for maintenance or emergent property of recurrent interactions between neural areas? • activate amygdala and ventrolateral PFC X in schematic outline represents multiplicative modulation, causing attentional amplification in object map by IMC. Paradigm Working Memory • deactivate DLPFC and parietal cortex memory task Lateral inhibition between nodes in object map, exogenous goals, corollary discharge and IMC modules. CODAM attention framework is used to simulate Dolcos & McCarthy find that emotional distracters during delay period in visual WM task detection task OFC orbito-frontal Simulated BOLD responses DLPFC Nienke Korsten Fragopanagos, N., Kockelkoren, S., and Taylor, J. G. (2005) "A neurodynamic model of the attentional blink," Cognitive Brain Research 24(3) 568-586 Korsten, N., Fragopanagos, N., Hartley, M., Taylor, N. and Taylor, J.G. (2006) “Attention as a Controller” Neural Networks In Press Perlstein, W. M., Elbert, T., and Stenger, V. A. (2002) "Dissociation in human prefrontal cortex of affective influences on working memory-related activity," PNAS 99(3) 1736-1741 Taylor, J. G. (2000) "Attentional Movement: the Control Basis for Consciousness," Abstracts of the Society of Neuroscience 26 2231 (#839.3) CNS Group Taylor, J. G. (2005) "Mind and consciousness: Towards a final answer?," Physics of Life Reviews 2(1) 1-45 Dept. of Mathematics