Cortical activity after emotional visual stimulation in minimally conscious state patients

Little is known about the propensity for certain emotional stimuli, such as historically familiar pictures, to activate a large neural network in patients exhibiting a minimally conscious state (MCS). A study was conducted in nine MCS patients and 10 healthy control subjects to explore the degree to which passive stimulation of pictures with different emotional valences--intimate family pictures (FPs), high-stimulating pictures (HSPs), and medium-stimulating pictures (MSPs), all selected from the International Affective Picture System (IAPS)--could elicit activation of large-scale visual networks during functional magnetic resonance imaging (fMRI) scaning. Good cortical activity was evoked in control subjects through visual networks, including the occipital, temporal, parietal, prefrontal, and orbito-frontal gyrus. Although the activation volume was less than that of normal control subjects, similar visual activation was found for MCS patients: six cases with FP, two cases with HSP, and three cases with MSP. We concluded that MCS patients can retain widely distributed visual cortical networks with the potential for visual cognitive function. Picture stimulation, especially with strong emotional FPs with which patients were familiar before brain injury, can elicit conscious brain activity. In this study, we have provided further evidence of the residual functional substrates in MCS patients with respect to increased cortical activity with emotional visual stimulation. The results of this study underscore the need for further research to confirm whether this type of stimulation can facilitate emergence from the MCS status.