To start, there are five groups of RSNs one might consider in this discussion, i.e., default mode, frontoparietal, salience, attention (dorsal and ventral), memory and emotion networks and they can be categorized based on the brain functions they involve, i.e., self-awareness, arousal/attention, executive function, social behavior, memory, and emotion. 47 In our experience, it is uncommon to discuss neuropsychological outcomes with patients with focal lesions partly because of lack of confidence in the potential outcomes. These networks are more difficult to identify compared to motor, sensory, and even language networks. Besides preservation of traditionally eloquent function, neurosurgery is increasingly focused on preserving other less discrete functions (i.e., those associated with cognitive and emotional networks that can be mapped using rs-fMRI). Neurosurgery, possibly more than most other surgical specialties, involves balancing the risks and benefits of treatment to achieve an optimal functional outcome. Identifying cognitive and emotional networks Their initial experience in 6 brain tumor patients indicated good spatial agreement among the eloquent networks using rs-fMRI and DES awake mapping. 72 This toolbox provides the ICA results of different numbers of components and automatically identifies the motor, primary visual, and language networks. developed a promising toolbox, ReStNeuMap, to automatically extract the RSNs in neurosurgical patients. proposed an automatic algorithm of component identification to match language networks, and achieved a level of sensitivity that was superior to the SCA approach. proposed and studied the feasibility of mapping language areas based on rs-fMRI data using a semi-automated approach for identification of language components from ICA output. The most common application of rs-fMRI in pre-operative mapping is to identify traditionally eloquent cortex, i.e., mainly the regions involving motor control and language processing. 34 However, resting signal fluctuations have been linked to both structural anatomy of human white matter pathways and neuropsychological outcomes, which increases the confidence in the functional significance of these network measurements. 49 The rs-fMRI acquisition does not require that patients perform a task, which, unfortunately, makes inferring function more challenging. in 1995, 3 and has evolved as technique to depict and quantify certain pathophysiological characteristics of human brain networks. 19 Rs-fMRI was introduced by Biswal et al. 44 Unlike the task-based fMRI that detects brain activation during performance of a certain task, rs-fMRI measures spontaneous low-frequency (<0.1 Hz) BOLD signal fluctuations at rest. 32 BOLD fMRI has entered clinical settings primarily for pre-operative mapping of eloquent cortex in neurosurgical patients. The emergence of blood oxygen level-dependent (BOLD) fMRI makes it possible to noninvasively visualize inferred brain activity when the subject is performing a certain task. In this review, the authors give an overview of the rs-fMRI technique and associated cognitive and emotional resting-state networks, discuss the potential applications of rs-fMRI, and propose future directions for the mapping of cognition and emotion in neurosurgical patients. ![]() Rs-fMRI may be able to map cognitive and emotional networks for individual patients. Resting-state functional MRI is a non-invasive imaging modality that is able to measure spontaneous low-frequency BOLD signal fluctuations at rest to infer neuronal activity. ![]() In addition, there is growing interest in mapping these functions in patients with a broad range of neurosurgical diseases. The focus of these techniques has rightfully been identification and preservation of so called “eloquent” brain functions (i.e., motor and language), but there is building momentum for more extensive mapping of cognitive and emotional networks. ![]() In certain patients with brain tumors and epilepsy, intraoperative electrical stimulation has revealed direct links between these networks and their function. ![]() Over the last two decades we have seen dramatic improvements in the way we can image the human brain and non-invasively estimate the location of critical functional networks. Neurosurgery has been at the forefront of a paradigm shift from a localizationist perspective to a network-based approach to brain mapping.
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