Neural Indications of Stress-Induced Mental Overload
Condition: Healthy; Stress, Psychological
MeSH terms: Stress, Psychological
Study type: Observational

Summary: 
      The aim of the current research is to characterize the complex interaction between stress and
      cognitive workload. Furthermore, the investigators aim to create a functional magnetic
      resonance imaging (fMRI) inspired Electroencephalogram (EEG) brain-based bio-marker for
      cognitive load under stress.

      Secondary project 1 aim: The aim of this study is to characterize the link between
      sensorimotor network (SMN) within and between functional connectivity following the stress
      response and its association with physiological indices and self-report measures.

      Secondary project 2 aim: To elucidate temporal alterations of topological patterns (i.e.,
      integration and segregation), the investigators seek to examine resting state fMRI data
      before and after a cognitive load task and an acute stress induction.
    

Detailed description: 
      Research in the past years on stress and its influence on cognitive workload suggests that
      their relationship is not simply linear. On one hand, stress disrupts the processes of
      attention, memory, and complicated decision-making. While on the other hand, stress response
      allows the individual to recognize threats quickly, react accordingly, return the body to
      homeostasis, and prepare the organism for future challenges. However, it is still unclear why
      different individuals deal with cognitive workload under stress differently, and which brain
      mechanisms are underlying these processes.

      In this current research the use of non-invasive imaging techniques, such as EEG and fMRI, in
      addition to physiological measurements, such as heart rate, skin conductance, and eye
      movements, will allow an objective characterization of the individual's response to cognitive
      workload under stress.

      Secondary Project 1: Psychological stress has an immense influence on mental and physical
      homeostasis. Stress reactivity and recovery involve distributed neural activation, but it is
      unclear which neural mechanism underlies mental and physical associations of stress
      adversities. One candidate for such a connection is the sensorimotor network (SMN); comprised
      of S1, M1, the posterior insula, and the ventral posterior thalamus. The most recognized role
      of the somato-sensorimotor network is the processing of bodily sensory inputs, represented in
      the sensory homunculus. Despite the clear involvement of body reaction to stress, evidence
      regarding the involvement of the sensorimotor network in the modulation of the mental stress
      response is currently lacking.

      Previous studies found decreased or increased resting state-FC (rsFC) between the Posterior
      PCC (PCC); a major node in DMN, and two major nodes in the SMN, the posterior insula and
      thalamus, respectively (Vaisvaser et al., 2013). Additionally, a recent study (Zhang et al.,
      2020) that applied graph analysis, a method to depict segregation and integration typology of
      brain networks, found that under lab-induced stress, the SMN exhibited higher
      between-networks FC, the DMN exhibited enhanced within-FC, and the CEN exhibited decreased
      within-FC. Moreover, the SMN was found to have a high connection ratio within its own network
      nodes. These findings demonstrate an enhanced tendency of the SMN to communicate with other
      functional networks under acute stress. These findings could be framed as a change in network
      typology under conditions of high demands; assuming higher between networks FC in contrast to
      states of low demand (Shine, 2019). Nevertheless, there is limited evidence about the change
      of resting-state functional brain networks following a stressful event. Such an approach will
      help portray the neural mechanism of reactivity and possibly recovery from stress; a major
      source of inter-individual differences. We aim to uncover the involvement of the sensorimotor
      network in response to acute stress and its association with other functional neural
      networks, physiological stress response, and self-report characteristics.

      Secondary Project 2: Functional connectivity changes due to a stressogenic experience were
      thoroughly researched. For the most part, studies have only assessed functional connectivity
      using the conventional static connectivity approach; thus, neglecting temporal alterations of
      topological patterns (i.e., integration and segregation) that remained unclear.
    

Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Healthy male subjects who are eligible to participate in the study according to the
        eligibility criteria.
      
Keywords: Stress response; Cognitive Load