The current study examined gender differences in neural correlates of online stress‐induced anxiety response in men and women with commensurable levels of STAI anxiety and perceived stress. We report gender‐specific neural correlates of anxiety during stress provocation, mainly in the medial prefrontal and parietal cortices, with opposite patterns of associations in men and women. The observed neural difference indicates that men and women differentially use neural resources when experiencing anxiety during stress.

On the other hand, females exhibited increased activity in the occipital lobe, right temporal gyrus, and insula—regions that are associated with visual processing, verbal expression, and emotional experience, respectively (Grill‐Spector et al., 1998 ; Golby et al., 2001 ; Singer et al., 2009 ). The increased activity in the visual cortex and temporal gyrus indicates that, compared with men, women may be more likely to engage in visualizing their experiences and semantic processing during imagery experiences. The insula is related to emotional arousal and interoceptive processing (Singer et al., 2009 ), suggesting greater emotional and interoceptive activity during imagery in women. In addition, women displayed greater heart rate responses than men, regardless of condition, replicating results of prior studies (Ryan et al., 1994 ; Agelink et al., 2001 ). Higher heart rate has been linked to greater emotional response via autonomic nervous system arousal (Everhart and Harrison, 2002 ; Sinha et al., 2009 ). Elevated heart rate is also often associated with emotional disorders including depression (Lahmeyer and Bellur, 1987 ). Taken together, these findings suggest that during guided imagery, women may experience emotions and feelings via more sensory and semantic processing in the brain and greater autonomic nervous system arousal.

In task‐related activity, a significant gender main effect was observed in corticostriatal regions: men displayed a greater response in the caudate, ACC/PCC, midbrain, thalamus, and parts of the cerebellum, while women showed a greater response in the posterior insula, right temporal gyrus, and occipital lobe. However, no gender × task interaction was observed, suggesting that there are sex differences in neural responses to a general imagery experience, but not specifically to the stress or neutral‐relaxing condition. Specifically, males displayed greater activation in the caudate, midbrain, ACC, and thalamus—brain areas involved in instrumental action and in motor functions. The caudate plays a role in motor processes, planning and execution of movement, and goal‐directed action (Grahn et al., 2008 ), and the midbrain functions in motor movement as well (Boecker et al., 2008 ). The ACC is involved in action selection, error correction, and behavioral adjustment (Shenhav et al., 2013 ). Additionally, the thalamus functions as a motor relay center (Sommer, 2003 ), and the cerebellum also contributes importantly to motor control (Paulin, 1993 ), with some involvement in cognitive and emotional processing (Schmahmann, 2004 ; Stoodley and Schmahmann, 2009 ).

Gender Differences in Neural Correlates of Stress‐Induced Anxiety

Gender differences were evident in the neural correlates of stress‐induced anxiety, even when experiencing similar levels of anxiety during stress. During stress exposure, men and women displayed opposite patterns of associations in the dmPFC, parietal cortex (including left IPL), left temporal gyrus, occipital cortex, and cerebellum regions, where stress‐induced anxiety was associated with greater neural activity in women, but with decreased neural activity in men, in each of these regions. These findings suggest that women experiencing anxiety during acute stress may have difficulty regulating hyperactivity in these regions. On the other hand, men may experience increased anxiety in response to stress because of hypoactivation, or even suppression, of these brain regions.

Differential association with stress‐induced anxiety by gender was observed in the dmPFC and IPL—regions that are involved in high‐level cognitive operations. Activity in the dmPFC is related to higher‐order executive functions and cognitive control (Seo et al., 2014), as well as cognitive awareness of anxious emotions (Etkin, 2010). Additionally, this region has been found to be associated with strategy‐oriented reasoning (Seo et al., 2014) and is involved in high‐level cognitive operations and regulation of response strategies (Matsuzaka et al., 2012). Similarly, increased activity in the left IPL has been associated with greater cognitive reappraisal and response strategies (Seo et al., 2014). Meanwhile, the precuneus is involved in self‐conscious and self‐referential thinking (Cavanna and Trimble, 2006). These studies, along with our findings, suggest that differential activation and engagement of these cognitive processing regions is associated with a gender‐specific anxiety experience during stress. Men and women may differ in the extent to which they engage in cognitive, self‐conscious and referential processes, which in turn may contribute to their differential subjective anxiety experiences.

Consistent with the above interpretation, evidence suggests that the medial PFC, including the dmPFC, is involved in self‐referential thinking, rumination, and depression (Cooney et al., 2010; Nejad et al., 2013). Thus, the higher levels of dmPFC activation associated with stress‐induced anxiety in females suggest that they may have a greater susceptibility to excessive stress‐consistent cognitive processing, including possibly negative cognitions related to the acute stress experience. Consistent with this notion, previous evidence indicates that females have a greater tendency to ruminate than males (Johnson and Whisman, 2013), which could increase their risk for depression and anxiety disorders relative to that of males (Nolen‐Hoeksema et al., 1999). Together, the observed results indicate that, compared with men, higher stress‐induced anxiety in women may be related to overengagement of cognitive processing during stressful events.

In contrast, stress‐induced anxiety in males was associated with decreased reactivity in the dmPFC, precuneus, and IPL. A preclinical study found that hyporeactivity to stress in the dmPFC is associated with a greater anxiety response in male rats (Kalisch et al., 2004). This study proposed that the failure to sufficiently activate the dmPFC in response to stress could contribute to high levels of anxiety. In a similar vein, a study on individuals with anxiety disorders concluded that adequate activation of the dmPFC is beneficial for reducing anxiety (Goldin et al., 2013). Additionally, electroencephalographic studies indicate that a reduced P300 response, which was collected from parietal scalp locations, was associated with externalizing behaviors in men, including aggression and substance abuse (Patrick et al., 2006). Furthermore, an fMRI study found a negative association between IPL activity and violent behavior in men (Kumari et al., 2006), suggesting vulnerability associated with reduced parietal function in men. Overall, the decreased parietal lobe and dmPFC activity observed in the current study could indicate that males have a hypoactive response to stress in regions involved in using cognitive resources or strategies when experiencing stress‐induced anxiety, which may in turn facilitate the tendencies to engage in more externalizing behaviors under stress.

The present study also found gender‐specific associations with stress‐induced anxiety in sensory motor regions including the left temporal gyrus, occipital cortices, and cerebellum. Prior studies indicate that the left temporal gyrus is involved in processing semantic information and verbal stimuli (Golby et al., 2001; Friederici et al., 2003). Along with increased activity in the visual cortex associated with stress‐induced anxiety, the observed patterns may suggest that females engage in more verbal and visual mental activity while experiencing stress, which could enhance their anxiety. The cerebellum is also known to be involved in cognitive and emotional processing (Schmahmann, 2004; Stoodley and Schmahmann, 2009). During emotional processes, cerebellar activity tends to be synchronized with cortical activity (Krienen and Buckner, 2009), suggesting that differential cerebellar activity likely reflects cortical activity (e.g., dmPFC, parietal lobe) in response to stress‐induced anxiety. Taken together, the observed differences in these regions suggest that men and women may differ in the extent to which they engage in verbal processing, visualization, self‐referential thinking, and cognitive processing during the experience of stress and anxiety.