## 3 Cerebellum and Emotional Processing
### Cerebellar Involvement in the Conscious Component of Emotions  
As discussed in the previous section, although the cerebellar vermis participates in fear-related somatic and autonomic aspects, the posterolateral hemispheres have been proposed to mediate the emotional content of fear conditioning at higher cognitive levels [114]. This assumption is supported by the presence of connections between the cerebellar hemispheres and the more ventral and caudal areas of the dentate nucleus, which in turn are connected to the temporal, parietal, and prefrontal cortices [115], which are involved in cognitive elaboration of emotional content [32]. Posterior regions of the cerebellum are activated during the anticipation [80], conscious feelings, and empathy of pain [82]. Furthermore, activation of the posterolateral cerebellar hemispheres is observed in the late acquisition phase of fear conditioning that is linked to the conscious elaboration of emotional content of associative learning [79; 114]. Consistent with these findings, the cerebellum appears to be involved in more complex functions that are inherent to emotions and affects. This idea is supported by neurophysiological data that show a connection between the cerebellum and higher-order cerebral domains [84; 85]. Whereas cerebellar input to autonomic pathways travels along a closed neuronal loop, event-related potentials (ERP) data has characterized the cerebellum in higher-order emotional processing as an active interface with large-scale cerebral pathways that are involved in emotionally conscious processes, including recognition and response to cues with emotional valence. Impairments in visual emotional attention [84] and emotional face recognition [85] have been reported in subjects affected by cerebellar hemispheres damage. Moreover, neuroimaging and neurostimulation studies have shown the involvement of the cerebellum in conscious processing of emotional facial expressions [69; 81; 85]. The processing of emotion from facial expressions requires various psychological processes that are controlled by a wide array of cerebral structures [116], which involve both unconscious and conscious processes [17; 78]. Facial perception is defined as \"higher-level visual processing of faces\" [117], involving perception and recognition of the emotional meaning [118]. Facial expressions are crucial to non-verbal social interactions and are markers of an internal state or an intention [119; 120]. Recognizing facial expressions is vital in a complex social world as it permits one to detect the emotional state of another person and provides cues on how to respond in social situations [121; 122]. As discussed in the previous section, the cerebellum has been linked to the implicit processing of facial expressions. However, fMRI studies have shown that the cerebellum is also activated in addition to the amygdala and prefrontal cortex during conscious processing of emotional faces [17; 36]. These findings are not surprising, considering that the cerebellum belongs to a widespread network, including the amygdala-medial prefrontal circuitry, which contributes to determine the meaning of external stimuli and to facilitate cortical processes to react to them coherently [17; 123]. Specifically, the medial prefrontal cortex is involved in emotional self-awareness, playing a key role in complex aspects of emotional processing, such as social interaction [124]. The amygdala is associated with the perception of emotion, specifically faces [118] and emotional arousing effects [125; 126; 127; 128]. Direct support of the hypothesis of cerebellar function in the conscious processing of emotional faces comes from stimulation studies that have observed a greater ability to recognize negative facial expressions after transcranial direct current stimulation (tDCS) is performed over the cerebellum [86].