###### Abstract  
Studies from the past three decades have demonstrated that there is cerebellar involvement in the emotional domain. Emotional processing in humans requires both unconscious and conscious mechanisms. A significant amount of evidence indicates that the cerebellum is one of the cerebral structures that subserve emotional processing, although conflicting data has been reported on its function in unconscious and conscious mechanisms. This review discusses the available clinical, neuroimaging, and neurophysiological data on this issue. We also propose a model in which the cerebellum acts as a mediator between the internal state and external environment for the unconscious and conscious levels of emotional processing.  
Keywords:cerebellum; emotions; affects; conscious; unconscious; psychopathology +
Footnote †: journal:  
Cerebellar function in emotions must be viewed with regards to its anatomical and functional connections with the neural circuits that subserve various emotional domains [19; 25; 26; 27]. It has been proposed that two neural systems are associated with emotional processing: one operating on an implicit level and another on an explicit level [28; 29; 30; 31; 32]. Whereas the cerebellum has been associated with information processing on an implicit level in other functional domains [33; 34; 35], it has been described as being involved in the implicit and explicit components of the emotional domain [36; 37].  
In cognitive science, the distinction between implicit and explicit processes corresponds to that between unconscious and conscious processes [38]. Emotional phenomena that are executed without conscious processing and occur automatically--such as peripheral physiological arousal--are considered to be implicit, whereas all emotional experiences that require processing at higher levels and evoke conscious feelings are defined as explicit [28; 32].  
Thus, according to this theoretical framework, the terms unconscious and implicit are synonymous, as are conscious and explicit in this report.  
Despite the copious data on the cerebellum and emotional processes [39], the cerebellar involvement in unconscious and conscious components of emotions is still unclear.  
In this article, we review the available clinical, neuroimaging, and neurophysiological data, to better clarify cerebellar function in these components of emotional processing.  
This approach will increase our understanding of the function of the 'emotional cerebellum' in addition to providing insights into cerebellar involvement in behavioral control and in neuropsychiatric and mood disorders.  
The following points will be highlighted:  
* Emotional processing implies the existence of unconscious and conscious components.
* The cerebellum is connected to cerebral structures that are involved in unconscious and conscious emotional processing.
* In the unconscious component of emotions, cerebellar involvement is supported by its influence in modulating autonomic reactions, the automatic component of emotional learning, and implicit processing of facial expressions.
* In the conscious component of emotions, the involvement of the cerebellum is supported by its influence on the emotional content of fear conditioning, conscious processing of emotional facial expression, the ability to recognize negative emotions, and self-perception of negative emotions.
* In the emotional domain, measuring cerebellar function with regards to state estimation and its ability to process and predict sequential events allows us to compare internal and external events on the unconscious and conscious levels.