Sentence:  In view of the important role which emotional disturbances play in the genesis of neurotic and psychotic disorders and the parallelism observed between autonomic states and psychological behavior in <WSD>several</WSD> instances , it is further suggested that a hypothalamic imbalance may play an important role in initiating mental changes . 
Meaning of the word marked with <WSD> tags:  (used with count nouns) of an indefinite number more than 2 or 3 but not many