The present invention provides compositions and methods for ameliorating neurological, attention, or memory disorders and improving learning and cognition through the delivery of insulin A-chain and analogs thereof to a subject. Insulin A-chain, peptides comprising the 21 amino acid sequence GIVEQ CCASV CSLYQ LENYC N (SEQ ID NO:1), and functional analogs thereof are disclosed to modulate neurological activity when administered to a subject. The methods of the invention can be used to prevent or treat neurological disorders as well as improve memory retention and acquisition. The invention includes pharmaceutical compositions comprising a therapeutically or prophylactically effective amount of insulin A-chain peptide or a functional analogs thereof.