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	  <link:definition>0003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
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	  <link:definition>0010 - Disclosure - Prepaid Expenses</link:definition>
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	  <link:definition>0011 - Disclosure - Accrued Expenses</link:definition>
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	  <link:definition>0012 - Disclosure - Convertible Promissory Notes and Other Notes Payable</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
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	  <link:definition>0014 - Disclosure - Capital Stock</link:definition>
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	  <link:definition>0015 - Disclosure - Related Party Transactions</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/SummaryOfSignificantAccountingPoliciesTables" id="SummaryOfSignificantAccountingPoliciesTables">
	  <link:definition>0018 - Disclosure - Summary of Significant Accounting Policies (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/PrepaidExpensesTables" id="PrepaidExpensesTables">
	  <link:definition>0019 - Disclosure - Prepaid Expenses (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/AccruedExpensesTables" id="AccruedExpensesTables">
	  <link:definition>0020 - Disclosure - Accrued Expenses (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://vistagen.com/role/ConvertiblePromissoryNotesAndOtherNotesPayableTables" id="ConvertiblePromissoryNotesAndOtherNotesPayableTables">
	  <link:definition>0021 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Tables)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/CapitalStockTables" id="CapitalStockTables">
	  <link:definition>0022 - Disclosure - Capital Stock (Tables)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/HistoryAndOrganizationDetailsTextuals" id="HistoryAndOrganizationDetailsTextuals">
	  <link:definition>0023 - Disclosure - History and Organization (Details Textuals)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	  <link:definition>0024 - Disclosure - Basis of Presentation and Going Concern (Details Textuals)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/SummaryOfSignificantAccountingPoliciesDetails" id="SummaryOfSignificantAccountingPoliciesDetails">
	  <link:definition>0025 - Disclosure - Summary of Significant Accounting Policies (Details)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/SummaryOfSignificantAccountingPoliciesDetailsTextuals" id="SummaryOfSignificantAccountingPoliciesDetailsTextuals">
	  <link:definition>0026 - Disclosure - Summary of Significant Accounting Policies (Details Textuals)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
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	  <link:definition>0027 - Disclosure - Fair Value Measurements (Details Textuals)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/PrepaidExpensesDetails" id="PrepaidExpensesDetails">
	  <link:definition>0028 - Disclosure - Prepaid Expenses (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/AccruedExpensesDetails" id="AccruedExpensesDetails">
	  <link:definition>0029 - Disclosure - Accrued Expenses (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
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	</link:roleType>
	<link:roleType roleURI="http://vistagen.com/role/ConvertiblePromissoryNotesAndOtherNotesPayableDetails" id="ConvertiblePromissoryNotesAndOtherNotesPayableDetails">
	  <link:definition>0030 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Details)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
	</link:roleType>
	<link:roleType roleURI="http://vistagen.com/role/ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals" id="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals">
	  <link:definition>0031 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Details Textuals)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals1" id="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals1">
	  <link:definition>0032 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Details Textuals 1)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	  <link:definition>0033 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Details Textuals 2)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals3" id="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals3">
	  <link:definition>0034 - Disclosure - Convertible Promissory Notes and Other Notes Payable (Details Textuals 3)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	  <link:definition>0035 - Disclosure - Capital Stock (Details)</link:definition>
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	<link:roleType roleURI="http://vistagen.com/role/CapitalStockDetails1" id="CapitalStockDetails1">
	  <link:definition>0036 - Disclosure - Capital Stock (Details 1)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
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	<link:roleType roleURI="http://vistagen.com/role/LicensingAndCollaborativeAgreementsDetailsTextuals" id="LicensingAndCollaborativeAgreementsDetailsTextuals">
	  <link:definition>0037 - Disclosure - Licensing and Collaborative Agreements (Details Textuals)</link:definition>
	  <link:usedOn>link:presentationLink</link:usedOn>
	  <link:usedOn>link:calculationLink</link:usedOn>
	  <link:usedOn>link:definitionLink</link:usedOn>
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	  <link:definition>0038 - Disclosure - Capital Stock (Details Textuals)</link:definition>
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	  <link:usedOn>link:calculationLink</link:usedOn>
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	  <link:definition>0039 - Disclosure - Related Party Transactions (Details Textuals)</link:definition>
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	  <link:definition>0040 - Disclosure - Subsequent Events (Details Textuals)</link:definition>
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    <element id="VSTA_InvestorRelationServicesMember" name="InvestorRelationServicesMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestorRelationsAndPublicCompanyServicesMember" name="InvestorRelationsAndPublicCompanyServicesMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
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    <element id="VSTA_QualifiedFinancingMember" name="QualifiedFinancingMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
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    <element id="VSTA_CatoHoldingCompanyMember" name="CatoHoldingCompanyMember" nillable="true" xbrli:periodType="duration" type="nonnum:domainItemType" substitutionGroup="xbrli:item" />
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    <element id="VSTA_BasisOfPresentationAndGoingConcernDetailsTextualsAbstract" name="BasisOfPresentationAndGoingConcernDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CashExpendituresMinimum" name="CashExpendituresMinimum" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CashExpendituresMaximum" name="CashExpendituresMaximum" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CommonStockSharesOutstanding1" name="CommonStockSharesOutstanding1" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_PercentOfConvertiblePromissoryNoteInPrincipalAmount" name="PercentOfConvertiblePromissoryNoteInPrincipalAmount" nillable="true" xbrli:periodType="instant" type="num:percentItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_PrincipalAmount" name="PrincipalAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_GrossProceeds" name="GrossProceeds" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestInQualifiedFinancing" name="InvestInQualifiedFinancing" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AnticipatedCashExpenditures" name="AnticipatedCashExpenditures" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_SummaryOfSignificantAccountingPoliciesDetailsAbstract" name="SummaryOfSignificantAccountingPoliciesDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_OutstandingOptionsUnder2008And1999StockIncentivePlanAnd1998ScientificAdvisoryBoardPlan" name="OutstandingOptionsUnder2008And1999StockIncentivePlanAnd1998ScientificAdvisoryBoardPlan" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_OutstandingWarrantsToPurchaseCommonStock" name="OutstandingWarrantsToPurchaseCommonStock" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_February201212ConvertiblePromissoryNotesAndAccruedInterest1" name="February201212ConvertiblePromissoryNotesAndAccruedInterest1" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_Total" name="Total" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_SummaryOfSignificantAccountingPoliciesDetailsTextualsAbstract" name="SummaryOfSignificantAccountingPoliciesDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_FairValueMeasurementsDetailsTextualsAbstract" name="FairValueMeasurementsDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_OriginalPrincipleBalanceOfNotes" name="OriginalPrincipleBalanceOfNotes" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_RepaymentOfDebtInPercentage" name="RepaymentOfDebtInPercentage" nillable="true" xbrli:periodType="instant" type="num:percentItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_IssuedWarrantToPurchaseCommonStock" name="IssuedWarrantToPurchaseCommonStock" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ChangeInFairValueOfTheWarrantLiability" name="ChangeInFairValueOfTheWarrantLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_IncreaseInPutOptionAndNoteTermExtensionOptionLiabilities" name="IncreaseInPutOptionAndNoteTermExtensionOptionLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_RemainingPutOptionAndNoteTermExtensionOptionLiabilities" name="RemainingPutOptionAndNoteTermExtensionOptionLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_PrepaidExpensesDetailsAbstract" name="PrepaidExpensesDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestorRelationsAndAwarenessServicesPaidByIssuanceOfCommonStockOrWarrants" name="InvestorRelationsAndAwarenessServicesPaidByIssuanceOfCommonStockOrWarrants" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_LegalFees1" name="LegalFees1" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestmentBankerFees" name="InvestmentBankerFees" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AccruedExpensesDetailsAbstract" name="AccruedExpensesDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AccruedResearchAndDevelopmentExpenses" name="AccruedResearchAndDevelopmentExpenses" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AccruedPlacementAgentFees" name="AccruedPlacementAgentFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AccruedRegistrationRightsPayments" name="AccruedRegistrationRightsPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConvertiblePromissoryNotesAndOtherNotesPayableDetailsAbstract" name="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_BeginningBalance1" name="BeginningBalance1" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AdditionsNotesPayable" name="AdditionsNotesPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_PaymentsOfNotesPayable" name="PaymentsOfNotesPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AmortizationOfNotes" name="AmortizationOfNotes" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ForeignCurrencyAdjustmentsotherReclassifications" name="ForeignCurrencyAdjustmentsotherReclassifications" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_EndingBalance" name="EndingBalance" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AccruedInterest" name="AccruedInterest" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals1Abstract" name="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals1Abstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ThresholdForQualifiedFinancingPerShare" name="ThresholdForQualifiedFinancingPerShare" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConversionFeatureOfNote" name="ConversionFeatureOfNote" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals2Abstract" name="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals2Abstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals3Abstract" name="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals3Abstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals4Abstract" name="ConvertiblePromissoryNotesAndOtherNotesPayableDetailsTextuals4Abstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_DebtInstrumentConvertibleTermsOfPayment" name="DebtInstrumentConvertibleTermsOfPayment" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AdditionalDebtAmount" name="AdditionalDebtAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CapitalStockDetailsAbstract" name="CapitalStockDetailsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_MarketPricePerShare" name="MarketPricePerShare" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ExercisePricePerShareWeightedAvg" name="ExercisePricePerShareWeightedAvg" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ExpectedTermYearsMaximum" name="ExpectedTermYearsMaximum" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_WeightedAverageFairValuePerShare" name="WeightedAverageFairValuePerShare" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CapitalStockDetails1Abstract" name="CapitalStockDetails1Abstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_WarrantsOptionAbstract" name="WarrantsOptionAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ExercisePrice" name="ExercisePrice" nillable="true" xbrli:periodType="instant" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ExpirationDate" name="ExpirationDate" nillable="true" xbrli:periodType="instant" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_LicensingAndCollaborativeAgreementsDetailsTextualsAbstract" name="LicensingAndCollaborativeAgreementsDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_MonthlyPayments" name="MonthlyPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AmountPaidForUhnRoyalties" name="AmountPaidForUhnRoyalties" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AwardGivenToSupportDevelopment" name="AwardGivenToSupportDevelopment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AwardedAmountIncreasedToSupportDevelopment" name="AwardedAmountIncreasedToSupportDevelopment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CapitalStockDetailsTextualsAbstract" name="CapitalStockDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestmentWarrantsExercisePrice" name="InvestmentWarrantsExercisePrice" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_SharePrice1" name="SharePrice1" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased1" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased1" nillable="true" xbrli:periodType="duration" type="num:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ContractualTerm1" name="ContractualTerm1" nillable="true" xbrli:periodType="duration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant1" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant1" nillable="true" xbrli:periodType="duration" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CommonStockValue1" name="CommonStockValue1" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AmountsDueForServices" name="AmountsDueForServices" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CommonStockPurchseDiscription" name="CommonStockPurchseDiscription" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_IncreasedValueOfWarrantsExercised" name="IncreasedValueOfWarrantsExercised" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_CommonStockOwned" name="CommonStockOwned" nillable="true" xbrli:periodType="instant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_SecuredConvertiblePromissoryNote1" name="SecuredConvertiblePromissoryNote1" nillable="true" xbrli:periodType="instant" type="num:percentItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_FinancingTransactionsGrossProceeds" name="FinancingTransactionsGrossProceeds" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_InvestmentInQualifiedFinancing" name="InvestmentInQualifiedFinancing" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_AmountOfCommitmentsFromOtherInvestors" name="AmountOfCommitmentsFromOtherInvestors" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_PeriodOfCommitmentsFromOtherInvestors2" name="PeriodOfCommitmentsFromOtherInvestors2" nillable="true" xbrli:periodType="instant" type="xbrli:durationItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_RelatedPartyTransactionsDetailsTextualsAbstract" name="RelatedPartyTransactionsDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_RevolvingLineOfCredit" name="RevolvingLineOfCredit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_UnsecuredPromissoryNotePrincipalAmount" name="UnsecuredPromissoryNotePrincipalAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="VSTA_SubsequentEventsDetailsTextualsAbstract" name="SubsequentEventsDetailsTextualsAbstract" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
</schema>
</XBRL>
