Eligibility Criteria:
Inclusion Criteria:
* Healthy volunteers:
* Person who is ≥ 18 years old and ≤ 70 years old
* Subject without neurological history
* Subject without psychiatric history in the semi-structured interview Mini International Neuropsychiatric Interview (MINI).
* Subject having read and understood the newsletter and signed the consent form
* Subject affiliated to a social security scheme.
* Subject capable of understanding spoken and written French.
* Woman of reproductive age with effective contraception as defined by the WHO, for at least three months or postmenopausal.
Patients with drug-resistant bipolar anhedonic depression:
* Patient whose age is ≥ 18 years and ≤ 70 years.
* Patient with depression meeting DSM-5 criteria (Appendix 4) evolving in the context of bipolar disorder.
* Patient with a resistance level greater than or equal to 1 according to the Pacchiarotti classification.
* Patient with an SHAPS anhedonia score greater than 5/14.
* Patient with no other psychiatric pathology in the semi-structured interview Mini International Neuropsychiatric Interview (MINI).
* Stable lithium treatment in the 7 days preceding the inclusion visit.
* Patient who has not received treatment with electroconvulsive therapy in the 2 months preceding the inclusion visit.
* Patient having a normal neurological examination.
* Patient who has read and understood the information letter and signed the consent form.
* Patient affiliated to a social security scheme.
* Patient able to understand spoken and written French.
* Woman of reproductive age with effective contraception as defined by the WHO, for at least three months or postmenopausal.Patient dont l'âge est ≥ 18 ans et ≤ 70 ans.
Patients with drug-resistant bipolar depression of the non-anhedonic type:
* Patient whose age is ≥ 18 years and ≤ 70 years.
* Presence of a depression meeting the criteria of DSM-5 (Annex 4) evolving in the context of bipolar disorder.
* Patient with a resistance level greater than or equal to 1 according to the Pacchiarotti classification.
* Patient with SHAPS anhedonia score less than or equal to 3/14.
* Absence of another psychiatric pathology in the semi-structured interview Mini International Neuropsychiatric Interview (MINI).
* Stable lithium treatment in the 7 days preceding the inclusion visit.
* Patient who has not received treatment with electroconvulsive therapy in the 2 months preceding the inclusion visit.
* Patient having a normal neurological examination.
* Patient who has read and understood the information letter and signed the consent form.
* Patient affiliated to a social security scheme.
* Patient able to understand spoken and written French.
* Woman of reproductive age with effective contraception as defined by the WHO, for at least three months.
Patients with Parkinson's disease :
* Patient whose age is ≥ 18 years and ≤ 70 years.
* Patient with idiopathic Parkinson's disease as defined by the diagnostic criteria of the United Kingdom Parkinson's Disease Society Brain Bank (UKPDSBB) (Annex 8).
* Patient with Parkinson's disease stage less than 3 (mild or moderate severity) according to the classification of Hoehn \& Yahr (Annex 7).
* Patient treated with L-DOPA associated with a dopa-decarboxylase inhibitor (DDC) and who has not changed antiparkinsonian treatment for at least 1 month before the inclusion visit.
* Patient with no neurological disorders other than those induced by Parkinson's disease.
* Patient without depression defined by a score less than or equal to 8 on the Montgomery-Åsberg Depression Rating Scale (MADRS) (Annex 10).
* Patient with no psychiatric pathology at the semi-structured interview Mini International Neuropsychiatric Interview (MINI) (Annex 9).
* Patient who has read and understood the information letter and signed the consent form.
* Patient affiliated to a social security scheme.
* Patient able to understand spoken and written French.
* Woman of childbearing age with effective contraception as defined by the WHO, for at least three months.
Exclusion Criteria:
* Healthy volunteers:
* Person with a psychiatric disorder in the semi-structured interview Mini International Neuropsychiatric Interview (MINI) (Annex 9).
* Person deprived of their liberty by an administrative or judicial decision or person placed under the protection of justice / sub-tutorship or curatorship.
* Subjects with poor understanding of spoken or written French
* Existence of a neurological, rheumatological, orthopedic or psychiatric history, presence of a severe progressive pathology which can modify brain activity or gait parameters.
* Woman of childbearing age not taking effective contraception according to the WHO definition (estrogen-progestogens or intrauterine device or tubal ligation), pregnant (positive urine pregnancy test) or breastfeeding.
* Taking unauthorized treatment during the study and:
* In the 7 days preceding inclusion for dopamine agonists, MAOIs, antiepileptics, antidepressants, benzodiazepines and L-DOPA combined with a dopa decarboxylase (DDC) or catechol-O-methyl transferase inhibitor (COMT).
* In the 28 days preceding inclusion for amphetamines, antivirals, antiemetics.
* In the 2 months preceding inclusion for electroconvulsive therapy
* In the 6 months prior to inclusion for antipsychotics.
* Dependence on a substance other than nicotine.
Patients with drug-resistant bipolar anhedonic depression:
* Patient with depression with psychotic characteristics.
* Patient deprived of liberty by an administrative or judicial decision or person placed under the protection of justice / sub-tutorship or curatorship.
* Subjects with poor understanding of spoken or written French
* Patient with SHAPS anhedonia score less than or equal to 5/14 (Annex 2).
* Patient with a neurological, rheumatological, orthopedic or psychiatric history, presence of a severe progressive pathology which can modify brain activity or gait parameters.
* Woman of childbearing age not taking effective contraception according to the WHO definition (estrogen-progestogens or intrauterine device or tubal ligation), pregnant (positive urine pregnancy test) or breastfeeding.
* Subject with a history of allergy or hypersensitivity to the active substance in DOPACIS (18Fluorodopa) or to any of its excipients.
* Taking unauthorized treatment during the study and:
* In the 7 days preceding inclusion for dopamine agonists, MAOIs, antiepileptics, antidepressants, benzodiazepines and L-DOPA combined with a dopa decarboxylase (DDC) or catechol-O-methyl transferase inhibitor (COMT).
* In the 28 days preceding inclusion for amphetamines, antivirals, antiemetics.
* In the 2 months preceding inclusion for electroconvulsive therapy
* In the 6 months prior to inclusion for antipsychotics.
* Dependence on a substance other than nicotine.
Patients with drug-resistant bipolar depression of the non-anhedonic type:
* Pa Patient with depression with psychotic characteristics.
* Patient deprived of liberty by an administrative or judicial decision or person placed under the protection of justice / sub-tutorship or curatorship.
* Subjects with poor understanding of spoken or written French
* Patient with SHAPS anhedonia score less than or equal to 5/14 (Annex 2).
* Patient with a neurological, rheumatological, orthopedic or psychiatric history, presence of a severe progressive pathology which can modify brain activity or gait parameters.
* Woman of childbearing age not taking effective contraception according to the WHO definition (estrogen-progestogens or intrauterine device or tubal ligation), pregnant (positive urine pregnancy test) or breastfeeding.
* Subject with a history of allergy or hypersensitivity to the active substance in DOPACIS (18Fluorodopa) or to any of its excipients.
* Taking unauthorized treatment during the study and:
* In the 7 days preceding inclusion for dopamine agonists, MAOIs, antiepileptics, antidepressants, benzodiazepines and L-DOPA combined with a dopa decarboxylase (DDC) or catechol-O-methyl transferase inhibitor (COMT).
* In the 28 days preceding inclusion for amphetamines, antivirals, antiemetics.
* In the 2 months preceding inclusion for electroconvulsive therapy
* In the 6 months prior to inclusion for antipsychotics.
* Dependence on a substance other than nicotine.
Patients with Parkinson's disease:
* Patient with depression.
* Patient deprived of liberty by an administrative or judicial decision or person placed under the protection of justice / sub-tutorship or curatorship.
* Subjects with poor understanding of spoken or written French
* Severe form of Parkinson's disease with a Hoehn and Yhar upper or equal 4 (Annex 7).
* Patient with other neurological, rheumatological, orthopedic or psychiatric history, presence of a severe progressive pathology which can modify brain activity or gait parameters.
* Woman of childbearing age not taking effective contraception according to the WHO definition (estrogen-progestogens or intrauterine device or tubal ligation), pregnant (positive urine pregnancy test) or breastfeeding.
* Subject with a history of allergy or hypersensitivity to the active substance in DOPACIS (18Fluorodopa) or to any of its excipients.
* Taking unauthorized treatment during the study and:
* In the 7 days preceding inclusion for dopamine agonists, MAOIs, antiepileptics, antidepressants, benzodiazepines and L-DOPA combined with a dopa decarboxylase (DDC) or catechol-O-methyl transferase inhibitor (COMT).
* In the 28 days preceding inclusion for amphetamines, antivirals, antiemetics.
* In the 2 months preceding inclusion for electroconvulsive therapy
* In the 6 months prior to inclusion for antipsychotics.
* Dependence on a substance other than nicotine.