USMLE STEP 1 NEUROLOGY 2026 |
COMPLETE STUDY GUIDE & HIGH-YIELD
PRACTICE QUESTIONS
| GRADED A+ | GUARANTEED SUCCESS
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales Included
,How does FGF affect chordin and FGF regulates chordin and noggin to down
noggin? regulate BMP which leads to neural plate induction
Three Primary Vesicles 1. Forebrain [Prosencephalon]
2. Midbrain [Mesencephalon]
3. Hindbrain [Rhombencphaln]
The Forebrain gives rise to: 1. Telencephalon [Cerebral hemispheres, lateral
ventricles]
2. Diencephalon [Thalamus, Third Ventricle]
The Midbrain gives rise to: 1. Mesencephalon [Midbrain, aqueduct]
The Hindbrain gives rise to: 1. Metencephalon [Pons, cerebellum, upper part of
the fourth ventricle]
2. Myelencephalon [Medulla, Lower part of the
fourth ventricle]
CNS/PNS Origins Neuroectoderm = CNS neurons, ependymal cell
[Inner lining of ventricles, makes CSF],
oligodendrocytes, astrocytes
Neural crest cells = PNS, schwann cells
Mesoderm = Microglia [Like Macrophages,
originate from Mesoderm]
,Neural tube defects NEUROPORES fail to fuse [4th week] → Persistent
connection between amniotic cavity and spinal
canal
Associated with:
1. Low folate levels before conception and during
pregnancy
2. ↑ a-fetoprotein levels [AFP] in amniotic and
maternal serum
3. ↑ AChE in amniotic fluid [Helpful confirmatory
test]
-- Fetal AChe in CSF transudates across defect into
amniotic fluid
Spina bifida occulta Failure of bony spinal canal to close, NO
STRUCTURAL HERNIATION
Usually seen at lower vertebral levels
DURA INTACT
Associated w/ tuft of hair or skin dimple at level of
bony defect
NORMAL AFP
, Meningocele Meninges [BUT NO NEURAL TISSUES] herniates
through bony defect
Meningomyelocele Meninges and neural tissue herniate through bony
defect
Associated w/ Arnold-Chiari Type II Malformation
Anencephaly Malformation of the ANTERIOR NEURAL TUBE →
1. No forebrain
2. Open calvarium
Clinical Findings:
1. ↑ a-fetoprotein levels [AFP]
2. Polyhydramnios [No swallowing center in brain]
3. Associated w/ MATERNAL TYPE I DIABETES
4. Maternal folate supplementation ↓ risk
COMPLETE STUDY GUIDE & HIGH-YIELD
PRACTICE QUESTIONS
| GRADED A+ | GUARANTEED SUCCESS
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales Included
,How does FGF affect chordin and FGF regulates chordin and noggin to down
noggin? regulate BMP which leads to neural plate induction
Three Primary Vesicles 1. Forebrain [Prosencephalon]
2. Midbrain [Mesencephalon]
3. Hindbrain [Rhombencphaln]
The Forebrain gives rise to: 1. Telencephalon [Cerebral hemispheres, lateral
ventricles]
2. Diencephalon [Thalamus, Third Ventricle]
The Midbrain gives rise to: 1. Mesencephalon [Midbrain, aqueduct]
The Hindbrain gives rise to: 1. Metencephalon [Pons, cerebellum, upper part of
the fourth ventricle]
2. Myelencephalon [Medulla, Lower part of the
fourth ventricle]
CNS/PNS Origins Neuroectoderm = CNS neurons, ependymal cell
[Inner lining of ventricles, makes CSF],
oligodendrocytes, astrocytes
Neural crest cells = PNS, schwann cells
Mesoderm = Microglia [Like Macrophages,
originate from Mesoderm]
,Neural tube defects NEUROPORES fail to fuse [4th week] → Persistent
connection between amniotic cavity and spinal
canal
Associated with:
1. Low folate levels before conception and during
pregnancy
2. ↑ a-fetoprotein levels [AFP] in amniotic and
maternal serum
3. ↑ AChE in amniotic fluid [Helpful confirmatory
test]
-- Fetal AChe in CSF transudates across defect into
amniotic fluid
Spina bifida occulta Failure of bony spinal canal to close, NO
STRUCTURAL HERNIATION
Usually seen at lower vertebral levels
DURA INTACT
Associated w/ tuft of hair or skin dimple at level of
bony defect
NORMAL AFP
, Meningocele Meninges [BUT NO NEURAL TISSUES] herniates
through bony defect
Meningomyelocele Meninges and neural tissue herniate through bony
defect
Associated w/ Arnold-Chiari Type II Malformation
Anencephaly Malformation of the ANTERIOR NEURAL TUBE →
1. No forebrain
2. Open calvarium
Clinical Findings:
1. ↑ a-fetoprotein levels [AFP]
2. Polyhydramnios [No swallowing center in brain]
3. Associated w/ MATERNAL TYPE I DIABETES
4. Maternal folate supplementation ↓ risk
