2021-09-07 07:22:52

Prelude (2:01)

Today’s topics

  • Announcement: Quiz 1 next Thursday (online via Canvas)
  • Warm-up
  • Wrap up on functional methods
  • Neuroanatomy
    • Through song and dance

Warm-up

What kind of brain imaging technique does this image represent?

What kind of structural brain imaging technique does this image represent?

  • A. Magnetic Resonance Imaging (MRI)
  • B. Positron Emission Tomography
  • C. Event-related potentials (ERP)

What kind of structural brain imaging technique does this image represent?

  • A. Magnetic Resonance Imaging (MRI)
  • B. Positron Emission Tomography
  • C. Event-related potentials (ERP)

Which of the following methods has temporal resolution on the order of seconds?

  • A. functional MRI
  • B. EEG
  • C. MEG
  • D. single-unit recording

Which of the following methods has temporal resolution on the order of seconds?

  • A. functional MRI
  • B. EEG
  • C. MEG
  • D. single-unit recording

Which of the following methods has high/fine spatial resolution?

  • A. functional MRI
  • B. PET
  • C. EEG
  • D. single-unit recording

Which of the following methods has high/fine spatial resolution?

  • A. functional MRI
  • B. PET
  • C. EEG
  • D. single-unit recording

Which measure(s) would you use to map connections between brain areas?

  • A. retrograde/anterograde cell tracers
  • B. diffusion tensor imaging (DTI)
  • C. PET neuroimaging
  • E. both A & B.

Which measure(s) would you use to measure connections between brain areas?

  • A. retrograde/anterograde cell tracers
  • B. diffusion tensor imaging (DTI)
  • C. PET neuroimaging
  • E. both A & B.

Wrap-up on functional methods

Manipulating the brain

  • Nature’s “experiments”
    • Stroke, head injury, tumor
    • Neuropsychology
  • If damage to X impairs performance on Y -> X critical for/controls Y
  • Poor spatial/temporal resolution, limited experimental control

Phineas Gage

Stimulating the brain

  • Pharmacological
  • Electrical (transcranial Direct Current Stimulation - tDCS)
    • Inject low levels of electric current
  • Magnetic (Transcranial magnetic stimulation - TMS)
    • Inject directed pulses of magnetic energy
  • Optically (optogenetics)
    • Light activates ion channels in neurons, causes current to flow

tDCS

TMS

Optogenetic stimulation

  • Insert light-sensitive ion channels into neuronal membrane using genetic engineering
  • Open/close channels (activate/inhibit neurons) with light

Evaluating stimulation methods

  • Spatial/temporal resolution?
    • Assume stimulation mimics natural activity. Does it?
    • Optogenetic stimulation similar to natural stimulation, others less so
  • Deep (electrical) brain stimulation as therapy
    • Parkinson’s Disease
    • Depression
    • Epilepsy

Deep brain stimulation

Simulating the brain

  • Computer/mathematical models of brain function
  • Example: neural networks
  • Cheap, noninvasive, can be stimulated or “lesioned”

Application: AI

Spatial and Temporal Resolution

Bottom line…

  • Neuroscientists…
    • need to use many tools
    • seek converging evidence

Neuroanatomy

Brain anatomy through dance

Finding our way around

Anterior/Posterior

Medial/Lateral

Superior/Inferior

Dorsal/Ventral

Rostral/Caudal

Finding our way around

Anterior/Posterior -> front/back

Medial/Lateral -> inside/outside

Superior/Inferior -> upward/downward

Dorsal/Ventral -> back-ward/belly-ward

Rostral/Caudal -> head-ward/tail-ward

Directional image

Wikipedia

Wikipedia

Bipeds vs. quadripeds

Wikipedia

Wikipedia

No matter how you slice it

Horizontal/Axial

Coronal/Transverse/Frontal

Sagittal (from the side)

Slice diagram

Supporting structures

Meninges

Ventricular system

Blood supply

Meninges

Dura mater

Arachnoid membrane

Subarachnoid space

Pia mater

Meninges

Ventricular system

Ventricles

Lateral (1st & 2nd)

3rd

Cerebral aqueduct

4th

(are filled with) Cerebrospinal fluid (CSF)

Blood Supply

Blood Supply

Arteries

  • external & internal carotid; vertebral -> basilar
  • Circle of Willis
  • anterior, middle, & posterior cerebral

Blood/brain barrier

  • Isolates CNS from blood stream
  • Active transport of molecules typically required
  • (endothelial) cells forming blood vessel walls are tightly packed

Blood/brain barrier

exception is Area Postrema

  • In brainstem
  • Blood-brain barrier thin
  • Detects toxins, evokes vomiting

Area Postrema

Organization of the Nervous System

Central Nervous System (CNS)

  • Brain
  • Spinal Cord
  • Everything encased in bone

Peripheral Nervous System (PNS)

Organization of the brain

Major division Ventricular Landmark Embryonic Division Structure
Forebrain Lateral Telencephalon Cerebral cortex
Basal ganglia
Hippocampus, amygdala
Third Diencephalon Thalamus
Hypothalamus
Midbrain Cerebral Aqueduct Mesencephalon Tectum, Tegmentum

Organization of the brain

Major division Ventricular Landmark Embryonic Division Structure
Hindbrain 4th Rhombencephalon Cerebellum, pons
– Medulla oblongata

Embryonic brain (~6 weeks gestation)

Next time…

  • More neuroanatomy…

References

Abbott, N. J., Rönnbäck, L., & Hansson, E. (2006). Astrocyte-endothelial interactions at the blood-brain barrier. Nature Reviews. Neuroscience, 7(1), 41–53. https://doi.org/10.1038/nrn1824

Begg, D. P., & Woods, S. C. (2013). The endocrinology of food intake. Nature Reviews. Endocrinology, 9(10), 584–597. https://doi.org/10.1038/nrendo.2013.136

Dayan, E., Censor, N., Buch, E. R., Sandrini, M., & Cohen, L. G. (2013). Noninvasive brain stimulation: From physiology to network dynamics and back. Nature Neuroscience, 16(7), 838–844. https://doi.org/10.1038/nn.3422

Sejnowski, T. J., Churchland, P. S., & Movshon, J. A. (2014). Putting big data to good use in neuroscience. Nature Neuroscience, 17(11), 1440–1441. https://doi.org/10.1038/nn.3839