Neurotechniques

• BRAIN SURGERY

  • neurosurgery
  • oldest medical 'speciality' of all times
  • cranial trepanation:

  1. boring holes in the skull
  2. evidence for brain surgery years ago
  3. evidence of skull trepanation as early as 7000 years ago
  4. purpose unclear --> healing/ritual
  5. some people survive multiple skull surgeries
  6. for physicians in ancient egypt, the heart not the brain was the seat of the soul and the repository of memories
• EXPERIMENTAL ABLATION

  • consists in lesioning/destroying specific parts of the brain to study its function

  1. shoaling behaviour in goldfish 
  2. `control group with intact brain and one without ablated telencephalon
  3. fish with ablated telencephalon did not swim with the rest and stood alone in the corner

  • not a common procedure
  • producing brain lesion requires stereotaxic surgery and atlas

  1. helps target regions of the brain
  2. animal is held with a holder, electrode/cannula is positioned in the region of the brain it is interested
  3. electrode --> current is passed through --> produces heat to kill cells
• WILDER PENFIELD

  • used brain stimulation on awake patients for the treatment of epilepsy
  • recorded patients reacition when stimulating certain
  • used the info gained to create a functional map of the cortext of the brain
  • stimulating cortex enabled him to develop a complete map of the motor cortex (motor homunculus)
  • areas for the hand and face are bigger than the rest of the body

  
• MODERN TECHNIQUE- DBS (deep brain stimulation)

  • involves implanting electrodes within certain areas of the brain
  • stimulation is controlled by a pacemaker like device placed under the skin in the upper chest
  • a wire that travels under your skin connects this device to the electrodes in your brain
  • does not destroy any nerve cell
  • regulate abnormal impulses in the brain or affect cert cells and chemicals within the brain
  • used as a treatment of parkinsons to reduce tremors 

  1. help the brain release more atp --> bind to receptor that reduced trauma
• MODERN TECHNIQUES-DBS (deep brain stimulation)

  • approved to treat

  1. dystonia
  2. essential tremor
  3. Parkinson's disease
  4. obsessive-compulsive disorder
  5. epilepsy

  • reserved for people who chant control their symptoms with normal medication
• MODERN TECHNIQUES- CT (computerised tomography)

  • combine a series of x-ray images taken from different angles and uses computer processing to create cross-sectional images
  • quickly examine people with internal injuries from accident or trauma
  • visualize all parts of the body and diagnose injuries or disease + plan medical-surgerical or radiation treatment 
  • used to:

  1. pinpoint the location of a tumour, infection or blood clot
  2. guide procedures such as surgery, biopsy and radiation therapy
  3. detect and monitor diseases such as cancer
  4. monitor treamtnet effectiveness
• MODERN TECHNIQUES- PET (positron emission tomography)

  • uses a radioactive drug (tracer) to show brain activity
  • useful in revealing or evaluating tumours and other brain disorders such as ad and seizures
  • can be combined with ct and mri
  • tacer is injected/swallowed/inhaled depending on the are aof study --> tracer collected in areas of your body that have higher levels of chemical activity which often responds to certain diseases

  -       show up as bright spots
• MODERN TECHNIQUES- MRI (magnetic resonance imaging)

  • uses a a magnetic field and radiowaves to create detailed images of the brain
  • used imaging test of the brain and spinal cord
  • used to diagnose aneurysms, disorders of the eye and inner ear, multiple sclerosis, spinal cord injuries, stroke, tumours and brain injuries from framua
  • special type of mri : functional mri (fmri)

  1. measures metabolic changes within the brain
  2. can be used to examine brain anatomy in people being considered for brain surgery
  3. assess damages from head injuries or disorders such as ad
• FUTURE TECHNIQUES- GENE THERAPY

  • involves altering the genes insdie the bodys cells to treate or stop disease, instead of using drugs or surgery
  • several approaches

  1. replacing a mutated gene that causes diseases with a healthy copy of the gene
  2. inactivating or knocking out a mutated gene that is functioning improperly
  3. introducing a new gene into the body to help fight a disease

  • risky and is understudy 
  • only for diseases with no other cures
• FUTURE TECHNIQUES- GENE THERAPY cont.

  • can be achieved by

  1. ex vivo gene transfer (insertion of genetically modified cells)
  2. direct in vivo injection of viral vectiors into the target tissue --> less invasive

  • common viral vectors:

  1. retroviral and elniviral (lv)
  2. adenovirus and adenosine-associated virus (aav)
  3. herpes simple virus (hsv)

  • steps

  1. new gene is inserted into vector
  2. vector enters target cells
  3. new genes is delivered into the nucleus and transferred to mRNA
• FUTURE TECHNIQUES- STEM CELLS

  • provide new cells for the body as it grows and replace specialized cells that are damaged or lost
  • unique properties

  1. self renewal
  2. change into other types of cells

  • main types:

  1. embryonic
  2. adult --> supply new cells and replace new cells (multipoint)
  3. induced plutipotent stem cells
  4. neural stem cells
• MODERN TECHNIQIUES- neural stem cells

  • self-renewing population that generates the neurons and glia of the developing brain
  •  can be isolated, proliferated, genetically manipulated in vitro and reintroduced into a developing adult or pathologically altered cns
  • considered for use in cell replacement therapies in various neurodegenerative diseases
  • treat mice with hyposmia 

  1. stem cells delivered intranasally engraft to produce olfactory neurons 
  2. new neurons project to the brain olfactory bulb 
  3. sense of smell was recovered