(DBS) DIRECT BRAIN STIMILATION

Direct brain stimulation Involves using a device that produces a weak electric current to activate or disrupt the normal activity of neurons in a specific brain area. Direct brain stimulation techniques identify the function of the brain Theres 2 types: (tms) transcranial magnetic stimulation and electrode stimulation This can be done using an electrode or with pulses of transcranial magnetic stimulation An electrode is a small electrified wire (or disc) that can be inserted into a specific area of the brain Direct stimulation of an area of the brain, will stimulate a response such as movement of a body part It is assumed that if direct stimulation initiates a response, then that are of the brain controls or is involved in that response.

Direct brain stimulation Advantages: electrode stimulation have helped researchers identify locations and functions of the brain as well as hemispheric specialisation for different functions. Helped basically map out the functions of brain Its extremely invasive resulting in risks that by today’s standards would be completely unacceptable. Also it is difficult to generalise results

Trancranial magnetic stimulation (TMS) A technique that stimulates the brain, by an electric current, thats generated by a magnetic field The magnetic field releases a harmless electric current in time varying charges(pulses) Tms is used to manipulate the state of brain, and perform experiments that suggest cause-effect relationships

Trancranial magnetic stimulation (TMS) Person is completley conscious When TMS is involved in delivering just a single pulse its called tms or non repeditive tms. When its involved in two or more pulses its called repeditive transcranial magnetic stimulation (rTMS) Can be used for: Patients who have suffered a stroke head or spinal injury or people with possible tumors or neuronal diseases such as parkinsons disease, motor neuron disese and multiple sclerosis.

Trancranial magnetic stimulation (TMS) Advantages: Non invasive Used to map brain areas No anesthesia is needed Use of electrodes have been useful and reliable- disadvantages Cant be used for individuals with any metal piece inside their body Only serious side affect has been induction of a seizure or epileptic convulsion when high level of stimulation has been used. When using rTMS a headache is often reported

Computerised axial tomography (cat) A neuro imaging technique that produces a computer enhanced image of cross sections of the brain , from x –rays taken at different angles procedure: patient must receive an injection of iodine into vein of their arm or hand this iodine goes straight to brain it is used to highlight brains bloood vessels which assists radiologist in interpreting the scan. involves a rotating arc around the head while a computer receives all the snapshots of the area being investigated This rotates around persons head

Computerised axial tomography (cat) An xray source is slowly moved in a circular motion around the head delivering small amounts of radiation at each position. Imagine your brain as a slice of bread. As you remove each slice of bread you can see the entire surface of that slice, from the crust to the centre.

Computerised axial tomography (cat) Advantages Non invasive Extremely useful for spotting and identifying the precise location , and extent of damage, to abnormalities in various brain areas. Help identify location of tumours and extent of damage caused by stroke, injury, or brain disorder. limitations: Significant limitation is that it only shows brain structure not function.

Magnetic resonance imaging (MRI) What is it:A neuro imaging technique that uses harmless magnetic fields and radio waves to vibrate atoms in the brains neurons to produce an image of the brain. How it works: The vibrations are detected by a huge magnet surrounding the person , and are then channelled to a computer that then processes the vibrations and assembles them into a coloured image that indicates areas of high and low brain activity More sensitive than ct . The image is more clearer and structers of the brain are more detailed