NeuroimagingTypes of Brain Scans

CT/CAT, MRI, fMRI, PET and SPECT

OverviewNeuroimaging falls into two broad categories: * Structural imaging, which deals with the structure of the brain

and the diagnosis of gross (large scale) intracranial disease (such as tumor), and injury, and

* functional imaging, which is used to diagnose metabolic diseases and lesions on a finer scale (such as Alzheimer's disease) and also for neurological and cognitive psychology research and building brain-computer interfaces.

Functional imaging enables, for example, the processing of information by centers in the brain to be visualized directly. Such processing causes the involved area of the brain to increase metabolism and "light up" on the scan.

Computed Axial TomographyCAT or CT Scan

• Series of x-rays of the head taken from many different directions

• Typically used for quickly viewing brain injuries

• Typically the information is presented as cross sections of the brain

Magnetic Resonance Imaging (MRI Scan)

• (MRI) uses magnetic fields and radio waves to produce high quality two- or three-dimensional images

• creates images of both surface and subsurface structures with a high degree of anatomical detail

Functional Magnetic Resonance Imaging (fMRI)

• Shows images of changing blood flow in the brain associated with neural activity

• Reflects which brain structures are activated (and how) during performance of different tasks.

• this image shows areas active for visual memory (green), aural memory (red), and both types of memory (yellow).

Positron Emission Tomography (PET Scan)

• used to image what the brain is doing

• PET Scan tests for glucose utilization - the greater the utilization of sugar, the higher the metabolic activity in that part of the brain

20 year old brain

Single Photon Emission Computed Tomography

(SPECT Scan)• looks at blood flow

and activity patterns• SPECT looks at how

the brain functions• http://www.amenclinics.com/brain-science/spect-image-gallery/

Brain Maturation

• The upper row of PET scans of a human newborn show the typical pattern of glucose uptake by the brain (dark indicates higher uptake).

• Compare these images with those of a one-year-old child, as shown in the lower panel. Courtesy of Harry T. Chugani

Brain Maturation

• Time-Lapse Imaging Tracks Brain Maturation from ages 5 to 20

• http://www.youtube.com/watch?v=LT7elnCz6SM&NR=1

Synaptic Activity

• This chart shows the rates of glucose consumption by various regions of the cerebral cortex, as a function of age.

• Note the rapid increase between birth and age three to a level that far exceeds that of adults and the gentle downward slope from around age 10.

Vision Occipital Lobes

• A full quarter of the cerebral cortex, the occipital lobes,is devoted to sight (more than any other sense)

Vision

• The complex visual system has been mapped by scientists in more detail than any other area of the brain

Vision

• Growth spurt 2-4 months - corresponds to when babies start to really notice the world

• Peaks about 8 months when each neuron may connect to 15,000 other neurons!

Vision• During this critical

development period brain cells that normally process vision must be properly stimulated– Under stimulated vision

cells either go off to perform another job, or they shrivel and die

– Window of opportunity for vision is the most specific and unforgiving.

– http://www.youtube.com/watch?v=2pK0BQ9CUHk&NR=1&feature=fvwp

Are the horizontal lines parallel or do they slope?

QuickTimeª and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Touch

• The parietal lobe processes touch

• Deprive an infant of touch and her brain and body will stop growing

Touch

• Touch right after birth stimulates growth of the baby’s sensory nerve endings involved in motor movements, spatial orientation and visual perception

Massage

• Premature infants

• Office workers

Movement

• Every movement is a sensory-motor event involving the parietal and frontal lobes and cerebellum

Movementvestibular system

• The vestibular system is a fluid-filled network of canals and chambers deep within the human ear that help us keep our balance and sense which way is up.

• This is the first system to fully develop and myelinate (by 5 months after conception)

Movement

• Critical period for movement lasts awhile

• Much of early brain organization depends on exploring the world through movement

• Movement anchors learning at any age

Movement

• Muscular activities, particularly coordinated movements, stimulate the production of neurotropohins, natural substances that stimulate the growth of nerve cells and increase the number of neural connections in the brain.

MovementImplications for Application

• Limit use of Infant car seats and other containers for babies

• Encourage crawling and other cross lateral movements

Language

Language

• When a child hears a sound repeated over and over again, neurons from the ear stimulate a formation of connections in the auditory cortex (temporal lobe)

Language

• The greater exposure an infant has to words, the faster the child learns language and builds a vocabulary

What do you notice?

Plasticity for language

• 3 month old - the brain can distinguish several hundred spoken sounds, many more than are present in a native language.

• http://www.youtube.com/watch?v=3kuOt4kZUn0&feature=related

Plasticity for language

• 6 month old- auditory map is different in English speaking homes than in Spanish

• http://www.youtube.com/watch?v=aiGNZtKtMCQ

Plasticity for language

• 12 months - babies are babbling in their native language

• http://www.youtube.com/watch?v=Aa9kv4ZhfgE

Plasticity for language

• Up to age 10 - the brain retains ability to re-learn sounds it has discarded; children can easily learn a new language

• http://www.youtube.com/watch?v=qsUfdSb8MXA&NR=1

• http://www.youtube.com/watch?v=msZlNUWc6VM

UW study of language

• UW research on learning a second language – With a live person– Watching a video of the

session– Listening to a tape of

session– http://www.youtube.com/watch?v=Fcb8nT0QC6o

Music• Window of opportunity is

3-10 years.• Early exposure to music

wires neural circuits differently. – The younger a child is when

taking up an instrument the more cortex is devoted to playing it.

• http://www.youtube.com/watch?v=LaDea5spQTc

• http://www.youtube.com/watch?v=Ty-p3Ew9mnc&feature=related

Music

• It’s never too late to learn to play a musical instrument for pleasure

• Circuits for math reside in the brain’s cortex near those for music

Mozart Effect

• Some researchers believe that the complex mathematical nature of Mozart’s music stimulates the brain

• Mozart played for premature babies has positive effect

Mozart Mice

• Mice and Music Experiment Mozart – MUSIC CAN BE

HAZARDOUS TO MOUSE HEALTH

• Be cautious of overly zealous claims

Music Activity

Windows of Opportunity

• Critical periods or windows of opportunity is a complex concept. Interpretations and implications are widespread and contradictory.

• Be cautious of extremes