Transcript HUMAN INFORMATION PROCESSING

HUMAN INFORMATION
PROCESSING
OTHER SYSTEMS AND
ORGANIZATION
Four volunteers lived for an
entire month in the strange
reverse world we see while
shaving or applying lipstick.
Wearing special 'prism
spectacles' designed to reverse
their vision meant that to go left
they had to turn right, and if
they looked one way to catch a
tennis ball, it would hit them on
the back
BRAIN ADAPTATION TO
REVERSED LEFT-RIGHT
PICTURES
It took three weeks of adaptation for correct answers to
appear, suggesting that a new imagined hand
representation was emerging; the volunteers said they
could visualize their own hands in two ways and could
even choose between the two images.
Brain scans associated activity with these new hand
images in a region called 'Broca's area' that creates
mental pictures of movement. These imagined images
help us plan -- and mimic -- movements says
Rushworth; explaining why a non-cricketer for
example, could do a passable impression of Brian Lara
after seeing him in action.
The results lend weight to an emerging theory that this
brain region helps us adapt when what we see and what
we experience clash, Rushworth adds. This brings
possible implications for understanding how braindamage patients recover, he says, but will be of little
clinical use at present
• MORE PICTURES
ILLUSTRATING
VISUAL
ALGORITHMS
- THE SYSTEM
CREATES STABLE
REPRESENTATION
ONE ANGLE OR
TWO
CHOPSTICKS ?
WE SEE HERE ILLUSORY CONTOURS OF OBJECTS
VISUAL SYSTEM IS REALLY GOOD IN EXTRACTING THEM
JUNCTIONS ARE CRITICAL FOR OBJECT
PERECPTION COMPARE LEFT AND RIGHT SIDES
• VISUAL SYSTEM ASSUMES THAT LIGHT
IS COMING FROM TOP
LIGHT DIRECTION
SAME PICTURE UPSIDE DOWN
• IN ALL FIGURES GREY ELEMENTS HAVE
THEY SAME INTENSITY
BUT PERCEIVED INTENSITY DEPENDS ON THE
SURROUNDING AREA. VISUAL SYSTEM IS THUS
NOT AN OBJECTIVE LIGHT INTENSITY MEASURING
DEVICE
• WHERE IS THE LIGHT SOURCE?
• WE CAN ESTABLISH ITS POSITION FROM
SHADOWS OF OBJECTS
• OBJECTS CAN BE EASILY RECOGNIZED
FROM MOTION OF DOTS IF THEY ARE
MOUNTED ON THE OBJECT
• VISUAL SYSTEM IS ONE IMPORANT
PART OF HIP BUT THERE ARE OTHERS:
-
ACOUSTICAL SYSTEM
HAPTIC SYSTEM (TOUCH)
VESTIBULAR (ORIENTATION IN SPACE)
SMELL
TASTE
• ACOUSTICAL SYSTEM
HEARING + SOUND/SPEECH PRODUCTION
THIS IS MATCHED RECEIVER-TRANSMITTER
VESTIBULAR
SYSTEM
• COCHLEA – SOUND TRANSDUCER
SOUND PRESSURE IS CHANGED INTO
FLUID PRESSURE
MODEL OF COHLEAR
TRANSDUCER
U
T
OUTPUT IS MAXIMUM FOR CERTAIN FREQUENCY
AT SOME POSITION ALONG THE TRANSDUCER
• HAIRS – CHANGE THE MECHANICAL
SIGNAL INTO ELECTRICAL
• ACOUSTICAL SIGNALS – CAN BE
ANALYZED IN TIME AND FREQUENCY OR
BOTH. AND BOTH SYSTEMS SEEM TO
BE PRESENT IN THE BRAIN
WE ARE ABLE TO DETECT PRECISELY
FREQUENCY OF TONES
E.G. SINUSOIDS
AND POSITION OF SOUNDS IN TIME
E.G. CLICKS
IN THE ACOUSTICAL CORTEX THERE
ARE TIME DETECTORS (PLACE) AND
FREQUENCY DETECTORS. BOTH TYPE
OF SYSTEMS OPERATE AT SOME
FREQUENCY RANGES (TOP)
FILTERS ARE BROADLY TUNED
(BOTTOM)
• THE STRUCTURE OF HEARING SYSTEM
WE CAN SEE SEVERAL
STAGES FOM COCHLEA TO
CORTEX
SUPERIOR OLIVARY
NUCLEUS IS THE PLACE
WHERE SPATIAL SOUND
PROCESSING STARTS
MAPPING INTO FREQUENCY
AND SPACE LOCATIONS IS
PRESENT, LIKE IN VISION
IT WAS FOR LOCAL SIGNAL
FEATURES
WE HAVE´SENSITIVITIES FOR
DIFFEERENT FREQUENCIES, HIGHEST IS
IN MIDDLE RANGE
MUSIC FROM INSTRUMENTS CAN BE VERY EFFICIENTLY
RECOGINZED. THIS MUST BE BASED ON DETAILED
FREQUENCY AND TIME ANALYSIS
LOCALIZATION OF SOUND SOURCES
IN SPACE IS BASED ON MEASURING
DIFFERENCES IN TIME OF SOUND ARRIVAL
BETWEEN THE EARS. THIS MUST BE VERY
PRECISE MEASUREMENT, ON THE ORDER
OF TENS OF MICROSECONDS
SOUND LOCALIZATION IS QUITE PRECISE
BUT HEAD MOVEMENTS AND VISUAL
CUES HELP A LOT, ERRORS IN LOCATION
CAN BE SEEN IN PICTURES
MUSIC PROCESSING....
CERTAIN TONES HAVE HARMONY, THEY SOUND NICE TO US,
OTHR TONES NOT. WE ARE PROBABLY BORN WITH A SYSTEM
WHICH PROCESSES TONES AND THUS WE ARE PREDISPOSED
FOR CERTAIN SOUNDS WHICH ARE ”NATURAL” FOR US
• SPEECH PROCESSING SYSTEM
A COMPLEX ELASTIC MECHANICAL SYSTEM CONTROLLED
ELECTRICALLY FOR REGULATION OF AIRFLOW
• BASIC UNITS OF SPEECH –PHONEMS
USING THESE UNITS SPEECH CAN BE GENERATED
HEARING AND SPEECH ARE PRECISLY MATCHED TO EACH OTHER
SPEECH CAN BE RECOGNIZED EVEN AT HIGH LEVEL OF NOISE
AND INTERFERENCE (COCTAIL PARTY EFFECT, MANY PEOPLE ARE
TALKING AT THE SMAE TIME BUT WE ARE ABLE TO CONCENTRATE
ON ONE SPEAKER.
• VESTIBULAR SYSTEM
NOTE THAT THE WORLD WE SEE IS STABLE, WHILE
PICTURES ON RETINAS OF EYES ARE NOT. MOVEMENTS
ARE COMPENSATED BY SIGNALS FROM VESTIBULAR
SYSTEM (ORIENTATION IN SPACE)
EXAMPLE: WHEN PERSON IS ROTATING ON A PLATFORM IN
DARK ROOM, HORIZONTAL LINE WILL BE DEFLECTED
• TOUCH SYSTEM
IT HAS RECEPTORS IN THE BODY.
IN THE BRAIN THERE IS MAPPING OF
THE BODY IN THE CORTEX
• VIEW OF BASIC BRAIN STRUCTURES
• MAPPING OF BODY PARTS IN THE
SOMATOSENSORY CORTEX
• SKIN RECEPTORS OF TOUCH
(CAPSULES AT THE NERVE ENDINGS)
• TOUCH SENSITIVITY THRESHOLD FOR
FEMALES OVER THE BODY
• TOUCH SENSITIVITY THRESHOLD FOR
MALES
FEMALES ARE MORE SENSITIVE!!!
• PAIN SYSTEM
WHAT IS PAIN?
IT IS SIGNALLING FROM THE
BODY TO THE BRAIN ABOUT
IMPROPER OPERATION
THE BRAIN CHANGES ITS ACTION
TO DEAL WITH THE PROBLEM
THERE IS ALSO A SYSTEM FOR
IHIBITING THE PAIN SIGNALS
• ACUPUNCTURE
IT IS ACTIVATION OF TOUCH
AND PAIN SYSTEM IN ORDER
TO STIMULATE OTHER
BRAIN STRUCTURES
PERHAPS IMMUNE SYSTEM IS
STIMULATED???
INTEGRATION OF SENSES
IN BIOLOGICAL SYSTEMS
WE COULD CALL IT
”BIOLOGICAL MULTIMEDIA”
but this is ONLY A JOKE!
• PEOPLE HAVE FANTASTIC CAPABILITIES
IN RECEIVING AND PRODUCING
INFORMATION BY DIFFERENT SENSES
AND SYSTEMS
FOR EXAMPLE THEY CAN SPEAK,
LISTEN AND DANCE AT THE SAME TIME
HOW SUCH THINGS ARE CONTROLLED
AND ORGANIZED IN THE BRAIN?
LET’S SEE FIRST SOME OF THE BRAIN CAPABILITIES
(SOME OF THEM QUITE FUNNY TOO)
CROSSMODAL MATCHING
HERE THE PERSON MUST RECOGNIZE OBJECT VISUALLY,
RECOGNIZE OBJECT TACTILLY, COMPARE THEM AND MATCH
HOW THIS IS DONE? PROBABLY INFORMATION FROM DIFFERENT
SENSES IS STORED IN SOME GENERAL WAY, INEPENDENT FROM
PARTICULAR SENSE
SOME PEOPLE HAVE PECULIAR
EXPERIENCE: THEY FEEL E.G. SPECIFIC
SHAPE WHEN FEEL SPECIFIC TASTE
THIS IS CALLED SYNESTHESIA, ONE CAN SPECULATE THAT
SENSORY SIGNALS GET MIXED UP SOMWHERE
• VENTRILOQUISM - BY COORDINATING
MOVEMENTS OF A PUPPET WITH SPEECH,
VENTIRLOQUIST INDUCES STRONG ILLUSION
THAT THE PUPPET IS SPEAKING
• HOW THE COORDINATION IS DONE?
DEEP IN THE BRAIN THERE IS A STRUCTURE CALLED
SUPERIOR COLLICULUS
• IN THIS STRUCTURE THERE ARE
NEURONS REACTING TO DIFFERENT
SENSORY INFORMATION:
THEY ARE MULTIMODAL
• STIMULATION OF DIFFERENT SENSORY
AREAS OF CORTEX WILL PRODUCE
RESPONSE FROM Superior Colliculus
NEURONS:
• THERE ARE MANY KINDS OF
MULTIMODAL NEURONS: SOME
RESPOND TO 2 DIFFERENT SENSES
AND SOME TO 3
• THESE NEURONS HAVE CONNECTIONS
FROM LAYERS OF SINGLE SENSORY
NEURONS
• HERE WE SEE LAYER OF VISUAL
NEURONS FOR DIFFERENT ANIMALS
THEY FORM A MAP OF VISUAL SPACE
• HERE WE SEE LAYER OF AUDITORY
NEURONS
THEY FORM A MAP OF AUDITORY SPACE
• THE DIFFERENT MAPS
ARE OVERLAID ON
EACH OTHER SO THEY
MATCH!
• THESE NEURONS RESPOND TO
OVERLAPPING AREAS FROM DIFFERENT
SENSORY MAPS. THEY HAVE
BROAD RESPONSE
RESPONSE PATTERNS FOR DIFFERENT
BODY AREAS
• CONTROL OF BODY MOVEMENTS
EAR POSITIONS
• REACTION OF VISUAL-ACOUSTICAL
NEURON. REPONSE IS GREATLY
ENHANCED FOR SIMULTANEOUS
VISUAL-ACOUSTICAL STIMULATION
PLEASE NOTE THAT SIGNALS ARE SYNCHRONIZED I N TIME!
• RESPONSE OF VISUAL-TOUCH
NEURON. RESPONSE IS ENHANCED
PLEASE NOTE THAT SIGNALS ARE SYNCHRONIZED I N TIME!
• TOUCH-VISUAL NEURON.
RESPONSE ENHANCED
PLEASE NOTE THAT SIGNALS ARE SYNCHRONIZED I N TIME!
• TRIMODAL NEURON- SENSITIVE TO 3
SENSES. RESPONSE TO TWO SENSES
AT A TIME
• DEPRESSION OF RESPONSE WHEN
SIGNALS ARE NOT OPTIMALLY
SYNCHRONIZED
• RECEPTIVE FIELD OF NEURON
RESPONSE
DEPRESSED
STRONGEST MULTISENSORY
RESPONSE
RESPONSE INCREASED
•
HOW RESPONSE DEPENDS
ON THE POINT OF
STIMULATION
WE CAN SEE
STRONG DEPRESSION
AND
ENHANCEMENT
• RESPONSE FOR VISUAL-TOUCH
NEURON
• RESPONSE FOR TOUCH-ACOUSTICAL
NEURON
• VISUAL-ACOUSTICAL RESPONSE IN
RELATION TO POSITION OF EARS
• WHAT HAPPENS IF STIMULATIONS ARE
NOT SYNCHRONIZED?
ACOUSTICAL SIGNAL IS EARLIER
THAN TOUCH BY 400, 200, ... MS
• TOUCH SIGNAL IS EARLIER
• ACOUSTICAL SIGNAL IS EARLIER
THAN VISUAL, VERY STRONG PEAK
RESPONSE BETWEEN 50 AND 0 MS
• STIMULATION NOT OPTIMAL IN
SPACE
• STIMULATION MUST BE SYNCHRONIZED
IN TIME AND IN SPATIAL POSITION
TO PROVIDE MAXIMUM RESPONSE
• WHY ALL THIS IS DONE? BECAUSE
MUTISENSORY SIGNALS PROVIDE
MORE AND MORE PRECISE INFORMATION
THE DELAY OF 50 MS FOR OPTIMAL AUDIO
VISUAL RESPONSE MIGHT BE COMING BECAUSE
OF THE DEALAY IN SOUND PROPAGATION
IN 50 MS SOUND MAKES
ABOUT 20 M WHICH
IS RANGE OF OPERATION