HUMAN INFORMATIONPROCESSING

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 TOREVERSED LEFT-RIGHTPICTURES

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 brain-damage 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 OBJECTPERECPTION 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 THESURROUNDING AREA. VISUAL SYSTEM IS THUSNOT AN OBJECTIVE LIGHT INTENSITY MEASURINGDEVICE

• 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-TRANSMITTERVESTIBULARSYSTEM

• COCHLEA – SOUND TRANSDUCER

SOUND PRESSURE IS CHANGED INTOFLUID PRESSURE

MODEL OF COHLEARTRANSDUCER

UT

OUTPUT IS MAXIMUM FOR CERTAIN FREQUENCYAT 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 BRAINWE 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 SOURCESIN SPACE IS BASED ON MEASURINGDIFFERENCES IN TIME OF SOUND ARRIVALBETWEEN THE EARS. THIS MUST BE VERYPRECISE MEASUREMENT, ON THE ORDEROF 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 SYSTEMWHICH PROCESSES TONES AND THUS WE ARE PREDISPOSEDFOR CERTAIN SOUNDS WHICH ARE ”NATURAL” FOR US

• SPEECH PROCESSING SYSTEMA COMPLEX ELASTIC MECHANICAL SYSTEM CONTROLLED

ELECTRICALLY FOR REGULATION OF AIRFLOW

• BASIC UNITS OF SPEECH –PHONEMSUSING THESE UNITS SPEECH CAN BE GENERATED

HEARING AND SPEECH ARE PRECISLY MATCHED TO EACH OTHERSPEECH CAN BE RECOGNIZED EVEN AT HIGH LEVEL OF NOISEAND INTERFERENCE (COCTAIL PARTY EFFECT, MANY PEOPLE ARETALKING AT THE SMAE TIME BUT WE ARE ABLE TO CONCENTRATEON ONE SPEAKER.

• VESTIBULAR SYSTEMNOTE 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 INDARK 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 SYSTEMWHAT IS PAIN?IT IS SIGNALLING FROM THEBODY TO THE BRAIN ABOUTIMPROPER OPERATIONTHE BRAIN CHANGES ITS ACTIONTO DEAL WITH THE PROBLEMTHERE IS ALSO A SYSTEM FOR IHIBITING THE PAIN SIGNALS

• ACUPUNCTUREIT IS ACTIVATION OF TOUCHAND PAIN SYSTEM IN ORDERTO STIMULATE OTHER BRAIN STRUCTURES

PERHAPS IMMUNE SYSTEM ISSTIMULATED???

INTEGRATION OF SENSESIN 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 THATSENSORY 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 INCREASEDRESPONSEDEPRESSED

STRONGEST MULTISENSORYRESPONSE

• HOW RESPONSE DEPENDS ON THE POINT OF

STIMULATION

WE CAN SEESTRONG DEPRESSIONAND 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? BECAUSEMUTISENSORY SIGNALS PROVIDE MORE AND MORE PRECISE INFORMATION

THE DELAY OF 50 MS FOR OPTIMAL AUDIOVISUAL RESPONSE MIGHT BE COMING BECAUSEOF THE DEALAY IN SOUND PROPAGATION

IN 50 MS SOUND MAKESABOUT 20 M WHICH IS RANGE OF OPERATION