Prof. Greg Francis 5/23/081Brain partsIIE 269: Cognitive PsychologyGreg FrancisLecture 02What’s the deal with left and right brains?The brain The source of cognition(consider transplant!) Weighs about 3 pounds Damage to some parts resultin immediate death ordisability Damage to other partsseems to have no effect! What brain parts areimportant to cognition? How do we discover the roleof each brain part? Fore-brain cortex Hind-brain brain stem)The brain Hind-brain (brainstem)Limbic Lobe(sexual behavior,emotional behavior,memory)Cerebellum(muscle control, learning)Thalamus(sensorygateway,exceptsmell)Hypothalamus(appetite, thirst,temperature,hormones)The brainFore-brain Cortex Similar to a thick,crumplednewspaper page Grooves (fissuresor sulci) separateregionsCentral SulcusFore-brain Cortex Similar to a thick,crumpled newspaperpage Grooves (fissures orsulci) separate regions Central SulcusProf. Greg Francis 5/23/082Fore-brain Cortex Similar to a thick,crumpled newspaperpage Grooves (fissures orsulci) separate regions Central SulcusFore-brain Cortex Similar to a thick,crumpled newspaperpage Grooves (fissures orsulci) separate regions Central SulcusContralateral processing Processing in the brain is done on theopposite side of your organs Control of your right arm is from the leftside of your brain Information from your left field of viewgoes to the right side of your brainContralateral processing Neural fibers from eye cross on way tocortexContralateral processing Brainhemispheresconnected bya mass ofneural fiberscalled thecorpuscollasumCut corpus collasum Behaviorchanges verylittle Subtle effectsProf. Greg Francis 5/23/083Brain sides If “nut” flashes on leftscreen subject cannot name it subject can pick up nutwith left hand If “nut” flashes on rightside subject can name it subject cannot pick upnut with left hand untilhe says “nut” out loudNobel Prize!Brain sides Results led to further study and common belief Left side: language, analytical, classification, Westernrationalization Right side: art, music, recognition of faces and shapes, Easternmysticism Vast oversimplification in a normal brain, both sides are involved in many tasks Results do support the idea that different parts of thebrain are involved in different cognitive tasks(modularity hypothesis)CogLab In the CogLabexperiment Brainasymmetry You saw a pair ofchimeric faces andwere asked tochoose which onelooked youngerChimeric faces The faces were made by taking a normal face and anartificially aged faceChimeric faces Take opposite halves of the facesChimeric faces Put them together, and make the other face by flipping it Thus, both faces are mirror images, they contain the sameinformationProf. Greg Francis 5/23/084CogLab If you stare at the middle of face, theinformation on the left goes to theright hemisphere which is supposed to be better able todeal with face information than the lefthemisphere So the information on the left side of theface should dominate the face decision This face should look relatively youngCogLab If you stare at the middle of face, theinformation on the left goes to theright hemisphere which is supposed to be better able todeal with face information than the lefthemisphere So the information on the left side of theface should dominate the face decision This face should look relatively oldCogLab So, we would expect people with brain asymmetrieswould usually choose as younger, the face that has theyounger half on the left side Left handed people typically do not show as much brainasymmetry effects as right handed people Thus, we can look for differences between left and righthanded people We expect right handed people to select the face with theyounger image on the left more often than left handed peopleCogLab Here is the data average for the class 132 right handed people 17 left handed people60.965.9Percentage ofchoices withyounger faceon leftRight handedLeft handedCogLab Here is data from everyone who has done the lab 6381 right handed people and 662 left handed people Not what we expected!64.465.0Percentage ofchoices withyounger faceon leftRight handedLeft handedAnatomy The cortex contains large fissures thatseparate five major areas Limbic (already discussed) Occipital Parietal Temporal Frontal Each has distinct propertiesProf. Greg Francis 5/23/085Occipital lobe Primary visualarea (V1) Receivesinformation fromthe eye Most investigatedarea of the brainParietal lobePrimarysensory area Sensations ofpain,temperature,touch, pressureParietal lobe Primary sensoryarea sensitivityinvolvesdisproportionateareas of the brain,relative to size ofbody partTemporal lobe Hearing speech (left) music (right) Memory andattention visual recognitionFrontal lobe Largest part ofcortex planning prediction motor area speech areaBrain structure Divide lobes into areas» layers e.g. Broadman Area 1, Area 12, … Area 200 Can partly identify function by looking atnerves coming in and out of areaProf. Greg Francis 5/23/086Broadman’s areas Monkeycortex issimilar tohumancortex ingeneralstructureArea specificity Seems to be separation of functional aspects e.g., for visual perceptionV1V2MTV4MSTITOrientationColorbinocularColorOrientationbinocularMotionbinocularRecognition?Brain layers There is order andfunction even withinan area The cortex is asheet of neurons In its thickness are6 layers of neurons numbered 1-6 sometimes includesubdivisions (4a, 4b,4cα, 4cβ, …)Conclusions Lots of research in this area New brain regions are being mapped outdaily with ever increasing resolution Cognitive neuroscience relies strongly onthe “modularity hypothesis” Putting everything together is very difficultNext time Brain scans EEG recordings MRI scans PET scans Functional MRI How to study the brain without killing