2007-10-01
Wednesday- essay test.
Thursday- multiple choice test. Chapter 3. Everything today should be review.
15 min- groups
Burn movie to DVD or CD.
Cerebral cortex
Frontal lobe, parietal lobe, occipital lobe, temporal lobe.
The major divisions of the brain: you have four lobes, all specified with functions. Fissures divide the lobes. There's a sylvian fissure, and then you have some other major fissures, like the central fissure (from the top of your head to your ear). Fissures are large, deep cracks in the cortex, where the brain can come apart. The biggest is the longitudinal fissure. Those are what divide the lobes into their specific regions. There are two main sections of your cortex that have very specific jobs: you have the motor and sensory cortex, which are strips that start in the middle of your head and go down to your ear.
Motor cortex- area at the rear of the frontal lobe.
The sensory and motor cortexes allocate space to processing information. How much fine-motor coordination does your hand have versus your thigh? There's more space allocated to your hand than to your thigh, it gives more control over to the fine-coordination stuff. There's more to your face and lips, for example, and there's lots of muscles in your face and in your tongue in order to be able to speak. The same with sensation on your sensory cortex: there's similar allocation. Areas of your body that have higher sensation or demand? They get more space.
Functional MRI scans show the visual cortex activated as the subject looks at faces. That's the occipital lobe. There are spots of neurons that recognize only faces. Without that functionality, you don't recognize faces. There's a book out there called "The Man Who Mistook his Wife for a Hat." Oliver Sacks. You can't interpret individual features or expressions without that ... each cortex region has a specific function.
The auditory cortex is right behind your ear. The occipital lobe has your visual cortex, the part you use to recognize any type of visual input.
The more intelligent the animal, the more space in your brain uncommited to specific jobs. Rats have very specified flexible spots for learning in their brains. Humans have larger areas than chimpanzees, for example. It makes us more flexible as creatures.
What happens if you damage sections of your brain? Aphasia- impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).
Broca's area- an area of the left frontal lobe that directs the muscle movements involved in speech. Broca is up front.
Wernicke's area- an area of the left temporal lobe involved in language comprehension and expression. interprets auditory code ... Wernicke is in the back. Think of it alphabetically.
Angular gyrus- transforms visual representations into an auditory code.
Plasticity
The occipital lobe takes information from the optic nerve, and so that's where the visual cortex interprets the visual stimuli, and that central fissure, that's where lots of the information gets stored, once it goes to the sensory cortex. So the occipital lobe outputs to the parietal lobe and temporal lobes (up high and on the sides).
"You don't see with your eyes. You see with your brain. We've proven this with false eyes (implants) and dreams. "The function of the eye is not to see. It is just a window. The visual cortex does all the interpretation."
Temporal lobe - auditory cortex - Inputs are auditory visual patterns- speech/face/word recognition, memory formation. The temporal lobe sends information to the limbic system- that's why sound is so strong in memory. There's also information out to the brain stem so that you can determine your sense of space and so on.
Basal ganglia- relay station.
Parietal lobe- that's up high on the back of the brain. The parietal lobe deals with sensory input, and it will take information from sense input and then deal with it. It has the somatosensory cortex, a sensory-strip of sorts. It's right between all of the different relay stations. It absorbs as much information as it can, to determine what is happening around you. The parietal is important for hand-eye coordination, telling the difference between stimulation, eye movements, attention, discernment, music and nonverbal sounds (screeching, banging, animal noises).
Frontal lobe- it's a clearinghouse and does not have any specific senses plugged into it. It's mostly discernment, calculation, analysis, planning, seeing into the future and making predictions, etc. So the frontal lobe does not have direct sensory input. Prefrontal area is for working memory. Right side: negative emotions and rage. Left side: positive emotions.
Finnieus Gauge- famous railroad worker that was impaled with a giant metal spike. This was like a labotomy- in the '50s they used to do this often when kids were maladjusted. They used to just send this metal pick up into the brain and just swirl it all around. You really want to keep your prefrontal lobe. You don't want alcohol until you're about 25 or 26. That's when it is finally developed enough to survive alcohol.
Wisconsin Card Sorting Task- does the person have damage to their prefrontal lobe?