hello everyone and welcome to week two of our course so this week we are covering biological psychology so our understanding of the relationship between the brain and your conscious mind has come a long way in the history of psychology so for example Greek philosopher Aristotle believed that the mind resid Ed in the heart however the Greek physician hypocrates did correctly believe that the Mind resided in the brain in the early 1800s France Gaul who was a German physician believed that studying the bumps on a person's head could reveal personality traits and information about their mental abilities that practice of reading bumps on the skull um was called phenology it was very popular at that time in Britain and was practiced in in North America as well it is of course nonsense um as we now know but it demonstrates I think how far we've come so today biological psychology is the scientific study of the relationship between biological processes so this includes things like your genetics hormones in the body neurotransmitters which we're going to talk about so the relationship between those biological processes and psychological processes now our brains are constantly changing the brain is of course influenced by our genes our genetics but the brain is also constantly making adjustments and creating new connections that are a result of your experience es with the world these changes are referred to as neuroplasticity so to understand the brain we need to recognize that we are a biopsychosocial system which means we are biological we are psychological and we are social and those systems interact and influence us over time so to demonstrate this or maybe to clarify it I wanted to look at a couple examples the first one is of taxy drivers so in one study this was done um with London taxi drivers researchers found that those taxi drivers who were able to learn and remember the over 26,000 different streets and locations had an enlarged hippocampus as a result the hip campus is responsible for processing spatial memories likewise those who play the piano and this is those who play the piano very very well so they've practiced and practiced and practice um have been found to have a larger auditory cortex in the brain which is the Sound Processing part of the brain so neurons are the basic cell that makes up the nervous system and they are the cell that receives and transmits messages to other cells within the nervous system now throughout life new neurons are created and unused neurons are destroyed and that of course like many things that we're going to talk about was not something that was always known it was once believed that you were born with however many neurons you were going to have and that's all you got um but that is not the case so there are three types of neurons first are sensory they're also called afren neurons they carry incoming information from your sensory receptors so think about like your fingers if you were to touch something so they carry incoming information from the sensory receptors to the brain and the spinal cord next are motor or eant neurons which carry out go ing information so carrying information from the brain and the spinal cord to your muscles that can tell you to move those muscles and third are interneurons which make up the bulk of neurons in the brain and they're also located in the spinal cord and they process information between sensory and motor neurons so they process that incoming outgoing information next let's look at the structure of an individual neuron so first we have the cell body or the Soma which contains the nucleus and it's the cell's life support center next we have the dendrites which receive messages from other cells so the dendrites are for incoming information and you can see on my picture there we're going to be talking about the direction that a message travels so from left to right dendrites receive incoming information third is the axon which passes the messages from the cell body down to the terminal buttons or the axon terminals so the axon terminals or The Terminal buttons form the junction with other cells so they are specialized for communication between cells another very important part is the myelin sheath which is a layer of fatty tissue that insulates the axon now the purpose of the myin sheath is to protect the axon and it also serves as an insulator for faster transmission of neural impulses now up to age 25 the myelin sheaths are still being created so this is an ongoing process and that process is called myelination and as this is happening judgments neural efficiency and self-control can continue to increase now multiple sclerosis can result if myelin degenerates or breaks down so the communication between our types of neurons that we talked about slows down which results in decreased muscle control and even cognitive impairment now when somebody refers to a nerve in the body so could be like the optic nerve or maybe a nerve in your leg or your back what they are actually talking about is long axons of many neurons that are bundled together and they form cable and that cable is what people are referring to when they say a nerve now supporting neurons so in our picture here the yellow ones are the neurons that we've already talked about so supporting neurons are G cells and those G cells which we have three different types here so we have the blue um the green green and the brown you can see um so they're different types but they they serve a lot of different functions one of those functions is to provide support for the neurons to grow on and round second um they deliver nutrients to neurons third they produce myelin for the myelin sheath which you can see that with the blue the igod dendrite you can see that uh it is making up the myin sheath there number four they clean up waste and dead neurons and five they also play a role in the transmission of information between neurons and so they play a role in memory as well now the brains of more complex animals have a greater proportion of G cells to neurons so for example when they examined Einstein's brain brain after his death researchers found a much greater number of gleo cells than what is seen in the average brain next we're going to look at how neurons communicate so neurons speak two languages so to say which is called an electrochemical process because it is the two languages they speak are electrical and chemical so they communicate neurons communicate with each other through neurotransmitters which is the chemical part neurotransmitters are chemicals second they communicate within themselves through Action potentials which is electrical okay so let's look at a very simplified example of this process so we're starting with we have three neurons here conveniently all in a line for us to see um so we can see let me see if I can get a pointer here okay so neuron number one is going to communicate with neuron number two chemically so a signal is going to be received from the other neuron so the axon end of this neuron is going to release a chemical neurotransmitter which is going to be received by the dendrites on our second neuron then within itself it's communicating electrically and if that electrical impulse is strong enough the neuron will fire and by fire I mean that it is going to release neurotransmitter so release that chemical from its axon end and then the process will repeat so I had said if the electrical impulse is strong enough um so that means that there is a minimum intensity needed in order to fire which is called the threshold so it is the minimum intensity needed for a neuron to Fire and when a neuron fires or when I say fire I'm talking about releasing neurotransmitter um it is an All or Nothing response so it's similar to firing a gun so the gun either fires or it doesn't so the intensity of which the neuron fire doesn't increase or decrease so there's not a weaker release of neurotransmitter or a stronger release of neuro neurotransmitter it just either fires or it doesn't okay so now let's look specifically at communication between neurons remember this is the chemical part of our elect trochemical process so communication takes place at the synapse which is the junction between the axon tip of the sending neuron and the dendrite of the receiving neuron just like in our picture from the slide before however they do not physically touch so the axon of one neuron does not physically touch the dendrite of the other neuron but they're very very close the gap between them is called the synaptic gap okay so in my picture here we can see we're zoomed in on the synapse and so this here is the axon end of our first first neuron and this is the dendrite end of our second neuron now the purple stuff in the picture represents neurotransmitter which is the chemical messenger that crosses the synaptic gap so it binds to receptor sites on this uh dendrite so on the receiving neuron which then influences whether or not this neuron will fire so if that neurotransmitter is excitatory it's going to tell the neuron to fire or release neurotransmitter if it's inhibitory it is telling the neuron no not to fire now we're going to talk about some common neurotransmitters um that will likely come up again throughout the course first is acetylcholine which enables muscle action and it also plays a role in learning and memory my example for this one um if someone is bit by a black widow spider the Venom from the black widow spider blocks the transmission of aetl choline and that leads to paralysis now this process also occurs with anesthesia and some types of poisons next is dopamine which is involved in movement it's also involved in learning attention emotion and what most people if you are familiar with dopamine what they think of it with is sensations of pleasure now too little dopamine is linked to Tremors and loss of coordination that is seen in those with Parkinson's disease too much dopamine is linked with schizophrenia next is serotonin and serotonin affects mood it affects hunger sleep and arousal or anxiety to little serotonin is linked to depression so let's take a little detour for just a minute so thinking back to our neurons after a neuron releases neurotransmitter what neurotransmitter is left over what's not used up by neighboring neurons has to be removed from that Gap to allow for future communication between neurons if we just just have neurotransmitter accumulating everywhere um that's going to be a problem so one of the ways that this is done the neurotransmitter is removed from that Gap is through a process called reuptake where the axon end of the sending neuron takes the leftovers back in and repackages them or recycles them for future use so I said we could have problems if we have all types of neurotransmitters just building up building up they have to be removed but we saw that too little serotonin is linked to depression so what if we prevented the re-uptake of Serotonin it would leave more serotonin out there available for use and selective serotonin reuptake Inhibitors also called SSRI eyes do just that so they inhibit the re-uptake of Serotonin so they prevent that re-uptake in order to to decrease the symptoms of depression Gaba is our major inhibitory neurotransmitter remember inhibitory neurotransmitters tell neurons not to fire having too little Gaba is linked to seizures TR s and insomnia glutamate is our major excitatory neurotransmitter and it is involved in learning and memory having too much glutamate can overstimulate the brain and can produce migraines or in extreme cases es even seizures caffeine like your morning coffee increases glutamate endorphins are the body's naturally produced opioids so they influence the perception of pain or pleasure Runners feel Runners high and what they are actually feeling is a flood of endorphins and when you are injured the release of endorphins will dull the pain okay so we talked about neurons the building blocks of the nervous system the ner nous system itself is that extensive network of cells that carry information throughout the body and the two main divisions of the nervous system are the central nervous system and the peripheral nervous system the central nervous system is composed of the brain and the spinal cord the spinal cord carries messages between the brain and the body and it also handles very fast life-saving reflexes so as an example when when you touch a hot pan your sensory receptors in your skin send this information via Sensory neurons to your spinal cord so the spinal cord with its inner neurons is going to send that information to the brain but but it also immediately sends signals to motor neurons to pull back your hand so this is why you will unconsciously pull back your hand before you consciously realize what even happened and say ow so two main divisions of the nervous system we have the Central and the peripheral central is the brain and the spinal cord so the peripheral nervous system consists of the sensory and motor neurons that connect the central nervous system to the rest of the body so if Central is just brain and spinal cord everything else we see in this image here that has the um purple pink color is the peripheral nervous system now the peripheral nervous system is also divided into two so first we have the somatic nervous system which is the nerves that control voluntary muscles of the body so these are muscles that you can move at will now if we think about you know um triggering a reflex on your knee well you're not thinking about doing that but you can move your leg so it only matters if you can move it at will if you can move it at will then it's the sematic nervous system the other part is the autonomic nervous system and it includes nerves that control the involuntary muscles of the body so things that you cannot move at will so things like your internal organs okay so the peripheral nervous system was divided into two the sematic and the autonomic the autonomic is also div divided into two so the first division is the sympathetic division which is the system that arouses the body so it's responsible for reacting to stressful events think of your fight ORF flight response so when the sympathetic division is activated one your pupils dilate two your heart rate increases three your breathing increases four digestion and excretion uh shut down and as a result of that number five saliva dries up because saliva the purpose of it is it is involved in digestion and so if digestion is shut down your saliva is shut off and that is why if you're very nervous for a public presentation and your lips are sticking to your teeth and your tongue is sticking to the roof of your mouth that is why your sympathetic division has been activated now it makes sense why that happens so your fight or flight response is activated when you have perceived that you are experiencing something very stressful and dangerous and so if you think about you've encountered a bear and while you're out hiking and you need to figure out what to do fighter flight has been activated your body knows that you're probably not at that moment going to sit down and eat a sandwich so digestion is not needed that's a waste of energy right now that energy needs to be put in into these other processes okay so first division was sympathetic second division parasympathetic so this activates when that stressful event is over its goal is to calm the body conserve energy and return the body to normal functioning example of this after a very stressful event most people will feel hungry again this is because digestion was off and now it's turned back on and they will also want to rest or take a nap we have the endocrine system so the endocrine system is the body's slow chemical Communication System it's slow compared to um the neuron communication with their chemicals neurotransmitters so it's slow compared to that it consists of the glands and fat tissue that secrete hormones into the bloodstream so hormones are the chemical messengers of the endocrine system just like neurotransmitter are the chemical Messengers um between neurons hormones are the chemical messenger in this endocrine system and though they are slower endocrine messages last longer an example of this um could involve anger so let's say that you're really angry at somebody that resolves maybe they apoll iiz to you but you still still continue to feel angry at least for a little bit um despite that being resolved so they kind of have this hangover um this is time that they they continue to go on sure I'm going to focus on two glands in the endocrine system we're going to talk about the adrenal glands and the pituitary gland so the adrenal glands are located on top of the kidneys and they release epinephrine also known as adrenaline and norepinephrine now these increase heart rate blood pressure and blood sugar and they provide those changes provide energy needed for the fight or flight response the pituitary gland is the master gland of the endocrine system um though it is only about the size of a PE um it is also controlled by the hypothalamus but why would we call the pituitary gland the master gland well the first reason is that it releases growth hormone it releases a lot of different hormones but among those is growth hormone which stimulates physical development it also releases oxytocin so this is number two and I'll smell oxytocin for you if you need to know it's oxy t c i n so it releases oxytocin um oxytocin enables orgasm it also enables labor contractions it also AIDS in milk flow while breastfeeding and it's also involved in Social connections as an example of this those with autism spectrum disorder who have issues with social connections also have lower than normal oxytocin levels okay the third reason the pituitary gland is the master gland is that it directs other endocrine glands to release their hormones um so for example the pituitary gland signals the adrenal glands to release cortisol which is a stress hormone so cortisol is Rel least when you are experiencing stress chronic increased cortisol levels in children are associated with increased risk of depression later so as adolescents as adults brain and I am going to focus on the cerebral cortex as you will cover the other structures in this week's homework assignment so the cerebrum is composed of the two hemispheres of the brain left and right so right now in this picture we are looking at the left hemisphere and the cerebrum makes up 85% of the brain's weight now covering these two hemispheres is what we are looking at right now so covering these hemispheres is this fabric of interconnected neural cells and it is called the cerebral cortex so it is this wrinkled layer that we're seeing when we look at this picture we are actually able to see the cerebral cortex the cerebrum is under that now the wrinkles the reason they are there is that they allow for more surface area to fit within the skull so each hemisphere's cortex is divided into four loes so again right now we're looking at the left hemisphere of the brain um so this would be right behind your forehead this is at the back of your head okay so we're looking at just the left side um so you'll see we have these different lobes we have a matching set on the right side so for each of the loes we have two a left and a right and these loes are separated by fissures or F holds which you can kind of see in my diagram here they're kind of the darker um black between them okay so first are the frontal loes they are located behind your forehead in blue here on my diagram the frontal loes are involved in speaking muscle movements making plans and judgments the parietal lobe um located top rear receives information from your sensory receptors that are related to touch and body position the occipital lobes are located at the back of the head and receive information from the visual Fields so an example to help you connect this um if somebody maybe falls and hits the back of their head pretty hard they may report seeing stars and that is due to the placement of the occipital loes which process visual information at the back of the head the temporal loes are located just above the ears and they receive information from auditory areas or things that you hear so an important note is that many of these functions require the participation of multiple loes and that is all of the information for this week's lecture