PSC 135 Study guide #1 - What is phrenology? What evidence supports aggregate field theory and what supports PDF

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What is phrenology? What evidence supports aggregate field theory and what supports localization theory? New histological techniques like the Golgi stain advanced our understanding of neuroscience because...Can you now understand all the parts of the synapse and how it works? Could you draw it out? ...

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case studies phrenology experimental ablation aggregate field theory localization

Think about your group activity on case studies. 1. What insights can they give us into brain function? 2. What are the limitations of using case studies? 3. How are case studies like those used by Willis and Jackson different from the ablation experiments that Flourens used? 4. How are they similar?

1. Pt cases that allow us to connect behavior with brain 2. Analyzing character and qualities based on skull shape and size, generalizing these associations to everyone 3. Cutting out a part of the brain causes damage so we can see how behavior changes when large areas are removed. 4. The whole area together is equally involved in producing behavior just that small cuts(ablations) “did not impact behavior” 5. Able to put functions in a specific location of the brain. 1. Behavioral issues correspond w/ brain changes/damage Brain function is the foundation to understanding what’s wrong when a pt presents with lack of function. what parts of the brain control what functions and putting signs and sx w/ brain structures. understand the damage and the effect that it caused the pt putting it together w/ signs and sx. 2. Very specific 3. Invasive, ablation is trying to answer a question and search for something very specific but the case studies can result from trauma 4. Both give insight to structure and function •Case studies are the intensive study of a single subject or small groups of subjects, usually with a medical abnormality. •Case studies provide “natural experiments” that may elucidate the function of the brain by giving an example of what can happen when something goes wrong. •They are limited in that they are not controlled or systematic, and often involve few research subjects .•They are profound in that they allow us to study phenomena in human beginnings that would otherwise be off limits. EM - Hemineglect. Pt is neglecting the L side of space which is shown when drawing. This also follows the pattern of damage to the R hemisphere of the brain.

HM - Anterograde Amnesia. The patient is unable to make new memories or recall recent events, but he can still remember events from before his surgery.

JB- Orbitofrontal syndrome. Pt is making impulsive and extreme decisions out of character. This condition is followed after a severe concussion which could have been caused by bilateral lesions of the orbitofrontal cortex and the medial face of the frontal lobe.

Dr. P - Integrative visual agnosia. Pt is able to “see” things but is unable to identify them which is compatible w/ the inability to integrate parts of an object into a coherent whole. 1. What is phrenology? 2. What is the premise of it?

Phrenologist would analyze the character of people then look at their skull shape and size and sometimes other qualities, and then suggest you can generalize these associations to everyone.

•Phrenology Is the study of the physical shape of the human head. It is based on the belief that variations in the skull's surface reflect personality and intellectual traits. •For this to be true, brain tissue would have to have an impact on the way the skill is shaped or vice versa, which is not the case.

What evidence supports aggregate field theory and what supports localization theory?

Aggregate field theory is supported by experimental ablations. Such that unless the entire section of the brain is removed the ablations will not impact behavior so the whole area is involved in producing behavior equally. •Localization theory states that different cerebral cortical territories serve different functions, such as vision and language. Each function is associated with a specific area of the cortex. •A great example of localization would be language output localized to Broca’s area. Continued research has found that some functions are more localized than others, and few functions work in complete isolation. Epilepsy pt’s supported the localization theory and so did broca’s area. - Broca's area is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production. •Experimental ablation is the systematic destruction of specific brain areas to study their impact on brain function. •This technique is useful for discerning specific deficits that may arise when function is lost in certain parts of the brain. •Aggregate field theory is the theory that all individual mental functions are performed by the brain as a whole, not as discrete parts. •Flourens Developed this theory after his experimental ablations in the cerebrum did not lead to significant behavior changes in his pigeons.

New histological techniques like the Golgi stain advanced our understanding of neuroscience because:

Golgi staining allowed us to see structures and this theory was the first step to understanding that muscular tissue and other neurons in tissue form a syncytium. •A syncytium is a continuous mass of tissue that shares a common cytoplasm. Although Golgi was incorrect about neurons forming a syncytium, other tissues, like muscular tissue, work this way. •The neuron doctrine states that the nervous system is made up of discrete individual cells. This is the opposite idea of a syncytium and was first proposed by Cajalafter using Golgi’s famous staining technique to examine neurons.

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soma dendrites axon myelin sheath synaptic gap/clef neurotransmitters (NT) presynaptic and postsynaptic ionotropic receptor

1. Cell body of a neuron which contains the organelles for the cell. 2. receiving branches of the neuron on the cell body. Dendritic spines can increase surface area. 3. The long part of the axon, covered in myelin sheath.“sending” branches of the neuron. Action potentials travel through these processes ending at a presynaptic terminal. 4. Insulation of the axon to increase the speed of the action potentials. A fatty substance that surrounds the axons of many neurons, increasing the speed of action potentials by enabling saltatory conduction.

9. metabotropic receptor 10. Excitatory 11. Inhibitory 12. Excitatory post synaptic potential (EPSP) 13. Inhibitory post synaptic potential (IPSP) 14. resting membrane potential 15. ion channel 16. summation 17. action potential

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Saltatory conduction is the mode of transmission of an action potential in a myelinated axon. Ion exchange can only occur at the nodes of Ranvier (spaces) between the myelin. Thus, the action potential appears to jump (thus the “saltare” in saltatory) from node to node, traveling more quickly.

5. Space between the presynaptic and postsynaptic cells where neurotransmitters will hang out until they are taken up into the presyn or used. NT diffuses across the synaptic gap to interact with receptors on the postsynaptic neuron. 6. chemical substances that transmit the signal between neurons at a synapse. Each NT has a receptor they bind to, (Ach, etc.) 7. Presynaptic cells carry vesicles w/ NT(NTs are stored in synaptic vesicles in the) and send the information, they have reuptake transporters. Postsynaptic cells have ion or metabotropic receptors and intake info. 8. forms a channel for ions to pass through the neuron membrane. When activated by a neurotransmitter, they allow one or more types of ions to pass in or out of the neuron, generating a postsynaptic potential. 9. is a type of membrane receptor that activates metabolic steps to modulate cell activity. This may include opening an ion channel to generate a postsynaptic potential, or it may impact the behavior of the neuron in some other way. 10. Increasing action potential 11. Decreasing action potential possibilities 12. Postsynaptic potentials (PSP) are changes in the electric polarization of the membrane of a neuron from resting state. They can be excitatory or inhibitory. ◎ An excitatory postsynaptic potential (EPSP) makes a postsynaptic neuron more likely to generate an action potential. This is often caused by an influx of sodium ions. f positive ions (like Na+) enter post synaptic cell it generates an excitatory postsynaptic potential (EPSP) 13. makes a postsynaptic neuron less likely to generate an action potential. This is often caused by an influx of chloride ions. If positive ions (like K+) leave the cell or Cl-enters it, it causes the cell to become more negative resulting in an inhibitory postsynaptic potential (IPSP) 14. The electrical potential of the membrane that the cell is in before exchange of ions. -70 mV. due to the higher concentration of negative charges inside the neuron than outside the neuron. 15. Channels that are open allow specific ions to travel through. Ion channels are specialized proteins in the plasma membrane that provide a passageway through which charged ions can cross the plasma membrane down their electrochemical gradient. -

The action potential travels down the axon as the neuron opens Na+ and K+ ion channels in response to the change in membrane potential

16. Adding all the EPSP and subtracting IPSP to give a number that will determine if a threshold potential can be reached. 17. Depolarization of the cell will lead to an action potential. Increasing influx of ca+ into the cell causes potassium to leak outl. is a rapid rise and fall of the membrane potential of the neuron.

Draw it out Think about your individual drawing activity. Can you now understand all the parts of the neuron? Could you draw it out?

Can you now understand all the parts of the synapse and how it works? Could you draw it out?

Draw it out

What could create an EPSP or IPSP?

influx of sodium ions. f positive ions (like Na+) enter the postsynaptic cell it generates an excitatory postsynaptic potential (EPSP) If positive ions (like K+) leave the cell or Cl-enters it, it causes the cell to become more negative resulting in an inhibitory postsynaptic potential (IPSP).

Do you understand how an action potential Action potential steps 1. If the sum of IPSP and EPSP causes the neuron membrane works? What forces and ions are involved electrical voltage to reach threshold (-55mV) which will cause in changing the membrane potential and sodium voltage gated channels to open how might this look over time on a graph of 2. Open Na+ channels will cause a large amount of sodium influx membrane potential? due to electrostatic and diffusion forces. This makes the 3.

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membrane potential very positive quickly known as depolarization. Depolarization causes voltage gated K+ ion channels to open up and K+ will move out of the cell due to electrostatic and diffusion forces. Na+ channels will close but K+ will remain open and potassium will continue to move out which will cause hyperpolarization since the cell will become even more negative at about -80 mV. K+ will close leaving the cell in an odd state of too much Na+ inside and K+ outside so the neuron will need to remove Na and add K (w/ sodium potassium pumps. 3 Na+ and 2 K+) to be ready for the next action potential. The cell returns to a resting state -70 mV actively transporting/pumping Na+ out and K+ requires energy to be spent by the cell.

Over time in a graph you would see the recording mainly on the resting membrane potential -70 mV voltage then slight increases towards threshold, once threshold is reached there will be a big peak (depolarization) and then a fall (repolarization) followed by hyperpolarization which is a lower dip than the resting membrane potential.

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Autonomic nervous system Brainstem Thalamus Hypothalamus Pituitary Cerebellum Cerebrum Sulci Gyri

1. PNS: Communicates w/ internal organs and glands, for automatic physiological functions like digestion to the heart, intestines, and other organs. Divided into sympathetic (arousing) and parasympathetic (claming). 2. Supports life functions like breathing and relays information from periphery to brain and back. Autonomic functions. 3. Relays info from senses to other areas of the brain. All sensory info (except smell) passes through the thalamus before reaching the cerebrum. Routing information. 4. Homeostasis. Maintains circadian (daily) rhythms in behavior such as sleep/wake cycle. Regulates the pituitary gland of the endocrine system. a. Pituitary and hypothalamus regulate hormones

(signaling molecules produced by glands) 5. 6. Densely packed neurons. Modulates behavior, especially error correction. Coordinates movement, especially important for fine movements like speaking and writing. Modulatory and motor roles. 7. “Thinking” happens. 8. Inner ridges, indentations 9. Outer folds, thick part of the brain Brain structures define

Four lobes on a diagram and what their function is.

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Psychometrics Temporal resolution Spatial resolution Invasive/non-invasive Single unit electrode recording Multi unit electrode recording Electroencephalography (EEG) Magnetic Resonance Imaging (MRI) Functional Magnetic Resonance Imaging (fMRI) 10. The blood oxygen level dependent (BOLD) signal 11. Subtraction technique

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Frontal lobe - planning and movement Parietal lobe - somatosensation and proprioception Temporal lobe - hearing and memory Occipital lobe - vision

1. Psychometrics are techniques for measuring mental capacities and processes ▰ Importantly, they allow for a way to quantify behavior and thought▰ Psychometric tests should have high reliability (re-test consistency) and validity (measures what it is supposed to measure). 2. Number of measurements per unit time 3. Number of measurements per unit space 4. Invasive techniques require inputting instruments or other objects into the brain. Such as placing an electrode in the brain and the introduction of a new gene by a virus 5. There is only one specific tissue that is being seen. sampling the activity of single neurons, or small clusters of neurons, using an array of microelectrodes implanted in the brain. 6. Multiple neurons. measurement of neuronal activity at a variety of scales, encompassing both averaged measurements of the activity of many thousands (sometimes millions) of neurons, as well as measurement of the individual action potentials 7. Electrodes in a net like fashion that go on top of the head to measure activity. non-invasive . highest temporal resolution place. These electrodes record the electrical activity of large

groups of neurons. EEG has low spatial resolution (1 cc to several cubic inches, depends on # of electrodes).▰EEG is better for measuring neurons closer to the surface of the brain, rather than deep within. -

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EEG can be used to look for patterns in whole brain activity, such as the different waveforms seen during the sleep stages.○These “brain waves” show characteristic patterns that are correlated with different states of mind. EEG is also used to investigate event-related potentials (ERP) which are the averaged brain response that is the direct result of a stimulus or movement. ○ERP recordings are especially useful for addressing questions regarding the time course and sequence of neural activity.

8. Hydrogen protons in neuron cells are being tracked and when they go into the machine they become parallel to the magnetic resonance. A radio frequency pulse (RFP) is applied to shift the axes of the protons, imbuing them with energy. That energy is released when the RF is turned off and the protons settle back into alignment with the magnetic field. After the hydrogen protons “relax” from the RF pulse and release energy, the computer array around the head picks up this energy signal. The computer constructs an image based on the strength of the signal, with brain areas high in carbon-chain hydrogen atoms appearing in white! 9. The brain deoxygenates the hemoglobin in blood as it works. Increased BOLD signal is what we see. We can also use an fmri w/ the subtraction technique. Which will measure brain activity before and during stimulus presentation. 10. BOLD signal is a change in oxygenated/deoxygenated ratio. The BOLD signal increases as oxygenated hemoglobin rushes in to feed the active neurons. a. Onset of neural activity: oxygen consumption, deoxyHb increased and BOLD signal is decreased b. Activated state: local blood flow increased, deoxyHb decreased, and BOLD signal is increased. - Computer algorithms show where the increased BOLD signal is in the brain. The signal from fmri is overlaid on a structural mri and we can see where the activity occurs. 11. Measures brain activity before and during stimulus presentation. Difference between activation determines what areas of the brain are active during manipulation. a. What are the brain activations associated with manipulating an object? Need to “subtract” just holding an object. b. (b)-(a)=(c) c. The subtraction technique is often used to interpret the results of brain imaging experiments.

How do psychologists operationalize (measure) thought processes?

Self reports and questionnaires. Because there is less experimental control of variables, more subjects are needed to reach statistical significance in self report studies.

How can psychologists use reaction time to better understand thought processes?

The faster you respond to something means that there is the part of the brain that is responsible for it so the _____is turned off.

What might reaction time suggest about a thought process (consider the “reaction time spectrum” we went over in lecture)?

The longer you take to answer something means that your thought process is slower or using a part of the brain that is not very much used. If the reaction time is faster means that there is a part of the brain that is used constantly.

How does each technique measure neuron activity? How do they differ in their spatial resolution, temporal resolution, and their invasiveness? -

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Invasive or not, brain or neuron, specific tissue, temporal or spatial resolution. Chart and image

Test

measures

resolution

Invasiness

fmri

Indirectly measures neural activity by looking at oxygen metabolism in neural tissues

Functional information when laid over an mri

non-invasive

mri

Structure differences between different groups or brain abnormalities.

Excellent Spatial. No temporal or functional information in a structural MRI

Non-invasive

EEG

Neurons closer to the surface of the brain, rather than deep within.

Highest Temporal resolution

Non invasive

Electrophysiolo gical

Only a selected portion of neural tissue (we need to know what area of the brain we want to record before we start)

Up to neuronlevel spatial resolution and exquisite temporal resolution.

invasive

psychometrics

Quantify behavior and thought

non-invasive

What sort of scientific questions can use answer with each technique?

Psychometrics: measuring cognitive process - Interest by eye tracking - Attention by accuracy and reaction time - Spatial memory by maze task - Explicit memory by word list recall - Rule following by card sort - Decision making by work problems - Will power by choice task - Personality by personality test - Depression by questionnaire

Natural experiment (also called “case

Brain damage is able to show us what part of the brain is used to do

studies” of brain damage) Transcranial magnetic stimulation (TMS)

specific things. If there is damage paired with signs and sx then we can assume that the brain structure that was damaged is responsible for that thing. -