lesson 3 the human brain Flashcards
what are neurons
cells in the nervous system that communicate with each other to perform information processing tasks
ramon y cajal
used golgi staining to come up with neuron doctrine
neuron doctrine
neurons are discrete cellular units
parts of a neuron
cell body (soma), dendrite, axon
what does soma have
Organelles like mitochondria and ribosomes, nucleus with dna/genes
what do dendrites do
take in information (post synaptic neuron) and relay to soma
what does axon do
carries information to other neurons muscles or glands (can be very long or short)
what are axons covered with
myelin sheath (why white matter is white)
what makes myelin
supporting glia cells (astrocytes, myelin making, or microglia)
why is myelin important
increases communication between neurons (without it, can cause multiple problems)
synapse
junction between axon of one neuron and dendrites/soma of another neuron
types of neurons
sensory, motor, interneurons
what do motor neurons do
carry signals from spinal cord to muscles to produce movement
what do sensory neurons do
receive information from external world and convey to the brain via spina cord (have specialized ending on dendrites to receive signals for senses)
what do interneurons do
connect all types of neurons
types of specialized neurons
purkinje (interneuron in cerebellum), pyramidal (cerebral cortex), bipolar (sensory neuron found in retina)
what is conduction
movement of an electric signal within neurons
what is transmission
movement of a signal from one neuron to another as a result of chemical signal across the synapse
resting potential
difference in electric charge between outside and inside of neuronal cell membrane
consciousness
a person’s subjective experience of the world and the mind
phenomenology
how things seem to the conscious person (in their understanding of mind and behaviour)
problem of other minds
difficulty of perceiving consciousness of others
what do people judge minds according to
capacity for experience (pleasure, pain, hunger) and agency (self control, planning, memory)
why is consciousness a problem for psych science?
the scientific method requires that any observation made by one scientist should be available for observation by any other scientist but other minds arent observable
mind body problem
the issue of how the mind is related to the brain
and body
Turing test
having a person observe a conversation between a person and a computer. The machine/computer is said to
have passed the test if the observer is unable to accurately determine which is the machine/computer and which is the human
four properties of consciousness
intentionality (directed toward an object), unity (can integrate senes into a whole), selectivity (include some objects and not others), and transience (tendency to change)
dichotic listening
in which people wearing headphones hear different messages in each ear
cocktail-party phenomenon
people tune in one message even while they filter out others nearby (like talking to someone and not listening to a conversation but hearing you name and your ears prick)
minimal consciousness
a low-level kind of sensory awareness and responsiveness that occurs when the mind inputs sensations and
may output behavior (you see a light, you turn toward it)
full consciousness
know and are able to report your mental state (are aware of pain and not just reacting to it)
self-consciousness
distinct level of consciousness in which the person’s attention is drawn to the self as an object (like when you’re embarrassed or the focus of attention)
experience-sampling or ecological momentary assessment (EMA)
in which people are asked to report their conscious experiences at particular times
daydreaming
a state of consciousness in which a seemingly purposeless flow of thoughts comes to mind
mental control
the attempt to change conscious states of mind
thought suppression
conscious avoidance of a thought (try not to think of a polar bear and you will think of it every minute)
rebound effect of thought suppression
the tendency of a thought to return to consciousness with greater frequency following suppression
ironic processes of mental control
ironic errors occur because the mental process that monitors errors can itself produce them
how do we know the brain is organized modularly
brain damage (broca vs wernicke, stroke)
electrical stimulation (penfield motor cortex, homonculus somatosensory cortex)
measurement (ct scan, mri, fmri, pet scan)
equipotentiality
brain is like a sponge (all parts equally capable of job, even if cut in half
localized function
if one part breaks, the rest still works but the part that is damaged no longer does its function
localization of function in the brain
accident, manipulation, measurement
accident (brain damage from tumor, stroke, trauma)
people with specific brain damage have specific deficits like brocas/wernickes aphasia which is how we know the brain is organized in parts that each have a function
who came up with surgical mapping
wilder penfield, who would poke around in brain until a response came from the patient
used brain stimulation to map out somatosensory cortex in parietal brain
electrical stimulation (to know brain is organized modularly)
penfield used to stimulate motor and somatosensory cortex; stimulus in certain area of brain caused reaction in certain part like hands, face, etc
measurement (to know brain is organized modularly)
mri used to measure detailed structures
dorsal/ventral
back/front (belly)
anterior/posterior
front/back
how is the brain organized
back is necessities (cerebellum for movement and coordination, brainstem for autonomic processes) and front is luxuries (frontal lobe for complex action, decisions, personality)
how does information flow in the brain
we take in information through eyes (occipital to thalamus back to other parts of brain)
left brain function
sensory processing and motor control of right side
linguistic analysis (word meaning and grammar)
right brain function
sensory processing and motor control of left side
paralinguistic analysis (tone of voice, humor, sarcasm)
features of modules
domain specific, neurally localized, parallel
what does domain specific mean
each do one specific thing
what does neurally localized mean
each module corresponds to a location in the brain
what does massively parallel mean (in terms of modularity)
all modules operate simultaneously
how does pain prove modularity
aspects of pain are processed in different brain regions (somatosensory and anterior cingulate)
what does mcgurk/snoop effect prove
that modules come into effect with each other (if shown the word yellow that is typed in red font, you get confused because you’re processing the word as yellow and the color as red and theyre in conflct)
conscious control
ability to flexibly alter or suppress automatic or prepotent response (associated with the frontal cortex)
what sense is modular
vision; making sure brightness, color, motion at once
what’s system 1
unconscious processing (like blindsight and cocktail party phenomenon)
what’s system 2
conscious experience
conflicts between system 1 and 2
like seeing a snake and freaking out then calming down a second later
ian waterman
had to rely on conscious control (system 2) and tell himself to balance and walk, had to look at limb for it to work vs us doing it without thinking
what is blindsight
responding to visual stimuli without consciously perceiving it (blind but can walk through hallway obstacle course)
what is a part of conscious experience
(conscious has a hard time controlling itself, like thought suppression polar bear)
what module can tweak the other modules
conscious control
phineas gage
had metal rode through frontal lobe, changed personalities and behavior, showed brain is modular
Mirror neurons
active when an animal performs a behavior, such as reaching for or manipulating an object, and are also activated when another animal observes that animal performing the same behavior
phantom limb syndrome
Patients can feel their missing limbs moving, even in
coordinated gestures such as shaking hands
hindbrain
spinal cord/lower levels of brain execute simple functions like reflex
executes more complex task of orienting toward an important stimulus in the environment
midbrain
forebrain
most complex tasks like thinking of life in the future
epigenetics
the study of environmental influences that determine whether or not genes are expressed, or the degree to which they are expressed, without altering the basic DNA sequences that constitute the genes themselves
epigenetic marks,
chemical modifications to
DNA that can turn genes on or off
DNA methylation
involves adding a methyl group to DNA. There are special enzymes, referred to as epigenetic writers, whose role is to add methyl groups to DNA. Although adding a methyl group doesn’t alter the basic DNA sequence, it switches off the methylated gene
Histone modification
involves adding chemical modifications to proteins called histones that are
involved in packaging DNA. DNA methylation switches genes off, histone modification can either switch genes off or turn them on. But just like DNA methylation, histone modifications influence gene expression without altering the underlying DNA sequence
chromosomes
strands of DNA wound around each other in a double helix configuration
gene
the major unit of hereditary transmission
Heritability
a measure of the variability of behavioral traits among individuals that can be accounted for by genetic factors
corpus callosum
the thick band of nerve fibers that allows the two hemispheres to communicate
homonculus
small man with big limbs showing somatosensory cortex (wilder penfield)
left hemisphere controls blank and vice versa (how does split brain procedure affect this)
right side of brain
person with a split brain, information entering one hemisphere stays there. Without an intact corpus callosum,
there’s no way for that information to reach the other hemisphere
with information presented to right, can say it’s a key but can’t differentiate it from other things
with information presented to right, knows it’s a key but cant produce speech for it
left vs right hemisphere activity
the left hemisphere controls speech, comprehension, arithmetic, and writing
the right hemisphere controls creativity, spatial ability, artistic, and musical skills. The left hemisphere is dominant in hand use and language in about 92% of people
how is fmri better than pet scan
fMRI does not require any exposure to a radioactive substance. Second,
fMRI can localize changes in brain activity across briefer periods than PET, which makes it more useful for
analyzing psychological processes that occur extremely quickly, such as reading a word or recognizing a face.
With PET, researchers often have to use experimental designs that differ from those they would use in the
psychology laboratory in order to adapt to the limitations of PET technology. With fMRI, researchers can design experiments that more closely resemble the ones they carry out in the psychology laboratory
positron emission tomography (PET)
a harmless radioactive substance is injected into a person’s bloodstream. The brain is then scanned by radiation detectors as the person performs perceptual or cognitive tasks, such as reading or speaking. Areas of the brain that are activated during these tasks demand more energy and greater blood flow, resulting in a higher amount of radioactivity in that region. The radiation detectors
record the level of radioactivity in each region, producing a computerized image of the activated areas
a device used to record electrical activity in the brain
electroencephalograph (EEG)
functional magnetic
resonance imaging (fMRI)
When active neurons demand more energy and blood flow, oxygenated
hemoglobin concentrates in the active areas; fMRI detects the oxygenated hemoglobin and provides a picture of
the level of activation in each brain area
frontal lobes
The frontal lobes are important for voluntary movement, expressive language and for managing higher level executive functions
processing auditory information and with the encoding of memory
temporal lobe
responsible for processing somatosensory information from the body; this includes touch, pain, temperature, and the sense of limb
parietal lobe
occipital lobe
vision
brain cells fire in patterns
a pattern corresponds to a thought
one pattern causes another pattern
steve pinker
Damage to somatosensory cortex
results in remarkably mild deficits. Surgical removal of this region in one hemisphere results in a reduced ability on the opposite side of the body in the detection of light touch and some difficulty identifying objects by touch (stereognosis).
