Chapter Three - Biology and Behavior Flashcards
dendrites
branchlike extensions of the neuron that detect information from other neurons
cell body
site, in the neuron, where information from thousands of other neurons is collected and integrated
axon
a long narrow outgrowth of a neuron by which information is transmitted to other neurons
terminal buttons
small nodules, at the end of axons, that release chemical signals from the neuron into the synapse
synapse
the site at which chemical communication occurs between neurons
synaptic cleft
the gap between the axon of a “sending” neuron and the dendrites of a “receiving” neuron; it contains extracellular fluid
myelin sheath
a fatty material, made up of glial cells, that insulates the axon and allows for the rapid movement of electrical impulses along the axon
nodes of Ranvier
small gaps of exposed axon, between the segments of myelin sheath, where action potentials are transmitted
resting membrane potential
the electrical charge of a neuron when it is not active
–> ratio of neg to pos ions in the neuron is greater than outside the neuron (more neg on inside)
action potential
the neural impulse that passes along the axon and subsequently causes the release of chemicals from the terminal buttons
all-or-none principle
the principle whereby a neuron fires with the same potency each time, although frequency can vary, a neuron either fires or not, it cannot partially fire
neurotransmitters
chemical substances that carry signals from one neuron to another
receptors
in neurons, specialized protein molecules on the postsynaptic membrane; neurotransmitters bind to these molecules after passing across the synaptic cleft
reuptake
the process whereby a neurotransmitter is taken back into the presynaptic terminal buttons, thereby stopping its activity
agonists
drugs that enhance the actions of neurotransmitters
antagonists
drugs that inhibit the actions of neurotransmitters
Broca’s area
a small portion of the left frontal region of the brain, crucial for the production of language
brain stem
an extension of the spinal cord; it houses structures that control functions associated with survival, such as breathing and swallowing
cerebellum
a large, convoluted protuberance at the back of the brain stem; it is essential for coordinated movement and balance
hypothalamus
a brain structure that is involved in the regulation of bodily functions, including blood pressure and blood glucose levels
influences are basic motivated behaviors
thalamus
gateway to the brain
receives almost all incoming sensory information before it reaches the cortex
hippocampus
a brain structure that is associated with the formation of memories
amygdala
a brain structure that serves a vital role in our learning to associate things with emotional responses and in processing emotional information
basal ganglia
a system of subcortical structures that are important for the production of planned movement
cerebral cortex
the outer layer of brain tissue
forms the convoluted surface of the brain
occipital lobes
regions of the cerebral cortex (at the back of the brain),=
important for vision
parietal lobes
regions of cerebral cortex - in front of occipital, behind frontal - important for sense of touch and for conceptualizing the spatial layout of an environment
temporal lobes
regions of the cerebral cortex - below the parietal and in front of the occipital - important for processing auditory information, for memory, and for object and face perception
frontal lobes (general definition)
regions of the cerebral cortex - at front of brain - important for movement and higher-level psychological processes associated with the prefrontal cortex
prefrontal cortex
the frontmost portion of the frontal lobes, especially prominent in humans, important for attention, working memory, decision making, appropriate social behavior, and personality
chromosomes
structures within the cell body that are made up of DNA. DNA consists of genes
genes
the unites of heredity that help determine characteristics of an organism
dominant gene
a gene that is expressed in offspring when present
recessive gene
gene that is expressed only when matched with a smilier gene from the other parent
genotype
genetic constitution of an organism, determined at the moment of conception (never changes)
phenotype
observable physical characteristics which result from both genetic and environmental characteristics (always changing)
monozygotic twins
“identical twins”
twin siblings that result from one zygote splitting in two and therefore share the same genes
dizygotic twins
“fraternal twins”
twin siblings that result from two separately fertilized eggs and therefore are no more similar than non twins
heritability
a statistical estimate of the extent to which variation in a trait within a population is due to genetic factors
plasticity
a property of the brain that allows it to change as a result of experience, drugs, or injury
synesthesia
cross-sensory experience (ex. visual image has a taste)
twin studies
compare similarities between different types of twins to determine the genetic basis of specific traits
adoption studies
compare similarities between biological relatives and adoptive relatives
Caspi study
longitudinal study of criminality
- followed 1000+ New Zealanders from birth-adulthood and examined factors of who would become a violent criminal
- MAO (enzyme: monoamine oxidase) low levels = more aggression
- low-MAO led to greater susceptibility of childhood mistreatment and a greater likelihood of being convicted of a crime
- -> showed that nature and nurture and inextricably intertwined
phantom limb
the intense sensation that the amputated body part still exists
-other areas of body take over sensitivity in somatosensory cortex where leg sensation used to be (touching face may feel like touching missing leg)
radical hemispherectomy
the surgical removal of an entire cerebral hemisphere
–>only done on kids who can reorganize their brain to use only one hemisphere
gender differences in brain
- males have larger brain
2. female brains are more bilaterally organized for language (use both sides of brain)
cerebral hemispheres
- two halves of cerebellum
- wrinkled surface
gyri
bumps on brain
sulci
valleys on brain
corpus callosum
connections between the left and right hemispheres
Frontal Lobe functions
- Motor Cortex: sends signals to body parts to move (organized by body part, unstructured organization)
- Broca’s Area: speech production (left hemisphere)
- Memory
- Emotion/Planning
Parietal Lobe functions
- Somatosensory Cortex (front section): feedback from muscles, touch, sensation, body mapped on this area (unstructured organization)
- Spatial Processing: finding your way, rotating objects in mental space, identifying body
Disorders: - phantom limb
- neglect syndrome
Neglect Syndrome
damage to right parietal lobe, don’t include left side of anything when remembering (only eat food on right side of plate)
Temporal Lobe functions
- Auditory cortex: conscious sound information
- Wernicke’s Area (left hemisphere): speech comprehension, can’t understand speech or make your speech comprehendible
- Hippocampus + memory
- Emotion/Aggression
Disorders: - Capgras Delusion
Capgras Delusion
believe their loved one or themselves has been replaced by an imposter
-connection between vision and emotion is cut
Occipital Lobe functions
- Visual Cortex: gives conscious experience of seeing
Disorders - Blindsight
- Alexia
Blindsight
damage to visual cortex, consciously blind but able to avoid obstacles, have peripheral vision
Alexia
inability to read, can see letters but unable to string words together
Techniques to study function
- case study: example is Phineas Gage –> showed link between parts of body and function (beginning of neuroscience)
- correlational: observe behavior while measuring brain activity
Recording Techniques
- EEG
2. Intercranial Recording Electrodes
EEG
(Electroencephalography)
tells overall state of consciousness
Intercranial Recording Electrodes
surgically implanted into brain in specific part to measure activity
–> just measuring activity not creating it
Imaging Techniques
- MRI Scans
- Functional MRI Scans
- PET Scan
MRI Scan
measure brain STRUCTURE in magnetic field to produce static image of brain tissue
pro: excellent measure of brain anatomy
con: NO info about activity/function
Functional MRI Scan
measure blood flow indirectly by assessing changes in the blood’s oxygen level
pro: excellent measure of brain activity and structure
con: lag time in recording signal
PET Scan
uses radioactive substance to produce activity-related image (injected into brain)
pro: good measure of activity, can label substances
con: weak measure of structure, radioactivity
Experimental Techniques
Brain Activation/Inactivation: precisely manipulate specific brain area, only method that provides cause/effect info
- Transcranial Magnetic Stimulation (TMS)
- Direct Brain Stimulation
- Intercranial Stimulation
- Deep Brain Stimulation
Transcranial Magnetic Stimulation (TMS)
magnetic field manipulates brain activity in a specific brain region with a wand
-most useful in structures near brain surface
Direct Brain Stimulation
stimulation during brain surgery –> mapping brain function anatomy on surface of brain
–> Wilder Penfield: neurosurgeon stimulated parts of brain so that he wouldn’t remove more than necessary
Intercranial Stimulation
electrodes implanted deep inside brain (temporary)
Deep Brain Stimulation
permenant implanted electrodes used to treat some disorders (ex. Parkinson’s)
Phrenology
study of skull to determine a person’s character/mental capacity
