module 3

biopsychology

• biopsychology explores the biological mechanisms that underlie behavior

• among may things, it studies

  • genetics - focusing on how inherited genes can affect not just the physiological, but psychological traits of a person

  • the structure and function of the nervous system

  • how the nervous system interacts with the endocrine system (hormones)

through this, helps researchers understand biological basis behind human behaviors, thoughts, and reactions

CHARLES DARWIN - theory of evolution

• explored concept of inheritance of traits throughout generations in theory through natural selection

• organisms that are better suited will survive, otherwise they will die

• characteristics that impact survival/reproduction

  • those that help protect against predators

  • those that increase access to food

  • those that help to offspring alive

genetic variations -

• chromosome - long strand of genetic information known as DNA

• DNA - helix-shaped molecule made of nucleotide base pairs

• gene - sequence of DNA that controls/partially controls physical characteristics known as traits

allele - specific version of a gene

genotype - genetic makeup of an individual

phenotype - individuals inherited physical characteristics which are a combination of genetic and environmental influences

TYPES OF ALLELES

dominant - will always result in the phenotype associated

recessive - only expressed physical if individual is homozygous for that allele

punnet square - a tool used to predict how genes will interact in the production of offspring\

gene-environment interactions

• nature and nurture work together like complex pieces of a human puzzle

• each of use represents unique reaction between genetic makeup and our environment

• according to range of reaction, genes set definite limits on potential and environment determines how much of that potential is achieved.

• genes and environment interact but also influence bidirectionally

  • parents’ genes influence environment → environment is well-suited to support genetic potential

• epigenetics → researchers study how the same genotype can be expressed in different ways

  • gene expression is often influenced by environmental context in ways not entirely obvious

cells of the nervous system

neuron structure

• axons → covered in myelin sheath made of a fatty substance that insulates axons and allows the signal to travel down the axon quicker.

• at the end of axons are terminal buttons that contain synaptic vessels

synaptic vessels → storage sites for chemical messengers called neurotransmitters

neuronal communication

resting potential

• neuron membrane potential is held in a state of readiness

• ions line up on either side of the cell membrane, ready to rush across the membrane when the neuron goes active and the membrane opens its gates

• ions in high concentration areas are ready to move in low concentration areas and positive ions are ready to move to areas with a negative charge

action potential

• neurotransmitters from nearby neurons attach to receptors on dendrites causing the membrane potential to change

• if the level of charge reaches the threshold of excitation an action potential will occur. ion channels open, causing Na+ to rush into the cell and the inside to momentarily become more positive

• action potentials act on an all-or-none principle - the incoming signal is either sufficient to reach the threshold of excitation if it is not.

reuptake

• once an action potential has occurred, excess neurotransmitters in the synapse either drift away, are broken down or are reabsorbed

• reuptake involves moving a neurotransmitter from the synapse back into the axon terminal from which it was released

acetylcholine - muscle action and memory (increased arousal, enhanced cognition)

beta-endorphin - pain and pleasure (decreased anxiety/tension)

dopamine - mood, sleep, learning (increased pleasure, suppressed appetite)

GABA - brain function, sleep (decreased anxiety/tension)
glutamate - memory, learning (increased learning, enhanced memory)

norepinephrine - heart, intestines, alertness (increased arousal, suppressed appetite)

serotonin - mood, sleep (modulated mood, suppressed appetite)

psychoactive drugs

• psychotropic medication - drugs that treat psychiatric symptoms by restoring neurotransmitter balance

• agonist - drug that mimics or strengthens the effects of a neurotransmitter

• antagonist - drug that blocks or impedes the normal activity of a given neurotransmitter

• reuptake inhibitors - prevent unused neurotransmitters from being transported back to the neuron

parts of the nervous system

two major subdivisions (Central nervous system (CNS), Peripheral nervous system (PNS)

CNS - made up of brain and spinal cord

PNS - connects the CNS to the rest of the body

PNS -

1. somatic nervous system - relays sensory and motor information to/from CNS

2. automatic nervous system - controls our internal organs and glands and can be divided into the sympathetic and parasympathetic nervous systems

• sympathetic nervous system - involved in stress-related actiities and functions; prepares us for fight/flight

• parasympathetic nervous system - associated with routine, day-to-day operations of the body under relaxed conditions

brain

• comprsied of billions of interconnected neuron and glia

• bilateral (two-sided)

• can be separated into distinct lobes but all areas interact with each other

spinal cord

• delivers messages to/from brain

• has own system of reflexes

• top merges with the brainsterm and the bottom ends just below the ribs

• functionally organized into 30 segments, each connected to a specific part of the body through the PNS

• sensory nerves bring messages in and up to the brain; motor nerves send messages out to the muscles and organs

• in moments of survival, automatic reflexes allow motor commands to be initiated without sending signals from sensory nerves to the brain first, allowing for very quick reactions

lateralization - concept that each hemisphere of the brain is associated with specialized functions

• left hemisphere controls right side of body

• right hemisphere controls the left side of the body

corpus callosum - section in middle of brain

forebrain, midbrain, hindbrain

lobes: frontal lobe, temporal lobe, parietal lobe, occipital lobe, cerebral cortex

frontal lobe: involved in executive functioning (planning, organization, judgement, attention, reasoning), motor control, emotion, and language

it contains:

• the motor cortex - strip of cortex involved in planning and coordinating movement

• prefrontal cortex - responsible for higher-level cognitive functioning

• broca’s area - region in the left hemisphere that is essential for language production

  • damage here will result in difficulties producing language

temporal lobe

• associated wiht hearing, memory, emotion, and some aspects of language.

• located on the side of the head (near the temples)

• it contains

  • the auditory cortex - strip of cortex in the temporal lobe that is responsible for processing auditory information

  • wernicke’s area - important for speech comprehension

    • damage here results in difficulty understanding language**

occipital lobe

• processes visual signals sent to brain

• contains the primary visual cortex which is responsible for interpreting incoming visual information

• organized retinotopically (parts of retina attached to neurons

other areas of the forebrain

• thalamus: relay center of the brain where most senses (excluding smell) are routed before being directed to other areas of the brain for processing

• limbic system: involved in mediating emotional response and memory

  • amygdala: involved in our experience of emotion and tying emotional meaning to our memories. involved in processing fear

  • hippocampus - structure associated with learning and memory (in particular spatial memory)

  • hypothalamus - regulates homeostatic processes including body temperature, appetite, and blood pressure

midbrain:

• reticular formation - important in regulating the sleep/wake cycle, arousal, alertness, and motor activity

• substantia nigra - where dopamine is produced; involved in control of movement

• ventral tegmental area (VTA) - where dopamine is produced; associated with mood, reward, and addiction

hindbrain:

• medulla - controls automated processes like breathing, blood pressure, and heart rate

• pons - connects the brain and the spinal cord; involved in regulating brain activity during sleep

• cerebellum - controls our balance coordination, movement, and motor skills, and is thought to be important in processing some types of memory.

brain imaging techniques:

• involving radiation

  • computerized tomography scan (CT)

  • positron emission tomography (PET)

• involving magnetic fields

  • magnetic resonance imaging (MRI)

  • functional magnetic resonance imaging (fMRI)

• involving electrical activity

  • electroencephalography (EEG)

the endocrine system

• series of glands that produce hormones to regulate normal body functions

• the hypothalamus links the nervous system and endocrine system by controlling the pituitary gland

• pituitary gland - serves as the master gland, controlling the secretions of all other glands

• thyroid - secretes thyroxine which regulates growth, metabolism, and appetite

• adrenal gland - secretes hormones involved in the stress response

• gonad - secretes sex hormones, which are important for successful reproduction, and regulate sexual motivation and behavior

• pancreas - secretes hormones that regulate blood sugar