PSYC - Chapter 3 (Biological Bases of Behaviour)

neuron

cell of the nervous system specialized for sending and receiving neural messages

sensory neurons

carry messages from the sensory organs (i.e. eyes, tongue, skin) to spinal cord and brain

motor neurons

carry messages from the brain and spinal cord to muscles and glands

interneurons

located within the brain and spinal cord collect, integrate & retrieve messages from various sources

dendrites

receive chemical messages from other neurons

cell body/soma

collects neural impulses, contains the nucleus, sustains cell functions

axon

transports electrical impulses to other neurons via the terminal branches

axon terminals/terminal branches

convert electrical signals into chemical messages for other neurons

myelin sheath

fatty layer that insulates the axons & speeds up transmission of electrical signals

glia

nervous system cells that perform variety of critical support functions

Action potential

neurons “talk” to each other by firing off electrical impulses

cell membrane

thin fatty “skin” enclosing the neuron

Resting potential

• more negatively charged particles inside cell relative to outside

• neuron cannot fire action potential in this state

ion channels

allow positively charged sodium ions to enter

Depolarization

Electrical charge across membrane begins to reverse

voltage threshold

critical level to which a neuron’s membrane potential must be depolarized to initiate action potential

Repolarization

potassium channels remain open → flow out of the cell

Refractory period

ensures that action potential is propagated forward during resting potential

synaptic cleft

gap separating neurons

neurotransmitters

chemical messengers that presynaptic neuron sends

receptor

channel in membrane of a neuron that binds neurotransmitters

diffusion

neurotransmitters drift out of synapse

degradation

neurotransmitters are broken down in the synapse

reuptake

neurotransmitters are reabosrbed into the presynaptic terminal brances

excitation

receiving neuron slightly deplorized

inhibition

receiving neuron slightly hyperpolarized

GABA

neurotransmitter that is responsible for downregulation of stress, anxiety, fear

Acetylcholine

Plays key role in autonomic nervous system, which carries commands from brain to glands & organs, regulates cardiac activity

Norepinephrine

• Important for “fight or flight response”

• regulation of arousal & vigilance

Serotonin

Contributes to regulation of sleep, appetite, mood, and aggression

Dopamine

Involved in movement, planning, and aspects of reward

Endorphins

Promote feelings of pleasure and reduce pain

psychoactive drugs

chemical substances that alter a person’s thoughts, feelings, or behaviors by influencing the activity or neurotransmitters in the nervous system

agonist

enhances action of a neurotransmitter

antagonist

inhibits actions of a neurotransmitter

Nervous system

complex network of nerves (bundles of neurons) that controls & regulates all bodily functions

Central nervous system (CNS)

brain & spinal cord

Peripheral nervous system (PNS)

nerves connecting brain to the rest of your body

Somatic nervous system

carries commands for voluntary movement from CNS to muscles

Autonomic nervous system

carries involuntary commands to organs, blood vessels, & gland

fight-or-flight response

expenditure of energy

Sympathetic nervous system (SNS)

Pupil dilation, increased breathing, heart rate & blood flow to muscles

rest-and-digest

returns body to resting state

Parasympathetic nervous system (PNS)

Controls gland & organs during calm periods, nutrient storage, repair, growth

endocrine system

network of glands (hormone-secreting organs) that work together with CNS and PNS

hormone

blood-borne chemical messengers

adrenal glands

located on top of kidneys, release of adrenaline and cortisol

pituitary gland

The ‘master gland’ that directs other glands and regulates hunger, sexual arousal, growth, sleep (via pineal gland), navigation of social world

oxytocin

Hormone released into bloodstream by pituitary gland which has a key aspect of reproductive systems

spinal cord

Major bundle of nerves connecting brain to rest of the body

spinal reflexes

initiated by spinal cord without involvement of the brain

brainstem

• Lowest region of the brain, sits on top of spinal cord

• Where spinal nerves & most cranial nerves connect

• Regulates vital functions; damage to this area is often lethal

midbrain

transmit info for vision & hearing, orientation towards salient stimuli (tegmentum), movement, motivation & reward, downregulation of pain

medulla

control vital processes like heart rate, blood pressure, reflexes like coughing and swallowing

pons

transmit messages, giving sensory (hearing & taste) and motor cues (balance & coordination) to the body

reticular formation

involved in various physiological functions (arousal, attention, wakefulness)

cerebellum

coordination, balance, precise movements & accurate timing

limbic system

Known as the ‘emotional brain’

hypothalamus

‘interface’ between brain & body, homeostatic regulation: temperature, thirst, hunger, biological rhythms, motivation, reward seeking, fight-or-flight response, directs the autonomic nervous system & endocrine system

thalamus

‘relay station’ for all sensory signals (except smell), alertness & consciousness

amygdala

processing emotional significance of sensory information

psychic blindness

normal vision, but visual stimuli lose their emotional significance

hippocampus

memory, spatial navigation, mental time-travel

basal ganglia

controlling voluntary movement, suppression of unwanted movement, reward & pleasure

cerebral cortex

Outermost and largest part of the human brain

corpus callosum

large bundle of nerve fibers

Frontal lobe

Movement and planning, judgement, decision-making

primary motor cortex

a “map” of the body’s muscles

prefrontal cortex

“personality center”

executive function

self-regulation & control of behaviour

Parietal lobe

Process touch and helps pay attention to and locate objects, navigate our surroundings

primary somatosensory cortex

a ”map” of the body’s skin surface

Occipital lobe

Vision & contains the primary visual cortex which is necessary for sight

Temporal Lobe

Allows you to hear and understand language and to recognize objects and people

primary auditory cortex

processes auditory information

primary olfactory cortex

learning & memory of odors

Insular lobe

Allows us to perceive our inner world & perceives state of internal organs

primary taste cortex

responsible for the perception of taste & flavour

association cortex

integrates incoming information from sensory areas with existing knowledge to produce meaningful experience of the world

interhemispheric transfer

Helps the two hemispheres “talk” to each other

Broca’s area

• Left frontal lobe

• Damage → telegraphic speech

  • ex) “I hungry”

• Can understand speech

Wernicke’s area

• Temporal lobe

• interpret sound & recognize language

phrenology

19th century belief that all mental faculties and characteristics are localized in specific brain regions and can be inferred from pattern of indentations on the skull

lesion

abnormal tissue resulting from disease, trauma, or surgical intervention

single dissociation

lesion to brain structure A disrupts function X but not function Y

double dissociation

lesion to brain structure A disrupts function X but not function Y, and lesion to brain structure B disrupts function Y but not function X

Deep brain stimulation

Stimulating specific parts of the brain with implanted electrodes

Transcranial Magnetic Stimulation (TMS)

Exposure to magnetic field to create temporary disruption or enhancement of cortical brain function

Transcranial Direct Current Stimulation (TDCS)

Low levels of direct current delivered via electrodes on the head to stimulate brain function

Functional Magnetic Resonance Imaging (FMRI)

Used to measure brain activity by detecting changes in blood oxygenation

PET

reveal changes in neurochemical activities (i.e., which neurotransmitters may be actively involved in a process)

single-cell recording

measurement of the electrical activity of a single neuron

Electroencephalography (EEG)

Recording of electrical waves from many thousands of neurons in the brain, gathered using electrodes placed on the scalp

Magnetoencephalography

The recording of the magnetic fields produced by the brain’s electrical currents

neural plasticity

brain’s ability to change and adapt throughout individual’s life

neurogenesis

process by which new neurons are formed in the brain

critical periods

specific timeframe during development when brain is particularly receptive to environmental stimuli, allowing for larger changes in neural connections

damage plasticity

neural modification/reorganization following injury

phantom limb syndrome

continuing sensation in limb that has been amputated