Psyc 100- Biological Bases of Behaviour

Sensory neurons

Deliver messages from the sensory organs (eyes, tongue, etc) to the brain and spinal cord.

Motor neurons

Carry messages from the brain and spinal cord to muscles and glands.

Interneurons

Work within the brain and spinal cord to collect, integrate, and retrieve messages from various sources.

Dendrites

Retrieve electrical impulses from other neurons

Cell body/soma

Responsible for collecting neural impulses

Axons

Responsible for transporting electrical impulses along the terminal branch to other neurons.

Terminal branches

Responsible for converting the electrical signals into chemical messages.

Myelin sheath

Supports neuronal functioning by insulating the axons and speeding up the signals.

Glial cells

The janitors of the nervous system that preform a variety of critical support functions like cleaning up debris, facilitating neurons and supplying nutrients.

Diffusion

Occurs when neurotransmitters drift off into the synaptic cleft

Degradation

Occurs when the neurotransmitters are broken down

Reuptake

Occurs when the neurotransmitters are reabsorbed into the presynaptic terminals.

Excitatory signals

Signals that are received when a neuron is slightly depolarized. This moves it closer to the voltage threshold. Think edging or muscle contractions.

Inhibitory signals

Signals that are received when a neuron is slightly hyperpolarized which moves it away from an action potential. An example of this is muscle relaxation. When inhibitory signals are broken, it could cause permanent muscle contraction such as lockjaw (TETANUS!)

GABA

The most common inhibitory neurotransmitter which are responsible for the down-regulation of stress, anxiety, and fear. Many sedative drugs target this transmitter.

Acetylcholine

A neurotransmitter that triggers both excitatory and inhibitory signals. It plays a key role in the autonomic nervous system which carries commands from the brain to glands and organs to regulate cardiac activity. Low levels are associated with dementia.

Norepinephrine

A neurotransmitter important for the ‘“fight-or"flight” response. Contributes to arousal and vigilance and an excess of this neurotransmitter can contribute to high blood pressure and anxiety

Serotonin

A neurotransmitter that contributes to the regulation of sleep, appetite, mood, and aggression. It is thought to play a role in depression.

Dopamine

A neurotransmitter involved in movement, planning, and aspects of reward. The most addictive drugs specifically target and stimulate increased activity in dopamine receptors and high levels are attributed to schizophrenia and low levels are associated with Parkinsons

Endorphines

Neurotransmitters that promote feelings of pleasure and reduce pain.

Psychoactive drugs

Chemical substances that alter an individual’s thoughts, feelings, or behaviours by influencing the activity of neurotransmitters in the nervous system.

Agonist

Enhances the action of a neurotransmitter, increasing release and mimicking neurotransmitters to activate receptors.

Antagonist

Inhibits the actions of a neurotransmitter and can block the release of action potentials or even destroy the neurotransmitter altogether. It can also mimic a neurotransmitter to properly block it. Think of the absolute enemy to an agonist. 

Central nervous system

The nervous system that includes the brain and spinal cord.

Peripheral nervous system

The nervous system with all the nerves and organs that connect the brain to the rest of the body.

Somatic nervous system

Carries commands for voluntary movement from the central nervous system to the muscles.

Autonomic nervous system

Carries involuntary commands to organs, blood vessels, and glands. It operates outside of conscious control and is further split up into the sympathetic and parasympathetic branches.

Sympathetic nervous system

Prepares the body for situations requiring expenditure of energy (fight-or-flight response)

Parasympathetic nervous system

Controls the glands and organs during calm periods and returns the body back to a resting state (rest-and-digest). It also stores nutrients, and repairs and grows the body.

Endocrine system

Network of glands (hormone-secreting organs) that work with the central nervous system and the peripheral nervous system. This system is involved in regulating arousal, metabolism, growth, and sex.

Pituitary gland

The ‘master gland’ which directs the other glands and regulates hunger, sexual arousal, growth, sleep (in the pineal gland), and the navigation of the social world. 

Oxytocin

A hormone that is released into the bloodstream by the pituitary gland and is involved in malnutrition (contractions during birth). It also plays a significant role in social bonding and has shown that an increase in oxytocin causes better social interaction and bonding among animals and humans.

Spinal reflex

 Initiated by the spinal cord without the involvement of the brain. This can be due to a number of reasons, with the most prominent being a response to a painful stimulus. 

Pons

Responsible for breathing, balance and coordination, relaying sensations (hearing and taste) to higher levels of the brain. Think of pons being a bridge to the higher levels.

Medulla oblongata

Responsible for your heart rate, blood pressure and reflexes such as coughing and swallowing. 

Reticular formation

In charge of arousal, attention, and wakefulness

Cerebellum

In charge of coordination, balance, precise movements, and accurate timing. It is also known as the “little brain”.

Hypothalamus

A region of the limbic system which is known as the ‘interface’ between the brain and the body. It is in charge of homeostatic regulation (drive reduction theory), motivation and reward-seeking, and fight or flight response, and also directs the autonomic nervous system and endocrine system. 

Thalamus

The as the ‘relay station’ for all sensory signals (except smell) and is also involved in alertness and consciousness

Amygdala

In charge of processing the emotional significance of sensory information, responding to positive and negative stimuli, working with the hippocampus to create vivid memories, and more.

Hippocampus

Predominantly involved with memory, spatial navigation, and mental time travel. 

Basal ganglia

Involved with planning, executing and controlling voluntary movement. It also suppresses unwanted movement and controls reward and pleasure.

Capgras syndrome

Hypothesized to be caused by damage to the amygdala due to the syndrome's impact on emotionally significant memories. An individual is unable to recognize individuals who are emotionally significant to them, so while they can recognize faces, they can’t know if they are emotionally significant to them or not.

Frontal lobe

 Involved with movement and planning and contains the primary motor cortex which has a map of the body’s muscles. It is also responsible for executive functioning which is the self-regulation and control of behaviour as well as planning, judgement, and decision-making.)

Parietal lobe

Contains the primary somatosensory cortex which is a map of the body’s skin surface, enabling us to process touch. It also helps us pay attention to, and locate objects and navigate our surroundings. 

Occipital lobe

Responsible for vision and contains the primary visual cortex which is necessary for sight. It also links to the temporal and parietal lobes which allow the brain to recognize objects and process their movement.

Temporal lobe

Contains the primary auditory cortex which allows us to hear and understand language and recognize objects and people (object memory)

Insular lobe

Allows us to perceive our inner world and the state of internal organs (racing heart and pain), it also contains the primary taste cortex.

Primary cortex

The first area to receive signals from their associated sensory nerves, think of the main branches of the sensory signals. 

Association cortex

Integrates incoming information FROM the sensory areas with existing knowledge to produce a meaningful experience of the world. An example is when you recognize a complex visual object or sound.

Contralateral organization

Refers to the similarities between the two hemispheres are their involvement in receiving sensory information from the body and sending commands to the muscles. Each hemisphere does this for the opposite side of the body. 

Lateralization

Refers to how some functions in the brain are located on either the right or left side
Areas in the left hemisphere specialize more in language while areas in the right hemisphere specialize more in nonverbal and visuospatial processing of information. 

Broca’s area

In charge of speaking. Damage to this area results in being able to understand and process language, but an inability to speak properly. 

Wernicke’s area

In charge of processing. Damage to this area results in being able to speak properly, but an inability to process or understand language. 

Single-cell recording

a measurement of the electrical activity of a single neuron.

Deep-brain stimulation

You stimulate specific parts of the brain with implanted electrodes. This is used to treat specific disorders like depression.

Transcranial Magnetic Stimulation (TMS)

You expose a patient to a magnetic field to create a temporary disruption or enhancement of cortical brain function. It allows for casual insight into brain function but doesn’t give you a good idea of where it actually is happening. 

Transcranial Direct Current Stimulation (TDCS)

You expose a patient to low levels of direct current delivered via electrodes on the head to stimulate brain function. Just like TMS it gives a great causal insight into brain function but doesn’t give a good idea of where the activity is actually occurring.

Positron Emission Tomography (PET)

You inject glucose into the brain and the radioactive liquid lights up when there is enhanced brain activity in certain areas. While this is great in showing where brain activity happens, it's incredibly invasive and doesn’t show WHEN brain activity happens.

Functional Magnetic Resonance Imaging (fMRI)

Used to measure brain activity by detecting changes in oxygen. When parts of the brain are active, they need more oxygen so more blood flows there, showing an increase in activity. It is far more accurate than PET when it comes to showing where brain activity happens and has a better estimate of WHEN it happens as well.

Electroencephalography (EEG)

A recording of electrical waves from many thousands of neurons in the brain, gathered using electrodes placed on the scalp. It can be used to diagnose brain states such as sleep and wakefulness. It can show us when something happens, but not where something happens.

Magnetoencephalography (MEG)

A recording of magnetic fields produced by the brain's electrical currents. It has the same limitations as EEG but has a greater accuracy when it comes to finding when something happens.

critical period

 A specific timeframe during development when the brain is particularly receptive to environmental stimuli, allowing for larger changes in neural connections. For example, visual stimulation in early life is crucial for developing depth perception and recognizing faces.

Neural plasticity

The brain's ability to change and adapt throughout an individual’s life.