The Biological Bases of Behaviour

Flashcards covering key vocabulary related to the biological bases of behavior, including neurons, neural impulses, neurotransmitters, brain structures, and brain study methods.

Neurons

Specialized cells that make up the nervous system, with four main parts: Cell body (soma), Dendrites, Axon, and Axon Terminals.

Cell body (soma)

The part of a neuron containing structures that keep the cell alive, including the nucleus.

Dendrites

Branches extending from the cell body that receive signals from other neurons.

Axon

Conducts electrical impulses away from the soma to other cells.

Axon Terminals

Sends signals to other cells.

Glial Cells

Support cells in the nervous system that hold neurons in place, make and move nutrients, form the Myelin Sheath, remove toxins, and contribute to the blood-brain barrier.

Neural Impulses

Electrical signals generated by neurons (action potentials) that allow them to communicate.

Resting Potential

The electrical state of a neuron when it is not stimulated, typically -70mV, maintained by a concentration of sodium ions outside and negative protein ions inside.

Action Potential

A neural impulse produced when a cell is stimulated, causing electrical charges (ions) to flow across the cell membrane, reversing the resting potential's charge.

Absolute Refractory Period

A period during which a neuron cannot fire again, limiting the frequency of nerve impulses and ensuring they travel in a single direction.

All-or-None Law

States that action potentials occur at a uniform and maximal intensity or do not occur at all; stronger signals create more action potentials, increasing the rate of cell firing.

Myelin Sheath

A fatty, whitish insulation layer derived from glial cells that insulates neurons, enabling faster signal conduction.

Nodes of Ranvier

Places where the myelin sheath is extremely thin or absent, allowing electrical conduction to 'skip ahead' for faster signals.

Synapses

Functional (not physical) connections between neurons and their target cells, where communication occurs across synaptic clefts without physical contact.

Synaptic Cleft

The gap across which neurons communicate, as they do not make physical contact.

Neurotransmitters

Chemical substances that carry messages across the synapse, either exciting other neurons or inhibiting their firing.

Inhibitory Neurotransmitter

A neurotransmitter that increases the resting potential (hyperpolarization) of the post-synaptic neuron, decreasing the likelihood of an action potential.

Excitatory Neurotransmitter

A neurotransmitter that decreases the resting potential (depolarization) of the post-synaptic neuron, increasing the likelihood of an action potential.

Glutamate (glutamic acid)

An excitatory neurotransmitter expressed throughout the brain, involved in the control of behaviors, especially learning and memory.

GABA (gamma-aminobutyric acid)

An inhibitory neurotransmitter expressed throughout the brain, involved in the control of behaviors, especially anxiety and motor control (e.g., Huntington’s disease).

Acetylcholine (ACh)

An excitatory neurotransmitter that functions at synapses involved in muscle movement and memory; implicated in memory loss in Alzheimer’s disease.

Norepinephrine

A neurotransmitter (excitatory and inhibitory) involved in learning, memory, wakefulness, and eating; associated with depression and panic disorders.

Serotonin

An inhibitory neurotransmitter (mostly) involved in mood, eating, sleep, and arousal; associated with depression, sleeping, and eating disorders.

Dopamine

A neurotransmitter (excitatory and inhibitory) involved in voluntary movement, learning, motivation, and pleasure; associated with depression, Parkinson’s disease, and schizophrenia.

Endorphin

An inhibitory neurotransmitter associated with insensitivity to pain (oversupply) or hypersensitivity to pain and immune problems (undersupply).

Sensory neurons

Carry input messages from the sense organs to the spinal cord and brain.

Motor neurons

Transmit output impulses from the brain and spinal cord to muscles and organs.

Interneurons

Perform connective or associative functions within the nervous system, being the most common type of neuron.

Central Nervous System (CNS)

Comprises the spinal cord and the brain.

Peripheral Nervous System (PNS)

Consists of the somatic system (voluntary muscle activation) and the autonomic system (involuntary control of smooth muscle, cardiac muscle, and glands).

Somatic Nervous System

Part of the PNS composed of sensory and motor neurons that bring information from sensory receptors and send information to muscles.

Autonomic Nervous System

Regulates the internal environment, controlling involuntary functions such as respiration, circulation, digestion, and aspects of motivation, emotional behavior, and stress responses.

Sympathetic Nervous System

Part of the autonomic nervous system responsible for activation or arousal functions, acting as a total unit (e.g., 'fight-or-flight' response).

Parasympathetic Nervous System

Part of the autonomic nervous system that slows down body processes, returning the body to a state of rest (e.g., 'feed-and-breed' system).

Spinal Cord

Connects parts of the peripheral nervous system with the brain, allowing nerves to enter and leave the CNS.

Spinal Reflexes

Simple stimulus-response sequences (reflexes) triggered at the level of the spinal cord without brain involvement.

Forebrain

The most anterior and highly developed part of the brain, responsible for numerous functions, including the cerebral cortex, basal ganglia, limbic system, thalamus, and hypothalamus.

Midbrain

Responsible for reflex actions and voluntary movements, including the reticular formation, superior colliculi, and inferior colliculi.

Hindbrain

Controls vital functions and coordinating movements, including the medulla, pons, and cerebellum.

Cerebral Cortex

The outer layer of the cerebral hemispheres, involved in thinking and mental processes, divided into four lobes: frontal, temporal, parietal, and occipital.

Basal Ganglia

Collections of neurons that are crucial to motor function.

Limbic System

A system involved in memory, emotion, and reward, including the hippocampus, amygdala, and nucleus accumbens.

Hippocampus

A part of the limbic system primarily involved in memory.

Amygdala

A part of the limbic system primarily involved in emotional responses.

Nucleus Accumbens

A part of the limbic system considered a reward center.

Thalamus

Relays incoming sensory information through groups of neurons to the appropriate region in the cerebral cortex.

Hypothalamus

Regulates basic biological drives such as hunger, thirst, and sexual behavior.

Reticular Formation

Located in the midbrain and extending into the hindbrain and forebrain, involved in the regulation of consciousness, sleep, wakefulness, and attention.

Superior Colliculi

Midbrain structures involved in vision, especially visual reflexes.

Inferior Colliculi

Midbrain structures involved in hearing.

Medulla

A part of the hindbrain that controls heart activity and largely controls breathing, swallowing, and digestion; contains ascending sensory and descending motor nerve tracts.

Pons

A part of the hindbrain that serves as a relay station for signals between higher and lower nervous system levels, regulates sleep and dreaming, and controls facial muscles/glands and respiration.

Cerebellum

A part of the hindbrain that controls bodily coordination, balance, muscle tone, and is involved in procedural memory (motor skills).

Motor Cortex

Controls the muscles involved in voluntary body movements.

Somatic Sensory Cortex

Receives input for sensations of heat, touch, cold, balance, and body position.

Primary Auditory Cortex

Located in the temporal lobe of both hemispheres, responsible for processing auditory information.

Primary Visual Cortex

Located in the occipital lobe, responsible for processing visual information.

Wernicke’s Area

A brain area involved in language comprehension.

Broca’s Area

A brain area involved in normal speech production.

Association Cortex

Found within all lobes of the cerebral cortex, involved in high-level functions like perception, thought, and language, and appears 'silent' to electrical stimulation.

Hemispheric Lateralization

The specialization of function in each of the brain's hemispheres, where the right hemisphere connects to the left side of the body and the left hemisphere connects to the right side of the body.

Right Hemisphere

Involved in feelings, intuition, humor, aesthetics, color, relationships, rhythm, physical senses, and motor skills (for the left side of the body).

Left Hemisphere

Involved in analytical thinking, rules, logic, structure, mathematics, planning, speech, language, and time (for the right side of the body).

Corpus Callosum

A bridge of nerve fibers connecting the two cerebral hemispheres, facilitating the transfer of information between them.

Corpus Callostomy

A surgical procedure where the corpus callosum is severed, resulting in 'split-brain' patients.

Split-Brain

A condition resulting from the severing of the corpus callosum, preventing communication between the brain's hemispheres.

Postmortem Studies

A method of studying the brain by examining brain tissue after death.

CT (Computer Tomography)

A brain imaging technique that builds a picture of the brain based on differential absorption of x-rays, revealing gross features.

PET (Positron Emission Tomography)

A brain imaging technique that uses trace amounts of short-lived radioactive material to map functional processes in the brain.

Structural MRI (Magnetic Resonance Imaging)

A brain imaging technique that uses a strong magnetic field to build a picture of the brain, revealing gross features and underlying structure, often used with fMRI.

fMRI (functional Magnetic Resonance Imaging)

A brain imaging technique that detects changes in blood oxygenation and flow, which are tied to neural activity, indicating areas of high brain activity.

DTI (Diffusion Tensor Imaging)

A brain imaging technique that uses an MRI scanner to observe water movement along specific neural tracts in the brain, offering high spatial resolution and directionality.

NIRS (Near Infrared Spectroscopy)

A brain imaging technique that measures changes in blood oxygenation by shining near-infrared light through the skull and detecting the attenuation of reemerging light, providing an indirect measure of brain activity.

EEG (Electroencephalography)

A method that measures electrical activity of the brain via electrodes placed on or in the skull, offering very good time resolution.

TMS (Transcranial Magnetic Stimulation)

A technique that induces electrical activity via a magnetic field, which can temporarily disrupt (or activate) cortical neural tissue to study its function.