Psych Chapter 3

What are the three basic types of neurons in the nervous system?

Sensory neurons, motor neurons, interneurons.

What do sensory neurons do?

Carry info from sensory receptors (sight, hearing, touch, etc.) to the brain for processing. 

What do motor neurons do? 

Send signals from the CNS to muscles and glands to produce movement. 

What do interneurons do, and where are they located? 

Found in the brain and spinal cord only; connect and integrate signals between sensory and motor neurons. 

Why are interneurons essential for complex behavior?

They form neural circuits that allow higher-level processing and decision-making.

What are dendrites?

Branch-life structures that receive input signals from other neurons.

What is the soma (cell body)?

The central part of a neuron containing the nucleus; integrates signals.

What is the axon? 

A long fiber that transmits electrical signals away from the soma. 

What are terminal branches?

The ends of axons that release neurotransmitters into synapses.

What is the myelin sheath?

A fatty insulation around axons that increases speed of signal transmission.

Which cells form the myelin sheath?

Glial cells.

What happens if the myelin is damaged?

Signal transmission slows or falls (e.g., in multiple sclerosis) 

What does the automatic nervous system (ANS) control?

Involuntary functions like heartbeat, breathing, digestion, blood vessels.

What is the role of the sympathetic nervous system (SNS)?

Activates fight-or-flight responses (increased heart rate, energy, blood flow to muscles). 

What is the role of the parasympathetic nervous system (PNS)?

Restores resting state after stress (slows heart rate, aids digestion).

What does the somatic nervous system control?

Voluntary skeletal muscle movements.

Are reflexes part of the somatic nervous system?

No; reflexes bypass conscious control and are handled by spinal circuits.

What are the three main brain regions?

Forebrain, midbrain, hindbrain.

What does the forebrain contain?

The cerebral cortex and subcortical structures (e.g., limbic system)

What does the midbrain do?

Serves as a relay center.

What does the hindbrain include?

The brainstem and cerebellum, controlling basic survival functions.

What is the cerebral cortex?

The wrinkled outer layer of the brain responsible for higher mental functions.

What is the neocortex?

The folded outermost layer that supports complex cognition.

What does the frontal lobe do? 

Complex thought, planning, voluntary movement. 

What does the parietal lobe do? 

Processes touch and spatial awareness. 

What does the occipital lobe do?

Processes vision.

What does the temporal lobe do?

Processes hearing and object memory.

What does the insular lobe do?

Taste and internal bodily awareness.

What is the primary motor cortex? 

Located at the back of the frontal lobe; controls voluntary movements. 

What is the primary somatosensory cortex?

Located at the front of the parietal lobe; processes touch sensations.

What are the basal ganglia responsible for?

Planning and executing movement; linking cortex and spinal cord.

What does the thalamus do?

Relays sensory information (except smell) to the cortex.

What does the hypothalamus regulate?

Hunger, thirst, body temp, sexual behavior, homeostasis.

What does the amygdala do? 

Processes emotional events, especially fear and anger; strengthens emotional memories.

What happens if the amygdala is damaged?

Reduced fear response; difficulty recognizing emotional significance.

What does the hippocampus do?

Forms memories and supports spatial navigation.

What is the brainstem’s main function?

Controls vital functions (breathing, heart rate, reflexes).

What does the pons control?

Breathing and relays sensory signals.

What does the medulla control? 

Automatic survival functions (heartbeat, reflexes like swallowing).

What does the reticular formation regulate?

Sleep and arousal.

What does the cerebellum do?

Coordinates movement, precision, balance, and timing.

What connects the hemispheres?

The corpus callosum, a fiber bridge.

What is contralateral control?

Each hemisphere controls the opposite side of the body.

Which hemisphere typically controls language?

The left hemisphere.

What was phrenology?

A pseudoscience claiming skull bumps reflect mental traits.

What is localization of function.

Idea that specific brain regions have specialized roles.

What is a lesion?

Abnormal brain tissue due to injury, disease, or surgery.

What is dissociation in neuropsychology? 

When one brain area controls a function while others remain intact. 

What is double dissociation?

Gold standard: two brain areas show opposite deficits, proving specialized functions. 

What is a CT scan?

Combines X-rays from multiple angles into a 3D brain image.

What is MRI?

Uses magnetic fields and radio waves to show brain tissue structure.

What is DTI (Diffusion Tensor Imaging)?

A variation of MRI that maps brain connectivity by tracking water flow in white matter. 

What is EEG?

Measures electrical activity across scalp from groups of neurons.

What is an ERP (Event-Related Potential)?

Averaged EEG responses to specific events, showing cognitive timing.

What is MEG?

Records magnetic fields from brain activity.

What is PET? 

Tracks radioactive glucose to see active brain areas. 

What is fMRI? 

Tracks oxygenated blood flow to measure brain activity. 

What is DBS (Deep Brain Stimulation)?

Electrodes implanted in brain to stimulate targeted regions.

What is TMS (Transcranial Magnetic Stimulation)?

Uses strong magnetic pulses to disrupt or enhance brain activity.

What is TDCS (Transcranial Direct Current Stimulation)?

Uses low current over minutes to modulate brain activity.

What is an action potential? 

A rapid voltage change in a neuron when it reaches threshold (~55mV)

What is resting potential? 

A neuron’s baseline negative charge (~70mV).

What happens when threshold is reached?

Sodium (Na+) channels open → depolarization.

What happens during repolarization?

Potassium (K+) exits neuron, restoring negativity.

What is the refractory period?

A brief time after firing when another action potential can’t occur.

What does “all-or-none” mean? 

Action potentials either fire fully if threshold is reached or not at all. 

What is a synapse?

The gap between neurons where neurotransmitters travel.

Why can’t electrical signals cross the synapse?

Because the gap requires chemical messengers (neurotransmitters).

What are neurotransmitters?

Chemical messengers that bind to receptors on receiving neurons.

What is the lock-and-key model?

Neurotransmitters fit specific receptors.

What does glutamate do? 

Main excitatory NT; helps form long-term memory.

What does GABA do?

Main inhibitory NT; regulates muscle tone.

What does norepinephrine do?

Involved in arousal and fight-or-flight response.

What does dopamine do?

Involved in reward, pleasure, and motivation.

What does serotonin do? 

Regulates mood, happiness, appetite, and sleep. 

What does acetylcholine do?

Supports learning, memory, and muscle control.

What are psychoactive drugs?

Drugs that alter neurotransmitter activity.

What are agonists? Give example. 

Drugs that mimic neurotransmitters (e.g., heroin mimics endorphins). 

What are antagonists? Example?

Drugs that block neurotransmitter action (e.g., naloxone blocks opioid receptors). 

What is neural plasticity?

The brain’s ability to reorganize, adapt, and form new connections.

What is neurogenesis?

The birth of new neurons.

What is synaptogenesis?

The creation of new synapses between neurons.

What are critical periods?

Early-life windows when certain experiences are necessary for normal development. 

What is damage plasticity? 

Brain reorganization following injury (e.g., stroke recovery).