Exam Study: Psychophysics, Neurons & Glia, Nervous System, Imaging & Brain Structures

Vocabulary flashcards covering psychophysics concepts, neurons & glia, nervous system divisions, spinal nerves & reflexes, imaging methods, and major brain structures.

Psychophysics

Field that aims to quantify perceptual responses to physical stimuli.

Absolute threshold

Smallest detectable stimulus 50% of the time.

Differential threshold (JND)

Smallest detectable difference between two stimuli.

Method of adjustment

Subject adjusts the stimulus until it becomes detectable.

Method of limits

Stimulus presented in ascending/descending series; detection is yes/no.

Method of constant stimuli

Random presentation of stimuli with varied intensities to measure thresholds.

Signal detection theory

Separates signal from noise using hits, misses, false alarms, and correct rejections.

Weber’s law

JND is a constant fraction of the original stimulus.

Fechner’s law

Perceived intensity is proportional to the logarithm of stimulus intensity.

Stevens’ power law

Perceived intensity is proportional to stimulus raised to the power a.

Neuron anatomy

Dendrites → soma → axon (myelin sheath) → terminals.

Oligodendrocytes

Glial cells that form myelin in the CNS.

Schwann cells

Glial cells that form myelin in the PNS.

Astrocytes

Glial cells that provide support and form the blood–brain barrier.

Microglia

Glial cells that act as immune cells in the CNS.

Neural plasticity

PNS regenerates better than CNS; brain can adapt structurally/functional.

Ion channels (ligand-gated)

Open in response to chemical neurotransmitters.

Ion channels (voltage-gated)

Open in response to changes in membrane potential.

Resting potential

Approximately −70 mV maintained by the Na+/K+ pump.

Action potential

Depolarization → repolarization → hyperpolarization; all-or-none.

CNS

Central nervous system: brain and spinal cord.

PNS

Peripheral nervous system: nerves outside the CNS.

Somatic nervous system

Voluntary control of skeletal muscles.

Autonomic nervous system

Involuntary control of bodily functions.

Sympathetic division

Fight/flight responses.

Parasympathetic division

Rest/digest functions.

Afferent (dorsal) roots

Carry sensory information to the CNS.

Efferent (ventral) roots

Carry motor information from the CNS to muscles.

Reflexes

Involuntary automatic responses (e.g., knee-jerk).

MRI

Structural imaging of the brain.

fMRI

Measures blood oxygenation level dependent signal to infer neural activity.

DTI

Diffusion tensor imaging; maps white matter tracts.

PET

Positron emission tomography; uses radioactive tracer to measure metabolic activity.

CAT/CT

X-ray based imaging slices; lower resolution than MRI.

EEG

Electrical activity recorded from scalp; used for sleep and epilepsy.

MEG

Magnetic fields generated by neural activity.

TMS

Transcranial magnetic stimulation; disrupts or stimulates cortex with magnetic pulses.

Frontal lobe

Involved in decision making, motor control; includes Broca’s area.

Parietal lobe

Processes touch and somatosensory information.

Occipital lobe

Primary visual processing.

Temporal lobe

Hearing, memory; includes Wernicke’s area.

Cerebral cortex

Outer layer of brain involved in higher cognition.

Corpus callosum

Bundle of fibers that connects the two cerebral hemispheres.

Basal ganglia

Movement regulation; includes the substantia nigra (Parkinson’s).

Cerebellum

Coordination and balance.

Hippocampus

Memory formation and spatial navigation.

Hypothalamus

Maintains homeostasis; SCN regulates circadian rhythm.

Pineal gland

Produces melatonin; regulates sleep.

Endocrine system

Glands and hormones that regulate bodily functions.

Thalamus

Sensory relay station (except for smell).

Medulla oblongata

Regulates breathing and heart rate.

Sulci

Grooves/furrows on the cerebral cortex.

Gyri

Ridges/folds on the cerebral cortex.

Meninges

Protective layers around the brain: pia, arachnoid, dura mater.

Limbic system

Emotion and motivation processing network.

Reticular activating system

Regulates arousal and alertness.

Ventricles

Brain cavities filled with cerebrospinal fluid (CSF) for cushioning.

CSF (cerebrospinal fluid)

Nourishes and cushions the brain.

Medial forebrain bundle

Reward pathway linking limbic areas to dopaminergic systems.