Cerebral Anatomy: Lobes, Cortex, Tracts & Language Areas

Cerebrum

Largest brain region; supports conscious sensation, voluntary movement, thinking, language, and memory.

Longitudinal fissure

Deep groove separating the left and right cerebral hemispheres.

Insula

Cortical region hidden deep within lateral sulcus; involved in taste, balance awareness, and visceral sensation.

Gyrus (gyri)

Raised ridge or fold of the cerebral cortex.

Sulcus (sulci)

Groove in the cerebral cortex; along with gyri, increases cortical surface area.

Central sulcus

Groove separating the precentral motor gyrus from the postcentral sensory gyrus.

Lateral sulcus

Groove separating temporal lobe from overlying frontal and parietal regions.

Parieto-occipital sulcus

Groove marking boundary between parietal and occipital lobes, especially medially.

Gray matter

Neural tissue containing neuron cell bodies, dendrites, and unmyelinated axons.

Cerebral cortex

Superficial layer of gray matter in the cerebrum.

Nucleus (CNS)

Functional collection of neuron cell bodies deep within the brain.

White matter

Neural tissue mainly consisting of myelinated axons.

Tract

Bundle of axons traveling together in the central nervous system.

Projection tracts

White matter pathways connecting cerebrum with lower CNS regions, including spinal cord.

Commissural tracts

White matter pathways connecting left and right cerebral hemispheres.

Corpus callosum

Major commissural tract linking left and right cerebral hemispheres.

Association tracts

White matter pathways connecting regions within the same cerebral hemisphere.

Sensory cerebral areas

Areas responsible for conscious awareness of sensations.

Motor cerebral areas

Areas involved in voluntary motor control.

Association cortex

Cortical regions that integrate information from multiple areas; most of cortex.

Frontal lobe

Lobe involved in planning, behavioral regulation, and voluntary movement.

Prefrontal cortex

Large association cortex for planning, decision-making, self-awareness, and behavioral regulation; matures into roughly mid-20s.

Precentral gyrus

Site of primary motor cortex; controls voluntary movement.

Primary motor cortex

Cortical area on precentral gyrus sending commands for voluntary muscle movements.

Premotor cortex

Frontal cortical region for planning and coordinating movements.

Motor homunculus

Map of body parts across motor cortex; relative size reflects amount of cortex devoted to motor control.

Broca's area

Typically left frontal region for speech production, motor coordination of speech, and grammar.

Broca's aphasia

Impaired speech production with relatively preserved comprehension; speech is effortful and short, sometimes affects writing or signing.

Parietal lobe

Lobe involved in general sensation, attention, and spatial awareness.

Parietal association cortex

Supports spatial awareness and visual attention.

Postcentral gyrus

Site of primary somatosensory cortex for general body sensation.

Primary somatosensory cortex

Receives and consciously processes general body sensations.

Somatosensory association cortex

Integrates sensory inputs and supports tactile memory.

Sensory homunculus

Map of body parts in sensory cortex; size reflects cortical representation of sensation.

Temporal lobe

Lobe containing hearing and smell areas plus regions for recognition and language comprehension.

Primary auditory cortex

Cortical region receiving auditory information.

Olfactory cortex

Cortical region involved in perception of smell.

Auditory association cortex

Helps classify and interpret sounds.

Visual association cortex (temporal)

Helps recognize and interpret what is seen.

Wernicke's area

Usually left temporal region important for understanding spoken language and word meanings.

Wernicke's aphasia

Speech may be fluent but nonsensical; language comprehension, reading, and writing may be severely impaired.

Occipital lobe

Primary lobe for vision processing.

Primary visual cortex

Receives and processes visual input.

Visual association cortex (occipital)

Analyzes visual features such as color, shape, and orientation.

Vestibular cortex (insula)

Area associated with conscious awareness of balance.

Gustatory cortex (insula)

Area associated with conscious perception of taste.

Visceral sensory cortex (insula)

Area associated with internal organ sensations.

Basal nuclei

Deep cerebral gray matter structures helping initiate and regulate voluntary movement, habits, and procedural learning.

Caudate nucleus

One of the major components of the basal nuclei.

Putamen

One of the major components of the basal nuclei.

Globus pallidus

One of the major components of the basal nuclei.

Basal nuclei movement function

Support intended voluntary movements and inhibit unnecessary or antagonistic movements.

Basal nuclei nonmotor functions

Contribute to procedural learning, habitual behavior, and decision-making.

Limbic system

Network of brain regions involved in emotion and memory, including amygdala, hippocampus, and cingulate gyrus.

Cingulate gyrus

Limbic area involved in emotional expression.

Amygdala

Limbic structure strongly involved in fear responses.

Hippocampus

Limbic structure important for forming memories and spatial navigation.

Olfaction and limbic system

Smells can evoke emotional responses and memory formation or retrieval.

Memory

Encoding, storing, and retrieving information or experiences.

Declarative memory

Conscious recollection of facts and knowledge.

Nondeclarative memory

Unconscious memory expressed through skills and procedures.

Immediate memory

Information retained for just a few moments.

Short-term (working) memory

Limited information held temporarily, often for minutes.

Long-term memory

Information retained over long periods, potentially years.

Memory consolidation

Process stabilizing information into long-term memory; shaped by rehearsal, associations, and emotion.

Long-term potentiation (LTP)

Persistent increase in synaptic strength between associated neurons; supports memory formation.

Hippocampus in consolidation

Helps organize information into unified memories; supports LTP, dendrite growth, and transmitter release.

Long-term memory storage

Memory components can be stored in relevant cortical areas, such as sound-related details in auditory cortex.

Cognitive map

Mental representation of surroundings supporting spatial navigation; involves hippocampus.

London taxi driver study

Lecture example of increased hippocampal gray matter associated with extensive spatial navigation experience.

Diencephalon

Brain region including the thalamus, hypothalamus, and epithalamus.

Thalamus

Gatekeeper that filters, sorts, and relays signals to cerebral cortex.

Thalamus sensory role

Relays sensory information received from spinal cord and cranial nerves to cortex.

Thalamus motor role

Processes input from basal nuclei and cerebellum for regulation of motor cortex activity.

Thalamus emotional role

Processes input from limbic system and hypothalamus for emotional awareness and response.

Hypothalamus

Major homeostatic control center coordinating temperature, hunger, thirst, hormones, sleep, ANS, and emotion.

Homeostasis

Maintenance of relatively stable internal conditions.

Hypothalamic thermoregulation

Maintains body-temperature set point and helps initiate fever.

Hypothalamic food regulation

Monitors blood chemistry and hunger/fullness signals to regulate appetite and satiety.

Hypothalamic fluid regulation

Monitors blood osmolarity, causes thirst, and helps kidneys conserve water.

Osmolarity

Concentration of dissolved particles in a fluid; monitored for water balance.

Antidiuretic hormone (ADH)

Hormone produced by hypothalamus that helps kidneys conserve water.

Oxytocin

Hormone produced in hypothalamus and released by posterior pituitary.

Hypothalamus and pituitary

Hypothalamus regulates pituitary activity and influences endocrine function.

Circadian clock

Hypothalamic timing system coordinating daily rhythms of behavior and physiology.

Homeostatic sleep drive

Sleep pressure that grows as time spent awake increases.

Hypothalamus and ANS

Uses signals from organs, cortex, and limbic system to regulate autonomic centers in brainstem.

Hypothalamus and emotions

Links limbic activity to conscious emotional perception and bodily autonomic responses.

Epithalamus

Diencephalic region that includes pineal gland and participates in circadian timing.

Pineal gland

Releases melatonin on a circadian schedule to coordinate biological timing.

Melatonin

Hormone whose circadian secretion supports timing of sleep and other rhythms.

Emotion

Response involving interpretation of stimuli, bodily (autonomic and somatic) changes, and cognition.

Visceral motor emotional response

Autonomic bodily response such as racing heart or blushing.

Somatic motor emotional response

Skeletal-muscle response such as smiling or frowning.

Cognitive emotional response

Conscious recognition, expression, or regulation of emotion.

Circadian alerting system

Light signals from eyes to hypothalamus help promote alertness by day and sleep readiness at night.

Sleep onset

Hypothalamic actions reduce brainstem-thalamus communication and cortical responsiveness while brainstem functions continue.

NREM stage 1

Brief transition from wakefulness to sleep; lecture lists about 1-5 minutes.

NREM stage 2

Light sleep with reduced heart rate, breathing rate, blood pressure, body temperature, and stopped eye movements; about 10-60 minutes.

NREM stage 3

Deep sleep with muscle relaxation, reduced brain activity, tissue repair, and declarative-memory consolidation; about 20-40 minutes.