Neuroscience: Brain Structures and Functions

Gray and White Matter Locations

• Gray matter is found in horns, nuclei within the brain, and the outer cortex of the cerebrum and cerebellum.
• White matter is located in columns, beneath the cortex, and includes the corpus callosum.

Basal Nuclei

• Structures: Caudate nucleus, putamen, globus pallidus.
  • Lentiform nucleus is composed of the globus pallidus and putamen.
  • Corpus striatum includes the caudate nucleus and lentiform nucleus.
• Function: Involved in semivoluntary movements like arm swinging during walking.

Sleep Stages and Brain Waves

• Stage 1 NREM: Alpha waves.
• Stage 2 NREM: Irregular brain waves.
• Stage 3 NREM: Theta and delta waves.
• Stage 4 NREM: Primarily delta waves.
• REM: Characterized by skeletal muscle paralysis.

Cerebrum Lobes and Functions

• Gustatory Cortex: Insula, responsible for taste perception.
• Olfactory Cortex: Temporal and frontal lobes, involved in smell perception.
• Primary Auditory Cortex: Temporal lobe, processes sound (volume and pitch).
• Primary Somatosensory Cortex: Postcentral gyrus, detects touch, temperature, and spatial awareness.
• Primary Visual Cortex: Occipital lobe, involved in interpreting light, color, shape, and movement.
• Vestibular Cortex: Insula, related to balance and equilibrium.
• Visceral Sensory Area: Insula, senses from internal organs.
• Auditory Association Area: Temporal lobes, interprets sounds.
• Somatosensory Association Area: Postcentral gyrus, interprets touch and textures.
• Visual Association Area: Occipital lobe, interprets visual stimuli.
• Premotor Cortex: Frontal lobe, involved in muscle memory.
• Primary Motor Cortex: Precentral gyrus, controls voluntary movements.
• Broca's Area: Left frontal lobe, speech (muscle movements).
• Wernicke's Area: Parietal and temporal lobes (left), processes visual and auditory stimuli.
• Prefrontal Cortex: Frontal lobe, higher-level thinking.

Diencephalon

• Epithalamus: Houses the pineal body, regulating melatonin production (important for sleep-wake cycles and seasonal affective disorder).
• Thalamus: Plays a key role in sensory relay, with the intermediate mass being a central feature.
• Hypothalamus: Controls the autonomic nervous system, influences the limbic system and endocrine system, and also plays a significant role in regulating behaviors like eating, drinking, temperature regulation, and monitoring the circadian rhythm.
• Mammillary Bodies: Involved in memory.

Brainstem

• Midbrain (Mesencephalon):
  • Cerebral peduncles: important pathways.
  • Superior colliculi: visual reflexes.
  • Inferior colliculi: auditory reflexes.
  • Substantia nigra: Crucial for dopamine production, plays a role in movement disorders.
  • Red nucleus: involved in motor control.
• Pons: Contains centers for salivation and respiration.
• Medulla Oblongata: Contains crucial centers for cardiovascular, respiratory, swallowing, and emetic (vomiting) functions.
  • Decussation (crossing over) occurs in the medulla.

Cerebellum

• Coordination of movement.

Brain Ventricles

• Fluid-filled spaces within the brain.

Functional Systems

• Reticular Formation: Maintaining consciousness.
• Limbic System: Regulates emotions, memory, and motivation.
  • Included structures include amygdala, cingulate gyrus, fornix, and hippocampus.