Lect 22 - structure and layout of major brain areas

Flashcards to review the structure and function of major brain areas, including lobes, white matter, motor and somatosensory pathways, and associated conditions.

Sulcus/Sulci

Furrows or valleys on the surface of the brain.

Gyrus/Gyri

Hills or ridges on the surface of the brain.

Central Sulcus

Separates the frontal and parietal lobes.

Lateral Sulcus

Separates the temporal lobe from the frontal and parietal lobes.

Parieto-occipital Sulcus

Separates the parietal and occipital lobes.

Transverse Fissure

Separates the cerebrum from the cerebellum.

Functions of the Frontal Lobe

Motor control, language, and personality.

Function of the Parietal Lobe

Somatosensory processing.

Functions of the Temporal Lobe

Memory and hearing.

Function of the Occipital Lobe

Vision.

Commissural Tracts

Axons cross from one side of the brain to the other (e.g., corpus callosum).

Projection Tracts

Axons extend between the cortex and other CNS areas outside the cerebrum (e.g., corticospinal tract).

Association Tracts

Axons on the same side within the cerebral cortex for communication between brain areas.

Location and Function of the 1° Motor Cortex

Precentral gyrus; controls specific regions of the body.

Location and Function of the 1° Somatosensory Cortex

Postcentral gyrus; receives sensory information from specific regions of the body.

Sensory Information Carried by the Dorsal/Posterior Column Pathway

Fine touch, vibration, pressure, and proprioception.

Dorsal/Posterior Pathway

Neuron 1:

Cell body: dorsal root ganglion (unipolar neuron)

Axon: peripheral fibre (input) from sensory receptor, central fibre (output) ascends in dorsal columns). synapse in medulla oblongata

Neuron 2:

Cell body: medulla oblongata

Axon: cross to opposite side in medulla oblongata and ascends. synapse on in thalamus

Neuron 3:

Cell body: thalamus

Axon: ascends to somatosensory cortex. makes synapse on cell body of somatosensory cortex neuron

Sensory Information Carried by the Spinothalamic Tract

Pain and temperature.

Spinothalamic Tract pathway

Neuron 1:

Cell body: dorsal root ganglion, which is located outside the spinal cord. (unipolar neuron)

Axon: makes synapse on neuron 2 in doral horn of spinal cord

Neuron 2: tract cell

Cell body: spinal cord

Axon: crosses to opposite side of spinal cord via anterior white commissure and ascends via spinothalamic tract. synapse on neuron 3 in thalamus

Neuron 3:

Cell body: thalamus

Axon: ascends to somatosensory cortex. synapse on cell body of somatosensory cortex neuron

Agnosia

Damage to a region involved with sensory perception, causing changes in perception.

Aphasia

Damage to regions governing language, causing changes in speech perception or production.

The Corticospinal Pathway

Upper motor neuron:

Cell body: primary motor cortex (precentral gyrus)

Axon: extends form motor cortex in braintem to spinal cord on opposite side in medulla oblongata. synapse in ventral horn of spinal cord

Lower motor neuron:

Cell body: ventral horn

Axon: extens out of spinal cord (through ventral root). synapse on skeletal muscle