Neuroingegneria

1. FUNCTIONAL NEUROANATOMY AND NEUROPHYSIOLOGY

(from the single cell to small networks)

1.1 Nervous System

• CNS: brain + spinal cord
  • receives info and gives orders for the muscles and glands to act.
• PNS: sensory + motor nerves
  • bring the messages into and out of the CNS

Anatomy and functional areas of the brain

• 2 cerebral hemisphere
• 4 lobes (frontal, parietal, occipital, temporal)
• primary motor cortex (lies along the anterior wall of cs)
• primary somatosensory cortex (in the posterior wall of cs)
• hippocampus: one in each temporal lobe. It plays a very important role in memory

1.2 Cerebral Cortex

• Each hemisphere is covered with cortex: it is composed of gray matter
  • outer layer of gray matter. It is convoluted into hundreds of fold's mode of gyri and sulci to optimize space. It contains neuronal soma (cell body) and unmyelinated axons.
• White matter: it is composed by myelinated axons
  • (long-range nerve fibers) that interconnect the various cortical areas and that connect the cortex to subcortical area.

1.3 Brain Connectivity

• Structural connectivity: + neurons are physically connected
  • stable within short time scale (sec. to minute)
  • variable within longer time scale due to plasticity

1. FUNCTIONAL NEUROANATOMY AND NEUROPHYSIOLOGY

Nervous system

• CNS: brain + spinal cord
  • receives info and gives orders for the muscles and glands to act.
• PNS: sensory + motor nerves
  • bring the messages into and out of the CNS

Anatomy and functional areas of the brain

• 2 cerebral hemispheres
• 4 lobes (frontal, parietal, occipital, temporal)
• Primary motor cortex (lies along the anterior wall of cs)
• Primary somatosensory cortex (in the posterior wall of cs)
• Hippocampus: one in each temporal lobe. It plays a very important role in memory

Cerebral cortex

• Each hemisphere is covered with cortex; it is composed by gray matter
  • Outer layer of gray matter. It is convoluted into hundreds of folds made of gyri and sulci to optimize space. It contains neuronal soma (cell body) and unmyelinated axons.

White matter: it is composed by myelinated axons.

• Long-range nerve fibers that interconnect the various cortical areas and that connect the cortex to subcortical areas.

BRAIN CONNECTIVITY

• Structural connectivity: neurons are physically connected
  • Stable within short time scale (sec. to minute)
  • Variable within longer time scale due to plasticity

Neocortex

is the largest part of the cerebral cortex. It is made up of 6 layers:

1. molecular layer: few neurons and it’s composed by dendrites
2. External granular layer: small pyramidal cells
3. External pyramidal layer: it is the primary source of fibers that interconnect the areas of the cortex
4. Internal granular layer: contains non-pyramidal neurons (afferent fibers)
5. Internal pyramidal layer: largest pyr. cells (efferent fibers)
6. Polymorphic layer: ± cells

The 6th layer is in contact with white matter. Motor cortex sends information to the CNS.

Each layer contains a characteristic distribution of neural cell types and connections with other cortical and subcortical regions.

Subcortical areas

The cortex is made up to other deeper gray matter structures:

• Thalamus: receives information from sensory areas and sends it to the cortex for processing
• Brainstem: it carries nerve fibers descending to and ascending from the spinal cord and a number of motor and sensory nuclei
• Basal ganglia: collection of interconnected nuclei strongly connected with the cerebral cortex. It plays a critical role in motor function.

Cerebellum: it is involved in the production of smooth, coordinated movements, motor learning and adaptation. It has no direct connections to the spinal cord, it influences movement indirectly.

Our cerebral cortex is protected by meninges (electrodes can be placed there).

Neurons

Basic unit of the brain

• it contain also neuroglia (or glial cells) which serve to support and protect the neurons.

There are specific types of neurons (size and shapes), they can be classified by func