1) Central Nervous System (CNS): Brain and spinal cord
2) Peripheral Nervous System (PNS): see below
Somatic nervous system
It conveys sensory information (from skin, muscles, bones, joints, eyes and ears) to and from the CNS
It sends motor stimuli from CNS to muscles (voluntary movement)
Autonomic nervous system
It regulates involuntary movement activity
It controls functions such heart rate, blood pressure, kidney function and breathing
It is composed by the sympathetic and the parasympathetic nervous systems
HINDBRAIN consists of:
the MEDULLA contains important nuclei responsible for regulation of breathing and cardiac functions
the PONS contains many ascending and descending fibre tracts and fibres linked to cerebellum
the CEREBELLUM coordinates movements
tegmentum (red nuclei and substantia nigra)
Forebrain - summary
The FOREBRAIN consists of:
Telencephalo, which contains:
Diencephalo, which contains:
Forebrain - Neocortex (in Telencephalo) 1
Fissure: it extends deeply into the brain v Sulcus: it is shallower Gyrus
Hemispheres: Left and right
Lobes: Frontal, Parietal, Occipital, Temporal
It consists of 6 layers of cells, numbered from I to VI starting from the surface.
Two main cell types:
Pyramidal cells: large multipolar neurons – large dendrites and long axon – projection neurons
Stellate (or star-shaped) cells: smaller soma – shorter axon – local information processing
•Size and density of cell bodies varies across layers
For example, in Layer III large pyramidal cells – efferent to other cerebral area; IV layer rich of stellate cells – it receives afferent information from thalamus;
•The thickness of each layer varies across different cortical areas, according to the local function
9 Sensory areas thick layer IV Motor area thick layer V
Forebrain - Neocortex 2: Brodmann's map
The variation of thickness and cell composition of each of the six layers is known as CYTOARCHITECTONICS.
On this basis Korbinian Brodmann developed Brodmann’s map.
Brodmann map consists of 52 areas (BA).
(See diagram and learn main areas)
There is some correspondence between areas defined by cytoarchitectonic method and their function.
Forebrain - Neocortex 3: Fibres
Associative fibres, which connect areas within the same hemisphere:
Superior and inferior longitudinal fasciculi Cinguale fasciculus
Superior and inferior occipital frontal fasciculus
Commissural fibres, which connect same areas in the two hemispheres:
Fibres of projections, which send (efferent) receive (afferent) information between cortex and other structures of the brain
(e.g. mainly thalamus through internal capsula)
Forebrain - Neocortex 4: Primary Sensory and Motor
Primary Sensory and Motor areas mediate elementary sensory or motor functions
Primary somatosensory area
Associative areas Further process of information
Forebrain - Issues
A few important issues about cortical and subcortical areas: (Schmahmann & Pandya, 2008)
- Lesions in basal ganglia and thalamus mimic deficits resulting from cortical lesions
Due to disruption of the interaction of domain-specific subcortical nuclei with the sensorimotor, association cortical areas.
- However there are qualitative differences between the manifestations of lesions in functionally related area of cortical and subcortical areas
Lesion of primary motor cortex hemiparesis
Lesion of putamen slowness in movements
Lesion of thalamus (VL) ataxia
Lesion of cerebellum lack of motor coordination
Subcortcial areas are topographically arranged
Multiple parallel loops between cortical and subcortical areas with no cross-modal communication within subcortical nuclei
Complex behaviour required interaction between different functional domains Cortex in particular associative areas
Forebrain - Basal Ganglia (in Telencephalo) 1
Basal ganglia are a group of subcortical structures.
The main structure are:
Forebrain - Basal Ganglia 2: Function
Basal ganglia receive direct input from cortical areas and limbic system however
They DO NOT project DIRECTLY to the cortex; Cortical projections travel trough the thalamus
The function of basal ganglia 