PSYC104 Lecture Notes - Lecture 12: Carl Wernicke, Red Nucleus, Globus Pallidus
1 Jun 2018
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Biological Psychology – Part Two
Structure of the Vertebrate Nervous System:
• For vertebrates, we distinguish the central nervous system from the
peripheral nervous system
o Peripheral nervous system = carries information to and from the
central nervous system
▪ Somatic nervous system → conveys sensory information to the
CNS and sends motor messages to muscles
▪ Autonomic nervous system → serves basic life functions such
as the beating of the heart and responses to stress
• Sympathetic nervous system = readies the body in
response to threat; activates the organism
• Parasympathetic nervous system = calms the body
down; maintains energy
o Central nervous system = directs psychological and basic life
processes; responds to stimuli
▪ Spinal cord → receives sensory input and sends information to
the brain – responds with motor output
▪ Brain → directs psychological activity, processes information
and maintains life supports
• Forebrain, Midbrain and Hindbrain
• Because the nervous system is 3D, we need several terms to describe it – the
brain can be cut into 3 different planes of orientation:
o Horizontal plane
o Sagittal plane
o Coronal plane
• The nervous system is symmetrical with a left and right side:
o Structures that lie on the same side are ipsilateral
o Structures that lay on opposite sides are contralateral
o Structures that are close to one another are proximal
o Structures that are far from one another are distal
• Terms referring to parts of the nervous sytem:
o Tract – a set of axons within the CNS
o Nerve – a set of axons in the periphery
o Nucleus – cluster of neuron cell bodies within the CNS
o Ganglion – cluster of neuron cell bodies usually outside CNS
Peripheral Nervous System:
• The somatic nervous system transmits sensory information to the CNS and
carries out its motor commands
• Sensory neurons receive information through receptors and motor neurons
direct the action of skeletal muscles
• The autonomic nervous system is a hidden partner in controlling behaviour – it
conveys information to and from internal bodily structures that carry out basic
life processes such as digestion and respiration
o This system consists of two parts:
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▪ Sympathetic nervous system → arouses the body for action i.e.
it prepares the organism to respond to emergencies, for ‘flight
or fight’
▪ Parasympathetic nervous system → facilitates vegetative,
nonemergency responses (to maintain the body’s store of
energy)
• These activities related to (generally opposite of)
sympathetic activities
Central Nervous System:
• The spinal cord sends information from sensory neurons in various parts of
the body to the brain, and then relays motor commands back to the muscles
and organs via motor neurons (it is also capable of reflex actions)
1. Fibres entering the dorsal root bring sensory information from sensory
receptors
2. Fibres leaving the ventral root carry motor information to the muscles
3. Collateral branches of sensory neurons may cross to the other side and
influence motor neurons there
4. White-matter fibre tracts carry information to and from the brain
• 31 pairs of spinal nerves (each named after the section of the spine they come
out of) are formed by the combination of nerve fibres from the dorsal and
ventral roots of the spinal cord, and carry information to and from the
periphery
• Inside the spinal cord, grey matter is densely packed with cell bodies and
dendrites – Bundles of axons (spinal tracts, which comprise much of white
matter) send impulses to and from the brain, relaying sensory messages and
motor commands
The human brain consists of three parts…
• Forebrain
o The cerebrum is divided into roughly two symmetrical halves or
cerebral hemispheres (left and right), each organized to receive
sensory information, mostly from the contralateral side of the body and
to control muscles mostly on the contralateral side
o Within the cerebrum are the limbic system and basal ganglia – the
outer portion is the cerebral cortex which is the largest component of
the forebrain
o The hypothalamus is responsible for almost all motivated behaviours
and interacts with the pituitary gland, providing a key link between the
nervous system and the endocrine system, largely by activating
pituitary hormones
o In the thalamus, all sensory modalities make synaptic relays before
continuing to the primary cortical sensory receiving areas – it also
receives inputs from the basal ganglia, cerebellum, cortex and medial
temporal lobe and sends projections back to these structures to create
circuits involved in many different functions
o The basal ganglia includes the caudate nucleus, putamen and globus
pallidus and plays major roles in voluntary motor control – some
neural circuits involving basal ganglia appear to inhibit movement
whereas others initiate it
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Document Summary
Inside the spinal cord, grey matter is densely packed with cell bodies and dendrites bundles of axons (spinal tracts, which comprise much of white matter) send impulses to and from the brain, relaying sensory messages and motor commands. A medically retired financial manager whose cardiac arrest was complicated by a hard fall onto his right temple was very responsive to his own needs and energetic in attempts to carry out plans. Unfortunately, he could no longer formulate plans well because of an inability to take all aspects of a situation into account and integrate them. His lack of awareness of his mistakes further aggravated this disability. In this regard, his mind was radically changed, so decidedly that his friends and acquaintances said he was no longer. Damage evident in the temporal gyrus: 2. Patients spoke fluently but did not make sense: 4.
