Brain structure and function

The nervous system is subdivided into

the central nervous system and the peripheral nervous system

The central nervous system is comprised of

brain and spinal cord

The peripheral nervous system is comprised of

everything, send information to the CNS from sensory receptors, and transmits messages from the CNS to the muscle and glands in the body.

The peripheral nervous system is divided into

autonomic nervous system and the somatic nervous system

The autonomic nervous system role is

transmits information to and from internal organs. It governs vital functions such as breathing, heart rate and so on.

The somatic nervous system role is

transmits information from the sensory receptors to the CNS. It also receives information from the CNS that governs the muscle movement.

The autonomic nervous system is subdivided into

sympathetic state and parasympathetic state

What occurs in the sympathetic state

increases function for ‘fight or flight’, i.e. increase in heart rate, increase breathing rate, dilated pupils, inhibits digestion, inhibits saliva production.

What occurs in the parasympathetic state

decreases function to conserve energy, i.e. decrease in heart rate, decrease breathing rate, constricts pupils, stimulates digestion, stimulates saliva production.

State the order of the embryonic development of the brain

• neural tube (1-2 weeks)

• primary brain vesicles (3-4 weeks)

• secondary brain vesicles (6-8 weeks)

What does the telencephalon consist of

cerebral cortex, basal ganglia

What does diencephalon consist of

thalamus, hypothalamus, retina

What does the mesencephalon consist of

midbrain

What does the metencephalon consist of

pons, cerebellum

What does the myencephalon consist of

medulla oblongata

What is the cranial nerve

12 pairs of nerves on the base of the brain, which pass through holes in the skull (cranium): analogous to spinal nerves leaving the spinal cord

What is the role of corpus callosum

connects the two cortical hemispheres

What is the role of the basal ganglia

control of behavioural patterns

What is the role of hypothalamus

homeostasis, emotion, control of endocrine (hormone) system

What is the role of thalamus

interface between cortex and the rest of the nervous system

What is the role of the spinal cord

nerves going to and from the rest of the body

What is the role of the brainstem

control of autonomic function

What is the role of the cerebellum

movement, balance, posture

What is the role of the hippocampus

learning and memory

Sulci

infoldings of the surface

Gyri

the bumps on the cortical surface

Functional neuroimaging measures areas

activated by different aspects of the task

The case of ‘Louis Leborgne’; post mortem study of the brain showed…

lesions towards back of left frontal lobe, first evidence for highly localised control of function in the cortex

Motor cortex

• primary motor cortex - motor output to skeletal muscles

• supplementary motor cortex - motor planning

• basal ganglia - motor patterns

• cerebellum - motor coordination

the cerebral cortex is divided into…

two hemispheres, left and right which are connected by a fibre bindle called the corpus callosum

Each hemisphere is divided into four lobes:

• frontal lobe - at the front of the brain

• parietal lobe - over the top of the brain

• occipital lobe - at the back of the brain

• temporal lobe - around the sides of the brain

The lobes are separated by….

deep inner foldings called sulci or fissures

Motor cortex

a band of tissue running along the posterior face of the frontal lobe

Sensory cortex

specific areas specialised for processing each sensory modality

Explain the primary and secondary area in sensory cortex

each area has a primary region where the input neurons arrive, and a secondary area where information from that sensory modality only is processed

The story of Phineas Gage

a rod entered his head through his left cheek, destroyed his eye, traversed the frontal part of the brain, and left the top of the skull at the other side

How was Phineas Gage after the accident

he became extravagant, anti-social, foulmouthed, bad mannered, and a liar. He couldn’t hold a job or plan his future

What is the frontal cortex for in terms of higher cognitive function

calculation, reasoning, inference, rule learning

What is the prefrontal cortex for in terms of higher cognitive function

personality, emotion

What is the temporal cortex for in terms of higher cognitive function

learning, memory, spatial recognition

Wisconsin card sort test

• Match the card to the category by colour, number or shape

• Researcher tells subject if they are correct or wrong (but no more)

• Rule changes periodically, without telling the subject

 

• Measure response accuracy; time to learn; perseveration on rule change

• People with damage to frontal lobes perform poorly

The case of HM

• Suffered from severe epilepsy, failed to respond to standard treatments

• large areas of hippocampus, amygdala and surrounding tissue removed

• no longer suffered from epilepsy but showed severe memory deficits

• unable to learn new information

• unable to remember anything from gayer the time of surgery (anterograde amnesia)

• incapable of adding new information to his long- term memory, implying a role for the hippocampus in memory storage

Cortical function - Frontal lobe

• planning

• thinking

• motor planning

• motor output

Cortical function - Temporal lobe

• hearing

• smell

• memory

• feelings

Cortical function - Occipital lobe

• vision

• visual processing

Cortical function - Pariteal lobe

• spatial processing

• spatial orientation

• somatosensory function