Neurophysiology 2 Flashcards
What are the major regions of the adult brain?
The adult brain is described in terms of four major regions:
the cerebrum,
the diencephalon
the brainstem and
the cerebellum
Describe the cerebrum
• The largest part of the brain and accounts for approximately 80 - 85% of the brains weight.
• Is responsible for all voluntary actions (e.g. motor skills), communication and many higher order neurological functions such as emotions, creativity, intelligence, personality and consciousness.
Its structure is made up of:
• 2 layers (inner and outer)
• 2 hemispheres (right and left)
• 4 lobes
• Several subcortical nuclei
Differentiate the layers of the cerebrum
- Outer Layer
• Known as the cerebral cortex.
• Houses the brain’s “grey matter”.
• Made up of neuronal cell bodies.
• Considered the centre of human consciousness.
• Higher functions all happen here: thinking, reasoning, planning, emotion, memory, the processing of sensory information, speech. - Inner layer
• Inner core of white matter
• Forms the sub-cortex consisting primarily of neuronal axons.
• Also houses several deep nuclei that are responsible for functions such as cognitive processing (e.g. associated with planning movements), learning and memory.
Describe the cerebral cortex
• A continuous layer of grey matter that wraps around either side of the forebrain.
• The gyrus (plural: gyri) and sulcus (sulci) are what give the brain its wrinkly appearance.
• The grooves (or fissures) of the brain are known as the sulci, while the bumps (or ridges) are called the gyri.
- Increase how much of the cerebral cortex can fit into the skull.
- Also create boundaries between the different sections of the brain, indicating specific regions of the cerebral cortex (e. g. the 2 hemispheres and 4 lobes of the cerebrum).
What is the corpus callosum?
• This tract interconnects the two hemispheres.
• The deep groove separating the hemispheres is called the longitudinal (or cerebral) fissure.
• It is the largest connective pathway in the brain.
• Serves as a bridge between the left and right hemispheres allowing the two sides of the brain to communicate.
List the lobes of the brain and state their functions
• The left and right hemispheres are each divided into 4 lobes:
• frontal : responsible for problem solving and planning, thought, behavior, speech, memory and movement
• parietal : responsible for processing information from the senses, language interpretation and spatial awareness
• occipital : visual processing center
• temporal lobes : responsible for memory, emotions, language and speech, auditory and visual processing
• They generally handle different functions but they don’t function alone.
What is the insula?
Thought of as the 5th cortex
• Insula plays role in memory encoding.
• Integrates sensory information with visceral responses.
• Assesses bodily states that accompany emotions.
How many Broadmann’s areas are there within the brain?
• 52 separate regions on the basis of the histology of the cortex, known as Broadmann’s areas.
• Areas 17 and 18 in the occipital lobe are responsible for primary visual perception.
• Areas 41 and 42 in the temporal lobe are associated with primary auditory sensation.
Describe the functional areas of the frontal lobe
• The primary motor cortex (precentral gyrus) is the location of all of the upper motor neurons that are responsible for movement.
• The frontal eye field region is associated with eye movement.
• Broca’s area is responsible for the production of language, or controlling movements responsible for speech (motor speech).
What are the functional areas of the occipital lobe?
Primary visual cortex
Describe the functional areas of the parietal lobe
The primary sensory cortex (postcentral gyrus) processes all sensory input from the contralateral side of the body.
• The angular gyrus is involved in performing mathematical calculations, writing, distinguishing left from right, and identifying fingers on the hand.
• Damage to the dominant parietal cortex results in Gerstmann syndrome.
• Damage to the non-dominant parietal cortex results in hemi-spatial neglect.
Describe the functional areas of the temporal lobe
• Superior temporal gyrus
- Contains the primary auditory cortex
- Contains Wernicke’s area (sensory speech) |
• Hippocampus - responsible for memory formation.
• Amygdala - associated with emotions and decision making.
What are the subcortical nuclei?
• Lie beneath the cerebral cortex.
• Augment cortical processes.
• The nuclei of the basal forebrain modulate the overall activity of the cortex, possibly leading to greater attention to sensory stimuli.
• The hippocampus and amygdala are medial-lobe structures that, along with the adjacent cortex, are involved in long-term memory formation and emotional responses.
Describe the basal ganglia (nuclei)?
• Responsible for comparing cortical processing with the general state of activity in the nervous system to influence the likelihood of movement taking place.
• The major structures that control movement are the caudate, putamen, and globus pallidus, which are located deep in the cerebrum.
• The caudate is a long nucleus that follows the basic C-shape of the cerebrum from the frontal lobe, through the parietal and occipital lobes, into the temporal lobe.
• The putamen is mostly deep in the anterior regions of the frontal and parietal lobes.
• Together, the caudate and putamen are called the striatum.
• The globus pallidus is a layered nucleus that lies just medial to the putamen; they are called the lenticular nuclei because they look like curved pieces fitting together like lenses.
• The globus pallidus has two subdivisions, the external and internal segments, which are lateral and medial, respectively.
• The basal nuclei in the cerebrum are connected with a few more nuclei in the brain stem that together act as a functional group that forms a motor pathway.
• All input to the basal nuclei is from the cortex into the striatum with two streams of information processing take place in the basal nuclei.
What is the correlation between the basal ganglia and the limbic system?
