Question

Anatomy Tutorial: the Cerebrum

Answer 1

\({\bf{Overview:}}\)
- divided into two hemispheres by the longitudinal fissure
- further divided into 4 lobes (fronta, occipital, temporal, parietal lobes)
- sensory and motor areas separated by the central sulcus



\({\bf{Sensory~and~Motor~Areas:}}\)
- precentral gyrus: anterior margin of the central sulcus; surface is the primary motor cortex which directs motor neurons in the brainstem/spinal cord. nuclei = pyridimal cells
- postcentral gyrus: posterior margin of the central sulucs; surface is the primary somatosensory cortex, which is the relay center for touch, pain, pressure, temperature pressure
- other cortices: visual (in the occipital lobe), auditory and olfactory (in the temporal lobe); gustatory (in the frontal lobe)

\({\bf{Association~Areas:}}\) integrate sensory information that arrives in the cerebral cortex
- sensorimotor association area: responsible for interpreting size, form, texture
- premotor cortex: coordinates motor activities

Answer 2

\({\bf{Higher-Order~Functions:}}\) are defined as
- being performed by the cerebral cortex
- involving communication within the cerebral cortex and between the cerebral cortex + the other parts of the brain
- involving unconscious and conscious processing
- are not "pre-programmed" by the brain and can evolve over time

\({\bf{Integrative~Centers:}}\) receive information from the association areas and control motor activities. often localized to 1 hemisphere.
- ex: prefrontal cortex: integrates information from sensory association areas
- Wernicke's center: language comprehension
- Broca's center: speech production
if you ever confuse these two, broca sounds like boca which is spanish for mouth, so broca = speaking, not listening or comprehension

Answer 3

\({\bf{Prefrontal~Cortex:}}\) integrates information from cortical association areas
- abstract intellectual functions
- interprets a situation and makes predictions
- does not finish developing until early 20's (which probably explains a lot about the user base of this site)
- prefrontal lobotomies were historically used as a treatment for violent or antisocial behavior

\({\bf{Lateralization:}}\)
- left hemisphere: language, analytical + decision-making skills
- right hemisphere: interpretation of sensory information, like facial recognition, shapes, spatial relationships



*** note **** the functions of the hemisphere are not exactly as divided/distinct as we once thought they were. ex: in children with severe seizures, the corpus callosum was sometimes cut to restrict the movement of information between the hemispheres, and over time one hemisphere could take over the functions of the other.

Answer 4

\({\bf{Central~White~Matter:}}\)
- area of white matter covered by gray matter
- contains myelinated fibers within the cortex or between the cortex and other brain areas
> association fibers: connect cortex w/in a single hemisphere
> commissral fibers: connect the two cerebral hemispheres, with the most famous example being the corpus callosum
> projection fibers: connect cerebrum w/ brain + spinal cord

\({\bf{Basal~Nuclei:}}\) masses of gray matter embedded w/in white matter
> main functions: control of muscle tone, coordination of movement patterns, processing and transmission of information from cerebral cortex to thalamus
- lentiform nucleus: contains the putamen and globus pallidus
- caudate nucleus + putamen (sometimes collectively called the corpus striatum) coordinate limbs during walking
- globus pallidus: controls muscle tone
- cladustrum: layer of gray matter near putamen

Answer 5

Adapted from Human Anatomy, Martini, et. al. 9th edition