Biopsych: Part 2

Primary motor and somatosensory cortices

  • The motor cortex sends messages to move muscles

  • The sensory cortex processes information from touch stimuli

Crossover (contralateral)

  • Left hemisphere controls right side of the body (vice versa)

  • Left hemisphere receives input from right side of the body (vice versa)

Mapping body parts

  • more sensitive (e.g. face) = larger parts of cortex

  • requires more control (e.g. hands)


Prefrontal cortex (PFC)

  • Rational thought (planning, decision making)

  • Important for maintaining social relationships

  • Understanding thoughts and emotions of others

  • Social norms

  • Directing and maintaining attention

Case study of Phineas Gage

  • Damage to frontal lobe (PFC)

  • Personality changes

-Loss of inhibition

-Inappropriate behavior

  • Functions of the PFC supported by later research


Lateralization

  • Neural impulses are constantly transmitted across the corpus callosum

  • Bridge consisting of millions of axons (white matter)

  • Each hemisphere has some specialized functions

-Lateralization

Brocas area: crucial for producing speech


Separating the hemispheres

  • Neural impulses are transmitted across the corpus callosum

  • Split-brain patients (Gazzaniga & Sperry)

-Corpus callosum has been severed

-Information from each side of the visual field cannot be sent to the other hemisphere


Split brain patients

  • Objects (baseball) presented in the right visual field can be named (verbalized)

  • Objects (hammer) in the left visual field- cannot verbalize


Brain plasticity

Plasticity

  • The brain can form new connections, reorganize, reassign brain areas to new functions

  • Change as a function of environment

Neurogenesis

  • Production of new neurons

Brain reorganization

  • Substitution of function

Neural connections

  • Forming & refining

  • Neural pruning


Studying the brain

  • Lesions: impairments indicate function of area that was damaged

  • Case studies & patient studies

  • Example: Broca & Patient Tan

-Broca’s aphasia: difficulty producing speech