Lecture 3 - Cerebral Cortex Organization and Function Flashcards
Granular (Stellate) Neurons
Short axons, interneurons, both excitatory (glutamate) and inhibitory (GABA)
Fusiform Neurons
Smaller output neurons
Pyramidal Neurons
Large output neurons
Layer IV of Cerebral Cortex
Termination of most incoming specific sensory signals
Layer V and VI of Cerebral Cortex
Origin of most output signals; fibers to thalamus from VI
Layers I, II, and III of Cerebral Cortex
Intracortical association functions
Primary Motor Areas
Direct connections with specific muscles
Primary Sensory Areas
Detect specific sensations
Secondary Motor Areas
Provide patterns of motor activity
Secondary Sensory Areas
Analyze meanings of specific sensory signals
Parieto-Occipitotemporal Association Area
Has area for analysis of spatial coordinates, Wernicke’s area, angular gyrus area, and area for naming objects
Prefrontal Association Area
Receives preanalyzed sensory information (esp. concerning spatial coordinates) necessary for planning effective movements; output passes through caudate portion of basal ganglia; carries out “thought” processes in the mind
Limbic Association Area
Concerned with behavior, emotions, and motivation
Broca’s Area
Provides circuitry for word formation; works closely with Wernicke’s area; almost always dominant on left side of brain
Wernicke’s Area
Language comprehension; area where somatic, visual, and auditory association areas all meet one another in the posterior part of the superior temporal lobe; located on left side in almost all people
Plays greatest single role of any part of the cerebral cortex for intelligence
Prefrontal Lobotomy Characteristics
Loss of ability to solve complex problems, inability to string together sequential tasks to reach complex goals, inability to do several parallel tasks at the same time, decrease in level of aggressiveness (ambition), inappropriate social responses, inability to carry through long trains of thought, loss of purpose while performing usual motor pattern functions
Abilities due to Brain’s Working Memory
Prognostication, planning for future, delay in response to incoming sensory signals, ability to consider consequences of motor actions, ability to solve complicated mathematical, legal, or philosophical problems, control of activities in accord with moral law
Corpus Callosum
Major commissure between the two hemispheres
What happens when you cut the corpus callosum?
Blocking of transfer of information from Wernicke’s area to nondominant motor cortex; prevention of the transfer of somatic and visual information from right hemisphere into wernicke’s area, results in 2 entirely separate conscious portions of the brain
Declarative Memory
Memory of various details of an integrated thought; might include memory of surroundings, time relationships, causes of experience, meaning of experience, or deductions as a result of experience
Reflexive (Skill) Memory
Associated with motor activities
Short-Term Memory
Exemplified by memory of a telephone number; lasts only as long as person thinks of number or facts (seconds)
Intermediate Long-Term Memory
Lasts many minutes or weeks; may become long-term memory (more permanent) if memory traces are activated enough
Mechanism for Facilitation
Stimulation of facilitator presynaptic terminal at the same time that sensory terminal is stimulated causes serotonin release at facilitator synapse; serotonin receptors in sensory terminal membrane activate adenyl cyclase to cAMP, which activates part of K+ channel; K+ channel is blocked for minutes to weeks
What does lack of K+ conductance cause?
Greatly prolonged action potential in synapse terminal
What does prolonged action potentials cause?
Prolonged activation of Ca2+ channels
What does prolonged activation of Ca2+ channels cause?
Prolongs transmitter release
Structural Changes in Long-Term Memory
Increase in vesicle release sites for secretion of transmitter substance, increase in number of transmitter vesicles released, increase in number of presynaptic terminals, and changes in structures of the dendritic spines
