Intellectual and Behavioral Functions

• Cerebral Cortex– frontal lobe: somatic motor cortex– primary sensory areas: first part of cortex to

receive sensory information• parietal lobe: somatic sensory cortex• occipital lobe: visual cortex• temporal lobe: auditory cortex

– association areas / interpretive areas: perception of patterns of sensation

• lines, edges, and color associated into an image• sounds associated into a word

Fig. 14.22

Intellectual and Behavioral Functions

– common integrative area / general interpretive area

• somatic, visual and auditory association areas meet together

• sensory patterns coordinated into a thought Guyton,

Medical Physiology

Example of Cortical

Pathways• word seen

– visual cortex

• word understood– visual and general

interpretive area

• thought develops to speak the word– Wernicke’s area [left cerebral hemisphere]

• speech coordinated– Broca’s (motor speech) area [left cerebral hemisphere]

• signals sent to cortical areas that control muscles of speech

Guyton,Guyton,Medical Medical PhysiologyPhysiologycf. Fig.14.25cf. Fig.14.25and p. 558and p. 558

Hemispheric Lateralization

•These general patterns are true for nearly all right-handed people and two-thirds of left-handed people.•Sex differences exist: e.g., lateralization is more pronounced in males, whereas verbal skills are more broadly distributed in females.

• categorical hemisphere– left

hemisphere– verbal skills– analytical

skills

• representa-tional

hemisphere– right

hemisphere– visual,

spatial and aural skills

– emotional perception

Fig. 14.26

Dominance and Creativity• It is incorrect to call the left

hemisphere “dominant.” The 2/3rds of left handed people whose left hemisphere is categorical show that motor control and verbal/categorical skills can exist on different hemispheres.

• Creativity, if it’s to be effective, also needs planning and analysis. Therefore, creativity is not a specialized “right-brain” function, but requires good function of and good communication between both hemispheres.

Fig. 14.16

Reasoning

• Prefrontal Area:control and elaboration of thought– planning, problem

solving, concentration, delayed gratification, social control

– Lesions cause loss of ambition, inability to perform complex tasks, rapid changes in emotions, loss of embarrassment … .

Phineas Gage’s injury

Lobotomies used to be performed on psychotic persons (fewer signals sent to limbic system / less aggression). The patients became more docile; the price - loss of their previous personality.

Fig. 15-1Ganong

cf. Fig. 14.20

http://content.nejm.org/content/vol351/issue23/images/data/e21/DC1/e21v2.mpg

Memory and Learning

• habituation– decreased response to unimportant

stimuli

• sensitization– increased response to important stimuli

Memory and Learning• short-term memory

– temporary (seconds to hours)– quickly recalled / quickly replaced– possible mechanisms

• reverberating circuits• parallel circuits• relatively long lasting EPSPs and IPSPs

Fig. 12.30

Memory and Learning

• long-term memory – hours to years– due to structural change in neural circuitry

• changing the number of synapses• changing the quality of synapses

– protein synthesis required» receptors: changing type, number, function» channels: adding or deleting

e.g., to change [Ca++]cytosol

– Aplysia

http://www.sahs.uth.tmc.edu/brainsurf/aplysia1.html

Memory and Learning

• consolidation– conversion of short term to

long term memory– requires rehearsal– hippocampal function

• medial portion of temporal lobe

– Alzheimer Disease includes a loss of cholinergic stimulation of the hippocampus.

• anterograde amnesia: inability to store new memories; past memories remain

• cf. retrograde amnesia: inability to recall past events– Trauma can cause loss of recently stored memories.

Fig. 14.17

Memory and Learning

• Memories are stored throughout the cortex.

• For rats – sensory-rich environment thicker and

more convoluted cerebral cortex• more cortical area for memory storage?

– mobiles over baby cribs(cf. detrimental effects of television)

EEG

• measures cortical activity

• On your own: p. 536– one or two phrases for

each pattern for adultsFig. 14.18