1. Brain: Higher Functions
Learning, Consciousness and Behavior

2. Divisions of the Nervous System

3. Electroencephalography (EEG)
The electroencephalograph (EEG) is the printout of an
electronic device that uses scalp electrodes to monitor
the internal neural activity in the brain cortex.

4. EEG as Clinical Tool
EEGs provide diagnostic information about the
location of abnormal activity in the brain,
such as shown in this record typical of a patient
undergoing an epileptic seizure.
EEGs record largely the surface electrical activity of underlying brain areas
Activity largely due to summated graded potentials of many neurons
Amplitude shows how much activity (degree of summation and/or number of neurons)

5. EEG waves
Alpha wave –dominant wave of a conscious relaxed adult with their eyes closed; associated with parietal-occipital lobes and decreased attention level
8-13Hz, amp= 50mcV
Decreased freq. by low blood glucose, low body temp., low gluco-corticoids or high PCO2
Beta wave –dominant wave of attentive adult; associated primarily with frontal lobe activity
Arousal response
>13Hz, lower amp

6. EEG waves during sleep
Theta waves –slower frequency (4-8 Hz) but higher amplitude; assoc. with hippocampus and seen in children occipital lobes
Delta waves –large, slow (<4/sec) pattern of deep NREM sleep

7. Sleep Patterns
NREM Stage 1 4: decreasing eye and skeletal muscle movement, increased threshold for arousal, increase size but decrease freq. of EEG
REM: EEG freq. increases with less amplitude (alpha like), increase HR, Resp. Rate, and eye movement, but still in deep sleep, high oxygen consumption in brain; dream sleep
4-5 cycles of NREM/REM sleep each night (every ~90 min)
(Persistent Insomnia can be fatal)

8. RAS (Reticular Activating System)
Brainstem nuclei intermingled with bundles of axons
Receives and integrates input from all regions of CNS
Involved in motor function, CV and respiratory control, attention, sleep/wakefulness
Most of the biogenic amine NT are released from axons of RAS
Aminergic neurons may dominate wakefulness and cholinergic neurons may dominate sleep
Preoptic area has GABAnergic neurons that inhibit RAS and hypothalamus
Suprachiasmatic nucleus regulates the pineal; which regulates sleep’s timing

10. Importance of Sleep
Slow wave sleep is thought to be restorative to brain function (Children have more total sleep time and are in stage 4 more than adults); Elderly have about the same total sleep time as adults but broken into smaller episodes, also spend less time in REM. Time spent in Stage 4 declines with age.
Person consistently deprived of REM may become moody or depressed; may exhibit other personality disorders

11. Coma & Brain Death
Coma is a severe loss in mental function due to brain damage; sustained loss of arousal (even with heavy stimuli), behavior response is lost, no sleep/wake cycles
Persistent Vegetative State (irreversible coma) –sleep/wake cycles are present; no sign of external awareness

12. Learning & Memory
Learning –acquisition and utilization of information from past experience
Memory –relatively permanent storage of information
Declarative memory –retention of conscious experience, facts, etc.; uses Limbic system & cortex (amygdala, hippocampus & thalamus)
Procedural memory –knowledge of how to do something (skilled behaviors); uses sensory cortex, basal nuclei, & cerebellum

13. Possible Memory Circuits
Procedural
Declarative
Sensory Inputs
Sensory & Motor Inputs
Association Areas
Association Areas
Medial Temporal Lobe (hippocampus, amygdala)
Substantia Nigra DA
Basal Nuclei
ACh
Basal Forebrain
Thalamus
Thalamus
Prefrontal cortex
ACh
Premotor cortex

14. Memory Processing
Automatic long term memory linked to noxious stimuli.
Many long term memories may be unretrievable consciously, but may still exist within the brain ??

15. Patient with right parietal lobe damage.

16. Dependency