2. Web sites Society for Neuroscience www.sfn.org
International Brain Research Organization

4. The brain carries out calculations at synapses, the sites at which neurons interact. While hundreds of neuro-transmitters and receptors have been identified, they can be functionally classified into two types: excitatory and inhibitory. Excitatory neurotransmitters increase the likelihood that the postsynaptic neuron will generate an action potential, while inhibitory neuro-transmitters make it less likely that the postsynaptic neuron will be active. The balance of excitation and inhibition determines how information is processed in the nervous system.

5. Some synapses are excitatory: An action potential in one (pink) neuron releases a chemical that turns on the second (blue) neuron. The second neuron therefore is more likely to transmit an action potential to other neurons.

6. BCP 5-13
e.g. glutamate

7. Some synapses are inhibitory: An action potential in one (pink) neuron releases a chemical that turns off the second (blue) neuron. So the second neuron is less likely to send action potentials to other neurons.

8. BCP 5-14
e.g. GABA
gamma-amino-
butyric acid

11. Information is carried around the nervous system as trains of action potentials
At any given moment, the sum of excitatory & inhibitory inputs to a neuron determines the probability that it will generate an action potential.
Circuits of interconnected neurons represent & process information in various ways.
Information is represented as patterns of electrical activity in groups of neurons.

12. Human Physiology Chapter 8 The Mechanisms of Body Function
Vander’s
Human Physiology
The Mechanisms of Body Function
Tenth Edition by
Widmaier • Raff • Strang
© The McGraw-Hill Companies, Inc.
Figures and tables from the book, with additional comments by:
John J. Lepri, Ph. D.,
The University of North Carolina at Greensboro

13. Consciousness, Brain, and Behavior
Chapter 8
Consciousness, Brain, and Behavior
Electroencephalography: a window on the brain
States of wakefulness and sleep
Limbic system: motivation and reward
Neurochemistry of drug abuse
Learning and memory

14. Figure 8-1 The electroencephalograph (EEG) is the printout of an
(typically microvolts)
VOLTAGE
The electroencephalograph (EEG) is the printout of an
electronic device that uses scalp electrodes to monitor
the internal neural activity in the brain; this is a record
from the parietal or occipital lobes of an awake person.
The units and scale of the axes are not included in my original– there should be some information about these on the figure.

15. 19-3: Generation of very small electrical fields by synaptic currents in pyramidal cells. When thousands of cells contribute their small voltages, the signal is strong enough to see at the surface of the scalp.

16. 19-4: (a) In a population of pyramidal cells under an EEG electrode, each neuron receives many synaptic inputs. (b) If the inputs fire at irregular intervals, the pyramidal cell responses are not synchronized, & the summed activity detected by the electrode has small amplitude. (c) If the same inputs fire within a narrow time window so the pyramidal cell responses are synchronized, the resulting EEG sum is much larger.

17. Figure 8-2 EEGs provide diagnostic information about the
(20 to 100 microvolts)
VOLTAGE
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.
The units and scale of the axes are not included in my original– there should be some information about these on the figure.

18. Figure 8-3 EEGs reflect mental state: contrasted here are
(20 to 100 microvolts)
VOLTAGE
(20 to 100 microvolts)
VOLTAGE
The units and scale of the axes are not included in my original– there should be some information about these on the figure.
EEGs reflect mental state: contrasted here are
mental relaxation (a) versus concentration (b).
Figure 8-3

19. Figure 8-4 EEG patterns undergo characteristic shifts in a
(20 to 100 microvolts)
VOLTAGE
The units and scale of the axes are not included in my original– there should be some information about these on the figure.
EEG patterns undergo characteristic shifts in a
sleeping person, reflecting the four stages of sleep;
the duration of the series is typically ~90 minutes, and
the entire pattern cycles 4 to 8 times per night.

20. Figure 8-5 The EEG pattern was analyzed to produce
this graph of a full
night’s sequence
of sleep stages;
also shown are cyclic
patterns in the periphery.

22. Figure 8-6 A model of some of the neurochemical changes across
the sleep-wake
continuum;
cause-and-effect
relationships are
under study.

23. 19-20: In the SCN, clock genes produce proteins that inhibit further transcription. Gene transcription & the firing rates of SCN neurons cycle up & down over 24 hr. The cycles are synchronized by light exposure (input from the retina.).
SCN = suprachiasmatic
nucleus

24. Figure 8-7 Neuronal changes in these CNS structures appear
to be essential
participants in
sleep-wake
transitions and in
biological rhythms.

26. Figure 8-8 Neural damage in the right parietal lobe of
this patient results in the
unilateral visual neglect
seen in this drawing task.
Although patient is not
impaired visually, does not
perceive part of visual
world.

28. 20-17: Self-portraits during recovery from a R parietal stroke that caused neglect syndrome.
Upper L: 2 months after stroke, virtually no L side to face.
Upper R: After 3.5 months, there is some detail on L.
Lower L & R: After 6 & 9 months, there is increasing treatment of the L side of the painting.

29. Figure 8-9 Alterations in the mesolimbic dopamine pathway
(shown here) appear to be a primary mechanism
by which psychoactive drugs change behavior.

30. Figure 8-10 Animal models, such as this rat performing lever-presses
stimulator
Animal models, such as this rat performing lever-presses
to receive rewarding neural stimulation through electrodes
implanted in its brain, have provided detailed insights into
the anatomical and neurochemical organization of the brain.

31. Figure 8-11 Changes in activity of the limbic system underlie some
of the primary needs of the organism, including
learning, motivation, appetite, and emotional response;
its malfunction is associated with affective disorders.

32. Figure 8-13 Psychoactive drugs that affect serotonin- receptors share
structural similarities
with serotonin.
Psychoactive drugs
that affect dopamine-
receptors share
structural similarities
with dopamine.

35. Figure 8-14 Declarative memory is associated with actual events
in a person’s direct experience.
Procedural memory is associated knowledge of the
sequence of events and relationships between events.

36. 23-1: Types of memory.

37. 23-8: Removing the medial temporal lobe from both sides to alleviate severe epilepsy caused severe anterograde amnesia in H.M.

39. PET scan showing blood flow in the cortex during language tasks

40. Images of the active areas in the brain in a male (left) & a female (right) during
a language task.
Note that both sides of a woman’s brain are used in processing language,
but a man’s brain is more compartmentalized.

41. Figure 8-17 The primary loci underlying the comprehension
of speech are in Wernicke’s area, whereas
the primary loci for the production of speech are
located in Broca’s area.

42. 20-p641: Wada test for hemispheric dominance.

43. 20-9: Language comprehension in R hemisphere of split-brain subject.

44. The End.