Biological Psychology Flashcards

Terminology to Describe the Nervous System

• Central Nervous System (CNS): The brain and the spinal cord.

• Peripheral Nervous System (PNS): Connects the brain and spinal cord to the rest of the body.

• Somatic Nervous System: Controls voluntary muscles and conveys sensory information to the CNS.

• Autonomic Nervous System: Controls the heart, intestines, and other organs.

Anatomical Directions in the Nervous System

• Anterior: Toward the front.

• Posterior: Toward the rear.

• Dorsal: Toward the back or top (for brain), away from the ventral (stomach) side.

• Ventral: Toward the stomach or bottom (for brain), away from the dorsal (back) side.

• Superior: Above another part.

• Inferior: Below another part.

• Lateral: Toward the side, away from the midline.

• Medial: Toward the midline, away from the side.

• Proximal: Located close to the point of origin or attachment.

• Distal: Located more distant from the point of origin or attachment.

• Ipsilateral: On the same side of the body.

• Contralateral: On the opposite side of the body.

• Coronal Plane (or Frontal Plane): A plane that shows brain structures as seen from the front.

• Sagittal Plane: A plane that shows brain structures as seen from the side.

• Horizontal Plane: A plane that shows brain structures as seen from above.

Anatomical Terms Referring to Parts of the Nervous System

• Lamina: A row or layer of cell bodies separated from other cell bodies by a layer of axons and dendrites.

• Column: A set of cells perpendicular to the surface of the cortex, with similar properties.

• Tract: A set of axons within the CNS, also known as a projection. Fibers "project" from structure A to B when axons extend from cell bodies in A to synapses in B.

• Nerve: A set of axons in the periphery, either from the CNS to a muscle or gland, or from a sensory organ to the CNS.

• Nucleus: A cluster of neuron cell bodies within the CNS.

• Ganglion: A cluster of neuron cell bodies, usually outside the CNS (as in the sympathetic nervous system).

• Gyrus (pl.: gyri): A protuberance on the surface of the brain.

• Sulcus (pl.: sulci): A fold or groove that separates one gyrus from another.

• Fissure: A long, deep sulcus.

The Spinal Cord

• Part of the CNS within the spinal column.

• Communicates with sense organs and muscles (except those of the head).

• Entering dorsal roots carry sensory information, and exiting ventral roots carry motor information.

• Cell bodies of sensory neurons are in dorsal root ganglia outside the spinal cord.

The Autonomic Nervous System

• Regulates automatic behaviors (heart rate, blood pressure, respiration, digestion).

• Two Subsystems:

  • Sympathetic Nervous System: Prepares organs for rigorous activity; increases heart rate, blood pressure, respiration ("fight or flight" response).

    • Composed of ganglia on the left and right of the spinal cord.

  • Parasympathetic Nervous System: Facilitates vegetative and nonemergency responses; decreases functions increased by the sympathetic nervous system.

    • Composed of long preganglion axons from the spinal cord and short postganglionic fibers to organs.

    • Dominant during relaxed states.

Major Divisions of the Vertebrate Brain

• Forebrain (Prosencephalon):

  • Diencephalon (Thalamus, hypothalamus)

  • Telencephalon (Cerebral cortex, hippocampus, basal ganglia)

• Midbrain (Mesencephalon):

  • Tectum

  • Tegmentum

  • Superior colliculus

  • Inferior colliculus

  • Substantia nigra

• Hindbrain (Rhombencephalon):

  • Medulla

  • Pons

  • Cerebellum

The Hindbrain

• Located at the posterior portion of the brain.

• Consists of the medulla, pons, and cerebellum.

• The hindbrain structures, midbrain, and other central brain structures make up the brain stem.

The Hindbrain—The Medulla and the Cranial Nerves

• Medulla:

  • Just above the spinal cord; an enlarged extension of the spinal cord.

  • Responsible for vital reflexes (breathing, heart rate, vomiting, salivation, coughing, sneezing).

• Cranial Nerves:

  • Allow the medulla to control sensations and muscle movements in the head, and many parasympathetic outputs.

  • I. Olfactory: Smell

  • II. Optic: Vision

  • III. Oculomotor: Control of eye movements; pupil constriction

  • IV. Trochlear: Control of eye movements

  • V. Trigeminal: Skin sensations from most of the face; control of jaw muscles for chewing and swallowing

  • VI. Abducens: Control of eye movements

  • VII. Facial: Taste from the anterior two-thirds of the tongue; control of facial expressions, crying, salivation, and dilation of the head’s blood vessels

  • VIII. Statoacoustic: Hearing; equilibrium

  • IX. Glossopharyngeal: Taste and other sensations from throat and posterior one-third of the tongue; control of swallowing, salivation, and throat movements during speech

  • X. Vagus: Sensations from neck and thorax; control of throat, esophagus, and larynx; parasympathetic nerves to control stomach, intestines, and other organs

  • XI. Accessory: Control of neck and shoulder movements

  • XII. Hypoglossal: Control of muscles of the tongue

The Hindbrain—The Pons

• Lies on each side of the medulla (ventral and anterior).

• Pons is Latin for “bridge.”

• Axons from each half of the brain cross to the opposite side of the spinal cord:

  • Left hemisphere controls muscles of the right side of the body, and vice versa.

The Hindbrain—The Cerebellum

• Structure with many deep folds in the hindbrain.

• Helps regulate motor movement, balance, and coordination.

• Important for shifting attention between auditory and visual stimuli.

The Midbrain

• Tectum: Roof of the midbrain.

• Superior and Inferior Colliculi: Processes sensory information.

• Tegmentum: Contains nuclei for cranial nerves and part of the reticular formation.

• Substantia Nigra: Gives rise to the dopamine-containing pathway, facilitating readiness for movement.

The Forebrain

• Most anterior and prominent part of the mammalian brain, with two cerebral hemispheres.

• Consists of the outer cortex and subcortical regions.

• Outer portion is the “cerebral cortex.”

• Each side receives sensory information and controls motor movement from the opposite (contralateral) side of the body.

The Forebrain—The Limbic System

• Interlinked structures forming a border around the brainstem.

• Includes the olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus of the cerebral cortex.

• Associated with motivation and emotions (eating, drinking, sexual activity, anxiety, aggression).

The Forebrain—Subcortical Regions

*Structures underneath the cortex.

• Thalamus: Relay station from the sensory organs; main source of input to the cortex.

• Hypothalamus: Small area near the base.

  • Conveys messages to the pituitary gland to alter hormone release.

  • Associated with behaviors such as eating, drinking, sexual behavior, and other motivated behaviors.

• The thalamus and hypothalamus form the “diencephalon."

The Forebrain—The Basal Ganglia

• Pituitary Gland: Hormone-producing gland at the base of the hypothalamus.

• Basal Ganglia: Comprises the caudate nucleus, the putamen, and the globus pallidus.

  • Associated with planning motor movement and with aspects of memory and emotional expression.

  • Critical for gradual learning of skills and habits.

The Forebrain—The Basal Forebrain

• Several structures on the dorsal surface of the forebrain.

• Contains the nucleus basalis.

  • Receives input from the hypothalamus and basal ganglia.

  • Sends axons that release acetylcholine to the cerebral cortex.

  • Important in arousal, wakefulness, and attention.

The Forebrain—The Hippocampus

• Large structure between the thalamus and cerebral cortex, toward the posterior portion of the forebrain.

• Critical for certain types of memory, especially memories for individual events.

The Ventricles

• Four fluid-filled cavities within the brain’s central canal containing cerebrospinal fluid.

• Cerebrospinal Fluid (CSF): Clear fluid in the brain and spinal cord.

  • Provides “cushioning” for the brain.

  • Reservoir of hormones and nutrition for the brain and spinal cord.

The Meninges

• Membranes that surround the brain and spinal cord.

• Contain pain receptors.

• Meningitis (inflammation of the meninges) is painful.

• Swollen blood vessels in the meninges cause migraine headaches.

The Cerebral Cortex

• Most prominent part of the mammalian brain.

• Cellular layers on the outer surface of the cerebral hemispheres.

• Divided into two halves.

• Joined by the corpus callosum and the anterior commissure.

• More highly developed in humans than other species.

Organization of the Cerebral Cortex

• Contains up to six distinct laminae (layers) parallel to the surface of the cortex.

• Cells divided into columns perpendicular to the laminae.

The Four Lobes of the Cerebral Cortex

• Occipital lobe

• Parietal lobe

• Temporal lobe

• Frontal lobe

The Occipital Lobe

• Located at the posterior end of the cortex.

• Known as the striate cortex or primary visual cortex.

• Highly responsible for visual input.

• Damage can result in cortical blindness.

The Parietal Lobe

• Contains the postcentral gyrus (“primary somatosensory cortex”).

• Primary target for touch sensations and information from muscle-stretch receptors and joint receptors.

• Responsible for processing and integrating information about eye, head, and body positions from muscles and joints.

• Essential for spatial and numerical information.

• Example: Using fingers to count represents an overlap of spatial and numerical tasks.

The Temporal Lobe

• Located on the lateral portion of each hemisphere near the temples.

• Target for auditory information and essential for processing spoken language.

• Responsible for complex aspects of vision, including movement and some emotional and motivational behaviors.

• Klüver-Bucy syndrome associated with temporal lobe damage.

• The temporoparietal junction is where the parietal and temporal lobes meet, close to the occipital lobe.

The Frontal Lobe

• Contains the prefrontal cortex and the precentral gyrus.

• Precentral Gyrus: Primary motor cortex; responsible for the control of fine motor movement.

• Prefrontal Cortex: Integration center for all sensory information and other areas of the cortex (most anterior portion of the frontal lobe).

• Several areas in the prefrontal cortex and the temporoparietal junction are known as the default network.

Prefrontal Lobotomy

• Surgical disconnection of the prefrontal cortex from the rest of the brain.

• ~40,000 performed in the 1940s and 1950s.

• Mostly schizophrenics, but later others with less severe mental illness.

• Patients left with apathy, lack of ability to plan, memory disorders, and lack of emotional expression.

The Prefrontal Cortex

• Responsible for:

  • Higher functions such as abstract thinking and planning.

  • Ability to remember recent events and information (“working memory”).

• People with damage to the prefrontal cortex exhibit delayed-response task:

  • Respond to something they see or hear after a delay.

• The anterior zone of the prefrontal cortex is important for making decisions, evaluating which of several courses of action is likely to achieve the best outcome.

How Do the Parts Work Together?

• Parts of the cerebral cortex do not work independently of each other.

• All areas of the brain communicate with each other, but no single central processor exists that puts it all together.

The Binding Problem

• How the visual, auditory, and other areas of the brain produce a perception of a single object. The brain binds activity in different areas when they produce synchronous waves of activity.

• For binding to occur, a person perceives two sensations as happening at the same time and in the same place.

• Example: A ventriloquist uses the visual stimulus to alter the response of the auditory cortex.

Stimulant Drugs

• Amphetamine and Cocaine: Stimulate dopamine synapses by increasing the release of dopamine from the presynaptic terminal.

• Methylphenidate (Ritalin): Blocks the reuptake of dopamine but in a more gradual and more controlled rate.

  • Often prescribed for people with ADHD.

Research Methods

• The main categories of research methods to study the brain include those that attempt to:

  • Examine the effects of brain damage

  • Examine the effects of stimulating a brain area

  • Record brain activity during behavior

  • Correlate brain anatomy with behavior

Effects of Brain Damage

• Brain damage can produce an inability to recognize faces, an inability to perceive motion, changes in emotional responses, and many more effects.

• Ablation: Removal of a brain area.

• Lesion: Damage to a brain area, often done for research.

• Stereotaxic Instrument: Used to damage structures in the interior of the brain.

• Another method is injecting a chemical that kills neurons or inactivates them temporarily.

Transcranial Magnetic Stimulation (TMS)

• Application of an intense magnetic field to a portion of the scalp to temporarily deactivate neurons below the magnet.

• Allows researchers to study behavior with a brain area active, then inactive, then active again.

Effects of Brain Stimulation

• Stimulation of a brain area should increase behavior.

• Optogenetics: A technique that allows researchers to turn on activity in targeted neurons by a device that shines a laser within the brain.

• Electrodes can probe the brain of a person undergoing brain surgery.

• A limitation is that complex behaviors depend on temporal pattern of activity in many areas.

• Because of the invasive nature of the method, it could be used in humans only when it might produce a medical benefit.

Recording Brain Activity—EEG

• Electroencephalograph (EEG): Records electrical activity produced by various brain regions.

• Can produce evoked potentials that self-reports sometimes do not reveal.

Recording Brain Activity—MEG and PET

• Magnetoencephalograph (MEG): Similar to EEG but measures faint magnetic fields generated by brain activity instead.

• Positron-Emission Tomography (PET): Records emission of radioactivity from injected radioactive chemicals to produce a high-resolution image.

Recording Brain Activity—fMRI

• Functional Magnetic Resonance Imaging (fMRI): Modified version of an MRI that uses oxygen consumption in the brain to provide a moving and detailed picture.

• Safer and less expensive than PET.

• Comparison tasks are used to compare brain pictures while person is engaged in different activities and recordings can allow researchers to predict the behavior.

Methods of Studying Brain-Behavior Relationships

• Examine Effects of Brain Damage

  • Study victims of stroke, etc.

    • Used with humans; each person has different damage

  • Lesion

    • Controlled damage in laboratory animals

  • Ablation

    • Removal of a brain area

  • Gene knockout

    • Affects wherever that gene is active (e.g., a receptor)

  • Transcranial magnetic stimulation

    • Intense application temporarily inactivates a brain area

• Examine Effects of Stimulating a Brain Area

  • Stimulating electrodes

    • Invasive; used with laboratory animals, rarely with humans

  • Optogenetic stimulation

    • Almost always with laboratory animals; can indicate function of a particular type of cell

• Record Brain Activity during Behavior

  • Record from electrodes in brain

    • Invasive; used with laboratory animals, rarely with humans

  • Electroencephalograph (EEG)

    • Records from scalp; measures changes by milliseconds, but with low resolution of location of the signal

  • Evoked potentials

    • Similar to EEG but in response to stimuli

  • Magnetoencephalograph (MEG)

    • Similar to EEG but measures magnetic fields

  • Positron emission tomography (PET)

    • Measures changes over both time and location but requires exposing brain to radiation

  • Functional magnetic resonance imaging (fMRI)

    • Measures changes over about 1 second, identifies location within 1 to 2 mm

• Correlate Brain Anatomy with Behavior

  • Computerized axial tomography (CAT)

    • Maps brain areas, using X-rays

  • Magnetic resonance imaging (MRI)

    • Maps brain areas in detail, using magnetic fields