Biological Basis of Behavior Flashcards
Quadriplegia
Inability to move arms and legs
Paraplegia
Inability to move legs
Paresis
Muscle weakness
Dura mater
Fibrous membrane that also forms the falx cerbri, which extends down longitudinal fissure that separates the 2 hemishperes
Arachnoid mater
Thinner and more delicate membrane separated from the dura by the subdural space through which passes series of veins
Pia mater
Most delicate and highly vascular membrane, which closely follows the contours of brain
Ventricular system
Has open chambers and channels filled with CSF, which circulate thru 2 large lateral ventricles, to the centrally located 3rd and 4th ventricle, to the brain stem
Choroid plexus
Linings of the lateral ventricles that form fluid
CSF
Maintains brain’s neural buoyancy in cranial vault and is important in protecting from infection and regulates blood flow in brain
Cortex
6 layers that forms the outer layer of the brain; aka gray matter
Frontal lobe
Largest, governs output, higher cortical and cognitive functioning.
Subdivisions include primary motor cortex, premotor cortex, orbitofrontal cortex, and prefrontal cortex – regions devoted to attention, cognition, reasoning, problem solving, and voluntary movement.
Primary motor cortex
Initiation of motor movements and isolated muscle groups are specifically represented along surface of gyrus.
Relative representation corresponds directly to the requisite accuracy of motor control.
Premotor cortex
Initiation and execution of limb movements in conjunction with input from other cortical regions.
Mirror neurons here associated with imitation and empathy.
Prefrontal and orbitofrontal regions
Higher-level cognitive functions (executive functions) which includes reasoning, planning, and judgment
Broca’s area
In inferior lateral region of the left frontal lobe.
Fluent production of oral and written speech + grammar and comprehension of syntax. Damage here –> Broca’s (expressive) aphasia.
Superior temporal gyrus
Auditory processing where conscious perception of sound occurs. Aka Heschel’s convolutions.
Reception of stimuli in this region is considered tonotopic, which corresponds to individual frequencies detected at the level of cochlea. Stimuli arrive by way of vestibulocochlear nerves and medial geniculate nuclei of thalamus.
Decussation
Process by which incoming stimuli are transmitted to contralateral hemisphere for processing.
Auditory association cortex
Where sound is processed further.
Wernicke’s area
In language-dominant hemisphere. Dedicated to comprehension of language. Damage –> disruption of ability to comprehend and meaningfully express language. Aka Wernicke’s (receptive) aphasia.
Parietal lobes
Include site of primary somatosensory processing.
Process visual information along dorsal and ventral pathways from occipital lobes to help coordinate movement and behaviors with the environment.
Damage –> neglect syndromes like hemispatial neglect – inability to attend to features of environment in the space contralateral to lesion site.
Heteromodal cortex
Within parietal lobes where sensory modalities are integrated to construct a complete picture
Primary somatosensory processing
Somatotopic detection of touch, pressure, pain, and temperature takes place.
Occipital lobes
Visual processing.
Primary visual processing located in region of occipital pole. Phototopic in nature, receiving stimuli from retina and optic nerve by way of lateral geniculate nucleus of the thalamus.
Primary visual striate (cortex)
Color and movement processed here. Then send for further processing and integration along dorsal stream to parietal regions for object location and ventral stream to temporal regions for object identification.
Hippocampus
Region in inferior temporal lobe. Critical for memory formation (i.e., transfer of memories to LT stores).
Amygdala
Processes emotions. Its connections to midbrain structures make it essential component of fight-or-flight response.
Also processes olfactory stimuli.
Thalamus
Performs critical relay functions b/w the cortex and brain stem.
Specific nuclei or nerve cells form specific transmission sites in thalamus to and from specific cortical regions.
Also performs important attention and perceptual functions.
Basal ganglia
Network of complex loops involved in motor output (i.e., descending motor pathways), emotions, cognition, and eye movements.
Includes caudate nucleus, putamen, global pallidus, subthalamic nucleus, and substantia nigra.
Cerebral cortex provides most of the input to basal ganglia, and primary outputs of basal ganglia to thalamus.
Extrapyramidal syndromes
Abnormalities in basal ganglia of coordination and rhythm of movement.
Parkinson’s and Huntington’s result from abnormalities in basal ganglia.
Bradykinesia
Slow movements
Brain stem
Inclusive of medulla, pons, and midbrain.
Pons (or bridge), followed by medulla, is essentially contiguous with spinal cord.
As a unit, brain stem is involved in control and regulation of autonomic functions and maintaining homeostasis - including breathing, HR, temperature, and BP.
Reticular formation
Includes reticular activating system. Plays role in alertness, consciousness, and pain. Also role in regulating respiratory and CV systems.
Cerebellum
Comprises gray matter cortex and subcortical white matter with interconnections to cortical regions of other hemispheres of brain. Associated w/ regulation of movement (automatic and rhythmic), coordination of limbs, and postural control.
Divided into superior, middle, and inferior cerebellar peduncles.
Middle cerebellar peduncle: only structure visible on surface of brain.
Neuron
Consists of cell body (contains nucleus), dendrites, and axons. Most neurons are multipolar - multiple dendrites and axons.
Myelin sheath
Insulating fatty later that surrounds axon and speeds up transmission.
Synapse
Space b/w 2 neurons where chemical/electrical communication occurs.
Mostly, the axon from one neuron communicates with the dendrites of another.
Neurotransmitter
Chemicals released presynaptically by axon terminal of one neuron and bind to NT receptors on postsynaptic neuron –> postsynaptic excitation or inhibition.
Action potential
When postsynaptic excitation reaches minimum threshold and causes neuron to send signal down its axon.
All-or-nothing phenomenon
Firing of neuron; strength of firing doesn’t vary in response to strength of input.
Biogenic amines
Smaller molecular messengers that include acetylcholine and serotonin
Catecholamines
Smaller molecular messengers that include dopamine, norepinephrine, and epinephrine
Amino acids
Smaller molecular messengers that include gamma-aminobutryic acid (GABA) and glutamate
Neuropeptides
Larger molecules including vasopressin, oxytocin, and substance P
Norepinephrine (NE)
Functions as hormone and NT. Formed in brain stem at the locus coeruleus and is found in the sympathetic NS and CNS. Underlies fight-or-flight response and is released into blood by adrenal gland in response to stress or arousal. Primarily excitatory.
Regulates mood, memory, alertness, hormones, and ability to feel pleasure.
Low levels = depression
High levels = anxiety