Neural Architecture

Question 1

Dendrites

Answer 1

. Sites for incoming stimuli
. Transmit electrical signals to the cell body
. Can develop APs

Question 2

Synapse types

Answer 2

. Axosomatic: axon ending on a cell soma/body
. Axodendritic: axon ending on dendrite
. Axoaxonic: axon ending on axon
. Motor end-plate: axon ending on muscle cell

Question 3

Neuron

Answer 3

. Morphological and functional unit of nervous system

. Primary function is communication through neurotransmitters mostly

Question 4

Neuronal language

Answer 4

. Function as electric switched
. Stimulates irritates neuron and electrical signal is conducts along axon and transmitted to another neuron (EPSP)
. If neuron is not stimulated enough to generate electrical signal then there is no communication amount neurons (IPSP)

Question 5

Spatial summation

Answer 5

. Individual neuron receives simultaneous inputs from multiple sources
. Small EPSPs contributed by many different synaptic terminals add up to produce single large EPSP (same goes for small IPSPs)
. EPSP and IPSPs may cancel each other out

Question 6

Temporal summation

Answer 6

. A second input arrives before the EPSP or IPSP elicited by the previous one has finished so it can add together

Question 7

Synaptic connection characteristics

Answer 7

. Have plasticity (continually form new connections and breaking old ones as you grow)
. Axons and dendrites can grow and branch or retract and reform

Question 8

Neural circuitry basic understandings

Answer 8

. Complexity of human behavior depends less on specialization of individual nerve cells and more on the fact that these cells are organized in precise anatomical circuits
. Nerve cells are able to convey unique info because they form specific networks

Question 9

Afferent versus efferent

Answer 9

. Afferent: info carried onward the CNS

. Efferent: info carried away from CNS

Question 10

Direct reflex arc

Answer 10

. Unlikely to be found in humans
. 2 neurons
. Sensory transfers input to a motor/efferent neurons that send the info (output) to a peripheral organ (muscle)

Question 11

Indirect reflex arc

Answer 11

. Interneuron between sensory and motor neuron

. Patellar reflex is example

Question 12

Divergence

Answer 12

. Output from 1 neuron onto many
. Each postsynaptic neuron receives input from the same presynaptic neuron, but may react to it different
. Divergent output allows the same signal to reach many different neurons of different circuitries

Question 13

Convergence

Answer 13

. Output from many neurons go onto 1 postsynaptic neuron
. Inputs can be excitatory or inhibitory
. Inputs may be active at different times

Question 14

Reverberating circuit

Answer 14

. Neuronal pathway arranged in circle so impulses are recycled in a loop to cause positive feedback/reverberation
. Important to facilitate or inhibit certain pathways

Question 15

Prolonged stimulation

Answer 15

. Occurs to a motor neuron

. Motor receives subsequent stimulation that are delayed in time

Question 16

Importance of increased numbers of interneurons

Answer 16

. Pools of interneurons can make more complex circuits that are in charge of intermediate processing and distribution of the input coming from sensory to motor neuron
. Allows more complex spatial and temporal distribution of the incoming info

Question 17

What happens to incoming information w/in spinal cord of brainstem

Answer 17

. Be passed to a motor neuron via reflex
. Travel up (ascending pathway) to subcortical/cortical areas, then info is distributed to interneurons in nuclei along ascending pathway creating divergence of input and spatial/temporal distribution of info

Question 18

Modality specificity

Answer 18

. Initially each sensory system has its own separate pathway
. Info transmitted from eye via optic n. Remains separate from auditory stuff initially
. Input will reach primary seniority cortex where stimuli of a single sensory modality are integrated

Question 19

Integration w/in modality across space

Answer 19

. Complex sensory stimulus causes activity in multiple receptors (neurons) corresponding to multiple channels
. Info processed in different channels has to combine to produce “big picture”

Question 20

Integration w/in modality across time

Answer 20

. Info present at 1 time has to be related to and linked w/ info that is present earlier and later

Question 21

Integration across modalities

Answer 21

.single modality info will pass to association vortices where the information will be elaborated and integrated w/ other sensory modalities
. Info from 1 modality is is coward w/ info from other modalities

Question 22

What occurs when information goes from sensory and association cortices to motor cortices?

Answer 22

. Info converges on upper motor neurons
. Their axons descend (descending pathway) down to brainstem/ spinal cord
. Brings response (output) that will be passed to final motor neuron (convergence) in brainstem/spinal cord (lower motor neuron)
. Ultimately passes the command to peripheral organ (muscle)

Question 23

Volitional response

Answer 23

. Motor command decided at cortical level
. Takes longer than reflex response because it is result of longer pathways and projections to different specialized cortical areas
. What starts as volitional response can turn into reflex response later in life

Question 24

What is important for accurate motor performance

Answer 24

. Sensing of motor action and motor feedback on sensory systems

Question 25

Learning and memory formation

Answer 25

. When motor action occurs, comparison of sensory input in 1 modality when compared w/ input from another modality can result in memories that lead to adjustment of the relation between the 2 modalities
. Happens extensively during postnatal development
. Info about seeing objects and reaching for them results in internal representation of space in which visual space is in register w/ somatosensory space

Question 26

Synthesis of info and creativity

Answer 26

. Brain stores information
. Information has capacity to transform information and recombine items of information in novel way
. Can create new sensory stimuli that we ha e never perceived in real world

Question 27

Types of neural maps

Answer 27

. One for sensory perceptions
. One for motor commands
. Interconnection of sensory and motor (association area) that elaborate and integrate sensations and plan motor actions

Question 28

Redundancy in neuronal circuitry

Answer 28

. Every single neuronal function recruits different groups of neurons that simultaneously process the same/ similar information

Question 29

Parallel processing

Answer 29

. Deployment of several circuits to process
. Mostly utilized for functions considered priority for the economy of the entire nervous system
. Preserved attempts to maintain key functions for building a more reliable and fast-processing brain

Question 30

What are the only subdivisions of CNS that communicate w/ periphery

Answer 30

. Spinal cord and brain stem

. Only exception is the cranial nerves