Chapter 3: Neuroscience Flashcards
Neuroscience
the study of the brian and the nervous system.
How Do Scientists Study the Nervous System?
Over the last several decades, and even centuries, human neuroscientists and biopsychologists relied largely on one of the following methods:
~ Examining autopsy tissue: allows neuroscientists to see what our brains look like.
~ Testing the behaviour of patients with assumed damage to certain parts of the brain.
~ Recording electrical brain activity through multiple electrodes attached to the surface of the scalp.
~ Animal studies.
Neuroimaging
techniques that allow for studying brain activity and structure by obtaining visual images in awake humans.
these methods include:
- MRI (uses a strong magnetic field to produce three-dimensional images of the anatomy anf physiology of the brain) and fMRI (combines the clarity of MRI scanning of neuroanatomy with a measure of activity).
- CT or CAT scans (produces clear, detailed, two-dimensional X-ray images taken from multiple angles results in a three-dimensional brain image that can be virtually “sliced” and examined from any angles).
- PET (procedure used to see the activity of the brain overall during a cognitive task) and TMS (delivers an electromagnetic pulse to a targeted brain area, temporarily disrupting brain activity in a conscious person)
- DTI (measures the orientation and integrity of white matter to assess damage in the brain and with the assistance of a computer, it produces a DTI colour map).
Advantages of Neuroimaging
~ the availability of these neuroimaging techniques has produced an explosion of research in understanding how human and animal brains work.
~ it is the creative combination of various imaging technologies, such as combining trancranial stimulation with positron emission tomography, that will allow scientists to continue to expand our understanding of how our brains and nervous systems work.
~ In the past, researchers of psychological issues in human ften avoided analyzing the brain, mainly because of limits in our study methods and technologies. Until recently it was difficult, if not impossible, to study what goes on in the human brain without causing damage to brain tissue.
How is the Nervous System Organized?
the human nervous system can be divided into 2 main components:
1) the Central Nervous System (CNS) - consists of the brain and the spinal cord.
2) the Peripheral Nervous System (PNS) - made up of all the nerves throughout our bodies that deliver information back and forth between the periphery and CNS.
Neurons
the cells that carry information between the various parts of our bodies and nervous systems. it is a nerve cell.
Afferent Neurons
neurons that carry signals from the PNS to the CNS. neurons that carry sensory information from the body to the CNS.
Efferent Neurons
neurons that carry signals from the CNS to the PNS. neurons that carry information out from the CNS to the muscles and glands.
Interneurons
neurons that connect two or more neurons. neurons that typically have a short axon and serve as a relay between different classes of neurons; in the spinal cord, interneurons communicate with both sensory and motor neurons.
The Peripheral Nervous System (PNS)
- main function of the PSN: to send info to and receive info from the CNS.
- consits of the SOMATIC NERVOUS SYSTEM and the AUTOMATIC NERVOUS SYSTEM.
somatic nervous system - made up of all of the nerves that gether sensory information (typically about touch and pain) from all over the body, neck, and head and deliver it to the spinal cord and brain, as well as the nerves that send information about movement from the CNS to the muscles of the body, neck, and head.
automatic nervous system - parts of it operate mostly without conscious control or thought by the CNS. Subdivided into 2 parts: the sympathetic nervous system and the parasympathetic nervous system. Both components of the automatic nervous system are made up of collections of nerve cells distributed throughout the body.
~ the sympathetic nervous system: activated under conditions of stress. "Flight-or fight" response. ~ the parasympathetic nervous system: inhibited during those times, but is active during more restful times.
The Central Nervous System (CNS)
consists of spinal cord and brain.
spinal cord - portion of the CNS that extends down from the base of the brain and mediates sensory and motor information.
More complex tasks requires the spinal cord and brain to work in partnership:
- Afferent sensory neurons in the PNS send messages to the spinal cord, which in turn relays the message to the brain. The brain sends commands through the efferent neurons to the spinal cord motor neurons, which in turn relay the message to the skeletal muscles, signalling them to contract.
Spinal Cord Injuries
A spinal cord injury occurs when the nerves make up the sinal cord itself are damged.
~ quadriplegic: paralyzed everywhere but the head and neck.
~ paraplegic: when the damage occurs farther down the back, then they may retain sensation and usage of the upper limbs and torso, but not the lower limbs.
Treatment:
- epidural electrical stimulation below the site of the spinal cord injury to boost electrical signals being sent from the brain to the lower body.
- “neural bypasses”: a computer chip commanding action.
- stem cell therapy
Structures of the brain
The Hindbrain
a. medulla
b. pons
c. cerebellum
The Midbrain
a. substantia nigra
The Forebrain
a. thalamus
b. hypothalamus
c. pituitary gland
d. limbic system
e. basal ganglia
Substantia Nigra and Dopamine
a brain region important in fluidity of movement and inhibiting movements. it is the major structure damages in Parkinson’s disease.
Dopamine: neurotransmitter produced by neurons in the hindbrain and involved in movement and reward mechanisms.
Reticular formation
a complex neural network extending from the hindbrain into the midbrain that plays a central role in regulating consciousness and arousal.
