The central nervous system and human behaviour Flashcards
Central nervous system (CNS)
-The nervous system is a specialised, complex network of cells
-It is the main internal communication system with two major functions:
1) collects, processes and responds to information from the environment
2) Coordinates the working of organs and cells in the body.
divided into two main subsystems:
1) Central nervous system (CNS), consists of spinal cord + brain.
2) peripheral nervous system (PNS)
Spinal cord
(tube-like extension of brain)
-Connected to the brain via brainstem
-Controls reflex action (e.g. pulling hand from a hot plate)
-Passes messages to and from the brain (linking with PSN)
Brain
(source of conscious awareness, where decision-making takes place)
-Divided into two near-symmetrical hemispheres connected by the corpus callosum
-Control of the body is mostly contralateral - left hemisphere controls right side of the body and vice versa
- Cerebral cortex (outer layer) is highly developed in humans. About 3mm thick and covers the ‘inner’ parts of the brain
Thalamus
Subcortical structures
‘inner’ part of the brain, structures that are ‘below the cortex’
Thalamus-
brains relay station, receives information from senses (e.g. hearing , touch) and passes to appropriate areas of the cerebral cortex for higher-level processing. Also does some initial processing of its own, so acts as a ‘gate’ or filter of information. Role in sleep, wakefulness and OCD
Hypothalamus
Subcortical structures
‘inner part of the brain, structures that are ‘below the cortex’
Hypothalamus-
controls motivational behaviours (e.g. hunger, thirst, sex). Key role in the body’s stress response through ‘fight of flight’. Maintains balance (homeostasis) in many bodily functions (e.g. temperature) and regulates activity of the endocrine system (hormones) via pituitary gland.
Limbic system
Subcortical structures
‘inner part of the brain, structures that are ‘below the cortex’
Limbic system
Several structures related to memory/ learning and to regulating emotion (amygdala). Highly interconnected and integrates cortical and subcortical parts of the brain.
Cerebellum
Subcortical structures
‘inner part of the brain, structures that are ‘below the cortex’
cerebellum
Means ‘little brain’. Has two hemispheres. Primary role to coordinate posture, balance and movement by integrating information from the spinal cord and other areas such as the motor cortex. Only about 10% of the brains entire weight but contains almost 50% of its neurons
corpus callosum
Subcortical structures
‘inner part of the brain, structures that are ‘below the cortex’
Corpus callous
Connects two hemispheres below the cerebral cortex, passing signals back and forth (critical given the brains contralateral control of the body, because it integrates the activities of both sides of the body)
Lateralisation
Hemispheres of the human brain are almost structurally identical but have different functions (e.g. language is associated with the left hemisphere)
Localisation
Certain areas are responsible for specific functions and behaviours (e.g. language functions are localised to specific areas within this hemisphere).
Cerebral cortex
Subdivided into four lobes (so there are eight, four on each hemisphere), each one associated with different functions (as predicted by localisation theory).
The cerebral cortex is wrinkly, with ‘ridges’ called gyro and ‘valleys’ called sulci. Convolutions increase the cortex’s surface area, giving it more processing power.
Frontal lobes
Located at the front of the brain, makes up 40% of the human cortex
- controls high-level cognitive functions, e.g. planning, decision-making
-Contains the motor cortex, one in each hemisphere, each one controlling voluntary movements on the opposite side of the body (contralateral)
-Left frontal lobe includes brokas area
Parietal lobes
posterior to the central sulcus. Contains the somatosensory cortex, which contralaterally processes sensory information from the skin (e.g. touch, temperature, pressure). The area of somatosensory cortex devoted to a particular body part reflects that parts sensitivity to touch (e.g. neurone from the face and hands take up over half the somatosensory cortex)
Temporal lobes
Lie beneath the lateral sulcus, containing the auditory cortex which deals with sound information coming mainly from the opposite ear. They process location, volume and pitch of sounds, so have a role in understanding language. left temporal lobe is the location of Wernickes area.
Occipital lobes
At the back (posterior) of the brain, each lobe contains a primary visual cortex and several secondary areas. Everything we see to the right of our field of Vision (from both left and right eye) is initially processed by the left visual cortex before being shared (via the corpus callous) with the right visual cortex (and vice versa).
