HOW, WHAT AND WHY??? THE INNER WORKS COLETTE BEECHER The Brain
Two Hemispheres Controls the right side of the body Speech areas- Brochas/wernickes Left Controls the left side of the body Perceptual interpretation & discrimination Right
Main areas & systems of communication Lower Centres: Brain stem (medulla oblongata, Pons and Mid Brain), Thalamus & Hypothalamus. Higher Centres: Basal Ganglia, Cerebellum, Cerebrum, (including Cortex of the brain, & limbic System.)
INCOMING: RECEIVING SENSORY INFORMATION All messages heading for the cortex ( Lobes)need to go through the lower centres of the thalamus and the Higher centre of the Basal ganglia. This will include sensory information coming from vision, hearing, and taste Motor messages, including touch, pressure, & proprioception (position & posture of joints, tendons and muscles) travel through the brain stem, to the Reticular formation (Basal Ganglia) to the Thalamus, signposted to specific areas of the Cortex.
OUTGOING Motor execution All messages sent by the higher centres ( Limbic/Cortex areas to execute voluntary movement/reaction ) will travel via Basal Ganglia, Thalamus, Cerebellum and Midbrain ( Reticular Formation) before leaving the brain via the brain stem, down to the spinal cord to produce the desired movement/response.
Motor execution All messages from the lower centres ( Thalamus, Hypothalamus ) to execute simple reflex or autonomic responses will travel via The Cerebellum, Midbrain ( Reticular Formation -BG) before leaving the brain via the lower brain stem components (Pons & medulla), down to the spinal cord to produce the desired response.
Main roles Brain stem: Involuntary respiratory, cardiac, system control. Hypothalamus and pituitary gland: Involuntary temperature control, thirst, hunger, adrenaline and thyroid hormone production ( Flight/fight responses and release of energy in response to activity) Thalamus: A cluster of nuclei that operate as a relay system. Messages travel through individual nuclei that will connect specifically to designated cortex areas.
Main Roles Cerebellum: Connected both to the thalamus and basal ganglia, the cerebellum monitors the production of reflex and voluntary movement, to assist with balance, co-ordination. The Cerebellum receives messages from the vestibular system (details of speed, balance, posture during movement) and then sends messages back to the cortex, so that the higher centres can adjust any motor plan to refine previous movement.
Main Roles Basal Ganglia: Also a cluster of nuclei, however these are not necessarily adjacent to one another, nevertheless all nuclei are connected through a system of communication. The main role of the basal ganglia is to initiate the release of neurotransmitters (chemical transmission) which allow messages to be sent from all areas of the lower and higher centres of the brain. All messages from the cortex travel through the basal ganglia to the thalamus.
Main Roles The cerebral Cortex: Four lobes: Frontal Parietal Occipital Temporal ( Lies underneath the parietal lobe, surrounding the basal ganglia and internal capsule)
Frontal lobe divisions Frontal Lobe Prefrontal Motor association area Primary Motor area (M1)
Parietal Lobe subdivisions Parietal Lobe Primary sensory area (S1) Sensory association area Posterior Parietal lobe
Temporal Lobe subdivisions Auditory & Auditory association area Medial Temporal lobe hippocampus- Encoding of working memory into long term. Anterior Medial Temporal lobe Amygdala Left hemisphere Verbal memory Right hemisphere Visual Memory
Subdivisions of the occipital Lobe Perception of shape, colour, size and depth. Perception of motion Perception of position Primary Visual Area (V1) Relates present vision to past visual experiences. Recognition/evaluation & orientation of what has been seen. Links with visual memory. Visual association area
Limbic System Refers to structures comprising of : Amygdala: connected to the hypothalamus & midbrain Hippocampus Septal area:connected to the hypothalaumus: sex drive Olfactory gyri: connected to the amygdala Cingulate gyrus: monitor/evaluates movement & speech – executive functioning