Two Brain Areas Compete for Control
The locus coeruleus and the ventral tegmental area compete for control over the formation of memory content. This has been shown by a team of neuroscientists using light-controlled nerve cells.
Published: 14.03.2025
Researchers at Ruhr University Bochum, Germany, have studied the impact of two brain areas on the nature of Memory content. The team from the Department of Neurophysiology showed in rats how the so-called locus coeruleus and the Ventral tegmental area permanently alter brain activity in the Hippocampus region, which is crucial for the formation of memory. The two areas compete with each other for influence to determine, for example, in what way emotionally charged and meaningful experiences are stored. Dr. Hardy Hagena and Professor Denise Manahan-Vaughan conducted the study using optogenetics. In the process, they genetically modified rats so that certain nerve cells could be activated or deactivated with light. They published their findings in the journal PNAS (Proceedings of the National Academy of Sciences) on December 30, 2024.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
ventral
A positional term – ventral means "towards the abdomen." In relation to the nervous system, it refers to a direction perpendicular to the neural axis, i.e., downwards or forwards.
In animals (that do not walk upright), the term is simpler, as it always means toward the abdomen. Due to the upright posture of humans, the brain bends in relation to the spinal cord, making ventral mean "forward."
Ventral tegmental area
Ventral tegmental area/Area tegmentalis ventralis7ventral tegmental area
Located in the midbrain, the uppermost section of the brain stem, is the ventral tegmental area (VTA) – a central component of the reward system. The area itself is not particularly large, but its influence is immense: the neurons of the VTA send their axons to the nucleus accumbens and widely into the prefrontal cortex (PFC), where they release the neuromodulator dopamine. In this way, they enhance learning processes, but can also contribute to the development of addictions.
Hippocampus
The hippocampus is the largest part of the archicortex and an area in the temporal lobe. It is also an important part of the limbic system. Functionally, it is involved in memory processes, but also in spatial orientation and learning. It comprises the subiculum, the dentate gyrus, and the Ammon's horn with its four fields CA1-CA4.
Changes in the structure of the hippocampus due to stress are associated with chronic pain. The hippocampus also plays an important role in the amplification of pain through anxiety.
The basis of learning
Neurotransmitters such as Dopamine and noradrenaline play a decisive role in information processing. They can permanently change the ability of nerve cells to communicate; this is known as synaptic plasticity, which in turn provides the cellular basis for Memory formation. Long-term potentiation increases the ability of the relevant synapses to communicate, while long-term Depression of synaptic transmission reduces the activity of certain synapses in the Hippocampus. This makes it possible to store and update experiences.
The locus coeruleus and the Ventral tegmental area release neurotransmitters into the hippocampus, where learning processes take place. Until now, it was not fully understood to what extent these regions play a role in synaptic Plasticity and, consequently, in learning processes. What has been established is that the ventral tegmental area is important for reward and aversion reactions, whereas the locus coeruleus is crucial for the Perception of novel stimuli and therefore controls attention.
Dopamine
Dopamine is an important neurotransmitter in the central nervous system that belongs to the catecholamine group. It plays a role in motor function, motivation, emotion, and cognitive processes. Disruptions in the function of this transmitter play a role in many brain disorders, such as schizophrenia, depression, Parkinson's disease, and substance dependence.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
Long-term potentiation
Long-term potentiation is a central mechanism for learning and memory formation. It is based on improved communication between two cells, referred to as strengthening the connection. This strengthening can occur, for example, through an enlargement of the connection point, the installation of new channels, or an increased release of transmitters (messenger substances).
Depression
A mental illness whose main symptoms are sadness and a loss of joy, motivation, and interest. Current classification systems distinguish between different types of depression.
Hippocampus
The hippocampus is the largest part of the archicortex and an area in the temporal lobe. It is also an important part of the limbic system. Functionally, it is involved in memory processes, but also in spatial orientation and learning. It comprises the subiculum, the dentate gyrus, and the Ammon's horn with its four fields CA1-CA4.
Changes in the structure of the hippocampus due to stress are associated with chronic pain. The hippocampus also plays an important role in the amplification of pain through anxiety.
ventral
A positional term – ventral means "towards the abdomen." In relation to the nervous system, it refers to a direction perpendicular to the neural axis, i.e., downwards or forwards.
In animals (that do not walk upright), the term is simpler, as it always means toward the abdomen. Due to the upright posture of humans, the brain bends in relation to the spinal cord, making ventral mean "forward."
Ventral tegmental area
Ventral tegmental area/Area tegmentalis ventralis7ventral tegmental area
Located in the midbrain, the uppermost section of the brain stem, is the ventral tegmental area (VTA) – a central component of the reward system. The area itself is not particularly large, but its influence is immense: the neurons of the VTA send their axons to the nucleus accumbens and widely into the prefrontal cortex (PFC), where they release the neuromodulator dopamine. In this way, they enhance learning processes, but can also contribute to the development of addictions.
Plasticity
Neuroplasticity
The term neuroplasticity describes the ability of synapses, nerve cells, and entire areas of the brain to change structurally and functionally depending on the degree to which they are used. Synaptic plasticity refers to the adaptation of the signal transmission strength of synapses to the frequency and intensity of incoming stimuli, for example in the form of long-term potentiation or depression. In addition, the size, interconnection, and activity patterns of different areas of the brain also change depending on their use. This phenomenon is referred to as cortical plasticity when it specifically affects the cortex.
Perception
The term describes the complex process of gathering and processing information from stimuli in the environment and from the internal states of a living being. The brain combines the information, which is perceived partly consciously and partly unconsciously, into a subjectively meaningful overall impression. If the data it receives from the sensory organs is insufficient for this, it supplements it with empirical values. This can lead to misinterpretations and explains why we succumb to optical illusions or fall for magic tricks.
attention
Attention
Attention serves as a tool for consciously perceiving internal and external stimuli. We achieve this by focusing our mental resources on a limited number of stimuli or pieces of information. While some stimuli automatically attract our attention, we can select others in a controlled manner. The brain also unconsciously processes stimuli that are not currently the focus of our attention.
How does the hippocampus affect memory formation?
Hagena and Manahan-Vaughan recorded the activity of synapses in the Hippocampus of rodents. The animals were genetically modified in such a way that the activity of certain cells of the locus coeruleus and the Ventral tegmental area could be either inhibited or stimulated with light. Activation of the ventral tegmental area resulted in Long-term potentiation in the hippocampus. The opposite was the case when the locus coeruleus was activated.
When the researchers inactivated the ventral tegmental area in behavioral experiments, long-term potentiation in the hippocampus was suppressed during the exploration of a new environment. Conversely, when they inactivated the locus coeruleus, long-term Depression was inhibited during the exploration of environmental features.
The hippocampus can process different aspects of spatial information through long-term potentiation and long-term depression. The researchers have now identified the physiological process that controls these changes in synaptic plasticity.
Hippocampus
The hippocampus is the largest part of the archicortex and an area in the temporal lobe. It is also an important part of the limbic system. Functionally, it is involved in memory processes, but also in spatial orientation and learning. It comprises the subiculum, the dentate gyrus, and the Ammon's horn with its four fields CA1-CA4.
Changes in the structure of the hippocampus due to stress are associated with chronic pain. The hippocampus also plays an important role in the amplification of pain through anxiety.
ventral
A positional term – ventral means "towards the abdomen." In relation to the nervous system, it refers to a direction perpendicular to the neural axis, i.e., downwards or forwards.
In animals (that do not walk upright), the term is simpler, as it always means toward the abdomen. Due to the upright posture of humans, the brain bends in relation to the spinal cord, making ventral mean "forward."
Ventral tegmental area
Ventral tegmental area/Area tegmentalis ventralis7ventral tegmental area
Located in the midbrain, the uppermost section of the brain stem, is the ventral tegmental area (VTA) – a central component of the reward system. The area itself is not particularly large, but its influence is immense: the neurons of the VTA send their axons to the nucleus accumbens and widely into the prefrontal cortex (PFC), where they release the neuromodulator dopamine. In this way, they enhance learning processes, but can also contribute to the development of addictions.
Long-term potentiation
Long-term potentiation is a central mechanism for learning and memory formation. It is based on improved communication between two cells, referred to as strengthening the connection. This strengthening can occur, for example, through an enlargement of the connection point, the installation of new channels, or an increased release of transmitters (messenger substances).
Depression
A mental illness whose main symptoms are sadness and a loss of joy, motivation, and interest. Current classification systems distinguish between different types of depression.
Process determines nature of memory content
“We were surprised that the effects were so specific,” concludes Hardy Hagena. “The fact that the Ventral tegmental area and the locus coeruleus induce these two different types of synaptic Plasticity provides us with an insight into how Motivation and attention influence synaptic responses relative to their relevance and the current Memory content.”
ventral
A positional term – ventral means "towards the abdomen." In relation to the nervous system, it refers to a direction perpendicular to the neural axis, i.e., downwards or forwards.
In animals (that do not walk upright), the term is simpler, as it always means toward the abdomen. Due to the upright posture of humans, the brain bends in relation to the spinal cord, making ventral mean "forward."
Ventral tegmental area
Ventral tegmental area/Area tegmentalis ventralis7ventral tegmental area
Located in the midbrain, the uppermost section of the brain stem, is the ventral tegmental area (VTA) – a central component of the reward system. The area itself is not particularly large, but its influence is immense: the neurons of the VTA send their axons to the nucleus accumbens and widely into the prefrontal cortex (PFC), where they release the neuromodulator dopamine. In this way, they enhance learning processes, but can also contribute to the development of addictions.
Plasticity
Neuroplasticity
The term neuroplasticity describes the ability of synapses, nerve cells, and entire areas of the brain to change structurally and functionally depending on the degree to which they are used. Synaptic plasticity refers to the adaptation of the signal transmission strength of synapses to the frequency and intensity of incoming stimuli, for example in the form of long-term potentiation or depression. In addition, the size, interconnection, and activity patterns of different areas of the brain also change depending on their use. This phenomenon is referred to as cortical plasticity when it specifically affects the cortex.
Motivation
A motive is a reason. When this motive takes effect, the living being feels motivation – it strives to satisfy its need. For example, for food, protection, or reproduction. Motivation can be intrinsic (from within, e.g., curiosity) or extrinsic (from outside, e.g., reward).
attention
Attention
Attention serves as a tool for consciously perceiving internal and external stimuli. We achieve this by focusing our mental resources on a limited number of stimuli or pieces of information. While some stimuli automatically attract our attention, we can select others in a controlled manner. The brain also unconsciously processes stimuli that are not currently the focus of our attention.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
Original publication
Hardy Hagena, Denise Manahan-Vaughan: Oppositional and Competitive Instigation of Hippocampal Synaptic Plasticity by the VTA and Locus Coeruleus, in: PNAS, 2024 DOI: 10.1073/pnas.2402356122
Plasticity
Neuroplasticity
The term neuroplasticity describes the ability of synapses, nerve cells, and entire areas of the brain to change structurally and functionally depending on the degree to which they are used. Synaptic plasticity refers to the adaptation of the signal transmission strength of synapses to the frequency and intensity of incoming stimuli, for example in the form of long-term potentiation or depression. In addition, the size, interconnection, and activity patterns of different areas of the brain also change depending on their use. This phenomenon is referred to as cortical plasticity when it specifically affects the cortex.
